mountpoint: add -n option (by Vladimir)

   text    data     bss     dec     hex filename
 799859     560    7748  808167   c54e7 busybox_old
 799845     560    7748  808153   c54d9 busybox_unstripped

2 files changed, 46 insertions, 39 deletions

diff --git a/include/usage.h b/include/usage.h
index 502fea7a0..000b864d6 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2788,12 +2788,13 @@
        "Returns 0 for success, number of failed mounts for -a, or errno for one mount."
 
 #define mountpoint_trivial_usage \
-       "[-q] <[-d] DIR | -x DEVICE>"
+       "[-q] <[-dn] DIR | -x DEVICE>"
 #define mountpoint_full_usage "\n\n" \
-       "mountpoint checks if the directory is a mountpoint\n" \
+       "Check if the directory is a mountpoint\n" \
      "\nOptions:" \
      "\n        -q      Quiet" \
      "\n        -d      Print major/minor device number of the filesystem" \
+     "\n        -n      Print device name of the filesystem" \
      "\n        -x      Print major/minor device number of the blockdevice" \
 
 #define mountpoint_example_usage \
diff --git a/miscutils/mountpoint.c b/miscutils/mountpoint.c
index 81ce429ea..b541ce28c 100644
--- a/miscutils/mountpoint.c
+++ b/miscutils/mountpoint.c
@@ -12,55 +12,61 @@
 #include "libbb.h"
 
 int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int mountpoint_main(int argc, char **argv)
+int mountpoint_main(int argc UNUSED_PARAM, char **argv)
 {
         struct stat st;
+        const char *msg;
         char *arg;
-        int opt = getopt32(argv, "qdx");
+        int rc, opt;
+
+        opt_complementary = "=1"; /* must have one argument */
+        opt = getopt32(argv, "qdxn");
 #define OPT_q (1)
 #define OPT_d (2)
 #define OPT_x (4)
+#define OPT_n (8)
+        arg = argv[optind];
+        msg = "%s";
 
-        if (optind != argc - 1)
-                bb_show_usage();
+        rc = (opt & OPT_x) ? stat(arg, &st) : lstat(arg, &st);
+        if (rc != 0)
+                goto err;
 
-        arg = argv[optind];
+        if (opt & OPT_x) {
+                if (S_ISBLK(st.st_mode)) {
+                        printf("%u:%u\n", major(st.st_rdev),
+                                                minor(st.st_rdev));
+                        return EXIT_SUCCESS;
+                }
+                errno = 0; /* make perror_msg work as error_msg */
+                msg = "%s: not a block device";
+                goto err;
+        }
+
+        errno = ENOTDIR;
+        if (S_ISDIR(st.st_mode)) {
+                dev_t st_dev = st.st_dev;
+                ino_t st_ino = st.st_ino;
+                char *p = xasprintf("%s/..", arg);
 
-        if ( (opt & OPT_x && stat(arg, &st) == 0) || (lstat(arg, &st) == 0) ) {
-                if (opt & OPT_x) {
-                        if (S_ISBLK(st.st_mode)) {
-                                printf("%u:%u\n", major(st.st_rdev),
-                                                        minor(st.st_rdev));
-                                return EXIT_SUCCESS;
-                        } else {
-                                if (opt & OPT_q)
-                                        bb_putchar('\n');
-                                else
-                                        bb_error_msg("%s: not a block device", arg);
-                        }
-                        return EXIT_FAILURE;
-                } else
-                if (S_ISDIR(st.st_mode)) {
-                        dev_t st_dev = st.st_dev;
-                        ino_t st_ino = st.st_ino;
-                        char *p = xasprintf("%s/..", arg);
+                if (stat(p, &st) == 0) {
+                        //int is_mnt = (st_dev != st.st_dev) || (st_dev == st.st_dev && st_ino == st.st_ino);
+                        int is_not_mnt = (st_dev == st.st_dev) && (st_ino != st.st_ino);
 
-                        if (stat(p, &st) == 0) {
-                                int ret = (st_dev != st.st_dev) ||
-                                        (st_dev == st.st_dev && st_ino == st.st_ino);
-                                if (opt & OPT_d)
-                                        printf("%u:%u\n", major(st_dev), minor(st_dev));
-                                else if (!(opt & OPT_q))
-                                        printf("%s is %sa mountpoint\n", arg, ret?"":"not ");
-                                return !ret;
-                        }
-                } else {
-                        if (!(opt & OPT_q))
-                                bb_error_msg("%s: not a directory", arg);
-                        return EXIT_FAILURE;
+                        if (opt & OPT_d)
+                                printf("%u:%u\n", major(st_dev), minor(st_dev));
+                        if (opt & OPT_n)
+                                printf("%s %s\n", find_block_device(arg), arg);
+                        if (!(opt & (OPT_q | OPT_d | OPT_n)))
+                                printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : "");
+                        return is_not_mnt;
                 }
+                arg = p;
+                /* else: stat had set errno, just fall through */
         }
+
+ err:
         if (!(opt & OPT_q))
-                bb_simple_perror_msg(arg);
+                bb_perror_msg(msg, arg);
         return EXIT_FAILURE;
 }