Cleanup headers and replace the zero padding with an even smaller version.

One of the pads turned out to be unnecessary: sizeof(struct TarHeader) is
TAR_BLOCK_SIZE, the padding's in the struct.  The others could be done inline
with bb_common_bufsiz1.

This is a cleanup I did to Denis' patch long ago, but got sidetracked by
what turned into svn 15660.

1 files changed, 10 insertions, 46 deletions

diff --git a/archival/tar.c b/archival/tar.c
index 91232bcf3..5d9e870fa 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -23,21 +23,10 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <fcntl.h>
-#include <getopt.h>
-#include <search.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <fnmatch.h>
-#include <string.h>
-#include <errno.h>
-#include <signal.h>
-#include <sys/wait.h>
-#include <sys/socket.h>
-#include <sys/sysmacros.h>     /* major() and minor() */
-#include "unarchive.h"
 #include "busybox.h"
+#include "unarchive.h"
+#include <fnmatch.h>
+#include <getopt.h>
 
 #ifdef CONFIG_FEATURE_TAR_CREATE
 
@@ -192,26 +181,6 @@ static int putOctal(char *cp, int len, long value)
         return TRUE;
 }
 
-/* Pad file to TAR_BLOCK_SIZE with zeros */
-static void block_write_zeroes(int fd, size_t size)
-{
-        char zerobuf[TAR_BLOCK_SIZE];
-        memset(zerobuf, 0, size);
-        /* No point in trying to continue on error */
-        if (full_write(fd, zerobuf, size) < 0)
-                bb_perror_msg_and_die("write");
-}
-
-static size_t pad_block_write(int fd, size_t size)
-{
-        size_t rem = (TAR_BLOCK_SIZE - size) & (TAR_BLOCK_SIZE-1);
-        if (rem) {
-                block_write_zeroes(fd, rem);
-                size += rem;
-        }
-        return size;
-}
-
 /* Write out a tar header for the specified file/directory/whatever */
 static int writeTarHeader(struct TarBallInfo *tbInfo,
                 const char *header_name, const char *fileName, struct stat *statbuf)
@@ -221,7 +190,7 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
         const unsigned char *cp = (const unsigned char *) &header;
         ssize_t size = sizeof(struct TarHeader);
 
-        memset(&header, 0, size);
+        bzero(&header, size);
 
         safe_strncpy(header.name, header_name, sizeof(header.name));
 
@@ -288,14 +257,7 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
         putOctal(header.chksum, 7, chksum);
 
         /* Now write the header out to disk */
-        size = full_write(tbInfo->tarFd, (char *) &header,
-                                        sizeof(struct TarHeader));
-        if (size < 0) {
-                bb_error_msg(bb_msg_io_error, fileName);
-                return FALSE;
-        }
-        /* Pad the header up to the tar block size */
-        size = pad_block_write(tbInfo->tarFd, size);
+        xwrite(tbInfo->tarFd, &header, sizeof(struct TarHeader));
 
         /* Now do the verbose thing (or not) */
 
@@ -421,7 +383,9 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
                 close(inputFileFd);
 
                 /* Pad the file up to the tar block size */
-                readSize = pad_block_write(tbInfo->tarFd, readSize);
+                readSize = (TAR_BLOCK_SIZE - readSize) & (TAR_BLOCK_SIZE-1);
+                bzero(bb_common_bufsiz1, readSize);
+                xwrite(tbInfo->tarFd, bb_common_bufsiz1, readSize);
         }
 
         return TRUE;
@@ -516,8 +480,8 @@ static int writeTarFile(const int tar_fd, const int verboseFlag,
                 include = include->link;
         }
         /* Write two empty blocks to the end of the archive */
-        block_write_zeroes(tbInfo.tarFd, TAR_BLOCK_SIZE);
-        block_write_zeroes(tbInfo.tarFd, TAR_BLOCK_SIZE);
+        bzero(bb_common_bufsiz1, 2*TAR_BLOCK_SIZE);
+        xwrite(tbInfo.tarFd, bb_common_bufsiz1, 2*TAR_BLOCK_SIZE);
 
         /* To be pedantically correct, we would check if the tarball
          * is smaller than 20 tar blocks, and pad it if it was smaller,