*: introduce and use bb_unsetenv_and_free

[oweals/busybox.git] / util-linux / mdev.c

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 9c9d95f8a08c24ba192727e628a971e615f8994d..b4042c07ecaeda7bbabc2a9ad5c4707d36a13caf 100644 (file)
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -140,7 +140,7 @@ static void make_device(char *path, int delete)
         * 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/") || strncmp(G.subsystem, "block", 5) == 0)
+       if (strstr(path, "/block/") || (G.subsystem && strncmp(G.subsystem, "block", 5) == 0))
                type = S_IFBLK;
 
        /* Make path point to "subsystem/device_name" */
@@ -204,7 +204,8 @@ static void make_device(char *path, int delete)
                                if (major < 0)
                                        continue; /* no dev, no match */
                                sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
-                               if (sc < 1 || major != cmaj
+                               if (sc < 1
+                                || major != cmaj
                                 || (sc == 2 && minor != cmin0)
                                 || (sc == 3 && (minor < cmin0 || minor > cmin1))
                                ) {
@@ -243,7 +244,8 @@ static void make_device(char *path, int delete)
 
                                /* If no match, skip rest of line */
                                /* (regexec returns whole pattern as "range" 0) */
-                               if (result || off[0].rm_so
+                               if (result
+                                || off[0].rm_so
                                 || ((int)off[0].rm_eo != (int)strlen(str_to_match))
                                ) {
                                        continue; /* this line doesn't match */
@@ -258,28 +260,34 @@ static void make_device(char *path, int delete)
                                bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno);
 
                        /* 3rd field: mode - device permissions */
-                       /* mode = strtoul(tokens[2], NULL, 8); */
                        bb_parse_mode(tokens[2], &mode);
 
                        val = tokens[3];
-                       /* 4th field (opt): >|=alias */
+                       /* 4th field (opt): ">|=alias" or "!" to not create the node */
 
                        if (ENABLE_FEATURE_MDEV_RENAME && val) {
-                               aliaslink = val[0];
-                               if (aliaslink == '>' || aliaslink == '=') {
-                                       char *a, *s, *st;
-                                       char *p;
-                                       unsigned i, n;
-
-                                       a = val;
-                                       s = strchrnul(val, ' ');
-                                       st = strchrnul(val, '\t');
-                                       if (st < s)
-                                               s = st;
-                                       val = (s[0] && s[1]) ? s+1 : NULL;
+                               char *a, *s, *st;
+
+                               a = val;
+                               s = strchrnul(val, ' ');
+                               st = strchrnul(val, '\t');
+                               if (st < s)
+                                       s = st;
+                               st = (s[0] && s[1]) ? s+1 : NULL;
+
+                               aliaslink = a[0];
+                               if (aliaslink == '!' && s == a+1) {
+                                       val = st;
+                                       /* "!": suppress node creation/deletion */
+                                       major = -1;
+                               }
+                               else if (aliaslink == '>' || aliaslink == '=') {
+                                       val = st;
                                        s[0] = '\0';
-
                                        if (ENABLE_FEATURE_MDEV_RENAME_REGEXP) {
+                                               char *p;
+                                               unsigned i, n;
+
                                                /* substitute %1..9 with off[1..9], if any */
                                                n = 0;
                                                s = a;
@@ -323,8 +331,13 @@ static void make_device(char *path, int delete)
                                /* Are we running this command now?
                                 * Run $cmd on delete, @cmd on create, *cmd on both
                                 */
-                               if (s2-s != delete)
+                               if (s2 - s != delete) {
+                                       /* We are here if: '*',
+                                        * or: '@' and delete = 0,
+                                        * or: '$' and delete = 1
+                                        */
                                        command = xstrdup(val + 1);
+                               }
                        }
                }
 
@@ -340,7 +353,7 @@ 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);
+                                       bb_perror_msg("can't create '%s'", node_name);
                                if (major == G.root_major && minor == G.root_minor)
                                        symlink(node_name, "root");
                                if (ENABLE_FEATURE_MDEV_CONF) {
@@ -361,14 +374,12 @@ static void make_device(char *path, int delete)
                                putenv(s1);
                                if (system(command) == -1)
                                        bb_perror_msg("can't run '%s'", command);
-                               unsetenv("SUBSYSTEM");
-                               free(s1);
-                               unsetenv("MDEV");
-                               free(s);
+                               bb_unsetenv_and_free(s1);
+                               bb_unsetenv_and_free(s);
                                free(command);
                        }
 
-                       if (delete) {
+                       if (delete && major >= 0) {
                                if (ENABLE_FEATURE_MDEV_RENAME && alias) {
                                        if (aliaslink == '>')
                                                unlink(device_name);