svn commit: trunk/busybox: archival libbb

[vda at busybox.net]

Author: vda
Date: 2006-11-24 06:55:23 -0800 (Fri, 24 Nov 2006)
New Revision: 16653

Log:
tar: cry murder and bail out if file shrinks under us while we tar it up


Modified:
   trunk/busybox/archival/tar.c
   trunk/busybox/libbb/copyfd.c


Changeset:
Modified: trunk/busybox/archival/tar.c
===================================================================
--- trunk/busybox/archival/tar.c	2006-11-24 14:54:27 UTC (rev 16652)
+++ trunk/busybox/archival/tar.c	2006-11-24 14:55:23 UTC (rev 16653)
@@ -59,7 +59,7 @@
 typedef struct TarHeader TarHeader;
 
 /*
-** writeTarFile(),  writeFileToTarball(), and writeTarHeader() are
+** writeTarFile(), writeFileToTarball(), and writeTarHeader() are
 ** the only functions that deal with the HardLinkInfo structure.
 ** Even these functions use the xxxHardLinkInfo() functions.
 */
@@ -397,7 +397,17 @@
 		off_t readSize = 0;
 
 		/* write the file to the archive */
-		readSize = bb_copyfd_eof(inputFileFd, tbInfo->tarFd);
+		readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
+		if (readSize != statbuf->st_size) {
+			/* Deadly. We record size into header first, */
+			/* and then write out file. If file shrinks in between, */
+			/* tar will be corrupted. So bail out. */
+			/* NB: GNU tar 1.16 warns and pads with zeroes */
+			/* or even seeks back and updates header */
+			bb_error_msg_and_die("short read from %s", fileName);
+		}
+		/* Check that file did not grow in between? */
+		/* if (safe_read(inputFileFd,1) == 1) warn but continue? */
 		close(inputFileFd);
 
 		/* Pad the file up to the tar block size */

Modified: trunk/busybox/libbb/copyfd.c
===================================================================
--- trunk/busybox/libbb/copyfd.c	2006-11-24 14:54:27 UTC (rev 16652)
+++ trunk/busybox/libbb/copyfd.c	2006-11-24 14:55:23 UTC (rev 16653)
@@ -46,8 +46,7 @@
 		} else if (rd < 0) {
 			bb_perror_msg(bb_msg_read_error);
 			break;
-		} else if (rd == 0) {
-			/* All done. */
+		} else { /* eof - all done. */
 			status = 0;
 			break;
 		}