mdev: make usage text more useful

function                                             old     new   delta
packed_usage                                       26235   26291     +56

2 files changed, 25 insertions, 19 deletions

diff --git a/include/usage.h b/include/usage.h
index c36a3bbd7..7111e90bc 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2556,8 +2556,14 @@
 #define mdev_full_usage "\n\n" \
        "        -s      Scan /sys and populate /dev during system boot\n" \
        "\n" \
-       "Called with no options (via hotplug) it uses environment variables\n" \
-       "to determine which device to add/remove."
+       "It can be run by kernel as a hotplug helper. To activate it:\n" \
+       " echo /bin/mdev >/proc/sys/kernel/hotplug\n" \
+        USE_FEATURE_MDEV_CONF( \
+       "It uses /etc/mdev.conf with lines\n" \
+       "DEVNAME UID:GID PERM" \
+                        USE_FEATURE_MDEV_RENAME(" [>|=PATH]") \
+                        USE_FEATURE_MDEV_EXEC(" [@|$|*COMMAND]") \
+        ) \
 
 #define mdev_notes_usage "" \
         USE_FEATURE_MDEV_CONFIG( \
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 6eaa66bf4..584df7df2 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -62,13 +62,13 @@ static void make_device(char *path, int delete)
         struct bb_uidgid_t ugid = { 0, 0 };
         parser_t *parser;
         char *tokens[5];
-#endif
-#if ENABLE_FEATURE_MDEV_EXEC
+# if ENABLE_FEATURE_MDEV_EXEC
         char *command = NULL;
-#endif
-#if ENABLE_FEATURE_MDEV_RENAME
+# endif
+# if ENABLE_FEATURE_MDEV_RENAME
         char *alias = NULL;
         char aliaslink = aliaslink; /* for compiler */
+# endif
 #endif
         char *dev_maj_min = path + strlen(path);
 
@@ -168,21 +168,21 @@ static void make_device(char *path, int delete)
 
                 val = tokens[3];
                 /* 4th field (opt): >alias */
-#if ENABLE_FEATURE_MDEV_RENAME
+# if ENABLE_FEATURE_MDEV_RENAME
                 if (!val)
                         break;
                 aliaslink = *val;
                 if (aliaslink == '>' || aliaslink == '=') {
                         char *s;
-#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+#  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
                         char *p;
                         unsigned i, n;
-#endif
+#  endif
                         char *a = val;
                         s = strchrnul(val, ' ');
                         val = (s[0] && s[1]) ? s+1 : NULL;
                         s[0] = '\0';
-#if ENABLE_FEATURE_MDEV_RENAME_REGEXP
+#  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
                         /* substitute %1..9 with off[1..9], if any */
                         n = 0;
                         s = a;
@@ -206,13 +206,13 @@ static void make_device(char *path, int delete)
                                 p++;
                                 s++;
                         }
-#else
+#  else
                         alias = xstrdup(a + 1);
-#endif
+#  endif
                 }
-#endif /* ENABLE_FEATURE_MDEV_RENAME */
+# endif /* ENABLE_FEATURE_MDEV_RENAME */
 
-#if ENABLE_FEATURE_MDEV_EXEC
+# if ENABLE_FEATURE_MDEV_EXEC
                 /* The rest (opt): command to run */
                 if (!val)
                         break;
@@ -233,7 +233,7 @@ static void make_device(char *path, int delete)
                                 command = xstrdup(val + 1);
                         }
                 }
-#endif
+# endif
                 /* end of field parsing */
                 break; /* we found matching line, stop */
         } /* end of "while line is read from /etc/mdev.conf" */
@@ -255,7 +255,7 @@ static void make_device(char *path, int delete)
 #if ENABLE_FEATURE_MDEV_CONF
                 chown(device_name, ugid.uid, ugid.gid);
 
-#if ENABLE_FEATURE_MDEV_RENAME
+# if ENABLE_FEATURE_MDEV_RENAME
                 if (alias) {
                         alias = build_alias(alias, device_name);
 
@@ -266,7 +266,7 @@ static void make_device(char *path, int delete)
 
                         free(alias);
                 }
-#endif
+# endif
 #endif
         }
 
@@ -406,7 +406,7 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
 
         xchdir("/dev");
 
-        if (argv[1] && !strcmp(argv[1], "-s")) {
+        if (argv[1] && strcmp(argv[1], "-s") == 0) {
                 /* Scan:
                  * mdev -s
                  */
@@ -501,5 +501,5 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
         if (ENABLE_FEATURE_CLEAN_UP)
                 RELEASE_CONFIG_BUFFER(temp);
 
-        return 0;
+        return EXIT_SUCCESS;
 }