mdev: do not complain if mdev.conf does not exist;

 use #if to prevent gcc from generating dead code
 (sadly, it's more ugly this way)

3 files changed, 166 insertions, 145 deletions

diff --git a/docs/mdev.txt b/docs/mdev.txt
index 555c2bf61..63ad40602 100644
--- a/docs/mdev.txt
+++ b/docs/mdev.txt
@@ -60,18 +60,23 @@ matched, then the default of 0:0 660 is used.  To set your own default, simply
 create your own total match like so:
         .* 1:1 777
 
-You can rename/relocate device nodes by using the next optional field.
-        <device regex> <uid>:<gid> <octal permissions> [>path]
+You can rename/move device nodes by using the next optional field.
+        <device regex> <uid>:<gid> <octal permissions> [=path]
 So if you want to place the device node into a subdirectory, make sure the path
 has a trailing /.  If you want to rename the device node, just place the name.
-        hda 0:3 660 >drives/
-This will relocate "hda" into the drives/ subdirectory.
-        hdb 0:3 660 >cdrom
+        hda 0:3 660 =drives/
+This will move "hda" into the drives/ subdirectory.
+        hdb 0:3 660 =cdrom
 This will rename "hdb" to "cdrom".
 
+Similarly, ">path" renames/moves the device but it also creates
+a direct symlink /dev/DEVNAME to the renamed/moved device.
+
 If you also enable support for executing your own commands, then the file has
 the format:
-        <device regex> <uid>:<gid> <octal permissions> [<@|$|*> <command>]
+        <device regex> <uid>:<gid> <octal permissions> [=path] [@|$|*<command>]
+    or
+        <device regex> <uid>:<gid> <octal permissions> [>path] [@|$|*<command>]
 The special characters have the meaning:
         @ Run after creating the device.
         $ Run before removing the device.
diff --git a/testsuite/mdev.tests b/testsuite/mdev.tests
index 572609e11..5c65ffc46 100755
--- a/testsuite/mdev.tests
+++ b/testsuite/mdev.tests
@@ -29,7 +29,6 @@ testing "mdev add /block/sda" \
         "env - ACTION=add DEVPATH=/block/sda chroot mdev.testdir /mdev 2>&1;
         ls -ln mdev.testdir/dev | $FILTER_LS" \
 "\
-mdev: /etc/mdev.conf: No such file or directory
 brw-rw---- 1 0 0 8,0 sda
 " \
         "" ""
diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 461d3c8c1..f6440b190 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -25,6 +25,7 @@ struct globals {
 /* We use additional 64+ bytes in make_device() */
 #define SCRATCH_SIZE 80
 
+#if ENABLE_FEATURE_MDEV_RENAME
 /* Builds an alias path.
  * This function potentionally reallocates the alias parameter.
  */
@@ -48,6 +49,7 @@ static char *build_alias(char *alias, const char *device_name)
 
         return alias;
 }
+#endif
 
 /* mknod in /dev based on a path like "/sys/block/hda/hda1" */
 /* NB: "mdev -s" may call us many times, do not leak memory/fds! */
@@ -56,12 +58,20 @@ 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
         uid_t uid = 0;
         gid_t gid = 0;
-        char *dev_maj_min = path + strlen(path);
+        parser_t *parser;
+        char *tokens[5];
+#endif
+#if ENABLE_FEATURE_MDEV_EXEC
         char *command = NULL;
+#endif
+#if ENABLE_FEATURE_MDEV_RENAME
         char *alias = NULL;
         char aliaslink = aliaslink; /* for compiler */
+#endif
+        char *dev_maj_min = path + strlen(path);
 
         /* Force the configuration file settings exactly. */
         umask(0);
@@ -93,148 +103,149 @@ static void make_device(char *path, int delete)
         if (strstr(path, "/block/"))
                 type = S_IFBLK;
 
