We need to enforce that the opened file is a block device, as opening a file with the O_EXCL flag on and the O_CREATE flag off has undefined behavior unless the file is a block device.
Signed-off-by: Ari Sundholm <[email protected]> --- util-linux/blkdiscard.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/util-linux/blkdiscard.c b/util-linux/blkdiscard.c index ace88a1..1b234fa 100644 --- a/util-linux/blkdiscard.c +++ b/util-linux/blkdiscard.c @@ -38,7 +38,7 @@ int blkdiscard_main(int argc UNUSED_PARAM, char **argv) uint64_t offset; /* Leaving these two variables out does not */ uint64_t length; /* shrink code size and hampers readability. */ uint64_t range[2]; -// struct stat st; + struct stat st; int fd; enum { @@ -51,11 +51,15 @@ int blkdiscard_main(int argc UNUSED_PARAM, char **argv) opts = getopt32(argv, "o:l:s", &offset_str, &length_str); argv += optind; + /* We need to enforce that the opened file is a block device, as + * opening a file with the O_EXCL flag on and the O_CREATE flag off has + * undefined behavior unless the file is a block device. + */ + xstat(argv[0], &st); + if (!S_ISBLK(st.st_mode)) + bb_error_msg_and_die("%s: not a block device", argv[0]); + fd = xopen(argv[0], O_RDWR|O_EXCL); -//Why bother, BLK[SEC]DISCARD will fail on non-blockdevs anyway? -// xfstat(fd, &st); -// if (!S_ISBLK(st.st_mode)) -// bb_error_msg_and_die("%s: not a block device", argv[0]); offset = xatoull_sfx(offset_str, kMG_suffixes); -- 1.9.1 _______________________________________________ busybox mailing list [email protected] http://lists.busybox.net/mailman/listinfo/busybox
