mount: code shrink without logic changes. Added a comment
authorDenis Vlasenko <vda.linux@googlemail.com>
Tue, 24 Jun 2008 18:59:59 +0000 (18:59 -0000)
committerDenis Vlasenko <vda.linux@googlemail.com>
Tue, 24 Jun 2008 18:59:59 +0000 (18:59 -0000)
on possible mismatch with util-linux in -o remount handling.

function                                             old     new   delta
mount_main                                           995     953     -42
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-42)             Total: -42 bytes

util-linux/mount.c

index de05580247ba38db516012f72a8cbaacad8e3436..61ad2352871a901f68af7644d879a50bab3d25a5 100644 (file)
@@ -407,7 +407,7 @@ static int mount_it_now(struct mntent *mp, long vfsflags, char *filteropts)
                                vfsflags, filteropts);
 
                // If mount failed, try
-               // helper program <mnt_type>
+               // helper program mount.<mnt_type>
                if (ENABLE_FEATURE_MOUNT_HELPERS && rc) {
                        char *args[6];
                        int errno_save = errno;
@@ -1727,11 +1727,11 @@ static int singlemount(struct mntent *mp, int ignore_busy)
 static const char must_be_root[] ALIGN1 = "you must be root";
 
 int mount_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int mount_main(int argc, char **argv)
+int mount_main(int argc ATTRIBUTE_UNUSED, char **argv)
 {
        char *cmdopts = xstrdup("");
        char *fstype = NULL;
-       char *storage_path = NULL;
+       char *storage_path;
        char *opt_o;
        const char *fstabname;
        FILE *fstab;
@@ -1740,43 +1740,35 @@ int mount_main(int argc, char **argv)
        struct mntent mtpair[2], *mtcur = mtpair;
        SKIP_DESKTOP(const int nonroot = 0;)
 
-       USE_DESKTOP( int nonroot = ) sanitize_env_if_suid();
+       USE_DESKTOP(int nonroot = ) sanitize_env_if_suid();
 
        // Parse long options, like --bind and --move.  Note that -o option
        // and --option are synonymous.  Yes, this means --remount,rw works.
-
-       for (i = j = 0; i < argc; i++) {
-               if (argv[i][0] == '-' && argv[i][1] == '-') {
-                       append_mount_options(&cmdopts, argv[i]+2);
-               } else argv[j++] = argv[i];
+       for (i = j = 1; argv[i]; i++) {
+               if (argv[i][0] == '-' && argv[i][1] == '-')
+                       append_mount_options(&cmdopts, argv[i] + 2);
+               else
+                       argv[j++] = argv[i];
        }
        argv[j] = NULL;
-       argc = j;
 
        // Parse remaining options
-
-#if ENABLE_FEATURE_MOUNT_VERBOSE
-       opt_complementary = "vv"; // -v is a counter
-#endif
+       // Max 2 params; -v is a counter
+       opt_complementary = "?2" USE_FEATURE_MOUNT_VERBOSE(":vv");
        opt = getopt32(argv, OPTION_STR, &opt_o, &fstype
                        USE_FEATURE_MOUNT_VERBOSE(, &verbose));
        if (opt & OPT_o) append_mount_options(&cmdopts, opt_o); // -o
        if (opt & OPT_r) append_mount_options(&cmdopts, "ro"); // -r
        if (opt & OPT_w) append_mount_options(&cmdopts, "rw"); // -w
        argv += optind;
-       argc -= optind;
-
-       // Three or more non-option arguments?  Die with a usage message.
-
-       if (argc > 2) bb_show_usage();
 
        // If we have no arguments, show currently mounted filesystems
-
-       if (!argc) {
+       if (!argv[0]) {
                if (!(opt & OPT_a)) {
                        FILE *mountTable = setmntent(bb_path_mtab_file, "r");
 
-                       if (!mountTable) bb_error_msg_and_die("no %s", bb_path_mtab_file);
+                       if (!mountTable)
+                               bb_error_msg_and_die("no %s", bb_path_mtab_file);
 
