diff options
Diffstat (limited to 'toys/lsb')
| -rw-r--r-- | toys/lsb/mount.c | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/toys/lsb/mount.c b/toys/lsb/mount.c new file mode 100644 index 00000000..949fb05d --- /dev/null +++ b/toys/lsb/mount.c @@ -0,0 +1,325 @@ +/* mount.c - mount filesystems + * + * Copyright 2014 Rob Landley <rob@landley.net> + * + * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/mount.html + * Note: -hV is bad spec, haven't implemented -FsLU yet + * no mtab (/proc/mounts does it) so -n is NOP. + +USE_MOUNT(NEWTOY(mount, "?O:afnrvwt:o*[-rw]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT)) + +config MOUNT + bool "mount" + default y + help + usage: mount [-afFrsvw] [-t TYPE] [-o OPTIONS...] [[DEVICE] DIR] + + Mount new filesystem(s) on directories. With no arguments, display existing + mounts. + + -a mount all entries in /etc/fstab (with -t, only entries of that TYPE) + -O only mount -a entries that have this option + -f fake it (don't actually mount) + -r read only (same as -o ro) + -w read/write (default, same as -o rw) + -t specify filesystem type + -v verbose + + OPTIONS is a comma separated list of options, which can also be supplied + as --longopts. + + This mount autodetects loopback mounts (a file on a directory) and + bind mounts (file on file, directory on directory), so you don't need + to say --bind or --loop. You can also "mount -a /path" to mount everything + in /etc/fstab under /path, even if it's noauto. +*/ + +#define FOR_mount +#include "toys.h" + +GLOBALS( + struct arg_list *optlist; + char *type; + char *bigO; + + unsigned long flags; + char *opts; + int okuser; +) + +// TODO detect existing identical mount (procfs with different dev name?) +// TODO user, users, owner, group, nofail +// TODO -p (passfd) +// TODO -a -t notype,type2 +// TODO --subtree +// TODO --rbind, -R +// TODO make "mount --bind,ro old new" work (implicit -o remount) +// TODO mount -a +// 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) +{ + struct { + char *name; + long flags; + } opts[] = { + // NOPs (we autodetect --loop and --bind) + {"loop", 0}, {"bind", 0}, {"defaults", 0}, {"quiet", 0}, + {"user", 0}, {"nouser", 0}, // checked in fstab, ignored in -o +// {"noauto", 0}, {"swap", 0}, + {"ro", MS_RDONLY}, {"rw", ~MS_RDONLY}, + {"nosuid", MS_NOSUID}, {"suid", ~MS_NOSUID}, + {"nodev", MS_NODEV}, {"dev", ~MS_NODEV}, + {"noexec", MS_NOEXEC}, {"exec", ~MS_NOEXEC}, + {"sync", MS_SYNCHRONOUS}, {"async", ~MS_SYNCHRONOUS}, + {"noatime", MS_NOATIME}, {"atime", ~MS_NOATIME}, + {"nodiratime", MS_NODIRATIME}, {"diratime", ~MS_NODIRATIME}, + {"loud", ~MS_SILENT}, + {"shared", MS_SHARED}, {"rshared", MS_SHARED|MS_REC}, + {"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}, {"move", MS_MOVE}, + // mand dirsync rec iversion strictatime + }; + + if (new) for (;;) { + char *comma = strchr(new, ','); + int i; + + if (comma) *comma = 0; + + // If we recognize an option, apply flags + for (i = 0; i < ARRAY_LEN(opts); i++) if (!strcasecmp(opts[i].name, new)) { + long ll = opts[i].flags; + + if (ll < 0) flags &= ll; + else flags |= ll; + + break; + } + + // If we didn't recognize it, keep string version + if (more && i == ARRAY_LEN(opts)) { + i = *more ? strlen(*more) : 0; + *more = xrealloc(*more, i + strlen(new) + 2); + if (i) (*more)[i++] = ','; + strcpy(i+*more, new); + } + + if (!comma) break; + *comma = ','; + new = comma + 1; + } + + return flags; +} + +static void mount_filesystem(char *dev, char *dir, char *type, + unsigned long flags, char *opts) +{ + FILE *fp = 0; + int rc = EINVAL; + + if (toys.optflags & FLAG_f) return; + + if (getuid()) { + if (TT.okuser) TT.okuser = 0; + else { + error_msg("'%s' not user mountable in fstab"); + return; + } + } + + // Autodetect bind mount or filesystem type + + if (type && !strcmp(type, "auto")) type = 0; + if (flags & MS_MOVE) { + if (type) error_exit("--move with -t"); + } else if (!type) { + struct stat stdev, stdir; + + // file on file or dir on dir is a --bind mount. + 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"); + } else if (!strcmp(type, "ignore")) return; + else if (!strcmp(type, "swap")) + toys.exitval |= xpclose(xpopen((char *[]){"swapon", "--", dev, 0}, 0), 0); + + for (;;) { + char *buf = 0; + + // If type wasn't specified, try all of them in order. + if (fp) { + size_t i; + + if (getline(&buf, &i, fp)<0) break; + type = buf; + // skip nodev devices + if (!isspace(*type)) { + free(buf); + continue; + } + // trim whitespace + while (isspace(*type)) type++; + i = strlen(type); + if (i) type[i-1] = 0; + } + if (toys.optflags & FLAG_v) + printf("try '%s' type '%s' on '%s'\n", dev, type, dir); + 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; + } + free(buf); + + if (!rc) break; + + // 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); + + break; + } + if (fp) fclose(fp); +} + +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, *remount = 0; + +// 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++) { + 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 >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? + // This covers -a, -o remount, one argument, all user mounts + if ((toys.optflags & FLAG_a) || (dev && (!dir || getuid() || remount))) { + if (!remount) mtl = xgetmountlist("/etc/fstab"); + + for (mm = remount ? remount : mtl; mm; mm = (remount ? mm->prev : mm->next)) + { + 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) { + // "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, mm->dir)) continue; + if (dev && strcmp(dev, mm->device) && (dir || strcmp(dev, mm->dir))) + continue; + } + + // user only counts from fstab, not opts. + 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 from /proc/mounts + } else if (!dev) { + for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) { + char *s = 0; + + if (TT.type && strcmp(TT.type, mm->type)) continue; + if (*mm->device == '/') s = xabspath(mm->device, 0); + xprintf("%s on %s type %s (%s)\n", + s ? s : mm->device, mm->dir, mm->type, mm->opts); + free(s); + } + + // two arguments + } else { + char *more = 0; + + mount_filesystem(dev, dir, TT.type, flag_opts(opts, flags, &more), more); + if (CFG_TOYBOX_FREE) free(more); + } +} |