1 files changed, 835 insertions, 820 deletions

diff --git a/updater/blockimg.cpp b/updater/blockimg.cpp
index a80180a9a..c614ccc47 100644
--- a/updater/blockimg.cpp
+++ b/updater/blockimg.cpp
@@ -18,7 +18,6 @@
 #include <errno.h>
 #include <dirent.h>
 #include <fcntl.h>
-#include <inttypes.h>
 #include <linux/fs.h>
 #include <pthread.h>
 #include <stdarg.h>
@@ -33,114 +32,130 @@
 #include <unistd.h>
 #include <fec/io.h>
 
-#include <map>
+#include <functional>
 #include <memory>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
+#include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/strings.h>
+#include <android-base/unique_fd.h>
+#include <applypatch/applypatch.h>
+#include <openssl/sha.h>
+#include <private/android_filesystem_config.h>
+#include <ziparchive/zip_archive.h>
 
-#include "applypatch/applypatch.h"
 #include "edify/expr.h"
 #include "error_code.h"
-#include "install.h"
-#include "openssl/sha.h"
-#include "minzip/Hash.h"
+#include "updater/install.h"
 #include "ota_io.h"
 #include "print_sha1.h"
-#include "unique_fd.h"
-#include "updater.h"
-
-#define BLOCKSIZE 4096
+#include "updater/updater.h"
 
 // Set this to 0 to interpret 'erase' transfers to mean do a
 // BLKDISCARD ioctl (the normal behavior).  Set to 1 to interpret
 // erase to mean fill the region with zeroes.
 #define DEBUG_ERASE  0
 
-#define STASH_DIRECTORY_BASE "/cache/recovery"
-#define STASH_DIRECTORY_MODE 0700
-#define STASH_FILE_MODE 0600
+static constexpr size_t BLOCKSIZE = 4096;
+static constexpr const char* STASH_DIRECTORY_BASE = "/cache/recovery";
+static constexpr mode_t STASH_DIRECTORY_MODE = 0700;
+static constexpr mode_t STASH_FILE_MODE = 0600;
 
 struct RangeSet {
-    size_t count;             // Limit is INT_MAX.
-    size_t size;
-    std::vector<size_t> pos;  // Actual limit is INT_MAX.
+  size_t count;  // Limit is INT_MAX.
+  size_t size;
+  std::vector<size_t> pos;  // Actual limit is INT_MAX.
+
+  // Get the block number for the ith(starting from 0) block in the range set.
+  int get_block(size_t idx) const {
+    if (idx >= size) {
+      LOG(ERROR) << "index: " << idx << " is greater than range set size: " << size;
+      return -1;
+    }
+    for (size_t i = 0; i < pos.size(); i += 2) {
+      if (idx < pos[i + 1] - pos[i]) {
+        return pos[i] + idx;
+      }
+      idx -= (pos[i + 1] - pos[i]);
+    }
+    return -1;
+  }
 };
 
 static CauseCode failure_type = kNoCause;
 static bool is_retry = false;
-static std::map<std::string, RangeSet> stash_map;
+static std::unordered_map<std::string, RangeSet> stash_map;
 
-static void parse_range(const std::string& range_text, RangeSet& rs) {
-
-    std::vector<std::string> pieces = android::base::Split(range_text, ",");
-    if (pieces.size() < 3) {
-        goto err;
-    }
+static RangeSet parse_range(const std::string& range_text) {
+  RangeSet rs;
 
-    size_t num;
-    if (!android::base::ParseUint(pieces[0].c_str(), &num, static_cast<size_t>(INT_MAX))) {
-        goto err;
-    }
+  std::vector<std::string> pieces = android::base::Split(range_text, ",");
+  if (pieces.size() < 3) {
+    goto err;
+  }
 
-    if (num == 0 || num % 2) {
-        goto err; // must be even
-    } else if (num != pieces.size() - 1) {
-        goto err;
-    }
+  size_t num;
+  if (!android::base::ParseUint(pieces[0], &num, static_cast<size_t>(INT_MAX))) {
+    goto err;
+  }
 
-    rs.pos.resize(num);
-    rs.count = num / 2;
-    rs.size = 0;
+  if (num == 0 || num % 2) {
+    goto err;  // must be even
+  } else if (num != pieces.size() - 1) {
+    goto err;
+  }
 
-    for (size_t i = 0; i < num; i += 2) {
-        if (!android::base::ParseUint(pieces[i+1].c_str(), &rs.pos[i],
-                                      static_cast<size_t>(INT_MAX))) {
-            goto err;
-        }
+  rs.pos.resize(num);
+  rs.count = num / 2;
+  rs.size = 0;
 
-        if (!android::base::ParseUint(pieces[i+2].c_str(), &rs.pos[i+1],
-                                      static_cast<size_t>(INT_MAX))) {
-            goto err;
-        }
+  for (size_t i = 0; i < num; i += 2) {
+    if (!android::base::ParseUint(pieces[i + 1], &rs.pos[i], static_cast<size_t>(INT_MAX))) {
+      goto err;
+    }
 
-        if (rs.pos[i] >= rs.pos[i+1]) {
-            goto err; // empty or negative range
-        }
+    if (!android::base::ParseUint(pieces[i + 2], &rs.pos[i + 1], static_cast<size_t>(INT_MAX))) {
+      goto err;
+    }
 
-        size_t sz = rs.pos[i+1] - rs.pos[i];
-        if (rs.size > SIZE_MAX - sz) {
-            goto err; // overflow
-        }
+    if (rs.pos[i] >= rs.pos[i + 1]) {
+      goto err;  // empty or negative range
+    }
 
-        rs.size += sz;
+    size_t sz = rs.pos[i + 1] - rs.pos[i];
+    if (rs.size > SIZE_MAX - sz) {
+      goto err;  // overflow
     }
 
-    return;
+    rs.size += sz;
+  }
+
+  return rs;
 
 err:
-    fprintf(stderr, "failed to parse range '%s'\n", range_text.c_str());
-    exit(1);
+  LOG(ERROR) << "failed to parse range '" << range_text << "'";
+  exit(EXIT_FAILURE);
 }
 
 static bool range_overlaps(const RangeSet& r1, const RangeSet& r2) {
-    for (size_t i = 0; i < r1.count; ++i) {
-        size_t r1_0 = r1.pos[i * 2];
-        size_t r1_1 = r1.pos[i * 2 + 1];
+  for (size_t i = 0; i < r1.count; ++i) {
+    size_t r1_0 = r1.pos[i * 2];
+    size_t r1_1 = r1.pos[i * 2 + 1];
 
-        for (size_t j = 0; j < r2.count; ++j) {
-            size_t r2_0 = r2.pos[j * 2];
-            size_t r2_1 = r2.pos[j * 2 + 1];
+    for (size_t j = 0; j < r2.count; ++j) {
+      size_t r2_0 = r2.pos[j * 2];
+      size_t r2_1 = r2.pos[j * 2 + 1];
 
-            if (!(r2_0 >= r1_1 || r1_0 >= r2_1)) {
-                return true;
-            }
-        }
+      if (!(r2_0 >= r1_1 || r1_0 >= r2_1)) {
+        return true;
+      }
     }
+  }
 
-    return false;
+  return false;
 }
 
 static int read_all(int fd, uint8_t* data, size_t size) {
@@ -149,7 +164,11 @@ static int read_all(int fd, uint8_t* data, size_t size) {
         ssize_t r = TEMP_FAILURE_RETRY(ota_read(fd, data+so_far, size-so_far));
         if (r == -1) {
             failure_type = kFreadFailure;
-            fprintf(stderr, "read failed: %s\n", strerror(errno));
+            PLOG(ERROR) << "read failed";
+            return -1;
+        } else if (r == 0) {
+            failure_type = kFreadFailure;
+            LOG(ERROR) << "read reached unexpected EOF.";
             return -1;
         }
         so_far += r;
@@ -167,7 +186,7 @@ static int write_all(int fd, const uint8_t* data, size_t size) {
         ssize_t w = TEMP_FAILURE_RETRY(ota_write(fd, data+written, size-written));
         if (w == -1) {
             failure_type = kFwriteFailure;
-            fprintf(stderr, "write failed: %s\n", strerror(errno));
+            PLOG(ERROR) << "write failed";
             return -1;
         }
         written += w;
@@ -189,7 +208,7 @@ static bool discard_blocks(int fd, off64_t offset, uint64_t size) {
     uint64_t args[2] = {static_cast<uint64_t>(offset), size};
     int status = ioctl(fd, BLKDISCARD, &args);
     if (status == -1) {
-        fprintf(stderr, "BLKDISCARD ioctl failed: %s\n", strerror(errno));
+        PLOG(ERROR) << "BLKDISCARD ioctl failed";
         return false;
     }
     return true;
@@ -199,7 +218,7 @@ static bool check_lseek(int fd, off64_t offset, int whence) {
     off64_t rc = TEMP_FAILURE_RETRY(lseek64(fd, offset, whence));
     if (rc == -1) {
         failure_type = kLseekFailure;
-        fprintf(stderr, "lseek64 failed: %s\n", strerror(errno));
+        PLOG(ERROR) << "lseek64 failed";
         return false;
     }
     return true;
@@ -213,7 +232,7 @@ static void allocate(size_t size, std::vector<uint8_t>& buffer) {
 }
 
 struct RangeSinkState {
-    RangeSinkState(RangeSet& rs) : tgt(rs) { };
+    explicit RangeSinkState(RangeSet& rs) : tgt(rs) { };
 
     int fd;
     const RangeSet& tgt;
@@ -225,7 +244,7 @@ static ssize_t RangeSinkWrite(const uint8_t* data, ssize_t size, void* token) {
     RangeSinkState* rss = reinterpret_cast<RangeSinkState*>(token);
 
     if (rss->p_remain == 0) {
-        fprintf(stderr, "range sink write overrun");
+        LOG(ERROR) << "range sink write overrun";
         return 0;
     }
 
@@ -296,8 +315,8 @@ static ssize_t RangeSinkWrite(const uint8_t* data, ssize_t size, void* token) {
 // rss and signals the condition again.
 
 struct NewThreadInfo {
-    ZipArchive* za;
-    const ZipEntry* entry;
+    ZipArchiveHandle za;
+    ZipEntry entry;
 
     RangeSinkState* rss;
 
@@ -305,7 +324,7 @@ struct NewThreadInfo {
     pthread_cond_t cv;
 };
 
-static bool receive_new_data(const unsigned char* data, int size, void* cookie) {
+static bool receive_new_data(const uint8_t* data, size_t size, void* cookie) {
     NewThreadInfo* nti = reinterpret_cast<NewThreadInfo*>(cookie);
 
     while (size > 0) {
@@ -337,8 +356,8 @@ static bool receive_new_data(const unsigned char* data, int size, void* cookie)
 }
 
 static void* unzip_new_data(void* cookie) {
-    NewThreadInfo* nti = (NewThreadInfo*) cookie;
-    mzProcessZipEntryContents(nti->za, nti->entry, receive_new_data, nti);
+    NewThreadInfo* nti = static_cast<NewThreadInfo*>(cookie);
+    ProcessZipEntryContents(nti->za, &nti->entry, receive_new_data, nti);
     return nullptr;
 }
 
@@ -398,7 +417,7 @@ struct CommandParameters {
     std::string stashbase;
     bool canwrite;
     int createdstash;
-    int fd;
+    android::base::unique_fd fd;
     bool foundwrites;
     bool isunresumable;
     int version;
@@ -410,34 +429,109 @@ struct CommandParameters {
     uint8_t* patch_start;
 };
 