                        while (getmntent_r(mountTable, &mtpair[0], getmntent_buf,
                                                                GETMNTENT_BUFSIZE))
@@ -1790,152 +1782,148 @@ int mount_main(int argc, char **argv)
                                                        mtpair->mnt_dir, mtpair->mnt_type,
                                                        mtpair->mnt_opts);
                        }
-                       if (ENABLE_FEATURE_CLEAN_UP) endmntent(mountTable);
+                       if (ENABLE_FEATURE_CLEAN_UP)
+                               endmntent(mountTable);
                        return EXIT_SUCCESS;
                }
-       } else storage_path = bb_simplify_path(argv[0]);
-
-       // When we have two arguments, the second is the directory and we can
-       // skip looking at fstab entirely.  We can always abspath() the directory
-       // argument when we get it.
-
-       if (argc == 2) {
-               if (nonroot)
-                       bb_error_msg_and_die(must_be_root);
-               mtpair->mnt_fsname = argv[0];
-               mtpair->mnt_dir = argv[1];
-               mtpair->mnt_type = fstype;
-               mtpair->mnt_opts = cmdopts;
-               if (ENABLE_FEATURE_MOUNT_LABEL) {
-                       resolve_mount_spec(&mtpair->mnt_fsname);
+               storage_path = NULL;
+       } else {
+               // When we have two arguments, the second is the directory and we can
+               // skip looking at fstab entirely.  We can always abspath() the directory
+               // argument when we get it.
+               if (argv[1]) {
+                       if (nonroot)
+                               bb_error_msg_and_die(must_be_root);
+                       mtpair->mnt_fsname = argv[0];
+                       mtpair->mnt_dir = argv[1];
+                       mtpair->mnt_type = fstype;
+                       mtpair->mnt_opts = cmdopts;
+                       if (ENABLE_FEATURE_MOUNT_LABEL) {
+                               resolve_mount_spec(&mtpair->mnt_fsname);
+                       }
+                       rc = singlemount(mtpair, 0);
+                       return rc;
                }
-               rc = singlemount(mtpair, 0);
-               goto clean_up;
+               storage_path = bb_simplify_path(argv[0]); // malloced
        }
 
+       // Past this point, we are handling either "mount -a [opts]"
+       // or "mount [opts] single_param"
+
        i = parse_mount_options(cmdopts, 0); // FIXME: should be "long", not "int"
        if (nonroot && (i & ~MS_SILENT)) // Non-root users cannot specify flags
                bb_error_msg_and_die(must_be_root);
 
        // If we have a shared subtree flag, don't worry about fstab or mtab.
-
        if (ENABLE_FEATURE_MOUNT_FLAGS
         && (i & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
        ) {
-               rc = verbose_mount("", argv[0], "", i, "");
-               if (rc) bb_simple_perror_msg_and_die(argv[0]);
-               goto clean_up;
+               rc = verbose_mount(/*source:*/ "", /*target:*/ argv[0],
+                               /*type:*/ "", /*flags:*/ i, /*data:*/ "");
+               if (rc)
+                       bb_simple_perror_msg_and_die(argv[0]);
+               return rc;
        }
 
        // Open either fstab or mtab
-
        fstabname = "/etc/fstab";
        if (i & MS_REMOUNT) {
+               // WARNING. I am not sure this matches util-linux's
+               // behavior. It's possible util-linux does not
+               // take -o opts from mtab (takes only mount source).
                fstabname = bb_path_mtab_file;
        }
        fstab = setmntent(fstabname, "r");
        if (!fstab)
                bb_perror_msg_and_die("cannot read %s", fstabname);
 
-       // Loop through entries until we find what we're looking for.
-
+       // Loop through entries until we find what we're looking for
        memset(mtpair, 0, sizeof(mtpair));
        for (;;) {
-               struct mntent *mtnext = (mtcur==mtpair ? mtpair+1 : mtpair);
+               struct mntent *mtother = (mtcur==mtpair ? mtpair+1 : mtpair);
 
