sandbox: Update os_open() to return an error code

It is convenient to be able to report the system error when available.
Update os_open() to return it.

Signed-off-by: Simon Glass <sjg@chromium.org>

arch/sandbox/cpu/os.c

@@ -100,7 +100,7 @@ off_t os_lseek(int fd, off_t offset, int whence)
 
 int os_open(const char *pathname, int os_flags)
 {
-	int flags;
+	int flags, ret;
 
 	switch (os_flags & OS_O_MASK) {
 	case OS_O_RDONLY:
@@ -127,7 +127,11 @@ int os_open(const char *pathname, int os_flags)
 	 */
 	flags |= O_CLOEXEC;
 
-	return open(pathname, flags, 0644);
+	ret = open(pathname, flags, 0644);
+	if (ret == -1)
+		return -errno;
+
+	return ret;
 }
 
 int os_close(int fd)
@@ -172,7 +176,7 @@ int os_write_file(const char *fname, const void *buf, int size)
 	fd = os_open(fname, OS_O_WRONLY | OS_O_CREAT | OS_O_TRUNC);
 	if (fd < 0) {
 		printf("Cannot open file '%s'\n", fname);
-		return -EIO;
+		return fd;
 	}
 	if (os_write(fd, buf, size) != size) {
 		printf("Cannot write to file '%s'\n", fname);
@@ -206,7 +210,7 @@ int os_read_file(const char *fname, void **bufp, int *sizep)
 	fd = os_open(fname, OS_O_RDONLY);
 	if (fd < 0) {
 		printf("Cannot open file '%s'\n", fname);
-		return -EIO;
+		return fd;
 	}
 	size = os_filesize(fd);
 	if (size < 0) {
@@ -242,7 +246,7 @@ int os_map_file(const char *pathname, int os_flags, void **bufp, int *sizep)
 	ifd = os_open(pathname, os_flags);
 	if (ifd < 0) {
 		printf("Cannot open file '%s'\n", pathname);
-		return -EIO;
+		return ifd;
 	}
 	size = os_filesize(ifd);
 	if (size < 0) {

drivers/block/host_dev.c

@@ -39,11 +39,11 @@ static int host_sb_attach_file(struct udevice *dev, const char *filename)
 		return ret;
 
 	fd = os_open(filename, OS_O_RDWR);
-	if (fd == -1) {
+	if (fd < 0) {
 		printf("Failed to access host backing file '%s', trying read-only\n",
 		       filename);
 		fd = os_open(filename, OS_O_RDONLY);
-		if (fd == -1) {
+		if (fd < 0) {
 			printf("- still failed\n");
 			return log_msg_ret("open", -ENOENT);
 		}

drivers/mtd/spi/sandbox.c

@@ -171,7 +171,7 @@ static int sandbox_sf_probe(struct udevice *dev)
 		memset(sandbox_sf_0xff, 0xff, sizeof(sandbox_sf_0xff));
 
 	sbsf->fd = os_open(pdata->filename, 02);
-	if (sbsf->fd == -1) {
+	if (sbsf->fd < 0) {
 		printf("%s: unable to open file '%s'\n", __func__,
 		       pdata->filename);
 		ret = -EIO;

drivers/scsi/sandbox_scsi.c

@@ -105,7 +105,7 @@ static int sandbox_scsi_probe(struct udevice *dev)
 
 	if (priv->pathname) {
 		priv->fd = os_open(priv->pathname, OS_O_RDONLY);
-		if (priv->fd != -1) {
+		if (priv->fd >= 0) {
 			ret = os_get_filesize(priv->pathname, &info->file_size);
 			if (ret)
 				return log_msg_ret("sz", ret);

drivers/usb/emul/sandbox_flash.c

@@ -342,7 +342,7 @@ static int sandbox_flash_probe(struct udevice *dev)
 	int ret;
 
 	priv->fd = os_open(plat->pathname, OS_O_RDWR);
-	if (priv->fd != -1) {
+	if (priv->fd >= 0) {
 		ret = os_get_filesize(plat->pathname, &info->file_size);
 		if (ret)
 			return log_msg_ret("sz", ret);

include/os.h

@@ -71,7 +71,7 @@ off_t os_filesize(int fd);
  *
  * @pathname:	Pathname of file to open
  * @flags:	Flags, like OS_O_RDONLY, OS_O_RDWR
- * Return:	file descriptor, or -1 on error
+ * Return:	file descriptor, or -errno on error
  */
 int os_open(const char *pathname, int flags);