[PATCH] kexec: determine size of block device

Andreas Fenkart afenkart at gmail.com
Fri Oct 9 06:27:18 PDT 2015


starting 'kexec -l /dev/mmcblk0p1' fails since the size of
a block device can not be determined with stat

Signed-off-by: Andreas Fenkart <andreas.fenkart at dev.digitalstrom.org>
---
 kexec/kexec.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kexec/kexec.c b/kexec/kexec.c
index ff024f3..8b8846e 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -26,7 +26,9 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <limits.h>
+#include <sys/ioctl.h>
 #include <sys/mman.h>
+#include <sys/mount.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/reboot.h>
@@ -554,6 +556,14 @@ char *slurp_file(const char *filename, off_t *r_size)
 			die("Can not seek to the begin of file %s: %s\n",
 					filename, strerror(errno));
 		buf = slurp_fd(fd, filename, size, &nread);
+    } else if (S_ISBLK(stats.st_mode)) {
+		/* taken from blockdev */
+		unsigned long long llu = -1;
+		err = ioctl(fd, BLKGETSIZE64, &llu);
+		if (err < 0)
+			die("Can't retrieve size of block device %s: %s\n",
+				filename, strerror(errno));
+		size = llu;
 	} else {
 		size = nread = stats.st_size;
 		buf = mmap(NULL, size,
-- 
2.5.1




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