svn commit: r213643 - head/usr.bin/ar

[Tim Kientzle]

Author: kientzle
Date: Sat Oct  9 05:31:08 2010
New Revision: 213643
URL: http://svn.freebsd.org/changeset/base/213643

Log:
  Add -D (deterministic) option to ar.
  When set, it forces all timestamps and owners to zero and
  modes to 0644.  Useful for producing libraries that are
  bitwise identical across multiple build runs.
  
  Submitted by:	Erik Cederstrand
  Reviewed by:	Kai Wang

Modified:
  head/usr.bin/ar/ar.1
  head/usr.bin/ar/ar.c
  head/usr.bin/ar/ar.h
  head/usr.bin/ar/write.c

Modified: head/usr.bin/ar/ar.1
==============================================================================
--- head/usr.bin/ar/ar.1	Sat Oct  9 02:50:23 2010	(r213642)
+++ head/usr.bin/ar/ar.1	Sat Oct  9 05:31:08 2010	(r213643)
@@ -62,6 +62,7 @@
 .Op Fl a Ar position-after
 .Op Fl b Ar position-before
 .Op Fl c
+.Op Fl D
 .Op Fl i Ar position-before
 .Op Fl j
 .Op Fl s
@@ -179,6 +180,16 @@ from the archive specified by argument
 .Ar archive .
 The archive's symbol table, if present, is updated to reflect
 the new contents of the archive.
+.It Fl D
+When used in combination with the 
+.Fl r
+or
+.Fl q
+option, insert 0's instead of the real mtime, uid and gid values 
+and 0644 instead of file mode from the members named by arguments
+.Ar files ... .
+This ensures that checksums on the resulting archives are reproducible
+when member contents are identical.
 .It Fl f
 Synonymous with option
 .Fl T .

Modified: head/usr.bin/ar/ar.c
==============================================================================
--- head/usr.bin/ar/ar.c	Sat Oct  9 02:50:23 2010	(r213642)
+++ head/usr.bin/ar/ar.c	Sat Oct  9 05:31:08 2010	(r213643)
@@ -154,7 +154,7 @@ main(int argc, char **argv)
 		}
 	}
 
-	while ((opt = getopt_long(argc, argv, "abCcdfijlMmopqrSsTtuVvxz",
+	while ((opt = getopt_long(argc, argv, "abCcdDfijlMmopqrSsTtuVvxz",
 	    longopts, NULL)) != -1) {
 		switch(opt) {
 		case 'a':
@@ -173,6 +173,9 @@ main(int argc, char **argv)
 		case 'd':
 			set_mode(bsdar, opt);
 			break;
+		case 'D':
+			bsdar->options |= AR_D;
+			break;
 		case 'f':
 		case 'T':
 			bsdar->options |= AR_TR;
@@ -269,6 +272,8 @@ main(int argc, char **argv)
 		only_mode(bsdar, "-c", "qr");
 	if (bsdar->options & AR_CC)
 		only_mode(bsdar, "-C", "x");
+	if (bsdar->options & AR_D)
+		only_mode(bsdar, "-D", "qr");
 	if (bsdar->options & AR_O)
 		only_mode(bsdar, "-o", "x");
 	if (bsdar->options & AR_SS)
@@ -356,9 +361,9 @@ bsdar_usage(void)
 	(void)fprintf(stderr, "\tar -m [-Tjsvz] archive file ...\n");
 	(void)fprintf(stderr, "\tar -m [-Tabijsvz] position archive file ...\n");
 	(void)fprintf(stderr, "\tar -p [-Tv] archive [file ...]\n");
-	(void)fprintf(stderr, "\tar -q [-Tcjsvz] archive file ...\n");
-	(void)fprintf(stderr, "\tar -r [-Tcjsuvz] archive file ...\n");
-	(void)fprintf(stderr, "\tar -r [-Tabcijsuvz] position archive file ...\n");
+	(void)fprintf(stderr, "\tar -q [-TcDjsvz] archive file ...\n");
+	(void)fprintf(stderr, "\tar -r [-TcDjsuvz] archive file ...\n");
+	(void)fprintf(stderr, "\tar -r [-TabcDijsuvz] position archive file ...\n");
 	(void)fprintf(stderr, "\tar -s [-jz] archive\n");
 	(void)fprintf(stderr, "\tar -t [-Tv] archive [file ...]\n");
 	(void)fprintf(stderr, "\tar -x [-CTouv] archive [file ...]\n");

Modified: head/usr.bin/ar/ar.h
==============================================================================
--- head/usr.bin/ar/ar.h	Sat Oct  9 02:50:23 2010	(r213642)
+++ head/usr.bin/ar/ar.h	Sat Oct  9 05:31:08 2010	(r213643)
@@ -43,6 +43,7 @@
 #define AR_U	0x0200		/* only extract or update newer members.*/
 #define AR_V	0x0400		/* verbose mode */
 #define AR_Z	0x0800		/* gzip compression */
+#define AR_D	0x1000		/* insert dummy mode, mtime, uid and gid */
 
 #define DEF_BLKSZ 10240		/* default block size */
 

Modified: head/usr.bin/ar/write.c
==============================================================================
--- head/usr.bin/ar/write.c	Sat Oct  9 02:50:23 2010	(r213642)
+++ head/usr.bin/ar/write.c	Sat Oct  9 05:31:08 2010	(r213643)
@@ -163,11 +163,24 @@ create_obj_from_file(struct bsdar *bsdar
 	if (mtime != 0 && bsdar->options & AR_U && sb.st_mtime <= mtime)
 		goto giveup;
 
-	obj->uid = sb.st_uid;
-	obj->gid = sb.st_gid;
-	obj->md = sb.st_mode;
+	/*
+	 * When option '-D' is specified, mtime and UID / GID from the file
+	 * will be replaced with 0, and file mode with 644. This ensures that 
+	 * checksums will match for two archives containing the exact same
+	 * files.
+	 */
+	if (bsdar->options & AR_D) {
+		obj->uid = 0;
+		obj->gid = 0;
+		obj->mtime = 0;
+		obj->md = S_IFREG | 0644;
+	} else {
+		obj->uid = sb.st_uid;
+		obj->gid = sb.st_gid;
+		obj->mtime = sb.st_mtime;
+		obj->md = sb.st_mode;
+	}
 	obj->size = sb.st_size;
-	obj->mtime = sb.st_mtime;
 	obj->dev = sb.st_dev;
 	obj->ino = sb.st_ino;
 
@@ -621,7 +634,8 @@ write_objs(struct bsdar *bsdar)
 	    bsdar->options & AR_S) {
 		entry = archive_entry_new();
 		archive_entry_copy_pathname(entry, "/");
-		archive_entry_set_mtime(entry, time(NULL), 0);
+		if ((bsdar->options & AR_D) == 0)
+			archive_entry_set_mtime(entry, time(NULL), 0);
 		archive_entry_set_size(entry, (bsdar->s_cnt + 1) *
 		    sizeof(uint32_t) + bsdar->s_sn_sz);
 		AC(archive_write_header(a, entry));