summaryrefslogtreecommitdiffstats
path: root/fuse/mount_util.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--fuse/mount_util.c350
1 files changed, 350 insertions, 0 deletions
diff --git a/fuse/mount_util.c b/fuse/mount_util.c
new file mode 100644
index 000000000..bfd801fff
--- /dev/null
+++ b/fuse/mount_util.c
@@ -0,0 +1,350 @@
+/*
+ FUSE: Filesystem in Userspace
+ Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
+
+ This program can be distributed under the terms of the GNU LGPLv2.
+ See the file COPYING.LIB.
+*/
+
+#include "mount_util.h"
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <signal.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <mntent.h>
+#include <paths.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/mount.h>
+#include <sys/param.h>
+
+#ifdef __NetBSD__
+#define umount2(mnt, flags) unmount(mnt, (flags == 2) ? MNT_FORCE : 0)
+#define mtab_needs_update(mnt) 0
+#else
+static int mtab_needs_update(const char *mnt)
+{
+ int res;
+ struct stat stbuf;
+
+ /* If mtab is within new mount, don't touch it */
+ if (strncmp(mnt, _PATH_MOUNTED, strlen(mnt)) == 0 &&
+ _PATH_MOUNTED[strlen(mnt)] == '/')
+ return 0;
+
+ /*
+ * Skip mtab update if /etc/mtab:
+ *
+ * - doesn't exist,
+ * - is a symlink,
+ * - is on a read-only filesystem.
+ */
+ res = lstat(_PATH_MOUNTED, &stbuf);
+ if (res == -1) {
+ if (errno == ENOENT)
+ return 0;
+ } else {
+ uid_t ruid;
+ int err;
+
+ if (S_ISLNK(stbuf.st_mode))
+ return 0;
+
+ ruid = getuid();
+ if (ruid != 0)
+ setreuid(0, -1);
+
+ res = access(_PATH_MOUNTED, W_OK);
+ err = (res == -1) ? errno : 0;
+ if (ruid != 0)
+ setreuid(ruid, -1);
+
+ if (err == EROFS)
+ return 0;
+ }
+
+ return 1;
+}
+#endif /* __NetBSD__ */
+
+static int add_mount(const char *progname, const char *fsname,
+ const char *mnt, const char *type, const char *opts)
+{
+ int res;
+ int status;
+ sigset_t blockmask;
+ sigset_t oldmask;
+
+ sigemptyset(&blockmask);
+ sigaddset(&blockmask, SIGCHLD);
+ res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
+ if (res == -1) {
+ fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno));
+ return -1;
+ }
+
+ res = fork();
+ if (res == -1) {
+ fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno));
+ goto out_restore;
+ }
+ if (res == 0) {
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+ setuid(geteuid());
+ execl("/bin/mount", "/bin/mount", "--no-canonicalize", "-i",
+ "-f", "-t", type, "-o", opts, fsname, mnt, NULL);
+ fprintf(stderr, "%s: failed to execute /bin/mount: %s\n",
+ progname, strerror(errno));
+ exit(1);
+ }
+ res = waitpid(res, &status, 0);
+ if (res == -1)
+ fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno));
+
+ if (status != 0)
+ res = -1;
+
+ out_restore:
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+
+ return res;
+}
+
+int fuse_mnt_add_mount(const char *progname, const char *fsname,
+ const char *mnt, const char *type, const char *opts)
+{
+ if (!mtab_needs_update(mnt))
+ return 0;
+
+ return add_mount(progname, fsname, mnt, type, opts);
+}
+
+static int exec_umount(const char *progname, const char *rel_mnt, int lazy)
+{
+ int res;
+ int status;
+ sigset_t blockmask;
+ sigset_t oldmask;
+
+ sigemptyset(&blockmask);
+ sigaddset(&blockmask, SIGCHLD);
+ res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
+ if (res == -1) {
+ fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno));
+ return -1;
+ }
+
+ res = fork();
+ if (res == -1) {
+ fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno));
+ goto out_restore;
+ }
+ if (res == 0) {
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+ setuid(geteuid());
+ execl("/bin/umount", "/bin/umount", "-i", rel_mnt,
+ lazy ? "-l" : NULL, NULL);
+ fprintf(stderr, "%s: failed to execute /bin/umount: %s\n",
+ progname, strerror(errno));
+ exit(1);
+ }
+ res = waitpid(res, &status, 0);
+ if (res == -1)
+ fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno));
+
+ if (status != 0) {
+ res = -1;
+ }
+
+ out_restore:
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+ return res;
+
+}
+
