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-rw-r--r--toys/pending/mount.c160
1 files changed, 100 insertions, 60 deletions
diff --git a/toys/pending/mount.c b/toys/pending/mount.c
index c816a192..e279db37 100644
--- a/toys/pending/mount.c
+++ b/toys/pending/mount.c
@@ -58,6 +58,10 @@ GLOBALS(
// TODO mount -o remount
// TODO fstab: lookup default options for mount
// TODO implement -v
+// TODO "mount -a -o remount,ro" should detect overmounts
+// TODO work out how that differs from "mount -ar"
+// TODO what if you --bind mount a block device somewhere (file, dir, dev)
+// TODO "touch servername; mount -t cifs servername path"
// Strip flags out of comma separated list of options, return flags,.
static long flag_opts(char *new, long flags, char **more)
@@ -170,38 +174,47 @@ 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);
-
- // Trying to autodetect loop mounts like bind mounts above (file on dir)
- // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if
- // you _do_ accept loop 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 (so "touch servername" becomes a potential
- // denial of service attack...)
- //
- // Solution: try the mount, let the kernel tell us it wanted a block device,
- // then 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);
+ for (;;) {
+ rc = mount(dev, dir, type, flags, opts);
+ if ((rc != EACCES && rc != EROFS) || (flags & MS_RDONLY)) break;
+ fprintf(stderr, "'%s' is read-only", dev);
+ flags |= MS_RDONLY;
}
-
- if (!fp || (rc && errno != EINVAL)) break;
free(buf);
+
+ if (rc) {
+ // Trying to autodetect loop mounts like bind mounts above (file on dir)
+ // isn't good enough because "mount -t ext2 fs.img dir" is valid, but if
+ // you _do_ accept loop 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 (so "touch servername" becomes a potential
+ // denial of service attack...)
+ //
+ // Solution: try the mount, let the kernel tell us it wanted a block
+ // device, then do the loopback setup and retry the mount.
+
+ if (fp && errno == EINVAL) continue;;
+
+ if (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);
+ rc = xpclose(pid, pipes);
+ if (!rc && len > 1) {
+ if (toybuf[len-1] == '\n') --len;
+ toybuf[len] = 0;
+ dev = toybuf;
+
+ continue;
+ } else error_msg("losetup failed %d", rc);
+ } else perror_msg("'%s'->'%s'", dev, dir);
+ }
}
if (fp) fclose(fp);
@@ -213,54 +226,80 @@ void mount_main(void)
char *opts = 0, *dev = 0, *dir = 0, **ss;
long flags = MS_SILENT;
struct arg_list *o;
- struct mtab_list *mtl, *mm;
+ struct mtab_list *mtl, *mm, *remount = 0;
-// TODO what do mount -aw and -ar do?
- for (o = TT.optlist; o; o = o->next) flags = flag_opts(o->arg, flags, &opts);
- if (toys.optflags & FLAG_r) flags |= MS_RDONLY;
- if (toys.optflags & FLAG_w) flags &= ~MS_RDONLY;
+// remount
+// - overmounts
+// shared subtree
+// -o parsed after fstab options
+// test if mountpoint already exists (-o noremount?)
+
+ // First pass; just accumulate string, don't parse flags yet. (This is so
+ // we can modify fstab entries with -a, or mtab with remount.)
+ for (o = TT.optlist; o; o = o->next) comma_collate(&opts, o->arg);
+ if (toys.optflags & FLAG_r) comma_collate(&opts, "ro");
+ if (toys.optflags & FLAG_w) comma_collate(&opts, "rw");
// Treat each --option as -o option
for (ss = toys.optargs; *ss; ss++) {
- if ((*ss)[0] && (*ss)[1]) flags = flag_opts(2+*ss, flags, &opts);
- else if (!dev) dev = *ss;
- else if (!dir) dir = *ss;
+ char *sss = *ss;
+
+ // If you realy, really want to mount a file named "--", we support it.
