[2725] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /* Copyright 2001 Glenn McGrath.
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| 3 | *
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| 4 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 5 | */
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| 6 |
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| 7 | #include "libbb.h"
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[3232] | 8 | #include "bb_archive.h"
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[2725] | 9 | #include "ar.h"
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| 10 |
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[3621] | 11 | /* WARNING: Clobbers str[len], so fields must be read in reverse order! */
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| 12 | static unsigned read_num(char *str, int base, int len)
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[2725] | 13 | {
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[3621] | 14 | int err;
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| 15 |
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| 16 | /* ar fields are fixed length text strings (padded with spaces).
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| 17 | * Ensure bb_strtou doesn't read past the field in case the full
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| 18 | * width is used. */
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| 19 | str[len] = 0;
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| 20 |
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[2725] | 21 | /* This code works because
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| 22 | * on misformatted numbers bb_strtou returns all-ones */
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[3621] | 23 | err = bb_strtou(str, NULL, base);
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[2725] | 24 | if (err == -1)
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| 25 | bb_error_msg_and_die("invalid ar header");
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| 26 | return err;
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| 27 | }
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| 28 |
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| 29 | char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
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| 30 | {
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| 31 | file_header_t *typed = archive_handle->file_header;
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| 32 | unsigned size;
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| 33 | union {
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| 34 | char raw[60];
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| 35 | struct ar_header formatted;
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| 36 | } ar;
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| 37 | #if ENABLE_FEATURE_AR_LONG_FILENAMES
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| 38 | static char *ar_long_names;
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| 39 | static unsigned ar_long_name_size;
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| 40 | #endif
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| 41 |
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| 42 | /* dont use xread as we want to handle the error ourself */
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| 43 | if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
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| 44 | /* End Of File */
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| 45 | return EXIT_FAILURE;
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| 46 | }
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| 47 |
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| 48 | /* ar header starts on an even byte (2 byte aligned)
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| 49 | * '\n' is used for padding
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| 50 | */
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| 51 | if (ar.raw[0] == '\n') {
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| 52 | /* fix up the header, we started reading 1 byte too early */
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| 53 | memmove(ar.raw, &ar.raw[1], 59);
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| 54 | ar.raw[59] = xread_char(archive_handle->src_fd);
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| 55 | archive_handle->offset++;
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| 56 | }
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| 57 | archive_handle->offset += 60;
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| 58 |
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| 59 | if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
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| 60 | bb_error_msg_and_die("invalid ar header");
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| 61 |
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[3621] | 62 | /*
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| 63 | * Note that the fields MUST be read in reverse order as
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| 64 | * read_num() clobbers the next byte after the field!
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| 65 | * Order is: name, date, uid, gid, mode, size, magic.
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| 66 | */
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| 67 | typed->size = size = read_num(ar.formatted.size, 10,
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| 68 | sizeof(ar.formatted.size));
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[2725] | 69 |
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| 70 | /* special filenames have '/' as the first character */
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| 71 | if (ar.formatted.name[0] == '/') {
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| 72 | if (ar.formatted.name[1] == ' ') {
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| 73 | /* This is the index of symbols in the file for compilers */
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| 74 | data_skip(archive_handle);
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| 75 | archive_handle->offset += size;
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| 76 | return get_header_ar(archive_handle); /* Return next header */
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| 77 | }
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| 78 | #if ENABLE_FEATURE_AR_LONG_FILENAMES
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| 79 | if (ar.formatted.name[1] == '/') {
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| 80 | /* If the second char is a '/' then this entries data section
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| 81 | * stores long filename for multiple entries, they are stored
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| 82 | * in static variable long_names for use in future entries
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| 83 | */
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| 84 | ar_long_name_size = size;
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| 85 | free(ar_long_names);
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| 86 | ar_long_names = xmalloc(size);
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| 87 | xread(archive_handle->src_fd, ar_long_names, size);
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| 88 | archive_handle->offset += size;
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| 89 | /* Return next header */
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| 90 | return get_header_ar(archive_handle);
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| 91 | }
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| 92 | #else
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| 93 | bb_error_msg_and_die("long filenames not supported");
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| 94 | #endif
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| 95 | }
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| 96 | /* Only size is always present, the rest may be missing in
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| 97 | * long filename pseudo file. Thus we decode the rest
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| 98 | * after dealing with long filename pseudo file.
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| 99 | */
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[3621] | 100 | typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode));
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| 101 | typed->gid = read_num(ar.formatted.gid, 10, sizeof(ar.formatted.gid));
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| 102 | typed->uid = read_num(ar.formatted.uid, 10, sizeof(ar.formatted.uid));
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| 103 | typed->mtime = read_num(ar.formatted.date, 10, sizeof(ar.formatted.date));
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[2725] | 104 |
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| 105 | #if ENABLE_FEATURE_AR_LONG_FILENAMES
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| 106 | if (ar.formatted.name[0] == '/') {
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| 107 | unsigned long_offset;
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| 108 |
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| 109 | /* The number after the '/' indicates the offset in the ar data section
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| 110 | * (saved in ar_long_names) that conatains the real filename */
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[3621] | 111 | long_offset = read_num(&ar.formatted.name[1], 10,
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| 112 | sizeof(ar.formatted.name) - 1);
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[2725] | 113 | if (long_offset >= ar_long_name_size) {
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| 114 | bb_error_msg_and_die("can't resolve long filename");
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| 115 | }
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| 116 | typed->name = xstrdup(ar_long_names + long_offset);
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| 117 | } else
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| 118 | #endif
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| 119 | {
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| 120 | /* short filenames */
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| 121 | typed->name = xstrndup(ar.formatted.name, 16);
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| 122 | }
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| 123 |
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| 124 | typed->name[strcspn(typed->name, " /")] = '\0';
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| 125 |
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| 126 | if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
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| 127 | archive_handle->action_header(typed);
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| 128 | #if ENABLE_DPKG || ENABLE_DPKG_DEB
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| 129 | if (archive_handle->dpkg__sub_archive) {
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| 130 | while (archive_handle->dpkg__action_data_subarchive(archive_handle->dpkg__sub_archive) == EXIT_SUCCESS)
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| 131 | continue;
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| 132 | } else
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| 133 | #endif
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| 134 | archive_handle->action_data(archive_handle);
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| 135 | } else {
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| 136 | data_skip(archive_handle);
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| 137 | }
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| 138 |
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| 139 | archive_handle->offset += typed->size;
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| 140 | /* Set the file pointer to the correct spot, we may have been reading a compressed file */
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| 141 | lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET);
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| 142 |
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| 143 | return EXIT_SUCCESS;
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| 144 | }
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