tmpfiles: add support for creating symlinks, char/block device nodes

2 files changed, 176 insertions, 31 deletions

diff --git a/man/tmpfiles.d.xml b/man/tmpfiles.d.xml
index 4a8e8316cd..080da6681b 100644
--- a/man/tmpfiles.d.xml
+++ b/man/tmpfiles.d.xml
@@ -67,27 +67,31 @@
 		<title>Configuration Format</title>
 
                 <para>Each configuration file is named in the style of
-                <filename>&lt;program&gt;.conf</filename>.
-                Files in <filename>/etc/</filename> overwrite
-                files with the same name in <filename>/usr/lib/</filename>.
-                Files in <filename>/run</filename> overwrite files with
-                the same name in <filename>/etc/</filename> and
-                <filename>/usr/lib/</filename>. Packages should install their
-                configuration files in <filename>/usr/lib/</filename>, files
-                in <filename>/etc/</filename> are reserved for the local
-                administration, which possibly decides to overwrite the
-                configurations installed from packages. All files are sorted
-                by filename in alphabetical order, regardless in which of the
-                directories they reside, to ensure that a specific
-                configuration file takes precedence over another file with
-                an alphabetically later name.</para>
+                <filename>&lt;program&gt;.conf</filename>.  Files in
+                <filename>/etc/</filename> override files with the
+                same name in <filename>/usr/lib/</filename>.  Files in
+                <filename>/run</filename> override files with the same
+                name in <filename>/etc/</filename> and
+                <filename>/usr/lib/</filename>. Packages should
+                install their configuration files in
+                <filename>/usr/lib/</filename>, files in
+                <filename>/etc/</filename> are reserved for the local
+                administrator, who may choose to override the
+                configurations installed from packages. The list of
+                configuration files are sorted by their filename in
+                alphabetical order, regardless in which of the
+                directories they reside, to guarantee that a
+                configuration file takes precedence over another
+                configuration file with an alphabetically later
+                name.</para>
 
 		<para>The configuration format is one line per path
-		containing action, mode, ownership and age
+		containing action, path, mode, ownership, age and argument
 		fields:</para>
 
-                <programlisting>Type Path          Mode UID  GID  Age
-d    /run/user 0755 root root 10d</programlisting>
+                <programlisting>Type Path        Mode UID  GID  Age Argument
+d    /run/user   0755 root root 10d -
+L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
 
                 <refsect2>
                         <title>Type</title>
@@ -118,6 +122,21 @@ d    /run/user 0755 root root 10d</programlisting>
                                 </varlistentry>
 
                                 <varlistentry>
+                                        <term><varname>L</varname></term>
+                                        <listitem><para>Create a symlink if it doesn't exist yet</para></listitem>
+                                </varlistentry>
+
+                                <varlistentry>
+                                        <term><varname>c</varname></term>
+                                        <listitem><para>Create a character device node if it doesn't exist yet</para></listitem>
+                                </varlistentry>
+
+                                <varlistentry>
+                                        <term><varname>b</varname></term>
+                                        <listitem><para>Create a block device node if it doesn't exist yet</para></listitem>
+                                </varlistentry>
+
+                                <varlistentry>
                                         <term><varname>x</varname></term>
                                         <listitem><para>Ignore a path
                                         during cleaning. Use this type
@@ -185,10 +204,11 @@ d    /run/user 0755 root root 10d</programlisting>
                         <para>The file access mode to use when
                         creating this file or directory. If omitted or
                         when set to - the default is used: 0755 for
-                        directories, 0644 for files. For z, Z lines
-                        if omitted or when set to - the file access mode will
-                        not be modified. This parameter is ignored for x, r, R
-                        lines.</para>
+                        directories, 0644 for all other file
+                        objects. For z, Z lines if omitted or when set
+                        to - the file access mode will not be
+                        modified. This parameter is ignored for x, r,
+                        R, L lines.</para>
                 </refsect2>
 
                 <refsect2>
@@ -200,7 +220,7 @@ d    /run/user 0755 root root 10d</programlisting>
                         omitted or when set to - the default 0 (root)
                         is used. For z, Z lines when omitted or when set to -
                         the file ownership will not be modified.
-                        These parameters are ignored for x, r, R lines.</para>
+                        These parameters are ignored for x, r, R, L lines.</para>
                 </refsect2>
 
                 <refsect2>
@@ -233,6 +253,16 @@ d    /run/user 0755 root root 10d</programlisting>
                         is done.</para>
                 </refsect2>
 
