1 /* vi: set sw=4 ts=4: */
2 /*
3 * Copyright 2001 Glenn McGrath.
4 *
5 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
6 */
7 #include "libbb.h"
8 #include "bb_archive.h"
9 #include "ar_.h"
10
11 /* WARNING: Clobbers str[len], so fields must be read in reverse order! */
read_num(char * str,int base,int len)12 static unsigned read_num(char *str, int base, int len)
13 {
14 int err;
15
16 /* ar fields are fixed length text strings (padded with spaces).
17 * Ensure bb_strtou doesn't read past the field in case the full
18 * width is used. */
19 str[len] = 0;
20
21 /* This code works because
22 * on misformatted numbers bb_strtou returns all-ones */
23 err = bb_strtou(str, NULL, base);
24 if (err == -1)
25 bb_simple_error_msg_and_die("invalid ar header");
26 return err;
27 }
28
get_header_ar(archive_handle_t * archive_handle)29 char FAST_FUNC get_header_ar(archive_handle_t *archive_handle)
30 {
31 file_header_t *typed = archive_handle->file_header;
32 unsigned size;
33 union {
34 char raw[60];
35 struct ar_header formatted;
36 } ar;
37
38 /* dont use xread as we want to handle the error ourself */
39 if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
40 /* End Of File */
41 return EXIT_FAILURE;
42 }
43
44 /* ar header starts on an even byte (2 byte aligned)
45 * '\n' is used for padding
46 */
47 if (ar.raw[0] == '\n') {
48 /* fix up the header, we started reading 1 byte too early */
49 memmove(ar.raw, &ar.raw[1], 59);
50 ar.raw[59] = xread_char(archive_handle->src_fd);
51 archive_handle->offset++;
52 }
53 archive_handle->offset += 60;
54
55 if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
56 bb_simple_error_msg_and_die("invalid ar header");
57
58 /*
59 * Note that the fields MUST be read in reverse order as
60 * read_num() clobbers the next byte after the field!
61 * Order is: name, date, uid, gid, mode, size, magic.
62 */
63 typed->size = size = read_num(ar.formatted.size, 10,
64 sizeof(ar.formatted.size));
65
66 /* special filenames have '/' as the first character */
67 if (ar.formatted.name[0] == '/') {
68 if (ar.formatted.name[1] == ' ') {
69 /* This is the index of symbols in the file for compilers */
70 data_skip(archive_handle);
71 archive_handle->offset += size;
72 return get_header_ar(archive_handle); /* Return next header */
73 }
74 #if ENABLE_FEATURE_AR_LONG_FILENAMES
75 if (ar.formatted.name[1] == '/') {
76 /* If the second char is a '/' then this entries data section
77 * stores long filename for multiple entries, they are stored
78 * in static variable long_names for use in future entries
79 */
80 archive_handle->ar__long_name_size = size;
81 free(archive_handle->ar__long_names);
82 archive_handle->ar__long_names = xzalloc(size + 1);
83 xread(archive_handle->src_fd, archive_handle->ar__long_names, size);
84 archive_handle->offset += size;
85 /* Return next header */
86 return get_header_ar(archive_handle);
87 }
88 #else
89 bb_simple_error_msg_and_die("long filenames not supported");
90 #endif
91 }
92 /* Only size is always present, the rest may be missing in
93 * long filename pseudo file. Thus we decode the rest
94 * after dealing with long filename pseudo file.
95 *
96 * GNU binutils in deterministic mode hard codes mode to 0644 (NOT
97 * 0100644). AR archives can only contain files, so force file
98 * mode.
99 */
100 typed->mode = read_num(ar.formatted.mode, 8, sizeof(ar.formatted.mode)) | S_IFREG;
101 typed->gid = read_num(ar.formatted.gid, 10, sizeof(ar.formatted.gid));
102 typed->uid = read_num(ar.formatted.uid, 10, sizeof(ar.formatted.uid));
103 typed->mtime = read_num(ar.formatted.date, 10, sizeof(ar.formatted.date));
104
105 #if ENABLE_FEATURE_AR_LONG_FILENAMES
106 if (ar.formatted.name[0] == '/') {
107 unsigned long_offset;
108
109 /* The number after the '/' indicates the offset in the ar data section
110 * (saved in ar__long_names) that contains the real filename */
111 long_offset = read_num(&ar.formatted.name[1], 10,
112 sizeof(ar.formatted.name) - 1);
113 if (long_offset >= archive_handle->ar__long_name_size) {
114 bb_simple_error_msg_and_die("can't resolve long filename");
115 }
116 typed->name = xstrdup(archive_handle->ar__long_names + long_offset);
117 } else
118 #endif
119 {
120 /* short filenames */
121 typed->name = xstrndup(ar.formatted.name, 16);
122 }
123
124 typed->name[strcspn(typed->name, " /")] = '\0';
125
126 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
127 archive_handle->action_header(typed);
128 #if ENABLE_DPKG || ENABLE_DPKG_DEB
129 if (archive_handle->dpkg__sub_archive) {
130 struct archive_handle_t *sa = archive_handle->dpkg__sub_archive;
131 while (archive_handle->dpkg__action_data_subarchive(sa) == EXIT_SUCCESS)
132 continue;
133 create_links_from_list(sa->link_placeholders);
134 } else
135 #endif
136 archive_handle->action_data(archive_handle);
137 } else {
138 data_skip(archive_handle);
139 }
140
141 archive_handle->offset += typed->size;
142 /* Set the file pointer to the correct spot, we may have been reading a compressed file */
143 lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET);
144
145 return EXIT_SUCCESS;
146 }
147