-        if (ENABLE_FEATURE_MDEV_CONF) {
-                parser_t *parser = config_open("/etc/mdev.conf");
-                char *tokens[5];
-
-                /* If we have config file, look up user settings */
-                if (!parser)
-                        goto end_parse;
-
-                while (config_read(parser, tokens, 4, 3, "# \t", PARSE_LAST_IS_GREEDY)) {
-                        regmatch_t off[1+9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
-                        char *val;
-
-                        /* Fields: regex uid:gid mode [alias] [cmd] */
-
-                        /* 1st field: regex to match this device */
-                        {
-                                regex_t match;
-                                int result;
-
-                                /* Is this it? */
-                                xregcomp(&match, tokens[0], REG_EXTENDED);
-                                result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
-                                regfree(&match);
-
-                                //bb_error_msg("matches:");
-                                //for (int i = 0; i < ARRAY_SIZE(off); i++) {
-                                //      if (off[i].rm_so < 0) continue;
-                                //      bb_error_msg("match %d: '%.*s'\n", i,
-                                //              (int)(off[i].rm_eo - off[i].rm_so),
-                                //              device_name + off[i].rm_so);
-                                //}
-
-                                /* 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))
-                                ) {
-                                        continue;
-                                }
+#if ENABLE_FEATURE_MDEV_CONF
+        parser = config_open2("/etc/mdev.conf", fopen_for_read);
+
+        /* If we have config file, look up user settings */
+        if (!parser)
+                goto end_parse;
+
+        while (config_read(parser, tokens, 4, 3, "# \t", PARSE_LAST_IS_GREEDY)) {
+                regmatch_t off[1 + 9*ENABLE_FEATURE_MDEV_RENAME_REGEXP];
+                char *val;
+
+                /* Fields: regex uid:gid mode [alias] [cmd] */
+
+                /* 1st field: regex to match this device */
+                {
+                        regex_t match;
+                        int result;
+
+                        /* Is this it? */
+                        xregcomp(&match, tokens[0], REG_EXTENDED);
+                        result = regexec(&match, device_name, ARRAY_SIZE(off), off, 0);
+                        regfree(&match);
+
+                        //bb_error_msg("matches:");
+                        //for (int i = 0; i < ARRAY_SIZE(off); i++) {
+                        //      if (off[i].rm_so < 0) continue;
+                        //      bb_error_msg("match %d: '%.*s'\n", i,
+                        //              (int)(off[i].rm_eo - off[i].rm_so),
+                        //              device_name + off[i].rm_so);
+                        //}
+
+                        /* 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))
+                        ) {
+                                continue;
                         }
+                }
 
-                        /* This line matches: stop parsing the file
-                         * after parsing the rest of fields */
-
-                        /* 2nd field: uid:gid - device ownership */
-                        {
-                                struct passwd *pass;
-                                struct group *grp;
-                                char *str_uid = tokens[1];
-                                char *str_gid = strchrnul(str_uid, ':');
-
-                                if (*str_gid)
-                                        *str_gid++ = '\0';
-                                /* Parse UID */
-                                pass = getpwnam(str_uid);
-                                if (pass)
-                                        uid = pass->pw_uid;
-                                else
-                                        uid = strtoul(str_uid, NULL, 10);
-                                /* Parse GID */
-                                grp = getgrnam(str_gid);
-                                if (grp)
-                                        gid = grp->gr_gid;
-                                else
-                                        gid = strtoul(str_gid, NULL, 10);
-                        }
+                /* This line matches: stop parsing the file
+                 * after parsing the rest of fields */
+
+                /* 2nd field: uid:gid - device ownership */
+                {
+                        struct passwd *pass;
+                        struct group *grp;
+                        char *str_uid = tokens[1];
+                        char *str_gid = strchrnul(str_uid, ':');
+
+                        if (*str_gid)
+                                *str_gid++ = '\0';
+                        /* Parse UID */
+                        pass = getpwnam(str_uid);
+                        if (pass)
+                                uid = pass->pw_uid;
+                        else
+                                uid = strtoul(str_uid, NULL, 10);
+                        /* Parse GID */
+                        grp = getgrnam(str_gid);
+                        if (grp)
+                                gid = grp->gr_gid;
+                        else
+                                gid = strtoul(str_gid, NULL, 10);
+                }
 
-                        /* 3rd field: mode - device permissions */
-                        mode = strtoul(tokens[2], NULL, 8);
+                /* 3rd field: mode - device permissions */
+                mode = strtoul(tokens[2], NULL, 8);
 
