mdev: add support for - "dont stop here" char

function                                             old     new   delta
make_device                                         1340    1362     +22
packed_usage                                       26291   26299      +8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 30/0)               Total: 30 bytes

2 files changed, 98 insertions, 83 deletions

diff --git a/include/usage.h b/include/usage.h
index 7111e90bc..d3bf7849e 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2560,7 +2560,7 @@
        " echo /bin/mdev >/proc/sys/kernel/hotplug\n" \
         USE_FEATURE_MDEV_CONF( \
        "It uses /etc/mdev.conf with lines\n" \
-       "DEVNAME UID:GID PERM" \
+       "[-]DEVNAME UID:GID PERM" \
                         USE_FEATURE_MDEV_RENAME(" [>|=PATH]") \
                         USE_FEATURE_MDEV_EXEC(" [@|$|*COMMAND]") \
         ) \
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 3b0ef351e..b1f3d051c 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -57,21 +57,12 @@ static char *build_alias(char *alias, const char *device_name)
 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
 static void make_device(char *path, int delete)
 {
-        const char *device_name;
-        int major, minor, type, len;
-        int mode = 0660;
 #if ENABLE_FEATURE_MDEV_CONF
-        struct bb_uidgid_t ugid = { 0, 0 };
         parser_t *parser;
-        char *tokens[5];
-# if ENABLE_FEATURE_MDEV_EXEC
-        char *command = NULL;
-# endif
-# if ENABLE_FEATURE_MDEV_RENAME
-        char *alias = NULL;
-        char aliaslink = aliaslink; /* for compiler */
-# endif
 #endif
+        const char *device_name;
+        int major, minor, type, len;
+        int mode;
         char *dev_maj_min = path + strlen(path);
 
         /* Force the configuration file settings exactly. */
@@ -111,14 +102,37 @@ static void make_device(char *path, int delete)
         parser = config_open2("/etc/mdev.conf", fopen_for_read);
 
         /* If we have config file, look up user settings */
-        while (config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
+        while (1) {
                 regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
-                char *val = tokens[0];
+                int keep_matching;
+                char *val;
+                struct bb_uidgid_t ugid;
+                char *tokens[4];
+# if ENABLE_FEATURE_MDEV_EXEC
+                char *command = NULL;
+# endif
+# if ENABLE_FEATURE_MDEV_RENAME
+                char *alias = NULL;
+                char aliaslink = aliaslink; /* for compiler */
+# endif
+                /* Defaults in case we won't match any line */
+                ugid.uid = ugid.gid = 0;
+                keep_matching = 0;
+                mode = 0660;
+
+                if (!config_read(parser, tokens, 4, 3, "# \t", PARSE_NORMAL)) {
+                        /* End of file, create dev node with default params */
+                        goto line_matches;
+                }
+
+                val = tokens[0];
+                keep_matching = ('-' == val[0]);
+                val += keep_matching; /* swallow leading dash */
 
                 /* Fields: regex uid:gid mode [alias] [cmd] */
 
                 /* 1st field: @<numeric maj,min>... */
-                if (tokens[0][0] == '@') {
+                if (val[0] == '@') {
                         /* @major,minor[-last] */
                         /* (useful when name is ambiguous:
                          * "/sys/class/usb/lp0" and
@@ -126,12 +140,12 @@ static void make_device(char *path, int delete)
                         int cmaj, cmin0, cmin1, sc;
                         if (major < 0)
                                 continue; /* no dev, no match */
-                        sc = sscanf(tokens[0], "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
+                        sc = sscanf(val, "@%u,%u-%u", &cmaj, &cmin0, &cmin1);
                         if (sc < 1 || major != cmaj
                          || (sc == 2 && minor != cmin0)
                          || (sc == 3 && (minor < cmin0 || minor > cmin1))
                         ) {
-                                continue; /* no match */
+                                continue; /* this line doesn't match */
                         }
                 } else { /* ... or regex to match device name */
                         regex_t match;
@@ -160,12 +174,12 @@ static void make_device(char *path, int delete)
                         if (result || off[0].rm_so
                          || ((int)off[0].rm_eo != (int)strlen(dev_name_or_subsystem))
                         ) {
-                                continue;
+                                continue; /* this line doesn't match */
                         }
                 }
 
-                /* This line matches: stop parsing the file
-                 * after parsing the rest of fields */
+                /* This line matches: stop parsing the file after parsing
+                 * the rest of fields unless keep_matching == 1 */
 
