libfstools: mtd: improve error handling

Use -1 to mark invalid file descriptors as 0 can theoretically be a
valid open file descriptor.
Do not ignore lseek() return value and check if an error has occured.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

diff --git a/libfstools/mtd.c b/libfstools/mtd.c
index c5dce500c20283f5610b198d2b63a90e1a641893..3696828902c14b27c871d9a4b3bee0f4a0f180eb 100644 (file)
--- a/libfstools/mtd.c
+++ b/libfstools/mtd.c
@@ -67,7 +67,7 @@ static void mtd_volume_close(struct mtd_volume *p)
                return;
 
        close(p->fd);
-       p->fd = 0;
+       p->fd = -1;
 }
 
 static int mtd_volume_load(struct mtd_volume *p)
@@ -76,17 +76,14 @@ static int mtd_volume_load(struct mtd_volume *p)
        struct mtd_info_user mtdInfo;
        struct erase_info_user mtdLockInfo;
 
-       if (p->fd) {
-               lseek(p->fd, 0, SEEK_SET);
-               return 0;
-       }
+       if (p->fd >= 0)
+               return (lseek(p->fd, 0, SEEK_SET) == -1);
 
        if (!p->chr)
                return -1;
 
        p->fd = mtd_open(p->chr, 0);
        if (p->fd < 0) {
-               p->fd = 0;
                ULOG_ERR("Could not open mtd device: %s\n", p->chr);
                return -1;
        }
@@ -167,6 +164,7 @@ static struct volume *mtd_volume_find(char *name)
        v->name = strdup(name);
        v->drv = &mtd_driver;
        p->idx = atoi(idx);
+       p->fd = -1;
 
        snprintf(buffer, sizeof(buffer), "/dev/mtdblock%s", idx);
        v->blk = strdup(buffer);