libfstools: Check return values for fread and system

libfstools/rootdisk.c: In function 'rootdisk_volume_identify':
libfstools/rootdisk.c:172:7: error: ignoring return value of 'fread', declared with attribute warn_unused_result [-Werror=unused-result]
  fread(&magic, sizeof(magic), 1, f);
       ^
libfstools/rootdisk.c:179:7: error: ignoring return value of 'fread', declared with attribute warn_unused_result [-Werror=unused-result]
  fread(&magic, sizeof(magic), 1, f);
       ^
libfstools/rootdisk.c: In function 'rootdisk_volume_init':
libfstools/rootdisk.c:268:9: error: ignoring return value of 'system', declared with attribute warn_unused_result [-Werror=unused-result]
   system(str);
         ^
cc1: all warnings being treated as errors

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

diff --git a/libfstools/rootdisk.c b/libfstools/rootdisk.c
index d4ff201..9a5892e 100644 (file)
--- a/libfstools/rootdisk.c
+++ b/libfstools/rootdisk.c
@@ -162,6 +162,7 @@ static int rootdisk_volume_identify(struct volume *v)
        struct rootdev_volume *p = container_of(v, struct rootdev_volume, v);
        int ret = FS_NONE;
        uint32_t magic = 0;
+       size_t n;
        FILE *f;
 
        f = fopen(rootdev, "r");
@@ -169,14 +170,18 @@ static int rootdisk_volume_identify(struct volume *v)
                return ret;
 
        fseeko(f, p->offset + 0x400, SEEK_SET);
-       fread(&magic, sizeof(magic), 1, f);
+       n = fread(&magic, sizeof(magic), 1, f);
+       if (n != 1)
+               return -1;
 
        if (magic == cpu_to_le32(0xF2F52010))
                ret = FS_F2FS;
 
        magic = 0;
        fseeko(f, p->offset + 0x438, SEEK_SET);
-       fread(&magic, sizeof(magic), 1, f);
+       n = fread(&magic, sizeof(magic), 1, f);
+       if (n != 1)
+               return -1;
        if ((le32_to_cpu(magic) & 0xffff) == 0xef53)
                ret = FS_EXT4;
 
@@ -251,6 +256,7 @@ static int rootdisk_volume_init(struct volume *v)
 {
        struct rootdev_volume *p = container_of(v, struct rootdev_volume, v);
        char str[128];
+       int ret = 0;
 
        if (!p->loop_name[0] && rootdisk_create_loop(p) != 0)
                return -1;
@@ -265,12 +271,12 @@ static int rootdisk_volume_init(struct volume *v)
                        snprintf(str, sizeof(str), "mkfs.f2fs -l rootfs_data %s", v->blk);
                else
                        snprintf(str, sizeof(str), "mkfs.ext4 -L rootfs_data %s", v->blk);
-               system(str);
+               ret = system(str);
                break;
        default:
                break;
        }
-       return 0;
+       return ret;
 }
 
 static struct driver rootdisk_driver = {