From: root <root@172.16.239.132>
Date: Sun, 16 Oct 2022 15:53:02 +0000 (+0800)
Subject: mkfs.cramfs: Support BSD lock
X-Git-Tag: v2.39-rc1~484
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=57fdc17c92295d37ccf12f3cf32a1760499dcd3d;p=thirdparty%2Futil-linux.git

mkfs.cramfs: Support BSD lock

Addresses: #1842 #921
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/disk-utils/mkfs.cramfs.8.adoc b/disk-utils/mkfs.cramfs.8.adoc
index 67f0e629d9..14ce8de823 100644
--- a/disk-utils/mkfs.cramfs.8.adoc
+++ b/disk-utils/mkfs.cramfs.8.adoc
@@ -62,6 +62,15 @@ This option is ignored. Originally the *-s* turned on directory entry sorting.
 *-z*::
 Make explicit holes.
 
+*-l*\fR[=\fImode\fR]::
+ Use exclusive BSD lock for device or file it operates.  The optional argument
+ \fImode\fP can be \fByes\fR, \fBno\fR (or 1 and 0) or \fBnonblock\fR.  If the \fImode\fR
+ argument is omitted, it defaults to \fB"yes"\fR.  This option overwrites
+ environment variable \fB$LOCK_BLOCK_DEVICE\fR.  The default is not to use any
+ lock at all, but it's recommended to avoid collisions with udevd or other
+ tools.
+ .TP
+
 include::man-common/help-version.adoc[]
 
 == EXIT STATUS
diff --git a/disk-utils/mkfs.cramfs.c b/disk-utils/mkfs.cramfs.c
index 1fcb927782..20966526f5 100644
--- a/disk-utils/mkfs.cramfs.c
+++ b/disk-utils/mkfs.cramfs.c
@@ -44,6 +44,7 @@
  */
 #include <zlib.h>
 
+#include "blkdev.h"
 #include "c.h"
 #include "cramfs.h"
 #include "md5.h"
@@ -140,6 +141,7 @@ static void __attribute__((__noreturn__)) usage(void)
 	printf(_(" -p             pad by %d bytes for boot code\n"), PAD_SIZE);
 	puts(_(  " -s             sort directory entries (old option, ignored)"));
 	puts(_(  " -z             make explicit holes"));
+	puts(_(  " -l lockmode    use exclusive device lock (yes, no or nonblock)"));
 	puts(_(  " dirname        root of the filesystem to be compressed"));
 	puts(_(  " outfile        output file"));
 	fputs(USAGE_SEPARATOR, stdout);
@@ -707,6 +709,7 @@ int main(int argc, char **argv)
 	loff_t fslen_ub = sizeof(struct cramfs_super);
 	unsigned int fslen_max;
 	char const *dirname, *outfile;
+	char *lockmode = 0;
 	uint32_t crc = crc32(0L, NULL, 0);
 	int c;
 	cramfs_is_big_endian = HOST_IS_BIG_ENDIAN; /* default is to use host order */
@@ -730,7 +733,7 @@ int main(int argc, char **argv)
 	strutils_set_exitcode(MKFS_EX_USAGE);
 
 	/* command line options */
-	while ((c = getopt(argc, argv, "hb:Ee:i:n:N:psVvz")) != EOF) {
+	while ((c = getopt(argc, argv, "hb:Ee:i:n:N:l:psVvz")) != EOF) {
 		switch (c) {
 		case 'h':
 			usage();
@@ -761,6 +764,14 @@ int main(int argc, char **argv)
 			image_length = st.st_size; /* may be padded later */
 			fslen_ub += (image_length + 3); /* 3 is for padding */
 			break;
+		case 'l':
+                        lockmode = "1";
+			if (optarg) {
+                                if (*optarg == '=')
+					optarg++;
+				lockmode = optarg;
+			}
+			break;
 		case 'n':
 			opt_name = optarg;
 			break;
@@ -800,6 +811,9 @@ int main(int argc, char **argv)
 	if (fd < 0)
 		err(MKFS_EX_USAGE, _("cannot open %s"), outfile);
 
+        if (blkdev_lock(fd, outfile, lockmode) != 0)
+		exit(MKFS_EX_ERROR);
+
 	root_entry = xcalloc(1, sizeof(struct entry));
 	root_entry->mode = st.st_mode;
 	root_entry->uid = st.st_uid;