[Fix] Avoid race condition on saving cache and reload

MFH: true

diff --git a/src/libserver/symbols_cache.c b/src/libserver/symbols_cache.c
index 74fcc0698dd02e71a3bd4e0f83f97208c3c06480..dca365e49bcd524735e49545d560cba97ddccd22 100644 (file)
--- a/src/libserver/symbols_cache.c
+++ b/src/libserver/symbols_cache.c
@@ -479,7 +479,10 @@ rspamd_symbols_cache_load_items (struct symbols_cache *cache, const gchar *name)
                return FALSE;
        }
 
+       rspamd_file_lock (fd, FALSE);
+
        if (fstat (fd, &st) == -1) {
+               rspamd_file_unlock (fd, FALSE);
                close (fd);
                msg_info_cache ("cannot stat file %s, error %d, %s", name,
                                errno, strerror (errno));
@@ -487,6 +490,7 @@ rspamd_symbols_cache_load_items (struct symbols_cache *cache, const gchar *name)
        }
 
        if (st.st_size < (gint)sizeof (*hdr)) {
+               rspamd_file_unlock (fd, FALSE);
                close (fd);
                errno = EINVAL;
                msg_info_cache ("cannot use file %s, error %d, %s", name,
@@ -497,19 +501,22 @@ rspamd_symbols_cache_load_items (struct symbols_cache *cache, const gchar *name)
        map = mmap (NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
 
        if (map == MAP_FAILED) {
+               rspamd_file_unlock (fd, FALSE);
                close (fd);
                msg_info_cache ("cannot mmap file %s, error %d, %s", name,
                                errno, strerror (errno));
                return FALSE;
        }
 
-       close (fd);
        hdr = map;
 
        if (memcmp (hdr->magic, rspamd_symbols_cache_magic,
                        sizeof (rspamd_symbols_cache_magic)) != 0) {
                msg_info_cache ("cannot use file %s, bad magic", name);
                munmap (map, st.st_size);
+               rspamd_file_unlock (fd, FALSE);
+               close (fd);
+
                return FALSE;
        }
 
@@ -521,11 +528,16 @@ rspamd_symbols_cache_load_items (struct symbols_cache *cache, const gchar *name)
                                ucl_parser_get_error (parser));
                munmap (map, st.st_size);
                ucl_parser_free (parser);
+               rspamd_file_unlock (fd, FALSE);
+               close (fd);
+
                return FALSE;
        }
 
        top = ucl_parser_get_object (parser);
        munmap (map, st.st_size);
+       rspamd_file_unlock (fd, FALSE);
+       close (fd);
        ucl_parser_free (parser);
 
        if (top == NULL || ucl_object_type (top) != UCL_OBJECT) {
@@ -607,10 +619,10 @@ rspamd_symbols_cache_save_items (struct symbols_cache *cache, const gchar *name)
        struct ucl_emitter_functions *efunc;
        gpointer k, v;
        gint fd;
-       FILE *f;
        bool ret;
 
-       fd = open (name, O_CREAT | O_TRUNC | O_WRONLY, 00644);
+       (void)unlink (name);
+       fd = open (name, O_CREAT | O_TRUNC | O_WRONLY | O_EXCL, 00644);
 
        if (fd == -1) {
                msg_info_cache ("cannot open file %s, error %d, %s", name,
@@ -618,6 +630,8 @@ rspamd_symbols_cache_save_items (struct symbols_cache *cache, const gchar *name)
                return FALSE;
        }
 
+       rspamd_file_lock (fd, FALSE);
+
        memset (&hdr, 0, sizeof (hdr));
        memcpy (hdr.magic, rspamd_symbols_cache_magic,
                        sizeof (rspamd_symbols_cache_magic));
@@ -625,6 +639,7 @@ rspamd_symbols_cache_save_items (struct symbols_cache *cache, const gchar *name)
        if (write (fd, &hdr, sizeof (hdr)) == -1) {
                msg_info_cache ("cannot write to file %s, error %d, %s", name,
                                errno, strerror (errno));
+               rspamd_file_unlock (fd, FALSE);
                close (fd);
 
                return FALSE;
@@ -648,14 +663,12 @@ rspamd_symbols_cache_save_items (struct symbols_cache *cache, const gchar *name)
                ucl_object_insert_key (top, elt, k, 0, false);
        }
 
-       f = fdopen (fd, "a");
-       g_assert (f != NULL);
-
-       efunc = ucl_object_emit_file_funcs (f);
+       efunc = ucl_object_emit_fd_funcs (fd);
        ret = ucl_object_emit_full (top, UCL_EMIT_JSON_COMPACT, efunc, NULL);
        ucl_object_emit_funcs_free (efunc);
        ucl_object_unref (top);
-       fclose (f);
+       rspamd_file_unlock (fd, FALSE);
+       close (fd);
 
        return ret;
 }