findmnt: add --nocanonicalize to avoid realpath()

 * in some cases is realpath() overkill
 * sometimes you want to search for explicitly specified paths (e.g.
   "findmnt --fstab /mnt/symlink") rather than for real paths
 * you want to avoid readlink() and stat() on NFS

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/misc-utils/findmnt.8 b/misc-utils/findmnt.8
index 0176cd13023915506a9cef0ac3a7dfe9c064fe87..9c874322586f937f4f14c9fff5096e2adf960880 100644 (file)
--- a/misc-utils/findmnt.8
+++ b/misc-utils/findmnt.8
@@ -48,6 +48,10 @@ Use ascii characters for tree formatting.
 .BR \-b , " \-\-bytes"
 Print the SIZE, USED and AVAIL column in bytes rather than in a human-readable format.
 .TP
+.BR \-C , " \-\-nocanonicalize"
+Do not canonicalize paths at all. This option affects paths comparation
+and tags (LABEL, UUID, etc.) evaluation.
+.TP
 .BR \-c , " \-\-canonicalize"
 Canonicalize all printed paths.
 .TP

diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 16250ae649d79c8e859e0bb4c0bc1779f14a4790..06fdd8f41074173640bb5e92569b2187a3267e9a 100644 (file)
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -61,6 +61,7 @@ enum {
        FL_ALL          = (1 << 11),
        FL_UNIQ         = (1 << 12),
        FL_BYTES        = (1 << 13),
+       FL_NOCACHE      = (1 << 14),
 
        /* basic table settings */
        FL_ASCII        = (1 << 20),
@@ -246,15 +247,19 @@ static void set_source_match(const char *data)
 
 static void enable_extra_target_match(void)
 {
-       char *cn = NULL, *mnt = NULL;
+       const char *cn = NULL, *mnt = NULL;
 
        /*
         * Check if match pattern is mountpoint, if not use the
         * real mountpoint.
         */
-       cn = mnt_resolve_path(get_match(COL_TARGET), cache);
-       if (!cn)
-               return;
+       if (flags & FL_NOCACHE)
+               cn = get_match(COL_TARGET);
+       else {
+               cn = mnt_resolve_path(get_match(COL_TARGET), cache);
+               if (!cn)
+                       return;
+       }
 
        mnt = mnt_get_mountpoint(cn);
        if (!mnt || strcmp(mnt, cn) == 0)
@@ -439,7 +444,7 @@ static char *get_tag(struct libmnt_fs *fs, const char *tagname, int col
        else {
                const char *dev = mnt_fs_get_source(fs);
 
-               if (dev)
+               if (dev && !(flags & FL_NOCACHE))
                        dev = mnt_resolve_spec(dev, cache);
 #ifdef HAVE_LIBUDEV
                if (dev)
@@ -1143,6 +1148,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
        fputs(_(" -a, --ascii            use ASCII chars for tree formatting\n"), out);
        fputs(_(" -b, --bytes            print sizes in bytes rather than in human readable format\n"), out);
        fputs(_(" -c, --canonicalize     canonicalize printed paths\n"), out);
+       fputs(_(" -C, --nocanonicalize   don't canonicalize when compare paths\n"), out);
        fputs(_(" -D, --df               imitate the output of df(1)\n"), out);
        fputs(_(" -d, --direction <word> direction of search, 'forward' or 'backward'\n"), out);
        fputs(_(" -e, --evaluate         convert tags (LABEL,UUID,PARTUUID,PARTLABEL) \n"
@@ -1214,6 +1220,7 @@ int main(int argc, char *argv[])
            { "pairs",        0, 0, 'P' },
            { "raw",          0, 0, 'r' },
            { "types",        1, 0, 't' },
+           { "nocanonicalize", 0, 0, 'C' },
            { "nofsroot",     0, 0, 'v' },
            { "submounts",    0, 0, 'R' },
            { "source",       1, 0, 'S' },
@@ -1228,6 +1235,8 @@ int main(int argc, char *argv[])
        };
 
        static const ul_excl_t excl[] = {       /* rows and cols in in ASCII order */
+               { 'C', 'c'},                    /* [no]canonicalize */
+               { 'C', 'e' },                   /* nocanonicalize, evaluate */
                { 'N','k','m','s' },            /* task,kernel,mtab,fstab */
                { 'P','l','r' },                /* pairs,list,raw */
                { 'm','p','s' },                /* mtab,poll,fstab */
@@ -1246,7 +1255,7 @@ int main(int argc, char *argv[])
        flags |= FL_TREE;
 
        while ((c = getopt_long(argc, argv,
-                               "AabcDd:ehifF:o:O:p::PklmnN:rst:uvRS:T:Uw:V",
+                               "AabCcDd:ehifF:o:O:p::PklmnN:rst:uvRS:T:Uw:V",
                                longopts, NULL)) != -1) {
 
                err_exclusive_options(c, longopts, excl, excl_st);
@@ -1261,6 +1270,9 @@ int main(int argc, char *argv[])
                case 'b':
                        flags |= FL_BYTES;
                        break;
+               case 'C':
+                       flags |= FL_NOCACHE;
+                       break;
                case 'c':
                        flags |= FL_CANONICALIZE;
                        break;
@@ -1452,12 +1464,14 @@ int main(int argc, char *argv[])
        if ((flags & FL_TREE) && (ntabfiles > 1 || !tab_is_tree(tb)))
                flags &= ~FL_TREE;
 
-       cache = mnt_new_cache();
-       if (!cache) {
-               warn(_("failed to initialize libmount cache"));
-               goto leave;
+       if (!(flags & FL_NOCACHE)) {
+               cache = mnt_new_cache();
+               if (!cache) {
+                       warn(_("failed to initialize libmount cache"));
+                       goto leave;
+               }
+               mnt_table_set_cache(tb, cache);
        }
-       mnt_table_set_cache(tb, cache);
 
        if (flags & FL_UNIQ)
                mnt_table_uniq_fs(tb, MNT_UNIQ_KEEPTREE, uniq_fs_target_cmp);