-// Do a source/target load for move/bsdiff/imgdiff in version 1.
-// We expect to parse the remainder of the parameter tokens as:
-//
-//    <src_range> <tgt_range>
-//
-// The source range is loaded into the provided buffer, reallocating
-// it to make it larger if necessary.
-
-static int LoadSrcTgtVersion1(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        std::vector<uint8_t>& buffer, int fd) {
+// Print the hash in hex for corrupted source blocks (excluding the stashed blocks which is
+// handled separately).
+static void PrintHashForCorruptedSourceBlocks(const CommandParameters& params,
+                                              const std::vector<uint8_t>& buffer) {
+  LOG(INFO) << "unexpected contents of source blocks in cmd:\n" << params.cmdline;
+  CHECK(params.tokens[0] == "move" || params.tokens[0] == "bsdiff" ||
+        params.tokens[0] == "imgdiff");
+
+  size_t pos = 0;
+  // Command example:
+  // move <onehash> <tgt_range> <src_blk_count> <src_range> [<loc_range> <stashed_blocks>]
+  // bsdiff <offset> <len> <src_hash> <tgt_hash> <tgt_range> <src_blk_count> <src_range>
+  //        [<loc_range> <stashed_blocks>]
+  if (params.tokens[0] == "move") {
+    // src_range for move starts at the 4th position.
+    if (params.tokens.size() < 5) {
+      LOG(ERROR) << "failed to parse source range in cmd:\n" << params.cmdline;
+      return;
+    }
+    pos = 4;
+  } else {
+    // src_range for diff starts at the 7th position.
+    if (params.tokens.size() < 8) {
+      LOG(ERROR) << "failed to parse source range in cmd:\n" << params.cmdline;
+      return;
+    }
+    pos = 7;
+  }
+
+  // Source blocks in stash only, no work to do.
+  if (params.tokens[pos] == "-") {
+    return;
+  }
+
+  RangeSet src = parse_range(params.tokens[pos++]);
+
+  RangeSet locs;
+  // If there's no stashed blocks, content in the buffer is consecutive and has the same
+  // order as the source blocks.
+  if (pos == params.tokens.size()) {
+    locs.count = 1;
+    locs.size = src.size;
+    locs.pos = { 0, src.size };
+  } else {
+    // Otherwise, the next token is the offset of the source blocks in the target range.
+    // Example: for the tokens <4,63946,63947,63948,63979> <4,6,7,8,39> <stashed_blocks>;
+    // We want to print SHA-1 for the data in buffer[6], buffer[8], buffer[9] ... buffer[38];
+    // this corresponds to the 32 src blocks #63946, #63948, #63949 ... #63978.
+    locs = parse_range(params.tokens[pos++]);
+    CHECK_EQ(src.size, locs.size);
+    CHECK_EQ(locs.pos.size() % 2, static_cast<size_t>(0));
+  }
+
+  LOG(INFO) << "printing hash in hex for " << src.size << " source blocks";
+  for (size_t i = 0; i < src.size; i++) {
+    int block_num = src.get_block(i);
+    CHECK_NE(block_num, -1);
+    int buffer_index = locs.get_block(i);
+    CHECK_NE(buffer_index, -1);
+    CHECK_LE((buffer_index + 1) * BLOCKSIZE, buffer.size());
 
-    if (params.cpos + 1 >= params.tokens.size()) {
-        fprintf(stderr, "invalid parameters\n");
-        return -1;
-    }
+    uint8_t digest[SHA_DIGEST_LENGTH];
+    SHA1(buffer.data() + buffer_index * BLOCKSIZE, BLOCKSIZE, digest);
+    std::string hexdigest = print_sha1(digest);
+    LOG(INFO) << "  block number: " << block_num << ", SHA-1: " << hexdigest;
+  }
+}
 
-    // <src_range>
-    RangeSet src;
-    parse_range(params.tokens[params.cpos++], src);
+// If the calculated hash for the whole stash doesn't match the stash id, print the SHA-1
+// in hex for each block.
+static void PrintHashForCorruptedStashedBlocks(const std::string& id,
+                                               const std::vector<uint8_t>& buffer,
+                                               const RangeSet& src) {
+  LOG(INFO) << "printing hash in hex for stash_id: " << id;
+  CHECK_EQ(src.size * BLOCKSIZE, buffer.size());
 
-    // <tgt_range>
-    parse_range(params.tokens[params.cpos++], tgt);
+  for (size_t i = 0; i < src.size; i++) {
+    int block_num = src.get_block(i);
+    CHECK_NE(block_num, -1);
 
-    allocate(src.size * BLOCKSIZE, buffer);
-    int rc = ReadBlocks(src, buffer, fd);
-    src_blocks = src.size;
+    uint8_t digest[SHA_DIGEST_LENGTH];
+    SHA1(buffer.data() + i * BLOCKSIZE, BLOCKSIZE, digest);
+    std::string hexdigest = print_sha1(digest);
+    LOG(INFO) << "  block number: " << block_num << ", SHA-1: " << hexdigest;
+  }
+}
 
-    return rc;
+// If the stash file doesn't exist, read the source blocks this stash contains and print the
+// SHA-1 for these blocks.
+static void PrintHashForMissingStashedBlocks(const std::string& id, int fd) {
+  if (stash_map.find(id) == stash_map.end()) {
+    LOG(ERROR) << "No stash saved for id: " << id;
+    return;
+  }
+
+  LOG(INFO) << "print hash in hex for source blocks in missing stash: " << id;
+  const RangeSet& src = stash_map[id];
+  std::vector<uint8_t> buffer(src.size * BLOCKSIZE);
+  if (ReadBlocks(src, buffer, fd) == -1) {
+      LOG(ERROR) << "failed to read source blocks for stash: " << id;
+      return;
+  }
+  PrintHashForCorruptedStashedBlocks(id, buffer, src);
 }
 
 static int VerifyBlocks(const std::string& expected, const std::vector<uint8_t>& buffer,
@@ -451,8 +545,8 @@ static int VerifyBlocks(const std::string& expected, const std::vector<uint8_t>&
 
     if (hexdigest != expected) {
         if (printerror) {
-            fprintf(stderr, "failed to verify blocks (expected %s, read %s)\n",
-                    expected.c_str(), hexdigest.c_str());
+            LOG(ERROR) << "failed to verify blocks (expected " << expected << ", read "
+                       << hexdigest << ")";
         }
         return -1;
     }
@@ -472,92 +566,58 @@ static std::string GetStashFileName(const std::string& base, const std::string&
     return fn;
 }
 
-typedef void (*StashCallback)(const std::string&, void*);
+// Does a best effort enumeration of stash files. Ignores possible non-file items in the stash
+// directory and continues despite of errors. Calls the 'callback' function for each file.
+static void EnumerateStash(const std::string& dirname,
+                           const std::function<void(const std::string&)>& callback) {
+  if (dirname.empty()) return;
 
-// Does a best effort enumeration of stash files. Ignores possible non-file
-// items in the stash directory and continues despite of errors. Calls the
-// 'callback' function for each file and passes 'data' to the function as a
-// parameter.
+  std::unique_ptr<DIR, decltype(&closedir)> directory(opendir(dirname.c_str()), closedir);
 
-static void EnumerateStash(const std::string& dirname, StashCallback callback, void* data) {
-    if (dirname.empty() || callback == nullptr) {
-        return;
-    }
-
-    std::unique_ptr<DIR, int(*)(DIR*)> directory(opendir(dirname.c_str()), closedir);
-
-    if (directory == nullptr) {
-        if (errno != ENOENT) {
-            fprintf(stderr, "opendir \"%s\" failed: %s\n", dirname.c_str(), strerror(errno));
-        }
-        return;
-    }
-
-    struct dirent* item;
-    while ((item = readdir(directory.get())) != nullptr) {
-        if (item->d_type != DT_REG) {
-            continue;
-        }
-
-        std::string fn = dirname + "/" + std::string(item->d_name);
-        callback(fn, data);
-    }
-}
-
-static void UpdateFileSize(const std::string& fn, void* data) {
-    if (fn.empty() || !data) {
-        return;
-    }
-
-    struct stat sb;
-    if (stat(fn.c_str(), &sb) == -1) {
-        fprintf(stderr, "stat \"%s\" failed: %s\n", fn.c_str(), strerror(errno));
-        return;
+  if (directory == nullptr) {
+    if (errno != ENOENT) {
+      PLOG(ERROR) << "opendir \"" << dirname << "\" failed";
     }
+    return;
+  }
 
-    int* size = reinterpret_cast<int*>(data);
-    *size += sb.st_size;
+  dirent* item;
+  while ((item = readdir(directory.get())) != nullptr) {
+    if (item->d_type != DT_REG) continue;
+    callback(dirname + "/" + item->d_name);
+  }
 }
 
 // Deletes the stash directory and all files in it. Assumes that it only
 // contains files. There is nothing we can do about unlikely, but possible
 // errors, so they are merely logged.
+static void DeleteFile(const std::string& fn) {
+  if (fn.empty()) return;
 
-static void DeleteFile(const std::string& fn, void* /* data */) {
-    if (!fn.empty()) {
-        fprintf(stderr, "deleting %s\n", fn.c_str());
+  LOG(INFO) << "deleting " << fn;
 
-        if (unlink(fn.c_str()) == -1 && errno != ENOENT) {
-            fprintf(stderr, "unlink \"%s\" failed: %s\n", fn.c_str(), strerror(errno));
-        }
-    }
-}
-
-static void DeletePartial(const std::string& fn, void* data) {
-    if (android::base::EndsWith(fn, ".partial")) {
-        DeleteFile(fn, data);
-    }
+  if (unlink(fn.c_str()) == -1 && errno != ENOENT) {
+    PLOG(ERROR) << "unlink \"" << fn << "\" failed";
+  }
 }
 
 static void DeleteStash(const std::string& base) {
-    if (base.empty()) {
-        return;
-    }
+  if (base.empty()) return;
 
-    fprintf(stderr, "deleting stash %s\n", base.c_str());
+  LOG(INFO) << "deleting stash " << base;
 
-    std::string dirname = GetStashFileName(base, "", "");
-    EnumerateStash(dirname, DeleteFile, nullptr);
+  std::string dirname = GetStashFileName(base, "", "");
+  EnumerateStash(dirname, DeleteFile);
 
-    if (rmdir(dirname.c_str()) == -1) {
-        if (errno != ENOENT && errno != ENOTDIR) {
-            fprintf(stderr, "rmdir \"%s\" failed: %s\n", dirname.c_str(), strerror(errno));
-        }
+  if (rmdir(dirname.c_str()) == -1) {
+    if (errno != ENOENT && errno != ENOTDIR) {
+      PLOG(ERROR) << "rmdir \"" << dirname << "\" failed";
     }
+  }
 }
 
-static int LoadStash(CommandParameters& params, const std::string& base, const std::string& id,
-        bool verify, size_t* blocks, std::vector<uint8_t>& buffer, bool printnoent) {
+static int LoadStash(CommandParameters& params, const std::string& id, bool verify, size_t* blocks,
+                     std::vector<uint8_t>& buffer, bool printnoent) {
     // In verify mode, if source range_set was saved for the given hash,
     // check contents in the source blocks first. If the check fails,
     // search for the stashed files on /cache as usual.
@@ -567,52 +627,47 @@ static int LoadStash(CommandParameters& params, const std::string& base, const s
             allocate(src.size * BLOCKSIZE, buffer);
 
             if (ReadBlocks(src, buffer, params.fd) == -1) {
-                fprintf(stderr, "failed to read source blocks in stash map.\n");
+                LOG(ERROR) << "failed to read source blocks in stash map.";
                 return -1;
             }
             if (VerifyBlocks(id, buffer, src.size, true) != 0) {
-                fprintf(stderr, "failed to verify loaded source blocks in stash map.\n");
+                LOG(ERROR) << "failed to verify loaded source blocks in stash map.";
+                PrintHashForCorruptedStashedBlocks(id, buffer, src);
                 return -1;
             }
             return 0;
         }
     }
 
