[git commit master 1/1] tar: fix --to-command wrt short writes

Denys Vlasenko vda.linux at googlemail.com
Sat Jun 26 16:11:44 UTC 2010


commit: http://git.busybox.net/busybox/commit/?id=d0a8a0d31243f2ac798531ced2cca45ddf1fea42
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master

function                                             old     new   delta
bb_copyfd_exact_size                                  51      98     +47
bb_full_fd_action                                    362     394     +32
get_header_tar                                      1546    1558     +12
data_extract_to_command                              430     439      +9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 100/0)             Total: 100 bytes

Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
 archival/libunarchive/data_extract_to_command.c |    2 +-
 libbb/copyfd.c                                  |   21 ++++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/archival/libunarchive/data_extract_to_command.c b/archival/libunarchive/data_extract_to_command.c
index 983c530..53a7217 100644
--- a/archival/libunarchive/data_extract_to_command.c
+++ b/archival/libunarchive/data_extract_to_command.c
@@ -108,7 +108,7 @@ void FAST_FUNC data_extract_to_command(archive_handle_t *archive_handle)
 		close(p[0]);
 		/* Our caller is expected to do signal(SIGPIPE, SIG_IGN)
 		 * so that we don't die if child don't read all the input: */
-		bb_copyfd_exact_size(archive_handle->src_fd, p[1], file_header->size);
+		bb_copyfd_exact_size(archive_handle->src_fd, p[1], -file_header->size);
 		close(p[1]);
 
 		if (safe_waitpid(pid, &status, 0) == -1)
diff --git a/libbb/copyfd.c b/libbb/copyfd.c
index f42eb76..2538d49 100644
--- a/libbb/copyfd.c
+++ b/libbb/copyfd.c
@@ -9,8 +9,10 @@
 
 #include "libbb.h"
 
-/* Used by NOFORK applets (e.g. cat) - must not use xmalloc */
-
+/* Used by NOFORK applets (e.g. cat) - must not use xmalloc.
+ * size < 0 means "ignore write errors", used by tar --to-command
+ * size = 0 means "copy till EOF"
+ */
 static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 {
 	int status = -1;
@@ -21,6 +23,12 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 #else
 	char *buffer;
 	int buffer_size;
+	bool continue_on_write_error = 0;
+
+	if (size < 0) {
+		size = -size;
+		continue_on_write_error = 1;
+	}
 
 	if (size > 0 && size <= 4 * 1024)
 		goto use_small_buf;
@@ -63,8 +71,11 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
 		if (dst_fd >= 0) {
 			ssize_t wr = full_write(dst_fd, buffer, rd);
 			if (wr < rd) {
-				bb_perror_msg(bb_msg_write_error);
-				break;
+				if (!continue_on_write_error) {
+					bb_perror_msg(bb_msg_write_error);
+					break;
+				}
+				dst_fd = -1;
 			}
 		}
 		total += rd;
@@ -108,7 +119,7 @@ off_t FAST_FUNC bb_copyfd_size(int fd1, int fd2, off_t size)
 void FAST_FUNC bb_copyfd_exact_size(int fd1, int fd2, off_t size)
 {
 	off_t sz = bb_copyfd_size(fd1, fd2, size);
-	if (sz == size)
+	if (sz == (size >= 0 ? size : -size))
 		return;
 	if (sz != -1)
 		bb_error_msg_and_die("short read");
-- 
1.7.1



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