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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8 | #include "bb_archive.h"
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9 | #include "ar.h"
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10 |
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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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13 | {
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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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21 | /* This code works because
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22 | * on misformatted numbers bb_strtou returns all-ones */
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23 | err = bb_strtou(str, NULL, base);
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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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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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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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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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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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111 | long_offset = read_num(&ar.formatted.name[1], 10,
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112 | sizeof(ar.formatted.name) - 1);
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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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