diff options
Diffstat (limited to 'archival/libunarchive/get_header_tar.c')
| -rw-r--r-- | archival/libunarchive/get_header_tar.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/archival/libunarchive/get_header_tar.c b/archival/libunarchive/get_header_tar.c new file mode 100644 index 0000000..639e2dc --- /dev/null +++ b/archival/libunarchive/get_header_tar.c @@ -0,0 +1,99 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Library General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "unarchive.h" +#include "libbb.h" + +file_header_t *get_header_tar(FILE *tar_stream) +{ + union { + unsigned char raw[512]; + struct { + char name[100]; /* 0-99 */ + char mode[8]; /* 100-107 */ + char uid[8]; /* 108-115 */ + char gid[8]; /* 116-123 */ + char size[12]; /* 124-135 */ + char mtime[12]; /* 136-147 */ + char chksum[8]; /* 148-155 */ + char typeflag; /* 156-156 */ + char linkname[100]; /* 157-256 */ + char magic[6]; /* 257-262 */ + char version[2]; /* 263-264 */ + char uname[32]; /* 265-296 */ + char gname[32]; /* 297-328 */ + char devmajor[8]; /* 329-336 */ + char devminor[8]; /* 337-344 */ + char prefix[155]; /* 345-499 */ + char padding[12]; /* 500-512 */ + } formated; + } tar; + file_header_t *tar_entry = NULL; + long sum = 0; + long i; + + if (archive_offset % 512 != 0) { + seek_sub_file(tar_stream, 512 - (archive_offset % 512)); + } + + if (fread(tar.raw, 1, 512, tar_stream) != 512) { + /* Unfortunatly its common for tar files to have all sorts of + * trailing garbage, fail silently */ +// error_msg("Couldnt read header"); + return(NULL); + } + archive_offset += 512; + + /* Check header has valid magic, unfortunately some tar files + * have empty (0'ed) tar entries at the end, which will + * cause this to fail, so fail silently for now + */ + if (strncmp(tar.formated.magic, "ustar", 5) != 0) { + return(NULL); + } + + /* Do checksum on headers */ + for (i = 0; i < 148 ; i++) { + sum += tar.raw[i]; + } + sum += ' ' * 8; + for (i = 156; i < 512 ; i++) { + sum += tar.raw[i]; + } + if (sum != strtol(tar.formated.chksum, NULL, 8)) { + error_msg("Invalid tar header checksum"); + return(NULL); + } + + /* convert to type'ed variables */ + tar_entry = xcalloc(1, sizeof(file_header_t)); + tar_entry->name = xstrdup(tar.formated.name); + + parse_mode(tar.formated.mode, &tar_entry->mode); + tar_entry->uid = strtol(tar.formated.uid, NULL, 8); + tar_entry->gid = strtol(tar.formated.gid, NULL, 8); + tar_entry->size = strtol(tar.formated.size, NULL, 8); + tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8); + tar_entry->link_name = strlen(tar.formated.linkname) ? + xstrdup(tar.formated.linkname) : NULL; + tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) + + strtol(tar.formated.devminor, NULL, 8); + + return(tar_entry); +}
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