1/* vi: set sw=4 ts=4: */ 2/* Copyright 2001 Glenn McGrath. 3 * 4 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. 5 */ 6 7#include "libbb.h" 8#include "unarchive.h" 9#include "ar.h" 10 11static unsigned read_num(const char *str, int base) 12{ 13 /* This code works because 14 * on misformatted numbers bb_strtou returns all-ones */ 15 int err = bb_strtou(str, NULL, base); 16 if (err == -1) 17 bb_error_msg_and_die("invalid ar header"); 18 return err; 19} 20 21char FAST_FUNC get_header_ar(archive_handle_t *archive_handle) 22{ 23 file_header_t *typed = archive_handle->file_header; 24 unsigned size; 25 union { 26 char raw[60]; 27 struct ar_header formatted; 28 } ar; 29#if ENABLE_FEATURE_AR_LONG_FILENAMES 30 static char *ar_long_names; 31 static unsigned ar_long_name_size; 32#endif 33 34 /* dont use xread as we want to handle the error ourself */ 35 if (read(archive_handle->src_fd, ar.raw, 60) != 60) { 36 /* End Of File */ 37 return EXIT_FAILURE; 38 } 39 40 /* ar header starts on an even byte (2 byte aligned) 41 * '\n' is used for padding 42 */ 43 if (ar.raw[0] == '\n') { 44 /* fix up the header, we started reading 1 byte too early */ 45 memmove(ar.raw, &ar.raw[1], 59); 46 ar.raw[59] = xread_char(archive_handle->src_fd); 47 archive_handle->offset++; 48 } 49 archive_handle->offset += 60; 50 51 if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n') 52 bb_error_msg_and_die("invalid ar header"); 53 54 /* FIXME: more thorough routine would be in order here 55 * (we have something like that in tar) 56 * but for now we are lax. */ 57 ar.formatted.magic[0] = '\0'; /* else 4G-2 file will have size="4294967294`\n..." */ 58 typed->size = size = read_num(ar.formatted.size, 10); 59 60 /* special filenames have '/' as the first character */ 61 if (ar.formatted.name[0] == '/') { 62 if (ar.formatted.name[1] == ' ') { 63 /* This is the index of symbols in the file for compilers */ 64 data_skip(archive_handle); 65 archive_handle->offset += size; 66 return get_header_ar(archive_handle); /* Return next header */ 67 } 68#if ENABLE_FEATURE_AR_LONG_FILENAMES 69 if (ar.formatted.name[1] == '/') { 70 /* If the second char is a '/' then this entries data section 71 * stores long filename for multiple entries, they are stored 72 * in static variable long_names for use in future entries 73 */ 74 ar_long_name_size = size; 75 free(ar_long_names); 76 ar_long_names = xmalloc(size); 77 xread(archive_handle->src_fd, ar_long_names, size); 78 archive_handle->offset += size; 79 /* Return next header */ 80 return get_header_ar(archive_handle); 81 } 82#else 83 bb_error_msg_and_die("long filenames not supported"); 84#endif 85 } 86 /* Only size is always present, the rest may be missing in 87 * long filename pseudo file. Thus we decode the rest 88 * after dealing with long filename pseudo file. 89 */ 90 typed->mode = read_num(ar.formatted.mode, 8); 91 typed->mtime = read_num(ar.formatted.date, 10); 92 typed->uid = read_num(ar.formatted.uid, 10); 93 typed->gid = read_num(ar.formatted.gid, 10); 94 95#if ENABLE_FEATURE_AR_LONG_FILENAMES 96 if (ar.formatted.name[0] == '/') { 97 unsigned long_offset; 98 99 /* The number after the '/' indicates the offset in the ar data section 100 * (saved in ar_long_names) that conatains the real filename */ 101 long_offset = read_num(&ar.formatted.name[1], 10); 102 if (long_offset >= ar_long_name_size) { 103 bb_error_msg_and_die("can't resolve long filename"); 104 } 105 typed->name = xstrdup(ar_long_names + long_offset); 106 } else 107#endif 108 { 109 /* short filenames */ 110 typed->name = xstrndup(ar.formatted.name, 16); 111 } 112 113 typed->name[strcspn(typed->name, " /")] = '\0'; 114 115 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) { 116 archive_handle->action_header(typed); 117#if ENABLE_DPKG || ENABLE_DPKG_DEB 118 if (archive_handle->dpkg__sub_archive) { 119 while (archive_handle->dpkg__action_data_subarchive(archive_handle->dpkg__sub_archive) == EXIT_SUCCESS) 120 continue; 121 } else 122#endif 123 archive_handle->action_data(archive_handle); 124 } else { 125 data_skip(archive_handle); 126 } 127 128 archive_handle->offset += typed->size; 129 /* Set the file pointer to the correct spot, we may have been reading a compressed file */ 130 lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET); 131 132 return EXIT_SUCCESS; 133} 134