-    if (base.empty()) {
-        return -1;
-    }
-
     size_t blockcount = 0;
 
     if (!blocks) {
         blocks = &blockcount;
     }
 
-    std::string fn = GetStashFileName(base, id, "");
+    std::string fn = GetStashFileName(params.stashbase, id, "");
 
     struct stat sb;
     int res = stat(fn.c_str(), &sb);
 
     if (res == -1) {
         if (errno != ENOENT || printnoent) {
-            fprintf(stderr, "stat \"%s\" failed: %s\n", fn.c_str(), strerror(errno));
+            PLOG(ERROR) << "stat \"" << fn << "\" failed";
+            PrintHashForMissingStashedBlocks(id, params.fd);
         }
         return -1;
     }
 
-    fprintf(stderr, " loading %s\n", fn.c_str());
+    LOG(INFO) << " loading " << fn;
 
     if ((sb.st_size % BLOCKSIZE) != 0) {
-        fprintf(stderr, "%s size %" PRId64 " not multiple of block size %d",
-                fn.c_str(), static_cast<int64_t>(sb.st_size), BLOCKSIZE);
+        LOG(ERROR) << fn << " size " << sb.st_size << " not multiple of block size " << BLOCKSIZE;
         return -1;
     }
 
-    int fd = TEMP_FAILURE_RETRY(open(fn.c_str(), O_RDONLY));
-    unique_fd fd_holder(fd);
-
+    android::base::unique_fd fd(TEMP_FAILURE_RETRY(ota_open(fn.c_str(), O_RDONLY)));
     if (fd == -1) {
-        fprintf(stderr, "open \"%s\" failed: %s\n", fn.c_str(), strerror(errno));
+        PLOG(ERROR) << "open \"" << fn << "\" failed";
         return -1;
     }
 
@@ -625,8 +680,15 @@ static int LoadStash(CommandParameters& params, const std::string& base, const s
     *blocks = sb.st_size / BLOCKSIZE;
 
     if (verify && VerifyBlocks(id, buffer, *blocks, true) != 0) {
-        fprintf(stderr, "unexpected contents in %s\n", fn.c_str());
-        DeleteFile(fn, nullptr);
+        LOG(ERROR) << "unexpected contents in " << fn;
+        if (stash_map.find(id) == stash_map.end()) {
+            LOG(ERROR) << "failed to find source blocks number for stash " << id
+                       << " when executing command: " << params.cmdname;
+        } else {
+            const RangeSet& src = stash_map[id];
+            PrintHashForCorruptedStashedBlocks(id, buffer, src);
+        }
+        DeleteFile(fn);
         return -1;
     }
 
@@ -634,13 +696,13 @@ static int LoadStash(CommandParameters& params, const std::string& base, const s
 }
 
 static int WriteStash(const std::string& base, const std::string& id, int blocks,
-        std::vector<uint8_t>& buffer, bool checkspace, bool *exists) {
+                      std::vector<uint8_t>& buffer, bool checkspace, bool *exists) {
     if (base.empty()) {
         return -1;
     }
 
     if (checkspace && CacheSizeCheck(blocks * BLOCKSIZE) != 0) {
-        fprintf(stderr, "not enough space to write stash\n");
+        LOG(ERROR) << "not enough space to write stash";
         return -1;
     }
 
@@ -655,7 +717,7 @@ static int WriteStash(const std::string& base, const std::string& id, int blocks
             // The file already exists and since the name is the hash of the contents,
             // it's safe to assume the contents are identical (accidental hash collisions
             // are unlikely)
-            fprintf(stderr, " skipping %d existing blocks in %s\n", blocks, cn.c_str());
+            LOG(INFO) << " skipping " << blocks << " existing blocks in " << cn;
             *exists = true;
             return 0;
         }
@@ -663,13 +725,17 @@ static int WriteStash(const std::string& base, const std::string& id, int blocks
         *exists = false;
     }
 
-    fprintf(stderr, " writing %d blocks to %s\n", blocks, cn.c_str());
-
-    int fd = TEMP_FAILURE_RETRY(open(fn.c_str(), O_WRONLY | O_CREAT | O_TRUNC, STASH_FILE_MODE));
-    unique_fd fd_holder(fd);
+    LOG(INFO) << " writing " << blocks << " blocks to " << cn;
 
+    android::base::unique_fd fd(
+        TEMP_FAILURE_RETRY(ota_open(fn.c_str(), O_WRONLY | O_CREAT | O_TRUNC, STASH_FILE_MODE)));
     if (fd == -1) {
-        fprintf(stderr, "failed to create \"%s\": %s\n", fn.c_str(), strerror(errno));
+        PLOG(ERROR) << "failed to create \"" << fn << "\"";
+        return -1;
+    }
+
+    if (fchown(fd, AID_SYSTEM, AID_SYSTEM) != 0) {  // system user
+        PLOG(ERROR) << "failed to chown \"" << fn << "\"";
         return -1;
     }
 
@@ -679,29 +745,27 @@ static int WriteStash(const std::string& base, const std::string& id, int blocks
 
     if (ota_fsync(fd) == -1) {
         failure_type = kFsyncFailure;
-        fprintf(stderr, "fsync \"%s\" failed: %s\n", fn.c_str(), strerror(errno));
+        PLOG(ERROR) << "fsync \"" << fn << "\" failed";
         return -1;
     }
 
     if (rename(fn.c_str(), cn.c_str()) == -1) {
-        fprintf(stderr, "rename(\"%s\", \"%s\") failed: %s\n", fn.c_str(), cn.c_str(),
-                strerror(errno));
+        PLOG(ERROR) << "rename(\"" << fn << "\", \"" << cn << "\") failed";
         return -1;
     }
 
     std::string dname = GetStashFileName(base, "", "");
-    int dfd = TEMP_FAILURE_RETRY(open(dname.c_str(), O_RDONLY | O_DIRECTORY));
-    unique_fd dfd_holder(dfd);
-
+    android::base::unique_fd dfd(TEMP_FAILURE_RETRY(ota_open(dname.c_str(),
+                                                             O_RDONLY | O_DIRECTORY)));
     if (dfd == -1) {
         failure_type = kFileOpenFailure;
-        fprintf(stderr, "failed to open \"%s\" failed: %s\n", dname.c_str(), strerror(errno));
+        PLOG(ERROR) << "failed to open \"" << dname << "\" failed";
         return -1;
     }
 
     if (ota_fsync(dfd) == -1) {
         failure_type = kFsyncFailure;
-        fprintf(stderr, "fsync \"%s\" failed: %s\n", dname.c_str(), strerror(errno));
+        PLOG(ERROR) << "fsync \"" << dname << "\" failed";
         return -1;
     }
 
@@ -712,121 +776,94 @@ static int WriteStash(const std::string& base, const std::string& id, int blocks
 // hash enough space for the expected amount of blocks we need to store. Returns
 // >0 if we created the directory, zero if it existed already, and <0 of failure.
 
-static int CreateStash(State* state, int maxblocks, const char* blockdev, std::string& base) {
-    if (blockdev == nullptr) {
-        return -1;
-    }
-
-    // Stash directory should be different for each partition to avoid conflicts
-    // when updating multiple partitions at the same time, so we use the hash of
-    // the block device name as the base directory
-    uint8_t digest[SHA_DIGEST_LENGTH];
-    SHA1(reinterpret_cast<const uint8_t*>(blockdev), strlen(blockdev), digest);
-    base = print_sha1(digest);
-
-    std::string dirname = GetStashFileName(base, "", "");
-    struct stat sb;
-    int res = stat(dirname.c_str(), &sb);
-
-    if (res == -1 && errno != ENOENT) {
-        ErrorAbort(state, kStashCreationFailure, "stat \"%s\" failed: %s\n",
-                   dirname.c_str(), strerror(errno));
-        return -1;
-    } else if (res != 0) {
-        fprintf(stderr, "creating stash %s\n", dirname.c_str());
-        res = mkdir(dirname.c_str(), STASH_DIRECTORY_MODE);
-
-        if (res != 0) {
-            ErrorAbort(state, kStashCreationFailure, "mkdir \"%s\" failed: %s\n",
-                       dirname.c_str(), strerror(errno));
-            return -1;
-        }
-
-        if (CacheSizeCheck(maxblocks * BLOCKSIZE) != 0) {
-            ErrorAbort(state, kStashCreationFailure, "not enough space for stash\n");
-            return -1;
-        }
+static int CreateStash(State* state, size_t maxblocks, const std::string& blockdev,
+                       std::string& base) {
+  if (blockdev.empty()) {
+    return -1;
+  }
+
+  // Stash directory should be different for each partition to avoid conflicts
+  // when updating multiple partitions at the same time, so we use the hash of
+  // the block device name as the base directory
+  uint8_t digest[SHA_DIGEST_LENGTH];
+  SHA1(reinterpret_cast<const uint8_t*>(blockdev.data()), blockdev.size(), digest);
+  base = print_sha1(digest);
+
+  std::string dirname = GetStashFileName(base, "", "");
+  struct stat sb;
+  int res = stat(dirname.c_str(), &sb);
+  size_t max_stash_size = maxblocks * BLOCKSIZE;
+
+  if (res == -1 && errno != ENOENT) {
+    ErrorAbort(state, kStashCreationFailure, "stat \"%s\" failed: %s\n", dirname.c_str(),
+               strerror(errno));
+    return -1;
+  } else if (res != 0) {
+    LOG(INFO) << "creating stash " << dirname;
+    res = mkdir(dirname.c_str(), STASH_DIRECTORY_MODE);
 
-        return 1;  // Created directory
+    if (res != 0) {
+      ErrorAbort(state, kStashCreationFailure, "mkdir \"%s\" failed: %s\n", dirname.c_str(),
+                 strerror(errno));
+      return -1;
     }
 
-    fprintf(stderr, "using existing stash %s\n", dirname.c_str());
-
-    // If the directory already exists, calculate the space already allocated to
-    // stash files and check if there's enough for all required blocks. Delete any
-    // partially completed stash files first.
-
-    EnumerateStash(dirname, DeletePartial, nullptr);
-    int size = 0;
-    EnumerateStash(dirname, UpdateFileSize, &size);
-
-    size = maxblocks * BLOCKSIZE - size;
-
-    if (size > 0 && CacheSizeCheck(size) != 0) {
-        ErrorAbort(state, kStashCreationFailure, "not enough space for stash (%d more needed)\n",
-                   size);
-        return -1;
+    if (chown(dirname.c_str(), AID_SYSTEM, AID_SYSTEM) != 0) {  // system user
+      ErrorAbort(state, kStashCreationFailure, "chown \"%s\" failed: %s\n", dirname.c_str(),
+                 strerror(errno));
+      return -1;
     }
 
-    return 0; // Using existing directory
-}
-
-static int SaveStash(CommandParameters& params, const std::string& base,
-        std::vector<uint8_t>& buffer, int fd, bool usehash) {
-
-    // <stash_id> <src_range>
-    if (params.cpos + 1 >= params.tokens.size()) {
-        fprintf(stderr, "missing id and/or src range fields in stash command\n");
-        return -1;
+    if (CacheSizeCheck(max_stash_size) != 0) {
+      ErrorAbort(state, kStashCreationFailure, "not enough space for stash (%zu needed)\n",
+                 max_stash_size);
+      return -1;
     }
-    const std::string& id = params.tokens[params.cpos++];
 
