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-rw-r--r--toys/pending/mount.c58
1 files changed, 35 insertions, 23 deletions
diff --git a/toys/pending/mount.c b/toys/pending/mount.c
index 3cec481b..fc4406c1 100644
--- a/toys/pending/mount.c
+++ b/toys/pending/mount.c
@@ -66,7 +66,7 @@ static long parse_opts(char *new, long flags, char **more)
{"slave", MS_SLAVE}, {"rslave", MS_SLAVE|MS_REC},
{"private", MS_PRIVATE}, {"rprivate", MS_SLAVE|MS_REC},
{"unbindable", MS_UNBINDABLE}, {"runbindable", MS_UNBINDABLE|MS_REC},
- {"remount", MS_REMOUNT}, {"bind", MS_BIND}, {"move", MS_MOVE},
+ {"remount", MS_REMOUNT}, {"move", MS_MOVE},
// mand dirsync rec iversion strictatime
};
@@ -110,31 +110,16 @@ static void mount_filesystem(char *dev, char *dir, char *type,
if (toys.optflags & FLAG_f) return;
+ // Autodetect bind mount or filesystem type
if (!type) {
struct stat stdev, stdir;
- if (!stat(dev, &stdev) && !stat(dir, &stdir)) {
- if (S_ISREG(stdev.st_mode)) {
- // Loopback mount?
- if (S_ISDIR(stdir.st_mode)) {
- char *losetup[] = {"losetup", "-fs", dev, 0};
- int pipes[2], len;
- pid_t pid;
-
- if (flags & MS_RDONLY) losetup[1] = "-fsr";
- pid = xpopen(losetup, pipes);
- len = readall(pipes[1], toybuf, sizeof(toybuf)-1);
- if (!xpclose(pid, pipes) && len > 1) {
- if (toybuf[len-1] == '\n') --len;
- toybuf[len] = 0;
- dev = toybuf;
- } else error_msg("losetup failed %d", len);
- } else if (S_ISREG(stdir.st_mode)) flags |= MS_BIND;
- } else if (S_ISDIR(stdev.st_mode) && S_ISDIR(stdir.st_mode))
- flags |= MS_BIND;
- }
-
- if (!(flags & MS_BIND)) fp = xfopen("/proc/filesystems", "r");
+ if (!stat(dev, &stdev) && !stat(dir, &stdir)
+ && ((S_ISREG(stdev.st_mode) && S_ISREG(stdir.st_mode))
+ || (S_ISDIR(stdev.st_mode) && S_ISDIR(stdir.st_mode))))
+ {
+ flags |= MS_BIND;
+ } else fp = xfopen("/proc/filesystems", "r");
}
for (;;) {
@@ -159,6 +144,33 @@ static void mount_filesystem(char *dev, char *dir, char *type,
if (toys.optflags & FLAG_v)
printf("try '%s' type '%s' on '%s'\n", dev, type, dir);
rc = mount(dev, dir, type, flags, opts);
+
+ // Looking for bind mounts in autodetect above isn't good enough because
+ // "mount -t ext2 fs.img dir" is valid, but if you _do_ accept bind mounts
+ // with -t how do you tell "-t cifs" isn't looking for a block device if
+ // it's not in /proc/filesystems yet because the module that won't be
+ // loaded until you try the mount, and if you can't then DEVICE
+ // existing as a file would cause a false positive loopback mount.
+ //
+ // Solution: try mount, let the kernel tell us it wanted a block device,
+ // do the loopback setup and retry the mount.
+ if (rc && errno == ENOTBLK) {
+ char *losetup[] = {"losetup", "-fs", dev, 0};
+ int pipes[2], len;
+ pid_t pid;
+
+ if (flags & MS_RDONLY) losetup[1] = "-fsr";
+ pid = xpopen(losetup, pipes);
+ len = readall(pipes[1], toybuf, sizeof(toybuf)-1);
+ if (!xpclose(pid, pipes) && len > 1) {
+ if (toybuf[len-1] == '\n') --len;
+ toybuf[len] = 0;
+ dev = toybuf;
+
+ continue;
+ } else error_msg("losetup failed %d", len);
+ }
+
if (!fp || (rc && errno != EINVAL)) break;
free(buf);
}