-                        val = tokens[3];
-                        /* 4th field (opt): >alias */
+                val = tokens[3];
+                /* 4th field (opt): >alias */
 #if ENABLE_FEATURE_MDEV_RENAME
-                        if (!val)
-                                break;
-                        aliaslink = *val;
-                        if (aliaslink == '>' || aliaslink == '=') {
-                                char *s;
+                if (!val)
+                        break;
+                aliaslink = *val;
+                if (aliaslink == '>' || aliaslink == '=') {
+                        char *s;
 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
-                                char *p;
-                                unsigned i, n;
+                        char *p;
+                        unsigned i, n;
 #endif
-                                char *a = val;
-                                s = strchr(val, ' ');
-                                val = (s && s[1]) ? s+1 : NULL;
+                        char *a = val;
+                        s = strchr(val, ' ');
+                        val = (s && s[1]) ? s+1 : NULL;
 #if ENABLE_FEATURE_MDEV_RENAME_REGEXP
-                                /* substitute %1..9 with off[1..9], if any */
-                                n = 0;
-                                s = a;
-                                while (*s)
-                                        if (*s++ == '%')
-                                                n++;
-
-                                p = alias = xzalloc(strlen(a) + n * strlen(device_name));
-                                s = a + 1;
-                                while (*s) {
-                                        *p = *s;
-                                        if ('%' == *s) {
-                                                i = (s[1] - '0');
-                                                if (i <= 9 && off[i].rm_so >= 0) {
-                                                        n = off[i].rm_eo - off[i].rm_so;
-                                                        strncpy(p, device_name + off[i].rm_so, n);
-                                                        p += n - 1;
-                                                        s++;
-                                                }
+                        /* substitute %1..9 with off[1..9], if any */
+                        n = 0;
+                        s = a;
+                        while (*s)
+                                if (*s++ == '%')
+                                        n++;
+
+                        p = alias = xzalloc(strlen(a) + n * strlen(device_name));
+                        s = a + 1;
+                        while (*s) {
+                                *p = *s;
+                                if ('%' == *s) {
+                                        i = (s[1] - '0');
+                                        if (i <= 9 && off[i].rm_so >= 0) {
+                                                n = off[i].rm_eo - off[i].rm_so;
+                                                strncpy(p, device_name + off[i].rm_so, n);
+                                                p += n - 1;
+                                                s++;
                                         }
-                                        p++;
-                                        s++;
                                 }
+                                p++;
+                                s++;
+                        }
 #else
-                                alias = xstrdup(a + 1);
+                        alias = xstrdup(a + 1);
 #endif
-                        }
+                }
 #endif /* ENABLE_FEATURE_MDEV_RENAME */
 
-                        /* The rest (opt): command to run */
-                        if (!val)
-                                break;
-                        if (ENABLE_FEATURE_MDEV_EXEC) {
-                                const char *s = "@$*";
-                                const char *s2 = strchr(s, *val);
-
-                                if (!s2)
-                                        bb_error_msg_and_die("bad line %u", parser->lineno);
-
-                                /* Correlate the position in the "@$*" with the delete
-                                 * step so that we get the proper behavior:
-                                 * @cmd: run on create
-                                 * $cmd: run on delete
-                                 * *cmd: run on both
-                                 */
-                                if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
-                                        command = xstrdup(val + 1);
-                                }
+#if ENABLE_FEATURE_MDEV_EXEC
+                /* The rest (opt): command to run */
+                if (!val)
+                        break;
+                {
+                        const char *s = "@$*";
+                        const char *s2 = strchr(s, *val);
+
+                        if (!s2)
+                                bb_error_msg_and_die("bad line %u", parser->lineno);
+
+                        /* Correlate the position in the "@$*" with the delete
+                         * step so that we get the proper behavior:
+                         * @cmd: run on create
+                         * $cmd: run on delete
+                         * *cmd: run on both
+                         */
+                        if ((s2 - s + 1) /*1/2/3*/ & /*1/2*/ (1 + delete)) {
+                                command = xstrdup(val + 1);
                         }
-                        /* end of field parsing */
-                        break; /* we found matching line, stop */
-                } /* end of "while line is read from /etc/mdev.conf" */
+                }
+#endif
+                /* end of field parsing */
+                break; /* we found matching line, stop */
+        } /* end of "while line is read from /etc/mdev.conf" */
 
-                config_close(parser);
-        }
+        config_close(parser);
  end_parse:
+#endif /* ENABLE_FEATURE_MDEV_CONF */
 
         if (!delete && sscanf(dev_maj_min, "%u:%u", &major, &minor) == 2) {
 
@@ -247,23 +258,26 @@ static void make_device(char *path, int delete)
                 if (major == root_major && minor == root_minor)
                         symlink(device_name, "root");
 
-                if (ENABLE_FEATURE_MDEV_CONF) {
-                        chown(device_name, uid, gid);
+#if ENABLE_FEATURE_MDEV_CONF
+                chown(device_name, uid, gid);
 
-                        if (ENABLE_FEATURE_MDEV_RENAME && alias) {
-                                alias = build_alias(alias, device_name);
+#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);
+                        /* 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);
-                        }
+                        free(alias);
                 }
+#endif
+#endif
         }
 
-        if (ENABLE_FEATURE_MDEV_EXEC && command) {
+#if ENABLE_FEATURE_MDEV_EXEC
+        if (command) {
                 /* setenv will leak memory, use putenv/unsetenv/free */
                 char *s = xasprintf("MDEV=%s", device_name);
                 putenv(s);
@@ -274,16 +288,19 @@ static void make_device(char *path, int delete)
                 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 (ENABLE_FEATURE_MDEV_RENAME && alias) {
+#if ENABLE_FEATURE_MDEV_RENAME
+                if (alias) {
                         alias = build_alias(alias, device_name);
                         unlink(alias);
                         free(alias);
                 }
+#endif
         }
 }