-    size_t blocks = 0;
-    if (usehash && LoadStash(params, base, id, true, &blocks, buffer, false) == 0) {
-        // Stash file already exists and has expected contents. Do not
-        // read from source again, as the source may have been already
-        // overwritten during a previous attempt.
-        return 0;
-    }
+    return 1;  // Created directory
+  }
 
-    RangeSet src;
-    parse_range(params.tokens[params.cpos++], src);
+  LOG(INFO) << "using existing stash " << dirname;
 
-    allocate(src.size * BLOCKSIZE, buffer);
-    if (ReadBlocks(src, buffer, fd) == -1) {
-        return -1;
+  // If the directory already exists, calculate the space already allocated to stash files and check
+  // if there's enough for all required blocks. Delete any partially completed stash files first.
+  EnumerateStash(dirname, [](const std::string& fn) {
+    if (android::base::EndsWith(fn, ".partial")) {
+      DeleteFile(fn);
     }
-    blocks = src.size;
+  });
 
-    if (usehash && VerifyBlocks(id, buffer, blocks, true) != 0) {
-        // Source blocks have unexpected contents. If we actually need this
-        // data later, this is an unrecoverable error. However, the command
-        // that uses the data may have already completed previously, so the
-        // possible failure will occur during source block verification.
-        fprintf(stderr, "failed to load source blocks for stash %s\n", id.c_str());
-        return 0;
+  size_t existing = 0;
+  EnumerateStash(dirname, [&existing](const std::string& fn) {
+    if (fn.empty()) return;
+    struct stat sb;
+    if (stat(fn.c_str(), &sb) == -1) {
+      PLOG(ERROR) << "stat \"" << fn << "\" failed";
+      return;
     }
+    existing += static_cast<size_t>(sb.st_size);
+  });
 
-    // In verify mode, save source range_set instead of stashing blocks.
-    if (!params.canwrite && usehash) {
-        stash_map[id] = src;
-        return 0;
+  if (max_stash_size > existing) {
+    size_t needed = max_stash_size - existing;
+    if (CacheSizeCheck(needed) != 0) {
+      ErrorAbort(state, kStashCreationFailure, "not enough space for stash (%zu more needed)\n",
+                 needed);
+      return -1;
     }
+  }
 
-    fprintf(stderr, "stashing %zu blocks to %s\n", blocks, id.c_str());
-    params.stashed += blocks;
-    return WriteStash(base, id, blocks, buffer, false, nullptr);
+  return 0;  // Using existing directory
 }
 
 static int FreeStash(const std::string& base, const std::string& id) {
-    if (base.empty() || id.empty()) {
-        return -1;
-    }
+  if (base.empty() || id.empty()) {
+    return -1;
+  }
 
-    std::string fn = GetStashFileName(base, id, "");
-    DeleteFile(fn, nullptr);
+  DeleteFile(GetStashFileName(base, id, ""));
 
-    return 0;
+  return 0;
 }
 
 static void MoveRange(std::vector<uint8_t>& dest, const RangeSet& locs,
@@ -858,41 +895,39 @@ static void MoveRange(std::vector<uint8_t>& dest, const RangeSet& locs,
 //    <tgt_range> <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
 //        (loads data from both source image and stashes)
 //
-// On return, buffer is filled with the loaded source data (rearranged
-// and combined with stashed data as necessary).  buffer may be
-// reallocated if needed to accommodate the source data.  *tgt is the
-// target RangeSet.  Any stashes required are loaded using LoadStash.
+// On return, params.buffer is filled with the loaded source data (rearranged and combined with
+// stashed data as necessary). buffer may be reallocated if needed to accommodate the source data.
+// *tgt is the target RangeSet. Any stashes required are loaded using LoadStash.
 
 static int LoadSrcTgtVersion2(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        std::vector<uint8_t>& buffer, int fd, const std::string& stashbase, bool* overlap) {
+                              bool* overlap) {
 
     // At least it needs to provide three parameters: <tgt_range>,
     // <src_block_count> and "-"/<src_range>.
     if (params.cpos + 2 >= params.tokens.size()) {
-        fprintf(stderr, "invalid parameters\n");
+        LOG(ERROR) << "invalid parameters";
         return -1;
     }
 
     // <tgt_range>
-    parse_range(params.tokens[params.cpos++], tgt);
+    tgt = parse_range(params.tokens[params.cpos++]);
 
     // <src_block_count>
     const std::string& token = params.tokens[params.cpos++];
     if (!android::base::ParseUint(token.c_str(), &src_blocks)) {
-        fprintf(stderr, "invalid src_block_count \"%s\"\n", token.c_str());
+        LOG(ERROR) << "invalid src_block_count \"" << token << "\"";
         return -1;
     }
 
-    allocate(src_blocks * BLOCKSIZE, buffer);
+    allocate(src_blocks * BLOCKSIZE, params.buffer);
 
     // "-" or <src_range> [<src_loc>]
     if (params.tokens[params.cpos] == "-") {
         // no source ranges, only stashes
         params.cpos++;
     } else {
-        RangeSet src;
-        parse_range(params.tokens[params.cpos++], src);
-        int res = ReadBlocks(src, buffer, fd);
+        RangeSet src = parse_range(params.tokens[params.cpos++]);
+        int res = ReadBlocks(src, params.buffer, params.fd);
 
         if (overlap) {
             *overlap = range_overlaps(src, tgt);
@@ -907,9 +942,8 @@ static int LoadSrcTgtVersion2(CommandParameters& params, RangeSet& tgt, size_t&
             return 0;
         }
 
-        RangeSet locs;
-        parse_range(params.tokens[params.cpos++], locs);
-        MoveRange(buffer, locs, buffer);
+        RangeSet locs = parse_range(params.tokens[params.cpos++]);
+        MoveRange(params.buffer, locs, params.buffer);
     }
 
     // <[stash_id:stash_range]>
@@ -919,51 +953,59 @@ static int LoadSrcTgtVersion2(CommandParameters& params, RangeSet& tgt, size_t&
         // stashed data should go.
         std::vector<std::string> tokens = android::base::Split(params.tokens[params.cpos++], ":");
         if (tokens.size() != 2) {
-            fprintf(stderr, "invalid parameter\n");
+            LOG(ERROR) << "invalid parameter";
             return -1;
         }
 
         std::vector<uint8_t> stash;
-        int res = LoadStash(params, stashbase, tokens[0], false, nullptr, stash, true);
+        int res = LoadStash(params, tokens[0], false, nullptr, stash, true);
 
         if (res == -1) {
             // These source blocks will fail verification if used later, but we
             // will let the caller decide if this is a fatal failure
-            fprintf(stderr, "failed to load stash %s\n", tokens[0].c_str());
+            LOG(ERROR) << "failed to load stash " << tokens[0];
             continue;
         }
 
-        RangeSet locs;
-        parse_range(tokens[1], locs);
+        RangeSet locs = parse_range(tokens[1]);
 
-        MoveRange(buffer, locs, stash);
+        MoveRange(params.buffer, locs, stash);
     }
 
     return 0;
 }
 
-// Do a source/target load for move/bsdiff/imgdiff in version 3.
-//
-// Parameters are the same as for LoadSrcTgtVersion2, except for 'onehash', which
-// tells the function whether to expect separate source and targe block hashes, or
-// if they are both the same and only one hash should be expected, and
-// 'isunresumable', which receives a non-zero value if block verification fails in
-// a way that the update cannot be resumed anymore.
-//
-// If the function is unable to load the necessary blocks or their contents don't
-// match the hashes, the return value is -1 and the command should be aborted.
-//
-// If the return value is 1, the command has already been completed according to
-// the contents of the target blocks, and should not be performed again.
-//
-// If the return value is 0, source blocks have expected content and the command
-// can be performed.
-
+/**
+ * Do a source/target load for move/bsdiff/imgdiff in version 3.
+ *
+ * We expect to parse the remainder of the parameter tokens as one of:
+ *
+ *    <tgt_range> <src_block_count> <src_range>
+ *        (loads data from source image only)
+ *
+ *    <tgt_range> <src_block_count> - <[stash_id:stash_range] ...>
+ *        (loads data from stashes only)
+ *
+ *    <tgt_range> <src_block_count> <src_range> <src_loc> <[stash_id:stash_range] ...>
+ *        (loads data from both source image and stashes)
+ *
+ * Parameters are the same as for LoadSrcTgtVersion2, except for 'onehash', which tells the function
+ * whether to expect separate source and targe block hashes, or if they are both the same and only
+ * one hash should be expected, and 'isunresumable', which receives a non-zero value if block
+ * verification fails in a way that the update cannot be resumed anymore.
+ *
+ * If the function is unable to load the necessary blocks or their contents don't match the hashes,
+ * the return value is -1 and the command should be aborted.
+ *
+ * If the return value is 1, the command has already been completed according to the contents of the
+ * target blocks, and should not be performed again.
+ *
+ * If the return value is 0, source blocks have expected content and the command can be performed.
+ */
 static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet& tgt, size_t& src_blocks,
-        bool onehash, bool& overlap) {
-
+                              bool onehash, bool& overlap) {
     if (params.cpos >= params.tokens.size()) {
-        fprintf(stderr, "missing source hash\n");
+        LOG(ERROR) << "missing source hash";
         return -1;
     }
 
@@ -974,14 +1016,13 @@ static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet& tgt, size_t&
         tgthash = srchash;
     } else {
         if (params.cpos >= params.tokens.size()) {
-            fprintf(stderr, "missing target hash\n");
+            LOG(ERROR) << "missing target hash";
             return -1;
         }
         tgthash = params.tokens[params.cpos++];
     }
 
-    if (LoadSrcTgtVersion2(params, tgt, src_blocks, params.buffer, params.fd, params.stashbase,
-            &overlap) == -1) {
+    if (LoadSrcTgtVersion2(params, tgt, src_blocks, &overlap) == -1) {
         return -1;
     }
 
@@ -992,7 +1033,7 @@ static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet& tgt, size_t&
     }
 
     if (VerifyBlocks(tgthash, tgtbuffer, tgt.size, false) == 0) {
-        // Target blocks already have expected content, command should be skipped
+        // Target blocks already have expected content, command should be skipped.
         return 1;
     }
 
@@ -1001,128 +1042,150 @@ static int LoadSrcTgtVersion3(CommandParameters& params, RangeSet& tgt, size_t&
         // resume from possible write errors. In verify mode, we can skip stashing
         // because the source blocks won't be overwritten.
         if (overlap && params.canwrite) {
-            fprintf(stderr, "stashing %zu overlapping blocks to %s\n", src_blocks,
-                    srchash.c_str());
+            LOG(INFO) << "stashing " << src_blocks << " overlapping blocks to " << srchash;
 
             bool stash_exists = false;
             if (WriteStash(params.stashbase, srchash, src_blocks, params.buffer, true,
                            &stash_exists) != 0) {
-                fprintf(stderr, "failed to stash overlapping source blocks\n");
+                LOG(ERROR) << "failed to stash overlapping source blocks";
                 return -1;
             }
 
             params.stashed += src_blocks;
-            // Can be deleted when the write has completed
+            // Can be deleted when the write has completed.
             if (!stash_exists) {
                 params.freestash = srchash;
             }
         }
 
-        // Source blocks have expected content, command can proceed
+        // Source blocks have expected content, command can proceed.
         return 0;
     }
 