                // Get next fstab entry
-
                if (!getmntent_r(fstab, mtcur, getmntent_buf
                                        + (mtcur==mtpair ? GETMNTENT_BUFSIZE/2 : 0),
-                               GETMNTENT_BUFSIZE/2))
-               {
-                       // Were we looking for something specific?
-
-                       if (argc) {
-
-                               // If we didn't find anything, complain.
-
-                               if (!mtnext->mnt_fsname)
-                                       bb_error_msg_and_die("can't find %s in %s",
-                                               argv[0], fstabname);
-
-                               mtcur = mtnext;
-                               if (nonroot) {
-                                       // fstab must have "users" or "user"
-                                       if (!(parse_mount_options(mtcur->mnt_opts, 0) & MOUNT_USERS))
-                                               bb_error_msg_and_die(must_be_root);
-                               }
-
-                               // Mount the last thing we found.
-
-                               mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
-                               append_mount_options(&(mtcur->mnt_opts), cmdopts);
-                               if (ENABLE_FEATURE_MOUNT_LABEL) {
-                                       resolve_mount_spec(&mtpair->mnt_fsname);
-                               }
-                               rc = singlemount(mtcur, 0);
-                               free(mtcur->mnt_opts);
-                       }
-                       goto clean_up;
+                               GETMNTENT_BUFSIZE/2)
+               ) { // End of fstab/mtab is reached
+                       mtcur = mtother; // the thing we found last time
+                       break;
                }
 
-               /* If we're trying to mount something specific and this isn't it,
-                * skip it.  Note we must match both the exact text in fstab (ala
-                * "proc") or a full path from root */
-
-               if (argc) {
+               // If we're trying to mount something specific and this isn't it,
+               // skip it.  Note we must match the exact text in fstab (ala
+               // "proc") or a full path from root
+               if (argv[0]) {
 
                        // Is this what we're looking for?
-
                        if (strcmp(argv[0], mtcur->mnt_fsname) &&
                           strcmp(storage_path, mtcur->mnt_fsname) &&
                           strcmp(argv[0], mtcur->mnt_dir) &&
                           strcmp(storage_path, mtcur->mnt_dir)) continue;
 
-                       // Remember this entry.  Something later may have overmounted
-                       // it, and we want the _last_ match.
-
-                       mtcur = mtnext;
-
-               // If we're mounting all.
+                       // Remember this entry.  Something later may have
+                       // overmounted it, and we want the _last_ match.
+                       mtcur = mtother;
 
+               // If we're mounting all
                } else {
                        // Do we need to match a filesystem type?
                        if (fstype && match_fstype(mtcur, fstype))
                                continue;
 
                        // Skip noauto and swap anyway.
-
                        if (parse_mount_options(mtcur->mnt_opts, 0) & (MOUNT_NOAUTO | MOUNT_SWAP))
                                continue;
 
                        // No, mount -a won't mount anything,
-                       // even user mounts, for mere humans.
-
+                       // even user mounts, for mere humans
                        if (nonroot)
                                bb_error_msg_and_die(must_be_root);
 
-                       // Mount this thing.
+                       // Mount this thing
                        if (ENABLE_FEATURE_MOUNT_LABEL)
                                resolve_mount_spec(&mtpair->mnt_fsname);
 
                        // NFS mounts want this to be xrealloc-able
                        mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
                        if (singlemount(mtcur, 1)) {
-                               /* Count number of failed mounts */
+                               // Count number of failed mounts
                                rc++;
                        }
                        free(mtcur->mnt_opts);
                }
        }
-       if (ENABLE_FEATURE_CLEAN_UP) endmntent(fstab);
 
- clean_up:
+       // End of fstab/mtab is reached.
+       // Were we looking for something specific?
+       if (argv[0]) {
+               // If we didn't find anything, complain
+               if (!mtcur->mnt_fsname)
+                       bb_error_msg_and_die("can't find %s in %s",
+                               argv[0], fstabname);
+               if (nonroot) {
+                       // fstab must have "users" or "user"
+                       if (!(parse_mount_options(mtcur->mnt_opts, 0) & MOUNT_USERS))
+                               bb_error_msg_and_die(must_be_root);
+               }
 
+               // Mount the last thing we found
+               mtcur->mnt_opts = xstrdup(mtcur->mnt_opts);
+               append_mount_options(&(mtcur->mnt_opts), cmdopts);
+               if (ENABLE_FEATURE_MOUNT_LABEL) {
+                       resolve_mount_spec(&mtpair->mnt_fsname);
+               }
+               rc = singlemount(mtcur, 0);
+               if (ENABLE_FEATURE_CLEAN_UP)
+                       free(mtcur->mnt_opts);
+       }
+
+       if (ENABLE_FEATURE_CLEAN_UP)
+               endmntent(fstab);
        if (ENABLE_FEATURE_CLEAN_UP) {
                free(storage_path);
                free(cmdopts);
        }
-
        return rc;
 }