[PATCH 1/2] libmtd: add `mtd_dev_present()' library function

[Brian Norris <computersforpeace@gmail.com>]

Will be used for `mtdinfo --all'

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
 include/libmtd.h |    9 +++++++++
 lib/libmtd.c     |   22 ++++++++++++----------
 2 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/include/libmtd.h b/include/libmtd.h
index 07c304a..a78c8cb 100644
--- a/include/libmtd.h
+++ b/include/libmtd.h
@@ -106,6 +106,15 @@ libmtd_t libmtd_open(void);
 void libmtd_close(libmtd_t desc);
 
 /**
+ * mtd_dev_present - check whether a MTD device is present.
+ * @desc: MTD library descriptor
+ * @mtd_num: MTD device number to check
+ *
+ * This function returns %1 if MTD device is present and %0 if not.
+ */
+int mtd_dev_present(libmtd_t desc, int mtd_num);
+
+/**
  * mtd_get_info - get general MTD information.
  * @desc: MTD library descriptor
  * @info: the MTD device information is returned here
diff --git a/lib/libmtd.c b/lib/libmtd.c
index c6e5b20..9786e83 100644
--- a/lib/libmtd.c
+++ b/lib/libmtd.c
@@ -713,10 +713,18 @@ out_close:
 	return -1;
 }
 
+int mtd_dev_present(libmtd_t desc, int mtd_num) {
+	struct stat st;
+	struct libmtd *lib = (struct libmtd *)desc;
+	char file[strlen(lib->mtd) + 10];
+
+	sprintf(file, lib->mtd, mtd_num);
+	return !stat(file, &st);
+}
+
 int mtd_get_dev_info1(libmtd_t desc, int mtd_num, struct mtd_dev_info *mtd)
 {
 	int ret;
-	struct stat st;
 	struct libmtd *lib = (struct libmtd *)desc;
 
 	memset(mtd, 0, sizeof(struct mtd_dev_info));
@@ -724,15 +732,9 @@ int mtd_get_dev_info1(libmtd_t desc, int mtd_num, struct mtd_dev_info *mtd)
 
 	if (!lib->sysfs_supported)
 		return legacy_get_dev_info1(mtd_num, mtd);
-	else {
-		char file[strlen(lib->mtd) + 10];
-
-		sprintf(file, lib->mtd, mtd_num);
-		if (stat(file, &st)) {
-			if (errno == ENOENT)
-				errno = ENODEV;
-			return -1;
-		}
+	else if (!mtd_dev_present(desc, mtd_num)) {
+		errno = ENODEV;
+		return -1;
 	}
 
 	if (dev_get_major(lib, mtd_num, &mtd->major, &mtd->minor))
-- 
1.7.5.4