-    if (overlap && LoadStash(params, params.stashbase, srchash, true, nullptr, params.buffer,
-                             true) == 0) {
+    if (overlap && LoadStash(params, srchash, true, nullptr, params.buffer, true) == 0) {
         // Overlapping source blocks were previously stashed, command can proceed.
         // We are recovering from an interrupted command, so we don't know if the
         // stash can safely be deleted after this command.
         return 0;
     }
 
-    // Valid source data not available, update cannot be resumed
-    fprintf(stderr, "partition has unexpected contents\n");
+    // Valid source data not available, update cannot be resumed.
+    LOG(ERROR) << "partition has unexpected contents";
+    PrintHashForCorruptedSourceBlocks(params, params.buffer);
+
     params.isunresumable = true;
 
     return -1;
 }
 
 static int PerformCommandMove(CommandParameters& params) {
-    size_t blocks = 0;
-    bool overlap = false;
-    int status = 0;
-    RangeSet tgt;
+  size_t blocks = 0;
+  bool overlap = false;
+  RangeSet tgt;
+  int status = LoadSrcTgtVersion3(params, tgt, blocks, true, overlap);
 
-    if (params.version == 1) {
-        status = LoadSrcTgtVersion1(params, tgt, blocks, params.buffer, params.fd);
-    } else if (params.version == 2) {
-        status = LoadSrcTgtVersion2(params, tgt, blocks, params.buffer, params.fd,
-                params.stashbase, nullptr);
-    } else if (params.version >= 3) {
-        status = LoadSrcTgtVersion3(params, tgt, blocks, true, overlap);
-    }
+  if (status == -1) {
+    LOG(ERROR) << "failed to read blocks for move";
+    return -1;
+  }
 
-    if (status == -1) {
-        fprintf(stderr, "failed to read blocks for move\n");
-        return -1;
-    }
+  if (status == 0) {
+    params.foundwrites = true;
+  } else if (params.foundwrites) {
+    LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
+  }
 
+  if (params.canwrite) {
     if (status == 0) {
-        params.foundwrites = true;
-    } else if (params.foundwrites) {
-        fprintf(stderr, "warning: commands executed out of order [%s]\n", params.cmdname);
+      LOG(INFO) << "  moving " << blocks << " blocks";
+
+      if (WriteBlocks(tgt, params.buffer, params.fd) == -1) {
+        return -1;
+      }
+    } else {
+      LOG(INFO) << "skipping " << blocks << " already moved blocks";
     }
+  }
 
-    if (params.canwrite) {
-        if (status == 0) {
-            fprintf(stderr, "  moving %zu blocks\n", blocks);
+  if (!params.freestash.empty()) {
+    FreeStash(params.stashbase, params.freestash);
+    params.freestash.clear();
+  }
 
-            if (WriteBlocks(tgt, params.buffer, params.fd) == -1) {
-                return -1;
-            }
-        } else {
-            fprintf(stderr, "skipping %zu already moved blocks\n", blocks);
-        }
+  params.written += tgt.size;
 
-    }
+  return 0;
+}
 
-    if (!params.freestash.empty()) {
-        FreeStash(params.stashbase, params.freestash);
-        params.freestash.clear();
-    }
+static int PerformCommandStash(CommandParameters& params) {
+  // <stash_id> <src_range>
+  if (params.cpos + 1 >= params.tokens.size()) {
+    LOG(ERROR) << "missing id and/or src range fields in stash command";
+    return -1;
+  }
 
-    params.written += tgt.size;
+  const std::string& id = params.tokens[params.cpos++];
+  size_t blocks = 0;
+  if (LoadStash(params, id, true, &blocks, params.buffer, false) == 0) {
+    // Stash file already exists and has expected contents. Do not read from source again, as the
+    // source may have been already overwritten during a previous attempt.
+    return 0;
+  }
 
+  RangeSet src = parse_range(params.tokens[params.cpos++]);
+
+  allocate(src.size * BLOCKSIZE, params.buffer);
+  if (ReadBlocks(src, params.buffer, params.fd) == -1) {
+    return -1;
+  }
+  blocks = src.size;
+  stash_map[id] = src;
+
+  if (VerifyBlocks(id, params.buffer, blocks, true) != 0) {
+    // Source blocks have unexpected contents. If we actually need this data later, this is an
+    // unrecoverable error. However, the command that uses the data may have already completed
+    // previously, so the possible failure will occur during source block verification.
+    LOG(ERROR) << "failed to load source blocks for stash " << id;
     return 0;
-}
+  }
 
-static int PerformCommandStash(CommandParameters& params) {
-    return SaveStash(params, params.stashbase, params.buffer, params.fd,
-            (params.version >= 3));
+  // In verify mode, we don't need to stash any blocks.
+  if (!params.canwrite) {
+    return 0;
+  }
+
+  LOG(INFO) << "stashing " << blocks << " blocks to " << id;
+  params.stashed += blocks;
+  return WriteStash(params.stashbase, id, blocks, params.buffer, false, nullptr);
 }
 
 static int PerformCommandFree(CommandParameters& params) {
-    // <stash_id>
-    if (params.cpos >= params.tokens.size()) {
-        fprintf(stderr, "missing stash id in free command\n");
-        return -1;
-    }
+  // <stash_id>
+  if (params.cpos >= params.tokens.size()) {
+    LOG(ERROR) << "missing stash id in free command";
+    return -1;
+  }
 
-    const std::string& id = params.tokens[params.cpos++];
+  const std::string& id = params.tokens[params.cpos++];
+  stash_map.erase(id);
 
-    if (!params.canwrite && stash_map.find(id) != stash_map.end()) {
-        stash_map.erase(id);
-        return 0;
-    }
-
-    if (params.createdstash || params.canwrite) {
-        return FreeStash(params.stashbase, id);
-    }
+  if (params.createdstash || params.canwrite) {
+    return FreeStash(params.stashbase, id);
+  }
 
-    return 0;
+  return 0;
 }
 
 static int PerformCommandZero(CommandParameters& params) {
 
     if (params.cpos >= params.tokens.size()) {
-        fprintf(stderr, "missing target blocks for zero\n");
+        LOG(ERROR) << "missing target blocks for zero";
         return -1;
     }
 
-    RangeSet tgt;
-    parse_range(params.tokens[params.cpos++], tgt);
+    RangeSet tgt = parse_range(params.tokens[params.cpos++]);
 
-    fprintf(stderr, "  zeroing %zu blocks\n", tgt.size);
+    LOG(INFO) << "  zeroing " << tgt.size << " blocks";
 
     allocate(BLOCKSIZE, params.buffer);
     memset(params.buffer.data(), 0, BLOCKSIZE);
@@ -1159,15 +1222,14 @@ static int PerformCommandZero(CommandParameters& params) {
 static int PerformCommandNew(CommandParameters& params) {
 
     if (params.cpos >= params.tokens.size()) {
-        fprintf(stderr, "missing target blocks for new\n");
+        LOG(ERROR) << "missing target blocks for new";
         return -1;
     }
 
-    RangeSet tgt;
-    parse_range(params.tokens[params.cpos++], tgt);
+    RangeSet tgt = parse_range(params.tokens[params.cpos++]);
 
     if (params.canwrite) {
-        fprintf(stderr, " writing %zu blocks of new data\n", tgt.size);
+        LOG(INFO) << " writing " << tgt.size << " blocks of new data";
 
         RangeSinkState rss(tgt);
         rss.fd = params.fd;
@@ -1203,55 +1265,43 @@ static int PerformCommandDiff(CommandParameters& params) {
 
     // <offset> <length>
     if (params.cpos + 1 >= params.tokens.size()) {
-        fprintf(stderr, "missing patch offset or length for %s\n", params.cmdname);
+        LOG(ERROR) << "missing patch offset or length for " << params.cmdname;
         return -1;
     }
 
     size_t offset;
     if (!android::base::ParseUint(params.tokens[params.cpos++].c_str(), &offset)) {
-        fprintf(stderr, "invalid patch offset\n");
+        LOG(ERROR) << "invalid patch offset";
         return -1;
     }
 
     size_t len;
     if (!android::base::ParseUint(params.tokens[params.cpos++].c_str(), &len)) {
-        fprintf(stderr, "invalid patch offset\n");
+        LOG(ERROR) << "invalid patch len";
         return -1;
     }
 
     RangeSet tgt;
     size_t blocks = 0;
     bool overlap = false;
-    int status = 0;
-    if (params.version == 1) {
-        status = LoadSrcTgtVersion1(params, tgt, blocks, params.buffer, params.fd);
-    } else if (params.version == 2) {
-        status = LoadSrcTgtVersion2(params, tgt, blocks, params.buffer, params.fd,
-                params.stashbase, nullptr);
-    } else if (params.version >= 3) {
-        status = LoadSrcTgtVersion3(params, tgt, blocks, false, overlap);
-    }
+    int status = LoadSrcTgtVersion3(params, tgt, blocks, false, overlap);
 
     if (status == -1) {
-        fprintf(stderr, "failed to read blocks for diff\n");
+        LOG(ERROR) << "failed to read blocks for diff";
         return -1;
     }
 
     if (status == 0) {
         params.foundwrites = true;
     } else if (params.foundwrites) {
-        fprintf(stderr, "warning: commands executed out of order [%s]\n", params.cmdname);
+        LOG(WARNING) << "warning: commands executed out of order [" << params.cmdname << "]";
     }
 
     if (params.canwrite) {
         if (status == 0) {
-            fprintf(stderr, "patching %zu blocks to %zu\n", blocks, tgt.size);
-
-            Value patch_value;
-            patch_value.type = VAL_BLOB;
-            patch_value.size = len;
-            patch_value.data = (char*) (params.patch_start + offset);
-
+            LOG(INFO) << "patching " << blocks << " blocks to " << tgt.size;
+            Value patch_value(VAL_BLOB,
+                    std::string(reinterpret_cast<const char*>(params.patch_start + offset), len));
             RangeSinkState rss(tgt);
             rss.fd = params.fd;
             rss.p_block = 0;
@@ -1269,24 +1319,24 @@ static int PerformCommandDiff(CommandParameters& params) {
             if (params.cmdname[0] == 'i') {      // imgdiff
                 if (ApplyImagePatch(params.buffer.data(), blocks * BLOCKSIZE, &patch_value,
                         &RangeSinkWrite, &rss, nullptr, nullptr) != 0) {
-                    fprintf(stderr, "Failed to apply image patch.\n");
+                    LOG(ERROR) << "Failed to apply image patch.";
                     return -1;
                 }
             } else {
                 if (ApplyBSDiffPatch(params.buffer.data(), blocks * BLOCKSIZE, &patch_value,
                         0, &RangeSinkWrite, &rss, nullptr) != 0) {
-                    fprintf(stderr, "Failed to apply bsdiff patch.\n");
+                    LOG(ERROR) << "Failed to apply bsdiff patch.";
                     return -1;
                 }
             }
 
             // We expect the output of the patcher to fill the tgt ranges exactly.
             if (rss.p_block != tgt.count || rss.p_remain != 0) {
-                fprintf(stderr, "range sink underrun?\n");
+                LOG(ERROR) << "range sink underrun?";
             }
         } else {
-            fprintf(stderr, "skipping %zu blocks already patched to %zu [%s]\n",
-                blocks, tgt.size, params.cmdline);
+            LOG(INFO) << "skipping " << blocks << " blocks already patched to " << tgt.size
+                      << " [" << params.cmdline << "]";
         }
     }
 
