tmpfiles: add new "L+" command as stronger version of "L", that removes the destinati...

Also, make use of this for mtab as long as mount insists on creating it
even if we invoke it with "-n".

diff --git a/man/tmpfiles.d.xml b/man/tmpfiles.d.xml
index 0081a6762aee3bc3d137b09c03c1be93b2a49ef4..2d8af981e9f0bbe68b4c63368b9593c3fd42f995 100644 (file)
--- a/man/tmpfiles.d.xml
+++ b/man/tmpfiles.d.xml
@@ -174,7 +174,16 @@ L    /tmp/foobar -    -    -    -   /dev/null</programlisting>
 
                                 <varlistentry>
                                         <term><varname>L</varname></term>
-                                        <listitem><para>Create a symlink if it does not exist yet.</para></listitem>
+                                        <term><varname>L+</varname></term>
+                                        <listitem><para>Create a
+                                        symlink if it does not exist
+                                        yet. If suffixed with
+                                        <varname>+</varname> and a
+                                        file already exists where the
+                                        symlink is to be created it
+                                        will be removed and be
+                                        replaced by the
+                                        symlink.</para></listitem>
                                 </varlistentry>
 
                                 <varlistentry>

diff --git a/src/shared/util.c b/src/shared/util.c
index d93a9680fde3890ad26a3dc808063e211d556ceb..d840dedfc6b899c32cbdc599c2e0ebc2b3b17d1f 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -4013,7 +4013,7 @@ int fopen_temporary(const char *path, FILE **_f, char **_temp_path) {
         assert(_f);
         assert(_temp_path);
 
-        t = strappend(path, ".XXXXXX");
+        t = tempfn_xxxxxx(path);
         if (!t)
                 return -ENOMEM;
 
@@ -4125,42 +4125,21 @@ int vt_disallocate(const char *name) {
 }
 
 int symlink_atomic(const char *from, const char *to) {
-        char *x;
-        _cleanup_free_ char *t;
-        const char *fn;
-        size_t k;
-        uint64_t u;
-        unsigned i;
-        int r;
+        _cleanup_free_ char *t = NULL;
 
         assert(from);
         assert(to);
 
-        t = new(char, strlen(to) + 1 + 16 + 1);
+        t = tempfn_random(to);
         if (!t)
                 return -ENOMEM;
 
-        fn = basename(to);
-        k = fn-to;
-        memcpy(t, to, k);
-        t[k] = '.';
-        x = stpcpy(t+k+1, fn);
-
-        u = random_u64();
-        for (i = 0; i < 16; i++) {
-                *(x++) = hexchar(u & 0xF);
-                u >>= 4;
-        }
-
-        *x = 0;
-
         if (symlink(from, t) < 0)
                 return -errno;
 
         if (rename(t, to) < 0) {
-                r = -errno;
-                unlink(t);
-                return r;
+                unlink_noerrno(t);
+                return -errno;
         }
 
         return 0;
@@ -6669,3 +6648,51 @@ int fflush_and_check(FILE *f) {
 
         return 0;
 }
+
+char *tempfn_xxxxxx(const char *p) {
+        const char *fn;
+        char *t;
+        size_t k;
+
+        assert(p);
+
+        t = new(char, strlen(p) + 1 + 6 + 1);
+        if (!t)
+                return NULL;
+
+        fn = basename(p);
+        k = fn - p;
+
+        strcpy(stpcpy(stpcpy(mempcpy(t, p, k), "."), fn), "XXXXXX");
+
+        return t;
+}
+
+char *tempfn_random(const char *p) {
+        const char *fn;
+        char *t, *x;
+        uint64_t u;
+        size_t k;
+        unsigned i;
+
+        assert(p);
+
+        t = new(char, strlen(p) + 1 + 16 + 1);
+        if (!t)
+                return NULL;
+
+        fn = basename(p);
+        k = fn - p;
+
+        x = stpcpy(stpcpy(mempcpy(t, p, k), "."), fn);
+
+        u = random_u64();
+        for (i = 0; i < 16; i++) {
+                *(x++) = hexchar(u & 0xF);
+                u >>= 4;
+        }
+
+        *x = 0;
+
+        return t;
+}

