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

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This commit is contained in:
Denis Vlasenko 2006-11-24 14:55:23 +00:00
parent 0b35470d9b
commit 4fbb584a0e
2 changed files with 13 additions and 4 deletions
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14
archival/tar.c
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@ -59,7 +59,7 @@ struct TarHeader { /* byte offset */
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 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
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 */

3
libbb/copyfd.c
View File

@ -46,8 +46,7 @@ static off_t bb_full_fd_action(int src_fd, int dst_fd, off_t size)
} 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;
}