diff options
| -rw-r--r-- | toys/pending/mount.c | 160 |
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); + } } |