mdev: fix subsystem passing (new kernels broke it again) - bugs 639, 721.

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

1 files changed, 32 insertions, 22 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 69e1e6937..9c9d95f8a 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -66,9 +66,6 @@ struct globals {
         char *subsystem;
 } FIX_ALIASING;
 #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
@@ -109,7 +106,7 @@ static char *build_alias(char *alias, const char *device_name)
  */
 static void make_device(char *path, int delete)
 {
-        char *device_name;
+        char *device_name, *subsystem_slash_devname;
         int major, minor, type, len;
         mode_t mode;
         parser_t *parser;
@@ -140,17 +137,29 @@ static void make_device(char *path, int delete)
         device_name = (char*) bb_basename(path);
         /* http://kernel.org/doc/pending/hotplug.txt says that only
          * "/sys/block/..." is for block devices. "/sys/bus" etc is not.
-         * But since 2.6.25 block devices are also in /sys/class/block,
-         * we use strstr("/block/") to forestall future surprises. */
+         * But since 2.6.25 block devices are also in /sys/class/block.
+         * We use strstr("/block/") to forestall future surprises. */
         type = S_IFCHR;
-        if (strstr(path, "/block/"))
+        if (strstr(path, "/block/") || strncmp(G.subsystem, "block", 5) == 0)
                 type = S_IFBLK;
 
         /* Make path point to "subsystem/device_name" */
-        if (path[5] == 'b') /* legacy /sys/block? */
+        subsystem_slash_devname = NULL;
+        /* Check for coldplug invocations first */
+        if (strncmp(path, "/sys/block/", 11) == 0) /* legacy case */
                 path += sizeof("/sys/") - 1;
-        else
+        else if (strncmp(path, "/sys/class/", 11) == 0)
                 path += sizeof("/sys/class/") - 1;
+        else {
+                /* Example of a hotplug invocation:
+                 * SUBSYSTEM="block"
+                 * DEVPATH="/sys" + "/devices/virtual/mtd/mtd3/mtdblock3"
+                 * ("/sys" is added by mdev_main)
+                 * - path does not contain subsystem
+                 */
+                subsystem_slash_devname = concat_path_file(G.subsystem, device_name);
+                path = subsystem_slash_devname;
+        }
 
         /* If we have config file, look up user settings */
         if (ENABLE_FEATURE_MDEV_CONF)
@@ -332,7 +341,7 @@ static void make_device(char *path, int delete)
                         if (!delete && major >= 0) {
                                 if (mknod(node_name, mode | type, makedev(major, minor)) && errno != EEXIST)
                                         bb_perror_msg("can't create %s", node_name);
-                                if (major == root_major && minor == root_minor)
+                                if (major == G.root_major && minor == G.root_minor)
                                         symlink(node_name, "root");
                                 if (ENABLE_FEATURE_MDEV_CONF) {
                                         chmod(node_name, mode);
@@ -347,7 +356,7 @@ static void make_device(char *path, int delete)
                         if (ENABLE_FEATURE_MDEV_EXEC && command) {
                                 /* setenv will leak memory, use putenv/unsetenv/free */
                                 char *s = xasprintf("%s=%s", "MDEV", node_name);
-                                char *s1 = xasprintf("%s=%s", "SUBSYSTEM", subsystem);
+                                char *s1 = xasprintf("%s=%s", "SUBSYSTEM", G.subsystem);
                                 putenv(s);
                                 putenv(s1);
                                 if (system(command) == -1)
@@ -381,6 +390,7 @@ static void make_device(char *path, int delete)
 
         if (ENABLE_FEATURE_MDEV_CONF)
                 config_close(parser);
+        free(subsystem_slash_devname);
 }
 
 /* File callback for /sys/ traversal */
@@ -398,7 +408,7 @@ static int FAST_FUNC fileAction(const char *fileName,
 
         strcpy(scratch, fileName);
         scratch[len] = '\0';
-        make_device(scratch, 0);
+        make_device(scratch, /*delete:*/ 0);
 
         return TRUE;
 }
@@ -412,10 +422,10 @@ static int FAST_FUNC dirAction(const char *fileName UNUSED_PARAM,
         /* Extract device subsystem -- the name of the directory
          * under /sys/class/ */
         if (1 == depth) {
-                free(subsystem);
-                subsystem = strrchr(fileName, '/');
-                if (subsystem)
-                        subsystem = xstrdup(subsystem + 1);
+                free(G.subsystem);
+                G.subsystem = strrchr(fileName, '/');
+                if (G.subsystem)
+                        G.subsystem = xstrdup(G.subsystem + 1);
         }
 
         return (depth >= MAX_SYSFS_DEPTH ? SKIP : TRUE);
@@ -500,8 +510,8 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                 struct stat st;
 
                 xstat("/", &st);
-                root_major = major(st.st_dev);
-                root_minor = minor(st.st_dev);
+                G.root_major = major(st.st_dev);
+                G.root_minor = minor(st.st_dev);
 
                 /* ACTION_FOLLOWLINKS is needed since in newer kernels
                  * /sys/block/loop* (for example) are symlinks to dirs,
@@ -538,8 +548,8 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                  */
                 action = getenv("ACTION");
                 env_path = getenv("DEVPATH");
-                subsystem = getenv("SUBSYSTEM");
-                if (!action || !env_path /*|| !subsystem*/)
+                G.subsystem = getenv("SUBSYSTEM");
+                if (!action || !env_path /*|| !G.subsystem*/)
                         bb_show_usage();
                 fw = getenv("FIRMWARE");
                 op = index_in_strings(keywords, action);
@@ -574,10 +584,10 @@ int mdev_main(int argc UNUSED_PARAM, char **argv)
                          * to happen and to cause erroneous deletion
                          * of device nodes. */
                         if (!fw)
-                                make_device(temp, 1);
+                                make_device(temp, /*delete:*/ 1);
                 }
                 else if (op == OP_add) {
-                        make_device(temp, 0);
+                        make_device(temp, /*delete:*/ 0);
                         if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE) {
                                 if (fw)
                                         load_firmware(fw, temp);