+                <refsect2>
+                        <title>Argument</title>
+
+                        <para>For L lines determines the destination
+                        path of the symlink. For c, b determines the
+                        major/minor of the device node, with major and
+                        minor formatted as integers, separated by :,
+                        e.g. "1:3". Ignored for all other lines.</para>
+                </refsect2>
+
         </refsect1>
 
         <refsect1>
@@ -241,7 +271,7 @@ d    /run/user 0755 root root 10d</programlisting>
                         <title>/etc/tmpfiles.d/screen.conf example</title>
                         <para><command>screen</command> needs two directories created at boot with specific modes and ownership.</para>
 
-                        <programlisting>d /var/run/screens 1777 root root 10d
+                        <programlisting>d /var/run/screens  1777 root root 10d
 d /var/run/uscreens 0755 root root 10d12h</programlisting>
                 </example>
         </refsect1>
diff --git a/src/tmpfiles.c b/src/tmpfiles.c
index 44e5c9d28d..2096019699 100644
--- a/src/tmpfiles.c
+++ b/src/tmpfiles.c
@@ -57,6 +57,9 @@ typedef enum ItemType {
         CREATE_DIRECTORY = 'd',
         TRUNCATE_DIRECTORY = 'D',
         CREATE_FIFO = 'p',
+        CREATE_SYMLINK = 'L',
+        CREATE_CHAR_DEVICE = 'c',
+        CREATE_BLOCK_DEVICE = 'b',
 
         /* These ones take globs */
         IGNORE_PATH = 'x',
@@ -70,11 +73,14 @@ typedef struct Item {
         ItemType type;
 
         char *path;
+        char *argument;
         uid_t uid;
         gid_t gid;
         mode_t mode;
         usec_t age;
 
+        dev_t major_minor;
+
         bool uid_set:1;
         bool gid_set:1;
         bool mode_set:1;
@@ -656,6 +662,60 @@ static int create_item(Item *i) {
 
                 break;
 
+        case CREATE_SYMLINK: {
+                char *x;
+
+                r = symlink(i->argument, i->path);
+                if (r < 0 && errno != EEXIST) {
+                        log_error("symlink(%s, %s) failed: %m", i->argument, i->path);
+                        return -errno;
+                }
+
+                r = readlink_malloc(i->path, &x);
+                if (r < 0) {
+                        log_error("readlink(%s) failed: %s", i->path, strerror(-r));
+                        return -errno;
+                }
+
+                if (!streq(i->argument, x)) {
+                        free(x);
+                        log_error("%s is not the right symlinks.", i->path);
+                        return -EEXIST;
+                }
+
+                free(x);
+                break;
+        }
+
+        case CREATE_BLOCK_DEVICE:
+        case CREATE_CHAR_DEVICE: {
+
+                u = umask(0);
+                r = mknod(i->path, i->mode | (i->type == CREATE_BLOCK_DEVICE ? S_IFBLK : S_IFCHR), i->major_minor);
+                umask(u);
+
+                if (r < 0 && errno != EEXIST) {
+                        log_error("Failed to create device node %s: %m", i->path);
+                        return -errno;
+                }
+
+                if (stat(i->path, &st) < 0) {
+                        log_error("stat(%s) failed: %m", i->path);
+                        return -errno;
+                }
+
+                if (i->type == CREATE_BLOCK_DEVICE ? !S_ISBLK(st.st_mode) : !S_ISCHR(st.st_mode)) {
+                        log_error("%s is not a device node.", i->path);
+                        return -EEXIST;
+                }
+
+                r = item_set_perms(i, i->path);
+                if (r < 0)
+                        return r;
+
+                break;
+        }
+
         case RELABEL_PATH:
 
                 r = glob_item(i, item_set_perms);
@@ -686,6 +746,9 @@ static int remove_item_instance(Item *i, const char *instance) {
         case TRUNCATE_FILE:
         case CREATE_DIRECTORY:
         case CREATE_FIFO:
+        case CREATE_SYMLINK:
+        case CREATE_BLOCK_DEVICE:
+        case CREATE_CHAR_DEVICE:
         case IGNORE_PATH:
         case RELABEL_PATH:
         case RECURSIVE_RELABEL_PATH:
@@ -701,8 +764,8 @@ static int remove_item_instance(Item *i, const char *instance) {
 
