From 431a7c9c53b69a7416091721da673bcff7c91a02 Mon Sep 17 00:00:00 2001 From: Denis Vlasenko Date: Tue, 19 Feb 2008 11:26:28 +0000 Subject: [PATCH] tar: optional autodetection of gz/bz2 compressed tarballs. +130 bytes. Closes bug 992. --- archival/Config.in | 36 +++++++++++------- archival/libunarchive/get_header_tar.c | 52 ++++++++++++++++++++++---- archival/tar.c | 35 ++++++++++++----- 3 files changed, 92 insertions(+), 31 deletions(-) diff --git a/archival/Config.in b/archival/Config.in index 160c54d64..6f803f4fe 100644 --- a/archival/Config.in +++ b/archival/Config.in @@ -166,6 +166,14 @@ config FEATURE_TAR_CREATE If you enable this option you'll be able to create tar archives using the `-c' option. +config FEATURE_TAR_GZIP + bool "Enable -z option" + default y + depends on TAR + help + If you enable this option tar will be able to call gzip, + when creating or extracting tar gziped archives. + config FEATURE_TAR_BZIP2 bool "Enable -j option to handle .tar.bz2 files" default n @@ -182,29 +190,29 @@ config FEATURE_TAR_LZMA If you enable this option you'll be able to extract archives compressed with lzma. -config FEATURE_TAR_FROM - bool "Enable -X (exclude from) and -T (include from) options)" +config FEATURE_TAR_COMPRESS + bool "Enable -Z option" default n depends on TAR help - If you enable this option you'll be able to specify - a list of files to include or exclude from an archive. + If you enable this option tar will be able to call uncompress, + when extracting .tar.Z archives. -config FEATURE_TAR_GZIP - bool "Enable -z option" - default y - depends on TAR +config FEATURE_TAR_AUTODETECT + bool "Let tar autodetect gz/bz2 compresses tarballs" + default n + depends on FEATURE_TAR_GZIP || FEATURE_TAR_BZIP2 help - If you enable this option tar will be able to call gzip, - when creating or extracting tar gziped archives. + With this option tar can automatically detect gzip/bzip2 compressed + tarballs. Currently it works only on seekable streams. -config FEATURE_TAR_COMPRESS - bool "Enable -Z option" +config FEATURE_TAR_FROM + bool "Enable -X (exclude from) and -T (include from) options)" default n depends on TAR help - If you enable this option tar will be able to call uncompress, - when extracting .tar.Z archives. + If you enable this option you'll be able to specify + a list of files to include or exclude from an archive. config FEATURE_TAR_OLDGNU_COMPATIBILITY bool "Enable support for old tar header format" diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c index 893cd5b79..54c8f7665 100644 --- a/archival/libunarchive/get_header_tar.c +++ b/archival/libunarchive/get_header_tar.c @@ -46,6 +46,9 @@ void BUG_tar_header_size(void); char get_header_tar(archive_handle_t *archive_handle) { static smallint end; +#if ENABLE_FEATURE_TAR_AUTODETECT + static smallint not_first; +#endif file_header_t *file_header = archive_handle->file_header; struct { @@ -115,7 +118,7 @@ char get_header_tar(archive_handle_t *archive_handle) * Read until the end to empty the pipe from gz or bz2 */ while (full_read(archive_handle->src_fd, &tar, 512) == 512) - /* repeat */; + continue; return EXIT_FAILURE; } end = 1; @@ -123,16 +126,49 @@ char get_header_tar(archive_handle_t *archive_handle) } end = 0; - /* Check header has valid magic, "ustar" is for the proper tar - * 0's are for the old tar format - */ - if (strncmp(tar.magic, "ustar", 5) != 0) { -#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY - if (memcmp(tar.magic, "\0\0\0\0", 5) != 0) + /* Check header has valid magic, "ustar" is for the proper tar, + * five NULs are for the old tar format */ + if (strncmp(tar.magic, "ustar", 5) != 0 + && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY + || memcmp(tar.magic, "\0\0\0\0", 5) != 0) + ) { +#if ENABLE_FEATURE_TAR_AUTODETECT + char (*get_header_ptr)(archive_handle_t *); + + /* tar gz/bz autodetect: check for gz/bz2 magic. + * If it is the very first block, and we see the magic, + * we can switch to get_header_tar_gz/bz2/lzma(). + * Needs seekable fd. I wish recv(MSG_PEEK) would work + * on any fd... */ + if (not_first) + goto err; +#if ENABLE_FEATURE_TAR_GZIP + if (tar.name[0] == 0x1f && tar.name[1] == 0x8b) { /* gzip */ + get_header_ptr = get_header_tar_gz; + } else #endif - bb_error_msg_and_die("invalid tar magic"); +#if ENABLE_FEATURE_TAR_BZIP2 + if (tar.name[0] == 'B' && tar.name[1] == 'Z' + && tar.name[2] == 'h' && isdigit(tar.name[3]) + ) { /* bzip2 */ + get_header_ptr = get_header_tar_bz2; + } else +#endif + goto err; + if (lseek(archive_handle->src_fd, -512, SEEK_CUR) != 0) + goto err; + while (get_header_ptr(archive_handle) == EXIT_SUCCESS) + continue; + return EXIT_FAILURE; + err: +#endif /* FEATURE_TAR_AUTODETECT */ + bb_error_msg_and_die("invalid tar magic"); } +#if ENABLE_FEATURE_TAR_AUTODETECT + not_first = 1; +#endif + /* Do checksum on headers. * POSIX says that checksum is done on unsigned bytes, but * Sun and HP-UX gets it wrong... more details in diff --git a/archival/tar.c b/archival/tar.c index 4ec454b88..e790f28ea 100644 --- a/archival/tar.c +++ b/archival/tar.c @@ -33,8 +33,17 @@ #define FNM_LEADING_DIR 0 #endif + #define block_buf bb_common_bufsiz1 + +#if !ENABLE_FEATURE_TAR_GZIP && !ENABLE_FEATURE_TAR_BZIP2 +/* Do not pass gzip flag to writeTarFile() */ +#define writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude, gzip) \ + writeTarFile(tar_fd, verboseFlag, dereferenceFlag, include, exclude) +#endif + + #if ENABLE_FEATURE_TAR_CREATE /* Tar file constants */ @@ -514,18 +523,23 @@ static int writeTarFile(const int tar_fd, const int verboseFlag, if (fstat(tbInfo.tarFd, &tbInfo.statBuf) < 0) bb_perror_msg_and_die("cannot stat tar file"); - if ((ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2) && gzip) { -// On Linux, vfork never unpauses parent early, although standard -// allows for that. Do we want to waste bytes checking for it? +#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2 + if (gzip) { +#if ENABLE_FEATURE_TAR_GZIP && ENABLE_FEATURE_TAR_BZIP2 + const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2"; +#elif ENABLE_FEATURE_TAR_GZIP + const char *zip_exec = "gzip"; +#else /* only ENABLE_FEATURE_TAR_BZIP2 */ + const char *zip_exec = "bzip2"; +#endif + // On Linux, vfork never unpauses parent early, although standard + // allows for that. Do we want to waste bytes checking for it? #define WAIT_FOR_CHILD 0 - volatile int vfork_exec_errno = 0; #if WAIT_FOR_CHILD struct fd_pair gzipStatusPipe; #endif struct fd_pair gzipDataPipe; - const char *zip_exec = (gzip == 1) ? "gzip" : "bzip2"; - xpiped_pair(gzipDataPipe); #if WAIT_FOR_CHILD xpiped_pair(gzipStatusPipe); @@ -584,6 +598,7 @@ static int writeTarFile(const int tar_fd, const int verboseFlag, bb_perror_msg_and_die("cannot exec %s", zip_exec); } } +#endif tbInfo.excludeList = exclude; @@ -934,11 +949,13 @@ int tar_main(int argc, char **argv) /* create an archive */ if (opt & OPT_CREATE) { +#if ENABLE_FEATURE_TAR_GZIP || ENABLE_FEATURE_TAR_BZIP2 int zipMode = 0; - if (ENABLE_FEATURE_TAR_GZIP && get_header_ptr == get_header_tar_gz) + if (ENABLE_FEATURE_TAR_GZIP && (opt & OPT_GZIP)) zipMode = 1; - if (ENABLE_FEATURE_TAR_BZIP2 && get_header_ptr == get_header_tar_bz2) + if (ENABLE_FEATURE_TAR_BZIP2 && (opt & OPT_BZIP2)) zipMode = 2; +#endif /* NB: writeTarFile() closes tar_handle->src_fd */ return writeTarFile(tar_handle->src_fd, verboseFlag, opt & OPT_DEREFERENCE, tar_handle->accept, @@ -946,7 +963,7 @@ int tar_main(int argc, char **argv) } while (get_header_ptr(tar_handle) == EXIT_SUCCESS) - /* nothing */; + continue; /* Check that every file that should have been extracted was */ while (tar_handle->accept) { -- 2.25.1