@@ -1307,25 +1357,24 @@ static int PerformCommandErase(CommandParameters& params) {
 
     struct stat sb;
     if (fstat(params.fd, &sb) == -1) {
-        fprintf(stderr, "failed to fstat device to erase: %s\n", strerror(errno));
+        PLOG(ERROR) << "failed to fstat device to erase";
         return -1;
     }
 
     if (!S_ISBLK(sb.st_mode)) {
-        fprintf(stderr, "not a block device; skipping erase\n");
+        LOG(ERROR) << "not a block device; skipping erase";
         return -1;
     }
 
     if (params.cpos >= params.tokens.size()) {
-        fprintf(stderr, "missing target blocks for erase\n");
+        LOG(ERROR) << "missing target blocks for erase";
         return -1;
     }
 
-    RangeSet tgt;
-    parse_range(params.tokens[params.cpos++], tgt);
+    RangeSet tgt = parse_range(params.tokens[params.cpos++]);
 
     if (params.canwrite) {
-        fprintf(stderr, " erasing %zu blocks\n", tgt.size);
+        LOG(INFO) << " erasing " << tgt.size << " blocks";
 
         for (size_t i = 0; i < tgt.count; ++i) {
             uint64_t blocks[2];
@@ -1335,7 +1384,7 @@ static int PerformCommandErase(CommandParameters& params) {
             blocks[1] = (tgt.pos[i * 2 + 1] - tgt.pos[i * 2]) * (uint64_t) BLOCKSIZE;
 
             if (ioctl(params.fd, BLKDISCARD, &blocks) == -1) {
-                fprintf(stderr, "BLKDISCARD ioctl failed: %s\n", strerror(errno));
+                PLOG(ERROR) << "BLKDISCARD ioctl failed";
                 return -1;
             }
         }
@@ -1352,339 +1401,292 @@ struct Command {
     CommandFunction f;
 };
 
-// CompareCommands and CompareCommandNames are for the hash table
-
-static int CompareCommands(const void* c1, const void* c2) {
-    return strcmp(((const Command*) c1)->name, ((const Command*) c2)->name);
-}
-
-static int CompareCommandNames(const void* c1, const void* c2) {
-    return strcmp(((const Command*) c1)->name, (const char*) c2);
-}
-
-// HashString is used to hash command names for the hash table
-
-static unsigned int HashString(const char *s) {
-    unsigned int hash = 0;
-    if (s) {
-        while (*s) {
-            hash = hash * 33 + *s++;
-        }
-    }
-    return hash;
-}
-
 // args:
 //    - block device (or file) to modify in-place
 //    - transfer list (blob)
 //    - new data stream (filename within package.zip)
 //    - patch stream (filename within package.zip, must be uncompressed)
 
-static Value* PerformBlockImageUpdate(const char* name, State* state, int /* argc */, Expr* argv[],
-        const Command* commands, size_t cmdcount, bool dryrun) {
-    CommandParameters params;
-    memset(&params, 0, sizeof(params));
-    params.canwrite = !dryrun;
-
-    fprintf(stderr, "performing %s\n", dryrun ? "verification" : "update");
-    if (state->is_retry) {
-        is_retry = true;
-        fprintf(stderr, "This update is a retry.\n");
-    }
-
-    Value* blockdev_filename = nullptr;
-    Value* transfer_list_value = nullptr;
-    Value* new_data_fn = nullptr;
-    Value* patch_data_fn = nullptr;
-    if (ReadValueArgs(state, argv, 4, &blockdev_filename, &transfer_list_value,
-            &new_data_fn, &patch_data_fn) < 0) {
-        return StringValue(strdup(""));
-    }
-    std::unique_ptr<Value, decltype(&FreeValue)> blockdev_filename_holder(blockdev_filename,
-            FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> transfer_list_value_holder(transfer_list_value,
-            FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> new_data_fn_holder(new_data_fn, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> patch_data_fn_holder(patch_data_fn, FreeValue);
-
-    if (blockdev_filename->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string",
-                   name);
-        return StringValue(strdup(""));
-    }
-    if (transfer_list_value->type != VAL_BLOB) {
-        ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
-        return StringValue(strdup(""));
-    }
-    if (new_data_fn->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
-        return StringValue(strdup(""));
-    }
-    if (patch_data_fn->type != VAL_STRING) {
-        ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string",
-                   name);
-        return StringValue(strdup(""));
-    }
-
-    UpdaterInfo* ui = reinterpret_cast<UpdaterInfo*>(state->cookie);
-
-    if (ui == nullptr) {
-        return StringValue(strdup(""));
-    }
-
-    FILE* cmd_pipe = ui->cmd_pipe;
-    ZipArchive* za = ui->package_zip;
-
-    if (cmd_pipe == nullptr || za == nullptr) {
-        return StringValue(strdup(""));
-    }
-
-    const ZipEntry* patch_entry = mzFindZipEntry(za, patch_data_fn->data);
-    if (patch_entry == nullptr) {
-        fprintf(stderr, "%s(): no file \"%s\" in package", name, patch_data_fn->data);
-        return StringValue(strdup(""));
-    }
-
-    params.patch_start = ui->package_zip_addr + mzGetZipEntryOffset(patch_entry);
-    const ZipEntry* new_entry = mzFindZipEntry(za, new_data_fn->data);
-    if (new_entry == nullptr) {
-        fprintf(stderr, "%s(): no file \"%s\" in package", name, new_data_fn->data);
-        return StringValue(strdup(""));
-    }
-
-    params.fd = TEMP_FAILURE_RETRY(open(blockdev_filename->data, O_RDWR));
-    unique_fd fd_holder(params.fd);
+static Value* PerformBlockImageUpdate(const char* name, State* state,
+                                      const std::vector<std::unique_ptr<Expr>>& argv,
+                                      const Command* commands, size_t cmdcount, bool dryrun) {
+  CommandParameters params = {};
+  params.canwrite = !dryrun;
+
+  LOG(INFO) << "performing " << (dryrun ? "verification" : "update");
+  if (state->is_retry) {
+    is_retry = true;
+    LOG(INFO) << "This update is a retry.";
+  }
+  if (argv.size() != 4) {
+    ErrorAbort(state, kArgsParsingFailure, "block_image_update expects 4 arguments, got %zu",
+               argv.size());
+    return StringValue("");
+  }
+
+  std::vector<std::unique_ptr<Value>> args;
+  if (!ReadValueArgs(state, argv, &args)) {
+    return nullptr;
+  }
+
+  const Value* blockdev_filename = args[0].get();
+  const Value* transfer_list_value = args[1].get();
+  const Value* new_data_fn = args[2].get();
+  const Value* patch_data_fn = args[3].get();
+
+  if (blockdev_filename->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string", name);
+    return StringValue("");
+  }
+  if (transfer_list_value->type != VAL_BLOB) {
+    ErrorAbort(state, kArgsParsingFailure, "transfer_list argument to %s must be blob", name);
+    return StringValue("");
+  }
+  if (new_data_fn->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "new_data_fn argument to %s must be string", name);
+    return StringValue("");
+  }
+  if (patch_data_fn->type != VAL_STRING) {
+    ErrorAbort(state, kArgsParsingFailure, "patch_data_fn argument to %s must be string", name);
+    return StringValue("");
+  }
+
+  UpdaterInfo* ui = static_cast<UpdaterInfo*>(state->cookie);
+  if (ui == nullptr) {
+    return StringValue("");
+  }
+
+  FILE* cmd_pipe = ui->cmd_pipe;
+  ZipArchiveHandle za = ui->package_zip;
+
+  if (cmd_pipe == nullptr || za == nullptr) {
+    return StringValue("");
+  }
+
+  ZipString path_data(patch_data_fn->data.c_str());
+  ZipEntry patch_entry;
+  if (FindEntry(za, path_data, &patch_entry) != 0) {
+    LOG(ERROR) << name << "(): no file \"" << patch_data_fn->data << "\" in package";
+    return StringValue("");
+  }
+
+  params.patch_start = ui->package_zip_addr + patch_entry.offset;
+  ZipString new_data(new_data_fn->data.c_str());
+  ZipEntry new_entry;
+  if (FindEntry(za, new_data, &new_entry) != 0) {
+    LOG(ERROR) << name << "(): no file \"" << new_data_fn->data << "\" in package";
+    return StringValue("");
+  }
+
+  params.fd.reset(TEMP_FAILURE_RETRY(ota_open(blockdev_filename->data.c_str(), O_RDWR)));
+  if (params.fd == -1) {
+    PLOG(ERROR) << "open \"" << blockdev_filename->data << "\" failed";
+    return StringValue("");
+  }
+
+  if (params.canwrite) {
+    params.nti.za = za;
+    params.nti.entry = new_entry;
+
+    pthread_mutex_init(&params.nti.mu, nullptr);
+    pthread_cond_init(&params.nti.cv, nullptr);
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
+
+    int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
+    if (error != 0) {
+      PLOG(ERROR) << "pthread_create failed";
+      return StringValue("");
+    }
+  }
+
+  std::vector<std::string> lines = android::base::Split(transfer_list_value->data, "\n");
+  if (lines.size() < 2) {
+    ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zd]\n",
+               lines.size());
+    return StringValue("");
+  }
+
+  // First line in transfer list is the version number.
+  if (!android::base::ParseInt(lines[0], &params.version, 3, 4)) {
+    LOG(ERROR) << "unexpected transfer list version [" << lines[0] << "]";
+    return StringValue("");
+  }
+
+  LOG(INFO) << "blockimg version is " << params.version;
+
+  // Second line in transfer list is the total number of blocks we expect to write.
+  size_t total_blocks;
+  if (!android::base::ParseUint(lines[1], &total_blocks)) {
+    ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]\n", lines[1].c_str());
+    return StringValue("");
+  }
+
+  if (total_blocks == 0) {
+    return StringValue("t");
+  }
+
+  size_t start = 2;
+  if (lines.size() < 4) {
+    ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]\n",
+               lines.size());
+    return StringValue("");
+  }
+
+  // Third line is how many stash entries are needed simultaneously.
+  LOG(INFO) << "maximum stash entries " << lines[2];
+
+  // Fourth line is the maximum number of blocks that will be stashed simultaneously
+  size_t stash_max_blocks;
+  if (!android::base::ParseUint(lines[3], &stash_max_blocks)) {
+    ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]\n",
+               lines[3].c_str());
+    return StringValue("");
+  }
+
+  int res = CreateStash(state, stash_max_blocks, blockdev_filename->data, params.stashbase);
+  if (res == -1) {
+    return StringValue("");
+  }
+
+  params.createdstash = res;
+
+  start += 2;
+
+  // Build a map of the available commands
+  std::unordered_map<std::string, const Command*> cmd_map;
+  for (size_t i = 0; i < cmdcount; ++i) {
+    if (cmd_map.find(commands[i].name) != cmd_map.end()) {
+      LOG(ERROR) << "Error: command [" << commands[i].name << "] already exists in the cmd map.";
+      return StringValue(strdup(""));
+    }
+    cmd_map[commands[i].name] = &commands[i];
+  }
+
+  int rc = -1;
+
+  // Subsequent lines are all individual transfer commands
+  for (auto it = lines.cbegin() + start; it != lines.cend(); it++) {
+    const std::string& line(*it);
+    if (line.empty()) continue;
+
+    params.tokens = android::base::Split(line, " ");
+    params.cpos = 0;
+    params.cmdname = params.tokens[params.cpos++].c_str();
+    params.cmdline = line.c_str();
+
+    if (cmd_map.find(params.cmdname) == cmd_map.end()) {
+      LOG(ERROR) << "unexpected command [" << params.cmdname << "]";
+      goto pbiudone;
+    }
+
+    const Command* cmd = cmd_map[params.cmdname];
 
