chiark / gitweb /
edd_id: fix "(null)" output if "mbr_signature" does not exist
[elogind.git] / extras / edd_id / edd_id.c
index 8fc690a..4ba89ed 100644 (file)
@@ -62,7 +62,7 @@ int main(int argc, char *argv[])
        int sysfs_fd;
        DIR *dir = NULL;
        int rc = 1;
-       char *match = NULL;
+       char match[NAME_MAX] = "";
 
        logging_init("edd_id");
 
@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
                } else
                        node = arg;
        }
-       if (!node) {
+       if (node == NULL) {
                err("no node specified");
                fprintf(stderr, "no node specified\n");
                goto exit;
@@ -82,7 +82,7 @@ int main(int argc, char *argv[])
 
        /* check for kernel support */
        dir = opendir("/sys/firmware/edd");
-       if (!dir) {
+       if (dir == NULL) {
                info("no kernel EDD support");
                fprintf(stderr, "no kernel EDD support\n");
                rc = 2;
@@ -156,32 +156,36 @@ int main(int argc, char *argv[])
 
                size = read(sysfs_fd, sysfs_id_buf, sizeof(sysfs_id_buf)-1);
                close(sysfs_fd);
-               if (size < 0) {
+               if (size <= 0) {
                        info("read sysfs '%s' failed", file);
                        continue;
                }
                sysfs_id_buf[size] = '\0';
                info("read '%s' from '%s'", sysfs_id_buf, file);
-
                sysfs_id = strtoul(sysfs_id_buf, NULL, 16);
+
+               /* look for matching value, that appears only once */
                if (disk_id == sysfs_id) {
-                       if (!match) {
-                               match = dent->d_name;
+                       if (match[0] == '\0') {
+                               /* store id */
+                               strlcpy(match, dent->d_name, sizeof(match));
                        } else {
+                               /* error, same signature for another device */
                                info("'%s' does not have a unique signature", node);
                                fprintf(stderr, "'%s' does not have a unique signature\n", node);
-                               rc=10;
+                               rc = 10;
                                goto exit;
                        }
                }
-
        }
 
-                       if (export)
-               printf("ID_EDD=%s\n", match);
-                       else
-               printf("%s\n", match);
-                       rc = 0;
+       if (match[0] != '\0') {
+               if (export)
+                       printf("ID_EDD=%s\n", match);
+               else
+                       printf("%s\n", match);
+               rc = 0;
+       }
 
 close:
        close(disk_fd);