+int fuse_mnt_umount(const char *progname, const char *abs_mnt,
+ const char *rel_mnt, int lazy)
+{
+ int res;
+
+ if (!mtab_needs_update(abs_mnt)) {
+ res = umount2(rel_mnt, lazy ? 2 : 0);
+ if (res == -1)
+ fprintf(stderr, "%s: failed to unmount %s: %s\n",
+ progname, abs_mnt, strerror(errno));
+ return res;
+ }
+
+ return exec_umount(progname, rel_mnt, lazy);
+}
+
+static int remove_mount(const char *progname, const char *mnt)
+{
+ int res;
+ int status;
+ sigset_t blockmask;
+ sigset_t oldmask;
+
+ sigemptyset(&blockmask);
+ sigaddset(&blockmask, SIGCHLD);
+ res = sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
+ if (res == -1) {
+ fprintf(stderr, "%s: sigprocmask: %s\n", progname, strerror(errno));
+ return -1;
+ }
+
+ res = fork();
+ if (res == -1) {
+ fprintf(stderr, "%s: fork: %s\n", progname, strerror(errno));
+ goto out_restore;
+ }
+ if (res == 0) {
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+ setuid(geteuid());
+ execl("/bin/umount", "/bin/umount", "--no-canonicalize", "-i",
+ "--fake", mnt, NULL);
+ fprintf(stderr, "%s: failed to execute /bin/umount: %s\n",
+ progname, strerror(errno));
+ exit(1);
+ }
+ res = waitpid(res, &status, 0);
+ if (res == -1)
+ fprintf(stderr, "%s: waitpid: %s\n", progname, strerror(errno));
+
+ if (status != 0)
+ res = -1;
+
+ out_restore:
+ sigprocmask(SIG_SETMASK, &oldmask, NULL);
+ return res;
+}
+
+int fuse_mnt_remove_mount(const char *progname, const char *mnt)
+{
+ if (!mtab_needs_update(mnt))
+ return 0;
+
+ return remove_mount(progname, mnt);
+}
+
+char *fuse_mnt_resolve_path(const char *progname, const char *orig)
+{
+ char buf[PATH_MAX];
+ char *copy;
+ char *dst;
+ char *end;
+ char *lastcomp;
+ const char *toresolv;
+
+ if (!orig[0]) {
+ fprintf(stderr, "%s: invalid mountpoint '%s'\n", progname,
+ orig);
+ return NULL;
+ }
+
+ copy = strdup(orig);
+ if (copy == NULL) {
+ fprintf(stderr, "%s: failed to allocate memory\n", progname);
+ return NULL;
+ }
+
+ toresolv = copy;
+ lastcomp = NULL;
+ for (end = copy + strlen(copy) - 1; end > copy && *end == '/'; end --);
+ if (end[0] != '/') {
+ char *tmp;
+ end[1] = '\0';
+ tmp = strrchr(copy, '/');
+ if (tmp == NULL) {
+ lastcomp = copy;
+ toresolv = ".";
+ } else {
+ lastcomp = tmp + 1;
+ if (tmp == copy)
+ toresolv = "/";
+ }
+ if (strcmp(lastcomp, ".") == 0 || strcmp(lastcomp, "..") == 0) {
+ lastcomp = NULL;
+ toresolv = copy;
+ }
+ else if (tmp)
+ tmp[0] = '\0';
+ }
+ if (realpath(toresolv, buf) == NULL) {
+ fprintf(stderr, "%s: bad mount point %s: %s\n", progname, orig,
+ strerror(errno));
+ free(copy);
+ return NULL;
+ }
+ if (lastcomp == NULL)
+ dst = strdup(buf);
+ else {
+ dst = (char *) malloc(strlen(buf) + 1 + strlen(lastcomp) + 1);
+ if (dst) {
+ unsigned buflen = strlen(buf);
+ if (buflen && buf[buflen-1] == '/')
+ sprintf(dst, "%s%s", buf, lastcomp);
+ else
+ sprintf(dst, "%s/%s", buf, lastcomp);
+ }
+ }
+ free(copy);
+ if (dst == NULL)
+ fprintf(stderr, "%s: failed to allocate memory\n", progname);
+ return dst;
+}
+
+int fuse_mnt_check_empty(const char *progname, const char *mnt,
+ mode_t rootmode, off64_t rootsize)
+{
+ int isempty = 1;
+
+ if (S_ISDIR(rootmode)) {
+ struct dirent *ent;
+ DIR *dp = opendir(mnt);
+ if (dp == NULL) {
+ fprintf(stderr,
+ "%s: failed to open mountpoint for reading: %s\n",
+ progname, strerror(errno));
+ return -1;
+ }
+ while ((ent = readdir(dp)) != NULL) {
+ if (strcmp(ent->d_name, ".") != 0 &&
+ strcmp(ent->d_name, "..") != 0) {
+ isempty = 0;
+ break;
+ }
+ }
+ closedir(dp);
+ } else if (rootsize)
+ isempty = 0;
+
+ if (!isempty) {
+ fprintf(stderr, "%s: mountpoint is not empty\n", progname);
+ fprintf(stderr, "%s: if you are sure this is safe, use the 'nonempty' mount option\n", progname);
+ return -1;
+ }
+ return 0;
+}
+
+int fuse_mnt_check_fuseblk(void)
+{
+ char buf[256];
+ FILE *f = fopen("/proc/filesystems", "r");
+ if (!f)
+ return 1;
+
+ while (fgets(buf, sizeof(buf), f))
+ if (strstr(buf, "fuseblk\n")) {
+ fclose(f);
+ return 1;
+ }
+
+ fclose(f);
+ return 0;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-05 00:06:27 +0100