3 files changed, 91 insertions, 16 deletions

diff --git a/uncrypt/Android.mk b/uncrypt/Android.mk
index e73c8f1b6..f31db4243 100644
--- a/uncrypt/Android.mk
+++ b/uncrypt/Android.mk
@@ -20,6 +20,8 @@ LOCAL_CLANG := true
 
 LOCAL_SRC_FILES := uncrypt.cpp
 
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/..
+
 LOCAL_MODULE := uncrypt
 
 LOCAL_STATIC_LIBRARIES := libbase liblog libfs_mgr libcutils
diff --git a/uncrypt/uncrypt.cpp b/uncrypt/uncrypt.cpp
index 8785b29af..aef480035 100644
--- a/uncrypt/uncrypt.cpp
+++ b/uncrypt/uncrypt.cpp
@@ -51,6 +51,8 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <memory>
+
 #include <base/file.h>
 #include <base/strings.h>
 #include <cutils/android_reboot.h>
@@ -60,6 +62,8 @@
 #define LOG_TAG "uncrypt"
 #include <log/log.h>
 
+#include "unique_fd.h"
+
 #define WINDOW_SIZE 5
 
 static const std::string cache_block_map = "/cache/recovery/block.map";
@@ -183,6 +187,7 @@ static int produce_block_map(const char* path, const char* map_file, const char*
         return -1;
     }
     FILE* mapf = fdopen(mapfd, "w");
+    unique_file mapf_holder(mapf);
 
     // Make sure we can write to the status_file.
     if (!android::base::WriteStringToFd("0\n", status_fd)) {
@@ -191,8 +196,7 @@ static int produce_block_map(const char* path, const char* map_file, const char*
     }
 
     struct stat sb;
-    int ret = stat(path, &sb);
-    if (ret != 0) {
+    if (stat(path, &sb) != 0) {
         ALOGE("failed to stat %s\n", path);
         return -1;
     }
@@ -221,15 +225,18 @@ static int produce_block_map(const char* path, const char* map_file, const char*
     size_t pos = 0;
 
     int fd = open(path, O_RDONLY);
-    if (fd < 0) {
+    unique_fd fd_holder(fd);
+    if (fd == -1) {
         ALOGE("failed to open fd for reading: %s\n", strerror(errno));
         return -1;
     }
 
     int wfd = -1;
+    unique_fd wfd_holder(wfd);
     if (encrypted) {
         wfd = open(blk_dev, O_WRONLY | O_SYNC);
-        if (wfd < 0) {
+        wfd_holder = unique_fd(wfd);
+        if (wfd == -1) {
             ALOGE("failed to open fd for writing: %s\n", strerror(errno));
             return -1;
         }
@@ -247,8 +254,7 @@ static int produce_block_map(const char* path, const char* map_file, const char*
         if ((tail+1) % WINDOW_SIZE == head) {
             // write out head buffer
             int block = head_block;
-            ret = ioctl(fd, FIBMAP, &block);
-            if (ret != 0) {
+            if (ioctl(fd, FIBMAP, &block) != 0) {
                 ALOGE("failed to find block %d\n", head_block);
                 return -1;
             }
@@ -288,8 +294,7 @@ static int produce_block_map(const char* path, const char* map_file, const char*
     while (head != tail) {
         // write out head buffer
         int block = head_block;
-        ret = ioctl(fd, FIBMAP, &block);
-        if (ret != 0) {
+        if (ioctl(fd, FIBMAP, &block) != 0) {
             ALOGE("failed to find block %d\n", head_block);
             return -1;
         }
@@ -313,14 +318,11 @@ static int produce_block_map(const char* path, const char* map_file, const char*
         ALOGE("failed to fsync \"%s\": %s\n", map_file, strerror(errno));
         return -1;
     }
-    fclose(mapf);
-    close(fd);
     if (encrypted) {
         if (fsync(wfd) == -1) {
             ALOGE("failed to fsync \"%s\": %s\n", blk_dev, strerror(errno));
             return -1;
         }
-        close(wfd);
     }
 
     return 0;
@@ -333,6 +335,8 @@ static void wipe_misc() {
         if (!v->mount_point) continue;
         if (strcmp(v->mount_point, "/misc") == 0) {
             int fd = open(v->blk_device, O_WRONLY | O_SYNC);
+            unique_fd fd_holder(fd);
+
             uint8_t zeroes[1088];   // sizeof(bootloader_message) from recovery
             memset(zeroes, 0, sizeof(zeroes));
 
@@ -349,10 +353,8 @@ static void wipe_misc() {
             }
             if (fsync(fd) == -1) {
                 ALOGE("failed to fsync \"%s\": %s\n", v->blk_device, strerror(errno));
-                close(fd);
                 return;
             }
-            close(fd);
         }
     }
 }
@@ -437,6 +439,7 @@ int main(int argc, char** argv) {
             ALOGE("failed to open pipe \"%s\": %s\n", status_file.c_str(), strerror(errno));
             return 1;
         }
+        unique_fd status_fd_holder(status_fd);
 
         if (argc == 3) {
             // when command-line args are given this binary is being used
@@ -447,7 +450,6 @@ int main(int argc, char** argv) {
             std::string package;
             if (!find_uncrypt_package(package)) {
                 android::base::WriteStringToFd("-1\n", status_fd);
-                close(status_fd);
                 return 1;
             }
             input_path = package.c_str();
@@ -457,12 +459,10 @@ int main(int argc, char** argv) {
         int status = uncrypt(input_path, map_file, status_fd);
         if (status != 0) {
             android::base::WriteStringToFd("-1\n", status_fd);
-            close(status_fd);
             return 1;
         }
 
         android::base::WriteStringToFd("100\n", status_fd);
-        close(status_fd);
     }
 
     return 0;
diff --git a/unique_fd.h b/unique_fd.h
new file mode 100644
index 000000000..98a7c7b67
--- /dev/null
+++ b/unique_fd.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef UNIQUE_FD_H
+#define UNIQUE_FD_H
+
+#include <stdio.h>
+
+#include <memory>
+
+class unique_fd {
+  public:
+    unique_fd(int fd) : fd_(fd) { }
+
+    unique_fd(unique_fd&& uf) {
+        fd_ = uf.fd_;
+        uf.fd_ = -1;
+    }
+
+    ~unique_fd() {
+        if (fd_ != -1) {
+            close(fd_);
+        }
+    }
+
+    int get() {
+        return fd_;
+    }
+
+    // Movable.
+    unique_fd& operator=(unique_fd&& uf) {
+        fd_ = uf.fd_;
+        uf.fd_ = -1;
+        return *this;
+    }
+
+    explicit operator bool() const {
+        return fd_ != -1;
+    }
+
+  private:
+    int fd_;
+
+    // Non-copyable.
+    unique_fd(const unique_fd&) = delete;
+    unique_fd& operator=(const unique_fd&) = delete;
+};
+
+// Custom deleter for unique_file to avoid fclose(NULL).
+struct safe_fclose {
+    void operator()(FILE *fp) const {
+        if (fp) {
+            fclose(fp);
+        };
+    }
+};
+
+using unique_file = std::unique_ptr<FILE, safe_fclose>;
+
+#endif  // UNIQUE_FD_H