findmnt: add --mountpoint command line option

The current --target <path> implementation check the <path> elements in
reverse order to get the mountpoint. The feature may be inwanted in
some cases when we really want to check for mountpoint specified by
the <path>. The new option "--mountpoint <path>" allows to be strict.

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

1 files changed, 17 insertions, 4 deletions

diff --git a/misc-utils/findmnt.c b/misc-utils/findmnt.c
index 1adc23124..f76ac2e04 100644
--- a/misc-utils/findmnt.c
+++ b/misc-utils/findmnt.c
@@ -62,6 +62,7 @@ enum {
 	FL_UNIQ		= (1 << 12),
 	FL_BYTES	= (1 << 13),
 	FL_NOCACHE	= (1 << 14),
+	FL_STRICTTARGET = (1 << 15),
 
 	/* basic table settings */
 	FL_ASCII	= (1 << 20),
@@ -259,7 +260,12 @@ static void set_source_match(const char *data)
 		set_match(COL_SOURCE, data);
 }
 
-/* @tb has to be from kernel (so no fstab or so)! */
+/*
+ * Extra functionality for --target <path>. The function mnt_table_find_mountpoint()
+ * also checks parents (path elements in reverse order) to get mountpoint.
+ *
+ * @tb has to be from kernel (so no fstab or so)!
+ */
 static void enable_extra_target_match(struct libmnt_table *tb)
 {
 	char *cn = NULL;
@@ -1201,7 +1207,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 	" %1$s [options]\n"
 	" %1$s [options] <device> | <mountpoint>\n"
 	" %1$s [options] <device> <mountpoint>\n"
-	" %1$s [options] [--source <device>] [--target <mountpoint>]\n"),
+	" %1$s [options] [--source <device>] [--target <path> | --mountpoint <dir>]\n"),
 		program_invocation_short_name);
 
 	fputs(USAGE_SEPARATOR, out);
@@ -1239,7 +1245,8 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
 	fputs(_(" -r, --raw              use raw output format\n"), out);
 	fputs(_(" -S, --source <string>  the device to mount (by name, maj:min, \n"
 	        "                          LABEL=, UUID=, PARTUUID=, PARTLABEL=)\n"), out);
-	fputs(_(" -T, --target <string>  the mountpoint to use\n"), out);
+	fputs(_(" -T, --target <path>    the path to the filesystem to use\n"), out);
+	fputs(_(" -M, --mountpoint <dir> the mountpoint directory\n"), out);
 	fputs(_(" -t, --types <list>     limit the set of filesystems by FS types\n"), out);
 	fputs(_(" -U, --uniq             ignore filesystems with duplicate target\n"), out);
 	fputs(_(" -u, --notruncate       don't truncate text in columns\n"), out);
@@ -1284,6 +1291,7 @@ int main(int argc, char *argv[])
 	    { "invert",       0, 0, 'i' },
 	    { "kernel",       0, 0, 'k' },
 	    { "list",         0, 0, 'l' },
+	    { "mountpoint",   1, 0, 'M' },
 	    { "mtab",         0, 0, 'm' },
 	    { "noheadings",   0, 0, 'n' },
 	    { "notruncate",   0, 0, 'u' },
@@ -1310,6 +1318,7 @@ 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 */
+		{ 'M', 'T' },			/* mountpoint, target */
 		{ 'N','k','m','s' },		/* task,kernel,mtab,fstab */
 		{ 'P','l','r' },		/* pairs,list,raw */
 		{ 'm','p','s' },		/* mtab,poll,fstab */
@@ -1326,7 +1335,7 @@ int main(int argc, char *argv[])
 	flags |= FL_TREE;
 
 	while ((c = getopt_long(argc, argv,
-				"AabCcDd:ehifF:o:O:p::PklmnN:rst:uvRS:T:Uw:V",
+				"AabCcDd:ehifF:o:O:p::PklmM:nN:rst:uvRS:T:Uw:V",
 				longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);
@@ -1439,6 +1448,9 @@ int main(int argc, char *argv[])
 			set_source_match(optarg);
 			flags |= FL_NOSWAPMATCH;
 			break;
+		case 'M':
+			flags |= FL_STRICTTARGET;
+			/* fallthrough */
 		case 'T':
 			set_match(COL_TARGET, optarg);
 			flags |= FL_NOSWAPMATCH;
@@ -1602,6 +1614,7 @@ int main(int argc, char *argv[])
 		if (rc != 0
 		    && tabtype == TABTYPE_KERNEL
 		    && (flags & FL_NOSWAPMATCH)
+		    && !(flags & FL_STRICTTARGET)
 		    && get_match(COL_TARGET)) {
 			/*
 			 * Found nothing, maybe the --target is regular file,