lsblk: add error messages and exit code when non-blockdevs are given

function                                             old     new   delta
process__sys_block_NAME                                -     461    +461
lsblk_main                                           511     550     +39
.rodata                                           106960  106977     +17
process_SYS_BLOCK_entry                              460       -    -460
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 2/0 up/down: 517/-460)           Total: 57 bytes

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

1 files changed, 39 insertions, 17 deletions

diff --git a/util-linux/lsblk.c b/util-linux/lsblk.c
index 3063d8ae9..560ccbaf8 100644
--- a/util-linux/lsblk.c
+++ b/util-linux/lsblk.c
@@ -71,8 +71,9 @@ struct blockdev_info {
 };
 
 struct globals {
-        unsigned count;
         struct blockdev_info *list;
+        unsigned count;
+        unsigned exitcode;
 };
 #define G (*ptr_to_globals)
 #define INIT_G() do { \
@@ -124,6 +125,8 @@ static char *get_majmin_from_stat(const char *filename)
                         (unsigned)minor(st.st_rdev)
                 );
         }
+        bb_error_msg("%s: not a block device", filename);
+        G.exitcode |= 64; /* util-linux compat */
         return NULL;
 }
 
@@ -159,9 +162,7 @@ static char *read_str(const char *path, const char *name)
 
         filename = concat_path_file(path, name);
         res = xmalloc_open_read_close(filename, NULL);
-#if 0
-bb_error_msg("open_read_close('%s'):'%s'", filename, res);
-#endif
+//bb_error_msg("open_read_close('%s'):'%s'", filename, res);
         free(filename);
 
         if (res)
@@ -184,10 +185,10 @@ bb_error_msg("open_read_close('%s'):'%s'", filename, res);
  *       MAJMIN1=open("/sys/block/DEV/PART/dev")+read
  *       recurse into handling MAJMIN1 for this partition
  */
-static void process_SYS_BLOCK_entry(const char *path, const char *devname);
+static void process__sys_block_NAME(const char *path, const char *devname);
 
 /* Note: consumes malloc'ed majmin */
-static void process_SYS_DEV_BLOCK_entry(const char *path, char *majmin, const char *devname)
+static void process__sys_dev_block_MAJMIN(const char *path, char *majmin, const char *devname)
 {
         DIR *dir;
         struct dirent *entry;
@@ -215,22 +216,24 @@ static void process_SYS_DEV_BLOCK_entry(const char *path, char *majmin, const ch
         while ((entry = readdir(dir)) != NULL) {
                 if (is_prefixed_with(entry->d_name, devname)) {
                         char *part = xasprintf("/sys/block/%s/%s", devname, entry->d_name);
-                        process_SYS_BLOCK_entry(part, entry->d_name);
+                        process__sys_block_NAME(part, entry->d_name);
                         free(part);
                 }
         }
         closedir(dir);
 }
-static void process_SYS_BLOCK_entry(const char *path, const char *devname)
+static void process__sys_block_NAME(const char *path, const char *devname)
 {
         char *majmin = read_str(path, "dev");
+//bb_error_msg("%s/dev:'%s'", path, majmin);
         if (majmin /*&& majmin[0]*/) {
                 char *sys_dev_block_MAJMIN = concat_path_file("/sys/dev/block", majmin);
-                process_SYS_DEV_BLOCK_entry(sys_dev_block_MAJMIN, majmin, devname);
+                process__sys_dev_block_MAJMIN(sys_dev_block_MAJMIN, majmin, devname);
                 /* ^^^ consumes malloc'ed majmin */
                 free(sys_dev_block_MAJMIN);
         }
         /* WRONG: free(majmin); */
+//      return !majmin; /* 1 if no PATH/dev was seen */
 }
 
 static int compare_devices(const void *a, const void *b)
@@ -254,7 +257,6 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
         /* If specific devices are requested, process them */
         if (*argv) {
                 while (*argv) {
-                        char *devname = *argv++;
                         char *majmin;
                         char *sys_dev_block_MAJMIN;
                         char *target;
@@ -264,19 +266,36 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
                          * cp -a /dev/DISK /tmp/bogusname; lsblk /tmp/bogusname
                          * ^^^^ should still show "DISK" as the name of blockdev, and show its partitions if any
                          */
-                        majmin = get_majmin_from_stat(devname);
+                        majmin = get_majmin_from_stat(*argv++);
+//bb_error_msg("get_majmin_from_stat('%s'):'%s'", argv[-1], majmin);
                         if (!majmin)
                                 continue;
 
                         sys_dev_block_MAJMIN = concat_path_file("/sys/dev/block", majmin);
                         /* util-linux 2.41.1 gets the "real name" from the symlink's last component */
                         target = xmalloc_readlink(sys_dev_block_MAJMIN);
+//bb_error_msg("target:'%s'", target);
                         if (target) {
                                 name = strrchr(target, '/');
-                                if (name && name[1]) {
-                                        char *sys_block_NAME = concat_path_file("/sys/block", ++name);
-                                        process_SYS_BLOCK_entry(sys_block_NAME, name);
-                                        free(sys_block_NAME);
+                                if (name && *++name) {
+                                        char *sys_block_NAME;
+// Maybe there's a reason why util-linux tries /sys/block/NAME first.
+// In which case uncomment this, and explain.
+//                                      int err;
+//
+//                                      sys_block_NAME = concat_path_file("/sys/block", name);
+//                                      err = process__sys_block_NAME(sys_block_NAME, name);
+//                                      free(sys_block_NAME);
+//                                      /* "/sys/block/NAME/dev" wasn't found? (Happens for "lsblk /dev/PARTITION") */
+//                                      if (err) {
+                                                /* util-linux seems to test for existence of /sys/dev/block/MAJMIN/partition,
+                                                 * if that exists, it *guesses* parent disk name (!!!).
+                                                 * We just try /sys/class/block/NAME, which exists for partitions too.
+                                                 */
+                                                sys_block_NAME = concat_path_file("/sys/class/block", name);
+                                                process__sys_block_NAME(sys_block_NAME, name);
+                                                free(sys_block_NAME);
+//                                      }
                                 }
                                 free(target);
                         }
@@ -294,12 +313,15 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
                         if (DOT_OR_DOTDOT(entry->d_name))
                                 continue;
                         sys_block_NAME = concat_path_file("/sys/block", entry->d_name);
-                        process_SYS_BLOCK_entry(sys_block_NAME, entry->d_name);
+                        process__sys_block_NAME(sys_block_NAME, entry->d_name);
                         free(sys_block_NAME);
                 }
                 closedir(dir);
         }
 
+        if (G.count == 0)
+                return 32; /* try "lsblk /dev/null DOES_NOT_EXIST" */
+
         /* Sort devices by name */
         qsort(G.list, G.count, sizeof(G.list[0]), compare_devices);
 
@@ -321,5 +343,5 @@ int lsblk_main(int argc UNUSED_PARAM, char **argv)
                 );
         }
 
-        fflush_stdout_and_exit_SUCCESS();
+        fflush_stdout_and_exit(G.exitcode);
 }