Fix "invalid file header"

Use stat before open the file to find out if the
file already exists. Only if file exists and
the header is invalid trigger connman_error

diff --git a/src/stats.c b/src/stats.c
index 6f6e2c7..b290c13 100644 (file)
--- a/src/stats.c
+++ b/src/stats.c
@@ -250,11 +250,12 @@ static int stats_open_file(struct connman_service *service,
                                struct stats_file *file,
                                connman_bool_t roaming)
 {
-       struct stat stat;
+       struct stat st;
        char *name;
        int err;
        size_t size;
        struct stats_file_header *hdr;
+       connman_bool_t new_file = FALSE;
 
        if (roaming == FALSE) {
                name = g_strdup_printf("%s/stats/%s.data", STORAGEDIR,
@@ -265,9 +266,16 @@ static int stats_open_file(struct connman_service *service,
        }
 
        file->name = name;
+
+       err = stat(file->name, &st);
+       if (err < 0) {
+               /* according documentation the only possible error is ENOENT */
+               new_file = TRUE;
+       }
+
        file->fd = open(name, O_RDWR | O_CREAT, 0644);
 
-       if (file->fd == -1) {
+       if (file->fd < 0) {
                connman_error("open error %s for %s",
                                strerror(errno), file->name);
                return -errno;
@@ -275,14 +283,10 @@ static int stats_open_file(struct connman_service *service,
 
        file->max_len = STATS_MAX_FILE_SIZE;
 
-       err = fstat(file->fd, &stat);
-       if (err < 0)
-               return -errno;
-
-       if (stat.st_size < sysconf(_SC_PAGESIZE))
+       if (st.st_size < sysconf(_SC_PAGESIZE))
                size = sysconf(_SC_PAGESIZE);
        else
-               size = (size_t)stat.st_size;
+               size = st.st_size;
 
        err = stats_file_remap(file, size);
        if (err < 0)
@@ -295,7 +299,15 @@ static int stats_open_file(struct connman_service *service,
                        hdr->end < sizeof(struct stats_file_header) ||
                        hdr->begin > file->len ||
                        hdr->end > file->len) {
-               connman_warn("invalid file header for %s", file->name);
+               if (new_file == FALSE) {
+                       /*
+                        * A newly created file can't have a correct
+                        * header so we only warn if the file already
+                        * existed and doesn't have a proper
+                        * header.
+                        */
+                       connman_warn("invalid file header for %s", file->name);
+               }
 
                hdr->magic = MAGIC;
                hdr->begin = sizeof(struct stats_file_header);