                 /* 2nd field: uid:gid - device ownership */
                 parse_chown_usergroup_or_die(&ugid, tokens[1]);
@@ -174,24 +188,25 @@ static void make_device(char *path, int delete)
                 mode = strtoul(tokens[2], NULL, 8);
 
                 val = tokens[3];
-                /* 4th field (opt): >alias */
+                /* 4th field (opt): >|=alias */
 # if ENABLE_FEATURE_MDEV_RENAME
                 if (!val)
-                        break;
-                aliaslink = *val;
+                        goto line_matches;
+                aliaslink = val[0];
                 if (aliaslink == '>' || aliaslink == '=') {
-                        char *s, *st;
+                        char *a, *s, *st;
 #  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
                         char *p;
                         unsigned i, n;
 #  endif
-                        char *a = val;
+                        a = val;
                         s = strchrnul(val, ' ');
                         st = strchrnul(val, '\t');
                         if (st < s)
                                 s = st;
                         val = (s[0] && s[1]) ? s+1 : NULL;
                         s[0] = '\0';
+
 #  if ENABLE_FEATURE_MDEV_RENAME_REGEXP
                         /* substitute %1..9 with off[1..9], if any */
                         n = 0;
@@ -223,12 +238,12 @@ static void make_device(char *path, int delete)
 # endif /* ENABLE_FEATURE_MDEV_RENAME */
 
 # if ENABLE_FEATURE_MDEV_EXEC
-                /* The rest (opt): command to run */
+                /* The rest (opt): @|$|*command */
                 if (!val)
-                        break;
+                        goto line_matches;
                 {
                         const char *s = "@$*";
-                        const char *s2 = strchr(s, *val);
+                        const char *s2 = strchr(s, val[0]);
 
                         if (!s2)
                                 bb_error_msg_and_die("bad line %u", parser->lineno);
@@ -244,71 +259,71 @@ static void make_device(char *path, int delete)
                         }
                 }
 # endif
-                /* end of field parsing */
-                break; /* we found matching line, stop */
-        } /* end of "while line is read from /etc/mdev.conf" */
-
-        config_close(parser);
+                /* End of field parsing */
+ line_matches:
 #endif /* ENABLE_FEATURE_MDEV_CONF */
 
-        if (!delete && major >= 0) {
-
-                if (ENABLE_FEATURE_MDEV_RENAME)
-                        unlink(device_name);
-
-                if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
-                        bb_perror_msg_and_die("mknod %s", device_name);
-
-                if (major == root_major && minor == root_minor)
-                        symlink(device_name, "root");
+                /* "Execute" the line we found */
 
+                if (!delete && major >= 0) {
+                        if (ENABLE_FEATURE_MDEV_RENAME)
+                                unlink(device_name);
+                        if (mknod(device_name, mode | type, makedev(major, minor)) && errno != EEXIST)
+                                bb_perror_msg_and_die("mknod %s", device_name);
+                        if (major == root_major && minor == root_minor)
+                                symlink(device_name, "root");
 #if ENABLE_FEATURE_MDEV_CONF
-                chown(device_name, ugid.uid, ugid.gid);
-
+                        chown(device_name, ugid.uid, ugid.gid);
 # if ENABLE_FEATURE_MDEV_RENAME
-                if (alias) {
-                        alias = build_alias(alias, device_name);
-
-                        /* move the device, and optionally
-                         * make a symlink to moved device node */
-                        if (rename(device_name, alias) == 0 && aliaslink == '>')
-                                symlink(alias, device_name);
-
-                        free(alias);
-                }
+                        if (alias) {
+                                alias = build_alias(alias, device_name);
+                                /* move the device, and optionally
+                                 * make a symlink to moved device node */
+                                if (rename(device_name, alias) == 0 && aliaslink == '>')
+                                        symlink(alias, device_name);
+                                free(alias);
+                        }
 # endif
 #endif
-        }
-
+                }
 #if ENABLE_FEATURE_MDEV_EXEC
-        if (command) {
-                /* setenv will leak memory, use putenv/unsetenv/free */
-                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);
-        }
+                if (command) {
+                        /* setenv will leak memory, use putenv/unsetenv/free */
+                        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);
+                }
 #endif
-
-        if (delete) {
-                unlink(device_name);
-                /* At creation time, device might have been moved
-                 * and a symlink might have been created. Undo that. */
+                if (delete) {
+                        unlink(device_name);
+                        /* At creation time, device might have been moved
+                         * and a symlink might have been created. Undo that. */
 #if ENABLE_FEATURE_MDEV_RENAME
-                if (alias) {
-                        alias = build_alias(alias, device_name);
-                        unlink(alias);
-                        free(alias);
-                }
+                        if (alias) {
+                                alias = build_alias(alias, device_name);
+                                unlink(alias);
+                                free(alias);
+                        }
 #endif
-        }
+                }
+
+#if ENABLE_FEATURE_MDEV_CONF
+                /* We found matching line.
+                 * Stop unless it was prefixed with '-' */
+                if (!keep_matching)
+                        break;
+        } /* end of "while line is read from /etc/mdev.conf" */
+
+        config_close(parser);
+#endif /* ENABLE_FEATURE_MDEV_CONF */
 }
 
 /* File callback for /sys/ traversal */