+ if (sss[0]=='-' && sss[1]=='-' && sss[2]) comma_collate(&opts, sss+2);
+ else if (!dev) dev = sss;
+ else if (!dir) dir = sss;
// same message as lib/args.c ">2" which we can't use because --opts count
else error_exit("Max 2 arguments\n");
}
- if ((toys.optflags & FLAG_a) && dir) error_exit("-a with DIR");
+ if ((toys.optflags & FLAG_a) && dir) error_exit("-a with >1 arg");
+
+ // For remount we need _last_ match (in case of overmounts), so traverse
+ // in reverse order.
+ if (comma_scan(opts, "remount", 1))
+ remount = dlist_terminate(mtl = xgetmountlist("/proc/mounts"));
// Do we need to do an /etc/fstab trawl?
- if (toys.optflags & FLAG_a || !dir || getpid()) {
- for (mtl = xgetmountlist("/etc/fstab"); mtl && (mm = dlist_pop(&mtl));
- free(mm))
+ // This covers -a, -o remount, one argument, all user mounts
+ if ((toys.optflags & FLAG_a) || remount || !dir || getuid()) {
+ if (!remount) mtl = xgetmountlist("/etc/fstab");
+ for (mm = remount ? remount : mtl; mm; mm = (remount ? mm->prev : mm->next))
{
- char *aopts = opts ? xstrdup(opts) : 0;
- int aflags;
+ int aflags, noauto, len;
+ char *aopts = 0;
+ // Check for noauto and get it out of the option list. (Unknown options
+ // that make it to the kernel give filesystem drivers indigestion.)
+ noauto = comma_scan(mm->opts, "noauto", 1);
if (toys.optflags & FLAG_a) {
- if (!mountlist_istype(mtl,TT.type) || !comma_scanall(mtl->opts,TT.bigO))
+ // "mount -a /path" to mount all entries under /path
+ if (dev) {
+ len = strlen(dev);
+ if (strncmp(dev, mm->dir, len)
+ || (mm->dir[len] && mm->dir[len] != '/')) continue;
+ } else if (noauto) continue; // never present in the remount case
+ if (!mountlist_istype(mm,TT.type) || !comma_scanall(mm->opts,TT.bigO))
continue;
-
} else {
- if (dir && strcmp(dir, mtl->dir)) continue;
- if (dev && strcmp(dev, mtl->device) && (dir || strcmp(dev, mtl->dir)))
+ if (dir && strcmp(dir, mm->dir)) continue;
+ if (dev && strcmp(dev, mm->device) && (dir || strcmp(dev, mm->dir)))
continue;
}
// user only counts from fstab, not opts.
- if (comma_scan(mtl->opts, "user", 1)) TT.okuser = 1;
- aflags = flag_opts(mtl->opts, flags, &aopts);
-
- mount_filesystem(mtl->device, mtl->dir, mtl->type, aflags, aopts);
+ TT.okuser = comma_scan(mm->opts, "user", 1);
+ aflags = flag_opts(mm->opts, flags, &aopts);
+ aflags = flag_opts(opts, aflags, &aopts);
+ mount_filesystem(mm->device, mm->dir, mm->type, aflags, aopts);
free(aopts);
+
+ if (!(toys.optflags & FLAG_a)) break;
}
- }
+ if (CFG_TOYBOX_FREE) llist_traverse(mtl, free);
- // show mounts
- if (!dir) {
+ // show mounts from /proc/mounts
+ } else if (!dev) {
for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) {
char *s = 0;
@@ -271,10 +310,11 @@ void mount_main(void)
free(s);
}
- // one argument: from fstab, remount, subtree
- } else if (!dev) {
- fprintf(stderr, "not yet\n"); // TODO
- return;
// two arguments
- } else mount_filesystem(dev, dir, TT.type, flags, opts);
+ } else {
+ char *more = 0;
+
+ mount_filesystem(dev, dir, TT.type, flag_opts(opts, flags, &more), more);
+ if (CFG_TOYBOX_FREE) free(more);
+ }
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-17 23:00:33 +0000