diff mbox

[1/2] get_partition_size() doens't require root privileges

Message ID 20170925201815.10161-2-kreijack@libero.it (mailing list archive)
State New, archived
Headers show

Commit Message

Goffredo Baroncelli Sept. 25, 2017, 8:18 p.m. UTC 
From: Goffredo Baroncelli <kreijack@inwind.it>

Allow the get_partition_size() to be called without
root privileges.

Signed-off-by: Goffredo baroncelli <kreijack@inwind.it>
---
 utils.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)
diff mbox

Patch

diff --git a/utils.c b/utils.c
index 7a2710fe..ee3ed544 100644
--- a/utils.c
+++ b/utils.c
@@ -2080,18 +2080,29 @@  u64 disk_size(const char *path)
 
 u64 get_partition_size(const char *dev)
 {
-	u64 result;
-	int fd = open(dev, O_RDONLY);
+	struct stat statbuf;
+	int r;
+	int fd;
+	char buf[100];
 
-	if (fd < 0)
-		return 0;
-	if (ioctl(fd, BLKGETSIZE64, &result) < 0) {
-		close(fd);
+	r = stat(dev, &statbuf);
+	if (r != 0)
 		return 0;
-	}
+
+	snprintf(buf, sizeof(buf),
+		"/sys/dev/block/%d:%d/size", major(statbuf.st_rdev),
+		 minor(statbuf.st_rdev));
+
+	fd = open(buf, O_RDONLY);
+	BUG_ON(fd < 0);
+
+	r = read(fd, buf, sizeof(buf)-1);
 	close(fd);
 
-	return result;
+	BUG_ON(r < 0);
+	buf[r] = 0;
+
+	return atoll(buf) * 512;
 }
 
 /*