         case TRUNCATE_DIRECTORY:
         case RECURSIVE_REMOVE_PATH:
-                if ((r = rm_rf(instance, false, i->type == RECURSIVE_REMOVE_PATH, false)) < 0 &&
-                    r != -ENOENT) {
+                r = rm_rf(instance, false, i->type == RECURSIVE_REMOVE_PATH, false);
+                if (r < 0 && r != -ENOENT) {
                         log_error("rm_rf(%s): %s", instance, strerror(-r));
                         return r;
                 }
@@ -724,6 +787,9 @@ static int remove_item(Item *i) {
         case TRUNCATE_FILE:
         case CREATE_DIRECTORY:
         case CREATE_FIFO:
+        case CREATE_SYMLINK:
+        case CREATE_CHAR_DEVICE:
+        case CREATE_BLOCK_DEVICE:
         case IGNORE_PATH:
         case RELABEL_PATH:
         case RECURSIVE_RELABEL_PATH:
@@ -761,6 +827,7 @@ static void item_free(Item *i) {
         assert(i);
 
         free(i->path);
+        free(i->argument);
         free(i);
 }
 
@@ -790,6 +857,15 @@ static bool item_equal(Item *a, Item *b) {
             (a->age_set && a->age != b->age))
             return false;
 
+        if (a->type == CREATE_SYMLINK &&
+            !streq(a->argument, b->argument))
+                return false;
+
+        if ((a->type == CREATE_CHAR_DEVICE ||
+             a->type == CREATE_BLOCK_DEVICE) &&
+            a->major_minor != b->major_minor)
+                return false;
+
         return true;
 }
 
@@ -804,7 +880,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         assert(line >= 1);
         assert(buffer);
 
-        if (!(i = new0(Item, 1))) {
+        i = new0(Item, 1);
+        if (!i) {
                 log_error("Out of memory");
                 return -ENOMEM;
         }
@@ -815,19 +892,22 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
                    "%ms "
                    "%ms "
                    "%ms "
+                   "%ms "
                    "%ms",
                    &type,
                    &i->path,
                    &mode,
                    &user,
                    &group,
-                   &age) < 2) {
+                   &age,
+                   &i->argument) < 2) {
                 log_error("[%s:%u] Syntax error.", fname, line);
                 r = -EIO;
                 goto finish;
         }
 
         switch(type) {
+
         case CREATE_FILE:
         case TRUNCATE_FILE:
         case CREATE_DIRECTORY:
@@ -839,11 +919,41 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         case RELABEL_PATH:
         case RECURSIVE_RELABEL_PATH:
                 break;
+
+        case CREATE_SYMLINK:
+                if (!i->argument) {
+                        log_error("[%s:%u] Symlink file requires argument.", fname, line);
+                        r = -EBADMSG;
+                        goto finish;
+                }
+                break;
+
+        case CREATE_CHAR_DEVICE:
+        case CREATE_BLOCK_DEVICE: {
+                unsigned major, minor;
+
+                if (!i->argument) {
+                        log_error("[%s:%u] Device file requires argument.", fname, line);
+                        r = -EBADMSG;
+                        goto finish;
+                }
+
+                if (sscanf(i->argument, "%u:%u", &major, &minor) != 2) {
+                        log_error("[%s:%u] Can't parse device file major/minor '%s'.", fname, line, i->argument);
+                        r = -EBADMSG;
+                        goto finish;
+                }
+
+                i->major_minor = makedev(major, minor);
+                break;
+        }
+
         default:
                 log_error("[%s:%u] Unknown file type '%c'.", fname, line, type);
                 r = -EBADMSG;
                 goto finish;
         }
+
         i->type = type;
 
         if (!path_is_absolute(i->path)) {
@@ -895,7 +1005,9 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
                 i->mode = m;
                 i->mode_set = true;
         } else
-                i->mode = i->type == CREATE_DIRECTORY ? 0755 : 0644;
+                i->mode =
+                        i->type == CREATE_DIRECTORY ||
+                        i->type == TRUNCATE_DIRECTORY ? 0755 : 0644;
 
         if (age && !streq(age, "-")) {
                 if (parse_usec(age, &i->age) < 0) {
@@ -909,7 +1021,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
 
         h = needs_glob(i->type) ? globs : items;
 
-        if ((existing = hashmap_get(h, i->path))) {
+        existing = hashmap_get(h, i->path);
+        if (existing) {
 
                 /* Two identical items are fine */
                 if (!item_equal(existing, i))
@@ -919,7 +1032,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
                 goto finish;
         }
 
-        if ((r = hashmap_put(h, i->path, i)) < 0) {
+        r = hashmap_put(h, i->path, i);
+        if (r < 0) {
                 log_error("Failed to insert item %s: %s", i->path, strerror(-r));
                 goto finish;
         }
@@ -1024,7 +1138,8 @@ static int read_config_file(const char *fn, bool ignore_enoent) {
 
         assert(fn);
 
-        if (!(f = fopen(fn, "re"))) {
+        f = fopen(fn, "re");
+        if (!f) {
 
                 if (ignore_enoent && errno == ENOENT)
                         return 0;