lkblk: list multiple MOUNTPOINTS

function                                             old     new   delta
lsblk_main                                           550     869    +319
.rodata                                           106977  107010     +33
process__sys_block_NAME                              461     356    -105
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 352/-105)          Total: 247 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 58 insertions, 22 deletions

diff --git a/util-linux/lsblk.c b/util-linux/lsblk.c
index 560ccbaf8..a482bfbbc 100644
--- a/util-linux/lsblk.c
+++ b/util-linux/lsblk.c
@@ -67,11 +67,12 @@ struct blockdev_info {
         unsigned long long size;
         const char *type;
         const char *majmin;
-        const char *mountpoint;
+        //const char *mountpoint;
 };
 
 struct globals {
         struct blockdev_info *list;
+        char *mountinfo;
         unsigned count;
         unsigned exitcode;
 };
@@ -93,27 +94,47 @@ static struct blockdev_info *get_or_create_info(const char *devname)
         return &G.list[G.count++];
 }
 
-static char *get_mountpoint(const char *devname)
+static char *get_mountpoints(const char *majmin)
 {
-        char devpath[256];
-        struct mntent *mnt;
-        FILE *mtab;
-        char *mountpoint = NULL;
-
-        snprintf(devpath, sizeof(devpath), "/dev/%s", devname);
-//TODO: use /proc/self/mountinfo instead, it has MAJ:MIN column which is unambiguous
-        mtab = setmntent(bb_path_mtab_file, "r");
-        if (mtab) {
-                while ((mnt = getmntent(mtab)) != NULL) {
-                        if (strcmp(mnt->mnt_fsname, devpath) == 0) {
-                                mountpoint = xstrdup(mnt->mnt_dir);
+        unsigned len;
+        char *p, *mountpoints;
+
+        mountpoints = NULL;
+        len = strlen(majmin);
+        p = G.mountinfo; // "/proc/self/mountinfo"
+        /* lines a-la "63 1 259:3 / /MNTPOINT per-mount_options - ext4 /dev/NAME per-superblock_options" */
+        while (*p) {
+                char *e, *f;
+
+                p = skip_non_whitespace(p);
+                if (*p != ' ') break;
+                // at " 1 259:3"
+                p = skip_non_whitespace(p + 1);
+                if (*p != ' ') break;
+                p++;
+                // at "259:3 / /MNTPOINT"
+                if (strncmp(p, majmin, len) != 0 || (p+=len)[0] != ' ') {
+                        p = strchr(p, '\n');
+                        if (!p)
                                 break;
-                        }
+                        p++;
+                        continue;
                 }
-                endmntent(mtab);
+                // at " / /MNTPOINT"
+                p = skip_non_whitespace(p + 1);
+                if (*p != ' ') break;
+
+                // at " /MNTPOINT"
+                e = skip_non_whitespace(p + 1);
+                // e is at the end of " /MNTPOINT"
+                f = mountpoints;
+// NO. We return " /MNT1 /MNT2 /MNT3" _with_ leading space!
+//              if (!f)
+//                      p++;
+                mountpoints = xasprintf("%s%.*s", f ? f : "", (int)(e - p), p);
+                free(f);
         }
-
-        return mountpoint;
+        return mountpoints;
 }
 
 static char *get_majmin_from_stat(const char *filename)
@@ -209,7 +230,7 @@ static void process__sys_dev_block_MAJMIN(const char *path, char *majmin, const
         info->majmin = majmin;
         //info->rm = ...;
         //info->ro = ...;
-        info->mountpoint = get_mountpoint(devname);
+        //info->mountpoint = get_mountpoint(majmin);
 
         /* Scan for partititons */
         dir = xopendir(path);
@@ -254,6 +275,8 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
         getopt32(argv, "a");
         argv += optind;
 
+        G.mountinfo = xmalloc_xopen_read_close("/proc/self/mountinfo", NULL);
+
         /* If specific devices are requested, process them */
         if (*argv) {
                 while (*argv) {
@@ -326,21 +349,34 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
         qsort(G.list, G.count, sizeof(G.list[0]), compare_devices);
 
         /* Print header */
-        printf("%-15s MAJ:MIN  SIZE TYPE MOUNTPOINT\n", "NAME");
+        printf("%-15s MAJ:MIN  SIZE TYPE MOUNTPOINTS\n", "NAME");
         //util-linux 2.41.1 default set of fields:
         //"NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS"
 
         /* Print devices */
         for (i = 0; i < G.count; i++) {
                 char buf6[6];
+                char *mnt, *e;
+
+                mnt = (get_mountpoints(G.list[i].majmin) ? : (char*)"");
+                e = strchrnul(mnt[0] ? mnt + 1 : "", ' ');
                 smart_ulltoa5(G.list[i].size * 512, buf6, " KMGTPEZY");
-                printf("%-15s %-7s %.5s %4s %s\n",
+                printf("%-15s %-7s %.5s %4s%.*s\n",
                         G.list[i].name,
                         G.list[i].majmin,
                         buf6,
                         G.list[i].type,
-                        (G.list[i].mountpoint ? G.list[i].mountpoint : "")
+                        (int)(e - mnt), mnt
                 );
+                while (*mnt == ' ') {
+//util-linux prints multiple mountpoints on separate lines:
+//DEVNAME     259:3    0 475.4G  0 part /MNT1
+//                                      /MNT2
+                        mnt = skip_non_whitespace(mnt + 1);
+                        if (!mnt[0]) break;
+                        e = strchrnul(mnt + 1, ' ');
+                        printf("%34s%.*s\n", "", (int)(e - mnt), mnt);
+                }
         }
 
         fflush_stdout_and_exit(G.exitcode);