Work in progress snapshot of mount, with fallout to umount. (Not done yet.)

1 files changed, 96 insertions, 35 deletions

diff --git a/toys/pending/mount.c b/toys/pending/mount.c
index fc4406c1..c816a192 100644
--- a/toys/pending/mount.c
+++ b/toys/pending/mount.c
@@ -6,7 +6,7 @@
  * Note: -hV is bad spec, haven't implemented -FsLU yet
  * no mtab (/proc/mounts does it) so -n is NOP.
 
-USE_MOUNT(NEWTOY(mount, "?>2afnrvwt:o*[-rw]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
+USE_MOUNT(NEWTOY(mount, "?O:afnrvwt:o*[-rw]", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_STAYROOT))
 
 config MOUNT
   bool "mount"
@@ -18,6 +18,7 @@ config MOUNT
     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)
@@ -29,7 +30,8 @@ config MOUNT
 
     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.
+    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
@@ -38,14 +40,27 @@ config MOUNT
 GLOBALS(
   struct arg_list *optlist;
   char *type;
+  char *bigO;
 
   unsigned long flags;
   char *opts;
+  int okuser;
 )
 
-// Strip flags out of comma separated list of options.
-// Return flags, 
-static long parse_opts(char *new, long flags, char **more)
+// 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
+
+// Strip flags out of comma separated list of options, return flags,.
+static long flag_opts(char *new, long flags, char **more)
 {
   struct {
     char *name;
@@ -53,6 +68,7 @@ static long parse_opts(char *new, long flags, char **more)
   } 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},
@@ -70,7 +86,7 @@ static long parse_opts(char *new, long flags, char **more)
     // mand dirsync rec iversion strictatime
   };
 
-  for (;;) {
+  if (new) for (;;) {
     char *comma = strchr(new, ',');
     int i;
 
@@ -110,17 +126,28 @@ static void mount_filesystem(char *dev, char *dir, char *type,
 
   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) {
+  if (!type || !strcmp(type, "auto")) {
     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;
@@ -145,15 +172,17 @@ static void mount_filesystem(char *dev, char *dir, char *type,
       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.
+    // 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 mount, let the kernel tell us it wanted a block device,
-    // do the loopback setup and retry the mount.
+    // 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;
@@ -181,39 +210,71 @@ static void mount_filesystem(char *dev, char *dir, char *type,
 
 void mount_main(void)
 {
+  char *opts = 0, *dev = 0, *dir = 0, **ss;
   long flags = MS_SILENT;
   struct arg_list *o;
-  char *opts = 0;
-
-  if (toys.optflags & FLAG_a) {
-    fprintf(stderr, "not yet\n");
-    return;
-  }
+  struct mtab_list *mtl, *mm;
 
+// 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;
-  for (o = TT.optlist; o; o = o->next)
-    flags = parse_opts(o->arg, flags, &opts);
 
-  // show mounts
-  if (!toys.optc) {
-    struct mtab_list *mtl = xgetmountlist(0), *m;
+  // 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;
+    // same message as lib/args.c ">2" which we can't use because --opts count
+    else error_exit("Max 2 arguments\n");
+  }
 
-    for (mtl = xgetmountlist(0); mtl && (m = dlist_pop(&mtl)); free(m)) {
+  if ((toys.optflags & FLAG_a) && dir) error_exit("-a with DIR");
+
+  // 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))
+    {
+      char *aopts = opts ? xstrdup(opts) : 0;
+      int aflags;
+
+      if (toys.optflags & FLAG_a) {
+        if (!mountlist_istype(mtl,TT.type) || !comma_scanall(mtl->opts,TT.bigO))
+          continue;
+        
+      } else {
+        if (dir && strcmp(dir, mtl->dir)) continue;
+        if (dev && strcmp(dev, mtl->device) && (dir || strcmp(dev, mtl->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);
+
+      free(aopts);
+    }
+  }
+
+  // show mounts
+  if (!dir) {
+    for (mtl = xgetmountlist(0); mtl && (mm = dlist_pop(&mtl)); free(mm)) {
       char *s = 0;
 
-      if (TT.type && strcmp(TT.type, m->type)) continue;
-      if (*m->device == '/') s = xabspath(m->device, 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 : m->device, m->dir, m->type, m->opts);
+              s ? s : mm->device, mm->dir, mm->type, mm->opts);
       free(s);
     }
 
   // one argument: from fstab, remount, subtree
-  } else if (toys.optc == 1) {
-    fprintf(stderr, "not yet\n");
+  } else if (!dev) {
+    fprintf(stderr, "not yet\n"); // TODO
     return;
   // two arguments
-  } else mount_filesystem(toys.optargs[0], toys.optargs[1], TT.type,
-                          flags, opts ? opts : "");
+  } else mount_filesystem(dev, dir, TT.type, flags, opts);
 }