diff --git a/src/shared/util.h b/src/shared/util.h
index 1796014f266ebbbd7bd3cd80f3a27fe0d5853a37..e8552410c06114377232191b1155090083be117d 100644 (file)
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -948,3 +948,6 @@ int umount_recursive(const char *target, int flags);
 int bind_remount_recursive(const char *prefix, bool ro);
 
 int fflush_and_check(FILE *f);
+
+char *tempfn_xxxxxx(const char *p);
+char *tempfn_random(const char *p);

diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 0fd2bd233af5801b7c67bc108fbc666b0ee1b0e1..0c1c2b17f4ebc2f45108b9f9f2373232bea52f0e 100644 (file)
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -103,6 +103,8 @@ typedef struct Item {
 
         bool keep_first_level:1;
 
+        bool force:1;
+
         bool done:1;
 } Item;
 
@@ -746,31 +748,38 @@ static int create_item(Item *i) {
 
                 break;
 
-        case CREATE_SYMLINK: {
-                _cleanup_free_ char *x = NULL;
+        case CREATE_SYMLINK:
 
                 label_context_set(i->path, S_IFLNK);
                 r = symlink(i->argument, i->path);
                 label_context_clear();
 
-                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;
-                }
+                        _cleanup_free_ char *x = NULL;
 
-                if (!streq(i->argument, x)) {
-                        log_error("%s is not the right symlink.", i->path);
-                        return -EEXIST;
+                        if (errno != EEXIST) {
+                                log_error("symlink(%s, %s) failed: %m", i->argument, i->path);
+                                return -errno;
+                        }
+
+                        r = readlink_malloc(i->path, &x);
+                        if (r < 0 || !streq(i->argument, x)) {
+
+                                if (i->force) {
+                                        label_context_set(i->path, S_IFLNK);
+                                        r = symlink_atomic(i->argument, i->path);
+                                        label_context_clear();
+
+                                        if (r < 0) {
+                                                log_error("symlink(%s, %s) failed: %m", i->argument, i->path);
+                                                return -errno;
+                                        }
+                                } else
+                                        log_debug("%s is not a symlink or does not point to the correct path.", i->path);
+                        }
                 }
 
                 break;
-        }
 
         case CREATE_BLOCK_DEVICE:
         case CREATE_CHAR_DEVICE: {
@@ -1135,10 +1144,17 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
                 return -EIO;
         }
 
-        if (strlen(action) > 2 || (strlen(action) > 1 && action[1] != '!')) {
-                log_error("[%s:%u] Unknown modifier '%s'", fname, line, action);
+        if (isempty(action)) {
+                log_error("[%s:%u] Command too short '%s'.", fname, line, action);
                 return -EINVAL;
-        } else if (strlen(action) > 1 && !arg_boot)
+        }
+
+        if (strlen(action) > 1 && !in_charset(action+1, "!+")) {
+                log_error("[%s:%u] Unknown modifiers in command '%s'", fname, line, action);
+                return -EINVAL;
+        }
+
+        if (strchr(action+1, '!') && !arg_boot)
                 return 0;
 
         type = action[0];
@@ -1147,6 +1163,8 @@ static int parse_line(const char *fname, unsigned line, const char *buffer) {
         if (!i)
                 return log_oom();
 
+        i->force = !!strchr(action+1, '+');
+
         r = specifier_printf(path, specifier_table, NULL, &i->path);
         if (r < 0) {
                 log_error("[%s:%u] Failed to replace specifiers: %s", fname, line, path);

diff --git a/tmpfiles.d/etc.conf b/tmpfiles.d/etc.conf
index 1294c9408b4125afb913ba816faa059b5321c6d4..e809dff2aa1eb684f8a1dcd98e142795da9bda04 100644 (file)
--- a/tmpfiles.d/etc.conf
+++ b/tmpfiles.d/etc.conf
@@ -9,5 +9,5 @@
 
 L /etc/os-release - - - - ../usr/lib/os-release
 L /etc/localtime - - - - ../usr/share/zoneinfo/UTC
-L /etc/mtab - - - - ../proc/self/mounts
+L+ /etc/mtab - - - - ../proc/self/mounts
 L /etc/resolv.conf - - - - ../run/systemd/resolve/resolv.conf