* unpack: handle tar header fields which are not NUL terminated * pack: handle 4+GB files correctly * pack: refuse to store 101+ softlinks (was truncating link target name) * pack: mask mode with 07777
228 lines
6.3 KiB
C
228 lines
6.3 KiB
C
/* vi: set sw=4 ts=4: */
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/* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*
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* FIXME:
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* In privileged mode if uname and gname map to a uid and gid then use the
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* mapped value instead of the uid/gid values in tar header
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*
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* References:
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* GNU tar and star man pages,
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* Opengroup's ustar interchange format,
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* http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
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*/
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#include "libbb.h"
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#include "unarchive.h"
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#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
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static char *longname = NULL;
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static char *linkname = NULL;
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#endif
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/* NB: _DESTROYS_ str[len] character! */
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static unsigned long long getOctal(char *str, int len)
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{
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unsigned long long v;
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/* Actually, tar header allows leading spaces also.
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* Oh well, we will be liberal and skip this...
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* The only downside probably is that we allow "-123" too :)
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if (*str < '0' || *str > '7')
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bb_error_msg_and_die("corrupted octal value in tar header");
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*/
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str[len] = '\0';
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v = strtoull(str, &str, 8);
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if (*str)
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bb_error_msg_and_die("corrupted octal value in tar header");
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return v;
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}
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void BUG_tar_header_size(void);
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char get_header_tar(archive_handle_t *archive_handle)
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{
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static int end = 0;
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file_header_t *file_header = archive_handle->file_header;
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struct {
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/* ustar header, Posix 1003.1 */
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char name[100]; /* 0-99 */
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char mode[8]; /* 100-107 */
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char uid[8]; /* 108-115 */
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char gid[8]; /* 116-123 */
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char size[12]; /* 124-135 */
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char mtime[12]; /* 136-147 */
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char chksum[8]; /* 148-155 */
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char typeflag; /* 156-156 */
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char linkname[100]; /* 157-256 */
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char magic[6]; /* 257-262 */
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char version[2]; /* 263-264 */
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char uname[32]; /* 265-296 */
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char gname[32]; /* 297-328 */
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char devmajor[8]; /* 329-336 */
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char devminor[8]; /* 337-344 */
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char prefix[155]; /* 345-499 */
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char padding[12]; /* 500-512 */
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} tar;
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char *cp;
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int sum, i;
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if (sizeof(tar) != 512)
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BUG_tar_header_size();
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/* Align header */
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data_align(archive_handle, 512);
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xread(archive_handle->src_fd, &tar, 512);
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archive_handle->offset += 512;
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/* If there is no filename its an empty header */
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if (tar.name[0] == 0) {
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if (end) {
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/* This is the second consecutive empty header! End of archive!
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* Read until the end to empty the pipe from gz or bz2
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*/
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while (full_read(archive_handle->src_fd, &tar, 512) == 512)
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/* repeat */;
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return EXIT_FAILURE;
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}
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end = 1;
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return EXIT_SUCCESS;
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}
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end = 0;
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/* Check header has valid magic, "ustar" is for the proper tar
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* 0's are for the old tar format
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*/
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if (strncmp(tar.magic, "ustar", 5) != 0) {
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#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATIBILITY
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if (memcmp(tar.magic, "\0\0\0\0", 5) != 0)
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#endif
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bb_error_msg_and_die("invalid tar magic");
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}
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/* Do checksum on headers */
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sum = ' ' * sizeof(tar.chksum);
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for (i = 0; i < 148 ; i++) {
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sum += ((char*)&tar)[i];
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}
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for (i = 156; i < 512 ; i++) {
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sum += ((char*)&tar)[i];
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}
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/* This field does not need special treatment (getOctal) */
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if (sum != xstrtoul(tar.chksum, 8)) {
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bb_error_msg_and_die("invalid tar header checksum");
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}
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#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
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if (longname) {
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file_header->name = longname;
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longname = NULL;
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}
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else if (linkname) {
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file_header->name = linkname;
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linkname = NULL;
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} else
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#endif
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{
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file_header->name = xstrndup(tar.name, sizeof(tar.name));
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if (tar.prefix[0]) {
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char *temp = file_header->name;
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file_header->name = concat_path_file(tar.prefix, temp);
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free(temp);
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}
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}
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/* getOctal trashes subsequent field, therefore we call it
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* on fields in reverse order */
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#define GET_OCTAL(a) getOctal((a), sizeof(a))
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if (tar.devmajor[0]) {
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unsigned minor = GET_OCTAL(tar.devminor);
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unsigned major = GET_OCTAL(tar.devmajor);
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file_header->device = makedev(major, minor);
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}
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file_header->mtime = GET_OCTAL(tar.mtime);
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file_header->size = GET_OCTAL(tar.size);
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file_header->gid = GET_OCTAL(tar.gid);
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file_header->uid = GET_OCTAL(tar.uid);
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file_header->link_name = !tar.linkname[0] ? NULL :
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xstrndup(tar.linkname, sizeof(tar.linkname));
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/* Set bits 0-11 of the files mode */
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file_header->mode = 07777 & GET_OCTAL(tar.mode);
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#undef GET_OCTAL
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/* Set bits 12-15 of the files mode */
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switch (tar.typeflag) {
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/* busybox identifies hard links as being regular files with 0 size and a link name */
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case '1':
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file_header->mode |= S_IFREG;
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break;
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case '7':
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/* Reserved for high performance files, treat as normal file */
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case 0:
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case '0':
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#ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATIBILITY
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if (last_char_is(file_header->name, '/')) {
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file_header->mode |= S_IFDIR;
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} else
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#endif
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file_header->mode |= S_IFREG;
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break;
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case '2':
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file_header->mode |= S_IFLNK;
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break;
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case '3':
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file_header->mode |= S_IFCHR;
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break;
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case '4':
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file_header->mode |= S_IFBLK;
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break;
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case '5':
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file_header->mode |= S_IFDIR;
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break;
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case '6':
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file_header->mode |= S_IFIFO;
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break;
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#ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
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case 'L':
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longname = xzalloc(file_header->size + 1);
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xread(archive_handle->src_fd, longname, file_header->size);
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archive_handle->offset += file_header->size;
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return get_header_tar(archive_handle);
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case 'K':
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linkname = xzalloc(file_header->size + 1);
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xread(archive_handle->src_fd, linkname, file_header->size);
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archive_handle->offset += file_header->size;
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file_header->name = linkname;
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return get_header_tar(archive_handle);
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case 'D': /* GNU dump dir */
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case 'M': /* Continuation of multi volume archive */
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case 'N': /* Old GNU for names > 100 characters */
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case 'S': /* Sparse file */
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case 'V': /* Volume header */
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#endif
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case 'g': /* pax global header */
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case 'x': /* pax extended header */
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bb_error_msg("ignoring extension type %c", tar.typeflag);
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break;
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default:
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bb_error_msg("unknown typeflag: 0x%x", tar.typeflag);
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}
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/* Strip trailing '/' in directories */
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/* Must be done after mode is set as '/' is used to check if its a directory */
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cp = last_char_is(file_header->name, '/');
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if (cp) *cp = '\0';
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if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
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archive_handle->action_header(archive_handle->file_header);
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archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
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archive_handle->action_data(archive_handle);
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llist_add_to(&(archive_handle->passed), file_header->name);
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} else {
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data_skip(archive_handle);
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}
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archive_handle->offset += file_header->size;
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free(file_header->link_name);
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return EXIT_SUCCESS;
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}
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