-    if (params.fd == -1) {
-        fprintf(stderr, "open \"%s\" failed: %s\n", blockdev_filename->data, strerror(errno));
-        return StringValue(strdup(""));
+    if (cmd->f != nullptr && cmd->f(params) == -1) {
+      LOG(ERROR) << "failed to execute command [" << line << "]";
+      goto pbiudone;
     }
 
     if (params.canwrite) {
-        params.nti.za = za;
-        params.nti.entry = new_entry;
-
-        pthread_mutex_init(&params.nti.mu, nullptr);
-        pthread_cond_init(&params.nti.cv, nullptr);
-        pthread_attr_t attr;
-        pthread_attr_init(&attr);
-        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
-
-        int error = pthread_create(&params.thread, &attr, unzip_new_data, &params.nti);
-        if (error != 0) {
-            fprintf(stderr, "pthread_create failed: %s\n", strerror(error));
-            return StringValue(strdup(""));
-        }
-    }
-
-    // Copy all the lines in transfer_list_value into std::string for
-    // processing.
-    const std::string transfer_list(transfer_list_value->data, transfer_list_value->size);
-    std::vector<std::string> lines = android::base::Split(transfer_list, "\n");
-    if (lines.size() < 2) {
-        ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zd]\n",
-                   lines.size());
-        return StringValue(strdup(""));
-    }
-
-    // First line in transfer list is the version number
-    if (!android::base::ParseInt(lines[0].c_str(), &params.version, 1, 4)) {
-        fprintf(stderr, "unexpected transfer list version [%s]\n", lines[0].c_str());
-        return StringValue(strdup(""));
-    }
-
-    fprintf(stderr, "blockimg version is %d\n", params.version);
-
-    // Second line in transfer list is the total number of blocks we expect to write
-    int total_blocks;
-    if (!android::base::ParseInt(lines[1].c_str(), &total_blocks, 0)) {
-        ErrorAbort(state, kArgsParsingFailure, "unexpected block count [%s]\n", lines[1].c_str());
-        return StringValue(strdup(""));
-    }
-
-    if (total_blocks == 0) {
-        return StringValue(strdup("t"));
+      if (ota_fsync(params.fd) == -1) {
+        failure_type = kFsyncFailure;
+        PLOG(ERROR) << "fsync failed";
+        goto pbiudone;
+      }
+      fprintf(cmd_pipe, "set_progress %.4f\n", static_cast<double>(params.written) / total_blocks);
+      fflush(cmd_pipe);
     }
+  }
 
-    size_t start = 2;
-    if (params.version >= 2) {
-        if (lines.size() < 4) {
-            ErrorAbort(state, kArgsParsingFailure, "too few lines in the transfer list [%zu]\n",
-                       lines.size());
-            return StringValue(strdup(""));
-        }
-
-        // Third line is how many stash entries are needed simultaneously
-        fprintf(stderr, "maximum stash entries %s\n", lines[2].c_str());
-
-        // Fourth line is the maximum number of blocks that will be stashed simultaneously
-        int stash_max_blocks;
-        if (!android::base::ParseInt(lines[3].c_str(), &stash_max_blocks, 0)) {
-            ErrorAbort(state, kArgsParsingFailure, "unexpected maximum stash blocks [%s]\n",
-                       lines[3].c_str());
-            return StringValue(strdup(""));
-        }
+  if (params.canwrite) {
+    pthread_join(params.thread, nullptr);
 
-        int res = CreateStash(state, stash_max_blocks, blockdev_filename->data, params.stashbase);
-        if (res == -1) {
-            return StringValue(strdup(""));
-        }
+    LOG(INFO) << "wrote " << params.written << " blocks; expected " << total_blocks;
+    LOG(INFO) << "stashed " << params.stashed << " blocks";
+    LOG(INFO) << "max alloc needed was " << params.buffer.size();
 
-        params.createdstash = res;
-
-        start += 2;
+    const char* partition = strrchr(blockdev_filename->data.c_str(), '/');
+    if (partition != nullptr && *(partition + 1) != 0) {
+      fprintf(cmd_pipe, "log bytes_written_%s: %zu\n", partition + 1, params.written * BLOCKSIZE);
+      fprintf(cmd_pipe, "log bytes_stashed_%s: %zu\n", partition + 1, params.stashed * BLOCKSIZE);
+      fflush(cmd_pipe);
     }
+    // Delete stash only after successfully completing the update, as it may contain blocks needed
+    // to complete the update later.
+    DeleteStash(params.stashbase);
+  } else {
+    LOG(INFO) << "verified partition contents; update may be resumed";
+  }
 
-    // Build a hash table of the available commands
-    HashTable* cmdht = mzHashTableCreate(cmdcount, nullptr);
-    std::unique_ptr<HashTable, decltype(&mzHashTableFree)> cmdht_holder(cmdht, mzHashTableFree);
-
-    for (size_t i = 0; i < cmdcount; ++i) {
-        unsigned int cmdhash = HashString(commands[i].name);
-        mzHashTableLookup(cmdht, cmdhash, (void*) &commands[i], CompareCommands, true);
-    }
-
-    int rc = -1;
-
-    // Subsequent lines are all individual transfer commands
-    for (auto it = lines.cbegin() + start; it != lines.cend(); it++) {
-        const std::string& line_str(*it);
-        if (line_str.empty()) {
-            continue;
-        }
-
-        params.tokens = android::base::Split(line_str, " ");
-        params.cpos = 0;
-        params.cmdname = params.tokens[params.cpos++].c_str();
-        params.cmdline = line_str.c_str();
-
-        unsigned int cmdhash = HashString(params.cmdname);
-        const Command* cmd = reinterpret_cast<const Command*>(mzHashTableLookup(cmdht, cmdhash,
-                const_cast<char*>(params.cmdname), CompareCommandNames,
-                false));
-
-        if (cmd == nullptr) {
-            fprintf(stderr, "unexpected command [%s]\n", params.cmdname);
-            goto pbiudone;
-        }
-
-        if (cmd->f != nullptr && cmd->f(params) == -1) {
-            fprintf(stderr, "failed to execute command [%s]\n", line_str.c_str());
-            goto pbiudone;
-        }
-
-        if (params.canwrite) {
-            if (ota_fsync(params.fd) == -1) {
-                failure_type = kFsyncFailure;
-                fprintf(stderr, "fsync failed: %s\n", strerror(errno));
-                goto pbiudone;
-            }
-            fprintf(cmd_pipe, "set_progress %.4f\n", (double) params.written / total_blocks);
-            fflush(cmd_pipe);
-        }
-    }
-
-    if (params.canwrite) {
-        pthread_join(params.thread, nullptr);
-
-        fprintf(stderr, "wrote %zu blocks; expected %d\n", params.written, total_blocks);
-        fprintf(stderr, "stashed %zu blocks\n", params.stashed);
-        fprintf(stderr, "max alloc needed was %zu\n", params.buffer.size());
-
-        const char* partition = strrchr(blockdev_filename->data, '/');
-        if (partition != nullptr && *(partition+1) != 0) {
-            fprintf(cmd_pipe, "log bytes_written_%s: %zu\n", partition + 1,
-                    params.written * BLOCKSIZE);
-            fprintf(cmd_pipe, "log bytes_stashed_%s: %zu\n", partition + 1,
-                    params.stashed * BLOCKSIZE);
-            fflush(cmd_pipe);
-        }
-        // Delete stash only after successfully completing the update, as it
-        // may contain blocks needed to complete the update later.
-        DeleteStash(params.stashbase);
-    } else {
-        fprintf(stderr, "verified partition contents; update may be resumed\n");
-    }
-
-    rc = 0;
+  rc = 0;
 
 pbiudone:
-    if (ota_fsync(params.fd) == -1) {
-        failure_type = kFsyncFailure;
-        fprintf(stderr, "fsync failed: %s\n", strerror(errno));
-    }
-    // params.fd will be automatically closed because of the fd_holder above.
-
-    // Only delete the stash if the update cannot be resumed, or it's
-    // a verification run and we created the stash.
-    if (params.isunresumable || (!params.canwrite && params.createdstash)) {
-        DeleteStash(params.stashbase);
-    }
-
-    if (failure_type != kNoCause && state->cause_code == kNoCause) {
-        state->cause_code = failure_type;
-    }
-
-    return StringValue(rc == 0 ? strdup("t") : strdup(""));
+  if (ota_fsync(params.fd) == -1) {
+    failure_type = kFsyncFailure;
+    PLOG(ERROR) << "fsync failed";
+  }
+  // params.fd will be automatically closed because it's a unique_fd.
+
+  // Only delete the stash if the update cannot be resumed, or it's a verification run and we
+  // created the stash.
+  if (params.isunresumable || (!params.canwrite && params.createdstash)) {
+    DeleteStash(params.stashbase);
+  }
+
+  if (failure_type != kNoCause && state->cause_code == kNoCause) {
+    state->cause_code = failure_type;
+  }
+
+  return StringValue(rc == 0 ? "t" : "");
 }
 
-// The transfer list is a text file containing commands to
-// transfer data from one place to another on the target
-// partition.  We parse it and execute the commands in order:
-//
-//    zero [rangeset]
-//      - fill the indicated blocks with zeros
-//
-//    new [rangeset]
-//      - fill the blocks with data read from the new_data file
-//
-//    erase [rangeset]
-//      - mark the given blocks as empty
-//
-//    move <...>
-//    bsdiff <patchstart> <patchlen> <...>
-//    imgdiff <patchstart> <patchlen> <...>
-//      - read the source blocks, apply a patch (or not in the
-//        case of move), write result to target blocks.  bsdiff or
-//        imgdiff specifies the type of patch; move means no patch
-//        at all.
-//
-//        The format of <...> differs between versions 1 and 2;
-//        see the LoadSrcTgtVersion{1,2}() functions for a
-//        description of what's expected.
-//
-//    stash <stash_id> <src_range>
-//      - (version 2+ only) load the given source range and stash
-//        the data in the given slot of the stash table.
-//
-//    free <stash_id>
-//      - (version 3+ only) free the given stash data.
-//
-// The creator of the transfer list will guarantee that no block
-// is read (ie, used as the source for a patch or move) after it
-// has been written.
-//
-// In version 2, the creator will guarantee that a given stash is
-// loaded (with a stash command) before it's used in a
-// move/bsdiff/imgdiff command.
-//
-// Within one command the source and target ranges may overlap so
-// in general we need to read the entire source into memory before
-// writing anything to the target blocks.
-//
-// All the patch data is concatenated into one patch_data file in
-// the update package.  It must be stored uncompressed because we
-// memory-map it in directly from the archive.  (Since patches are
-// already compressed, we lose very little by not compressing
-// their concatenation.)
-//
-// In version 3, commands that read data from the partition (i.e.
-// move/bsdiff/imgdiff/stash) have one or more additional hashes
-// before the range parameters, which are used to check if the
-// command has already been completed and verify the integrity of
-// the source data.
-
-Value* BlockImageVerifyFn(const char* name, State* state, int argc, Expr* argv[]) {
+/**
+ * The transfer list is a text file containing commands to transfer data from one place to another
+ * on the target partition. We parse it and execute the commands in order:
+ *
+ *    zero [rangeset]
+ *      - Fill the indicated blocks with zeros.
+ *
+ *    new [rangeset]
+ *      - Fill the blocks with data read from the new_data file.
+ *
+ *    erase [rangeset]
+ *      - Mark the given blocks as empty.
+ *
+ *    move <...>
+ *    bsdiff <patchstart> <patchlen> <...>
+ *    imgdiff <patchstart> <patchlen> <...>
+ *      - Read the source blocks, apply a patch (or not in the case of move), write result to target
+ *      blocks.  bsdiff or imgdiff specifies the type of patch; move means no patch at all.
+ *
+ *        See the comments in LoadSrcTgtVersion3() for a description of the <...> format.
+ *
+ *    stash <stash_id> <src_range>
+ *      - Load the given source range and stash the data in the given slot of the stash table.
+ *
+ *    free <stash_id>
+ *      - Free the given stash data.
+ *
+ * The creator of the transfer list will guarantee that no block is read (ie, used as the source for
+ * a patch or move) after it has been written.
+ *
+ * The creator will guarantee that a given stash is loaded (with a stash command) before it's used
+ * in a move/bsdiff/imgdiff command.
+ *
+ * Within one command the source and target ranges may overlap so in general we need to read the
+ * entire source into memory before writing anything to the target blocks.
+ *
+ * All the patch data is concatenated into one patch_data file in the update package. It must be
+ * stored uncompressed because we memory-map it in directly from the archive. (Since patches are
+ * already compressed, we lose very little by not compressing their concatenation.)
+ *
+ * Commands that read data from the partition (i.e. move/bsdiff/imgdiff/stash) have one or more
+ * additional hashes before the range parameters, which are used to check if the command has already
+ * been completed and verify the integrity of the source data.
+ */
+Value* BlockImageVerifyFn(const char* name, State* state,
+                          const std::vector<std::unique_ptr<Expr>>& argv) {
     // Commands which are not tested are set to nullptr to skip them completely
     const Command commands[] = {
         { "bsdiff",     PerformCommandDiff  },
@@ -1698,11 +1700,12 @@ Value* BlockImageVerifyFn(const char* name, State* state, int argc, Expr* argv[]
     };
 
