mdev: provide $SUBSYSTEM (by Vladimir)

function                                             old     new   delta
make_device                                         1265    1340     +75
dirAction                                             14      60     +46
mdev_main                                            676     695     +19
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 140/0)             Total: 140 bytes

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index ca5eaca487b793c8fada05fb333a941e3f692304..3b0ef351e4a7911d5081d7eae07a76140b31ab78 100644 (file)
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -14,10 +14,12 @@
 
 struct globals {
        int root_major, root_minor;
+       char *subsystem;
 };
 #define G (*(struct globals*)&bb_common_bufsiz1)
 #define root_major (G.root_major)
 #define root_minor (G.root_minor)
+#define subsystem (G.subsystem)
 
 /* Prevent infinite loops in /sys symlinks */
 #define MAX_SYSFS_DEPTH 3
@@ -111,7 +113,7 @@ static void make_device(char *path, int delete)
        /* If we have config file, look up user settings */
        while (config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
                regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
-               char *val;
+               char *val = tokens[0];
 
                /* Fields: regex uid:gid mode [alias] [cmd] */
 
@@ -134,10 +136,15 @@ static void make_device(char *path, int delete)
                } else { /* ... or regex to match device name */
                        regex_t match;
                        int result;
+                       const char *dev_name_or_subsystem = device_name;
+                       if ('/' == val[0] && subsystem) {
+                               dev_name_or_subsystem = subsystem;
+                               val++;
+                       }
 
                        /* Is this it? */
-                       xregcomp(&match, tokens[0], REG_EXTENDED);
-                       result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
+                       xregcomp(&match, val, REG_EXTENDED);
+                       result = regexec(&match, dev_name_or_subsystem, ARRAY_SIZE(off), off, 0);
                        regfree(&match);
 
                        //bb_error_msg("matches:");
@@ -151,7 +158,7 @@ static void make_device(char *path, int delete)
                        /* If not this device, skip rest of line */
                        /* (regexec returns whole pattern as "range" 0) */
                        if (result || off[0].rm_so
-                        || ((int)off[0].rm_eo != (int)strlen(device_name))
+                        || ((int)off[0].rm_eo != (int)strlen(dev_name_or_subsystem))
                        ) {
                                continue;
                        }
@@ -276,10 +283,14 @@ static void make_device(char *path, int delete)
 #if ENABLE_FEATURE_MDEV_EXEC
        if (command) {
                /* setenv will leak memory, use putenv/unsetenv/free */
-               char *s = xasprintf("MDEV=%s", device_name);
+               char *s = xasprintf("%s=%s", "MDEV", device_name);
+               char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
                putenv(s);
+               putenv(s1);
                if (system(command) == -1)
                        bb_perror_msg_and_die("can't run '%s'", command);
+               unsetenv("SUBSYSTEM");
+               free(s1);
                unsetenv("MDEV");
                free(s);
                free(command);
@@ -326,6 +337,13 @@ static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
                void *userData UNUSED_PARAM,
                int depth)
 {
+       /* Extract device subsystem -- the name of the directory under /sys/class/ */
+       if (1 == depth) {
+               subsystem = strrchr(fileName, '/');
+               if (subsystem)
+                       subsystem++;
+       }
+
        return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
 }
 
@@ -445,13 +463,14 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                char *env_path;
 
                /* Hotplug:
-                * env ACTION=... DEVPATH=... [SEQNUM=...] mdev
+                * env ACTION=... DEVPATH=... SUBSYSTEM=... [SEQNUM=...] mdev
                 * ACTION can be "add" or "remove"
                 * DEVPATH is like "/block/sda" or "/class/input/mice"
                 */
                action = getenv("ACTION");
                env_path = getenv("DEVPATH");
-               if (!action || !env_path)
+               subsystem = getenv("SUBSYSTEM");
+               if (!action || !env_path /*|| !subsystem*/)
                        bb_show_usage();
                fw = getenv("FIRMWARE");