     // Perform a dry run without writing to test if an update can proceed
-    return PerformBlockImageUpdate(name, state, argc, argv, commands,
+    return PerformBlockImageUpdate(name, state, argv, commands,
                 sizeof(commands) / sizeof(commands[0]), true);
 }
 
-Value* BlockImageUpdateFn(const char* name, State* state, int argc, Expr* argv[]) {
+Value* BlockImageUpdateFn(const char* name, State* state,
+                          const std::vector<std::unique_ptr<Expr>>& argv) {
     const Command commands[] = {
         { "bsdiff",     PerformCommandDiff  },
         { "erase",      PerformCommandErase },
@@ -1714,41 +1717,43 @@ Value* BlockImageUpdateFn(const char* name, State* state, int argc, Expr* argv[]
         { "zero",       PerformCommandZero  }
     };
 
-    return PerformBlockImageUpdate(name, state, argc, argv, commands,
+    return PerformBlockImageUpdate(name, state, argv, commands,
                 sizeof(commands) / sizeof(commands[0]), false);
 }
 
-Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[]) {
-    Value* blockdev_filename;
-    Value* ranges;
+Value* RangeSha1Fn(const char* name, State* state, const std::vector<std::unique_ptr<Expr>>& argv) {
+    if (argv.size() != 2) {
+        ErrorAbort(state, kArgsParsingFailure, "range_sha1 expects 2 arguments, got %zu",
+                   argv.size());
+        return StringValue("");
+    }
 
-    if (ReadValueArgs(state, argv, 2, &blockdev_filename, &ranges) < 0) {
-        return StringValue(strdup(""));
+    std::vector<std::unique_ptr<Value>> args;
+    if (!ReadValueArgs(state, argv, &args)) {
+        return nullptr;
     }
-    std::unique_ptr<Value, decltype(&FreeValue)> ranges_holder(ranges, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> blockdev_filename_holder(blockdev_filename,
-            FreeValue);
+
+    const Value* blockdev_filename = args[0].get();
+    const Value* ranges = args[1].get();
 
     if (blockdev_filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "blockdev_filename argument to %s must be string",
                    name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (ranges->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    int fd = open(blockdev_filename->data, O_RDWR);
-    unique_fd fd_holder(fd);
-    if (fd < 0) {
-        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", blockdev_filename->data,
-                   strerror(errno));
-        return StringValue(strdup(""));
+    android::base::unique_fd fd(ota_open(blockdev_filename->data.c_str(), O_RDWR));
+    if (fd == -1) {
+        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s",
+                   blockdev_filename->data.c_str(), strerror(errno));
+        return StringValue("");
     }
 
-    RangeSet rs;
-    parse_range(ranges->data, rs);
+    RangeSet rs = parse_range(ranges->data);
 
     SHA_CTX ctx;
     SHA1_Init(&ctx);
@@ -1756,16 +1761,16 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
     std::vector<uint8_t> buffer(BLOCKSIZE);
     for (size_t i = 0; i < rs.count; ++i) {
         if (!check_lseek(fd, (off64_t)rs.pos[i*2] * BLOCKSIZE, SEEK_SET)) {
-            ErrorAbort(state, kLseekFailure, "failed to seek %s: %s", blockdev_filename->data,
-                       strerror(errno));
-            return StringValue(strdup(""));
+            ErrorAbort(state, kLseekFailure, "failed to seek %s: %s",
+                       blockdev_filename->data.c_str(), strerror(errno));
+            return StringValue("");
         }
 
         for (size_t j = rs.pos[i*2]; j < rs.pos[i*2+1]; ++j) {
             if (read_all(fd, buffer, BLOCKSIZE) == -1) {
-                ErrorAbort(state, kFreadFailure, "failed to read %s: %s", blockdev_filename->data,
-                        strerror(errno));
-                return StringValue(strdup(""));
+                ErrorAbort(state, kFreadFailure, "failed to read %s: %s",
+                           blockdev_filename->data.c_str(), strerror(errno));
+                return StringValue("");
             }
 
             SHA1_Update(&ctx, buffer.data(), BLOCKSIZE);
@@ -1774,7 +1779,7 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
     uint8_t digest[SHA_DIGEST_LENGTH];
     SHA1_Final(digest, &ctx);
 
-    return StringValue(strdup(print_sha1(digest).c_str()));
+    return StringValue(print_sha1(digest));
 }
 
 // This function checks if a device has been remounted R/W prior to an incremental
@@ -1782,34 +1787,40 @@ Value* RangeSha1Fn(const char* name, State* state, int /* argc */, Expr* argv[])
 // 1st block of each partition and check for mounting time/count. It return string "t"
 // if executes successfully and an empty string otherwise.
 
-Value* CheckFirstBlockFn(const char* name, State* state, int argc, Expr* argv[]) {
-    Value* arg_filename;
+Value* CheckFirstBlockFn(const char* name, State* state,
+                         const std::vector<std::unique_ptr<Expr>>& argv) {
+     if (argv.size() != 1) {
+        ErrorAbort(state, kArgsParsingFailure, "check_first_block expects 1 argument, got %zu",
+                   argv.size());
+        return StringValue("");
+    }
 
-    if (ReadValueArgs(state, argv, 1, &arg_filename) < 0) {
+    std::vector<std::unique_ptr<Value>> args;
+    if (!ReadValueArgs(state, argv, &args)) {
         return nullptr;
     }
-    std::unique_ptr<Value, decltype(&FreeValue)> filename(arg_filename, FreeValue);
 
-    if (filename->type != VAL_STRING) {
+    const Value* arg_filename = args[0].get();
+
+    if (arg_filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    int fd = open(arg_filename->data, O_RDONLY);
-    unique_fd fd_holder(fd);
+    android::base::unique_fd fd(ota_open(arg_filename->data.c_str(), O_RDONLY));
     if (fd == -1) {
-        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", arg_filename->data,
+        ErrorAbort(state, kFileOpenFailure, "open \"%s\" failed: %s", arg_filename->data.c_str(),
                    strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     RangeSet blk0 {1 /*count*/, 1/*size*/, std::vector<size_t> {0, 1}/*position*/};
     std::vector<uint8_t> block0_buffer(BLOCKSIZE);
 
     if (ReadBlocks(blk0, block0_buffer, fd) == -1) {
-        ErrorAbort(state, kFreadFailure, "failed to read %s: %s", arg_filename->data,
+        ErrorAbort(state, kFreadFailure, "failed to read %s: %s", arg_filename->data.c_str(),
                 strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     // https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout
@@ -1827,56 +1838,60 @@ Value* CheckFirstBlockFn(const char* name, State* state, int argc, Expr* argv[])
         uiPrintf(state, "Last remount happened on %s", ctime(&mount_time));
     }
 
-    return StringValue(strdup("t"));
+    return StringValue("t");
 }
 
 
-Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[]) {
-    Value* arg_filename;
-    Value* arg_ranges;
+Value* BlockImageRecoverFn(const char* name, State* state,
+                           const std::vector<std::unique_ptr<Expr>>& argv) {
+    if (argv.size() != 2) {
+        ErrorAbort(state, kArgsParsingFailure, "block_image_recover expects 2 arguments, got %zu",
+                   argv.size());
+        return StringValue("");
+    }
 
-    if (ReadValueArgs(state, argv, 2, &arg_filename, &arg_ranges) < 0) {
-        return NULL;
+    std::vector<std::unique_ptr<Value>> args;
+    if (!ReadValueArgs(state, argv, &args)) {
+        return nullptr;
     }
 
-    std::unique_ptr<Value, decltype(&FreeValue)> filename(arg_filename, FreeValue);
-    std::unique_ptr<Value, decltype(&FreeValue)> ranges(arg_ranges, FreeValue);
+    const Value* filename = args[0].get();
+    const Value* ranges = args[1].get();
 
     if (filename->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "filename argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
     if (ranges->type != VAL_STRING) {
         ErrorAbort(state, kArgsParsingFailure, "ranges argument to %s must be string", name);
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     // Output notice to log when recover is attempted
-    fprintf(stderr, "%s image corrupted, attempting to recover...\n", filename->data);
+    LOG(INFO) << filename->data << " image corrupted, attempting to recover...";
 
     // When opened with O_RDWR, libfec rewrites corrupted blocks when they are read
-    fec::io fh(filename->data, O_RDWR);
+    fec::io fh(filename->data.c_str(), O_RDWR);
 
     if (!fh) {
-        ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data,
+        ErrorAbort(state, kLibfecFailure, "fec_open \"%s\" failed: %s", filename->data.c_str(),
                    strerror(errno));
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     if (!fh.has_ecc() || !fh.has_verity()) {
         ErrorAbort(state, kLibfecFailure, "unable to use metadata to correct errors");
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
     fec_status status;
 
     if (!fh.get_status(status)) {
         ErrorAbort(state, kLibfecFailure, "failed to read FEC status");
-        return StringValue(strdup(""));
+        return StringValue("");
     }
 
-    RangeSet rs;
-    parse_range(ranges->data, rs);
+    RangeSet rs = parse_range(ranges->data);
 
     uint8_t buffer[BLOCKSIZE];
 
@@ -1889,8 +1904,8 @@ Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[
 
             if (fh.pread(buffer, BLOCKSIZE, (off64_t)j * BLOCKSIZE) != BLOCKSIZE) {
                 ErrorAbort(state, kLibfecFailure, "failed to recover %s (block %zu): %s",
-                           filename->data, j, strerror(errno));
-                return StringValue(strdup(""));
+                           filename->data.c_str(), j, strerror(errno));
+                return StringValue("");
             }
 
             // If we want to be able to recover from a situation where rewriting a corrected
@@ -1905,8 +1920,8 @@ Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[
             //     read and check if the errors field value has increased.
         }
     }
-    fprintf(stderr, "...%s image recovered successfully.\n", filename->data);
-    return StringValue(strdup("t"));
+    LOG(INFO) << "..." << filename->data << " image recovered successfully.";
+    return StringValue("t");
 }
 
 void RegisterBlockImageFunctions() {