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
10char get_header_ar(archive_handle_t *archive_handle)
11{
12	int err;
13	file_header_t *typed = archive_handle->file_header;
14	union {
15		char raw[60];
16		struct {
17			char name[16];
18			char date[12];
19			char uid[6];
20			char gid[6];
21			char mode[8];
22			char size[10];
23			char magic[2];
24		} formatted;
25	} ar;
26#if ENABLE_FEATURE_AR_LONG_FILENAMES
27	static char *ar_long_names;
28	static unsigned ar_long_name_size;
29#endif
30
31	/* dont use xread as we want to handle the error ourself */
32	if (read(archive_handle->src_fd, ar.raw, 60) != 60) {
33		/* End Of File */
34		return EXIT_FAILURE;
35	}
36
37	/* ar header starts on an even byte (2 byte aligned)
38	 * '\n' is used for padding
39	 */
40	if (ar.raw[0] == '\n') {
41		/* fix up the header, we started reading 1 byte too early */
42		memmove(ar.raw, &ar.raw[1], 59);
43		ar.raw[59] = xread_char(archive_handle->src_fd);
44		archive_handle->offset++;
45	}
46	archive_handle->offset += 60;
47
48	/* align the headers based on the header magic */
49	if (ar.formatted.magic[0] != '`' || ar.formatted.magic[1] != '\n')
50		bb_error_msg_and_die("invalid ar header");
51
52	/* (we have something like that in tar) */
53	/* but for now we are lax. This code works because */
54	/* on misformatted numbers bb_strtou returns all-ones */
55	typed->mode = err = bb_strtou(ar.formatted.mode, NULL, 8);
56	if (err == -1) bb_error_msg_and_die("invalid ar header");
57	typed->mtime = err = bb_strtou(ar.formatted.date, NULL, 10);
58	if (err == -1) bb_error_msg_and_die("invalid ar header");
59	typed->uid = err = bb_strtou(ar.formatted.uid, NULL, 10);
60	if (err == -1) bb_error_msg_and_die("invalid ar header");
61	typed->gid = err = bb_strtou(ar.formatted.gid, NULL, 10);
62	if (err == -1) bb_error_msg_and_die("invalid ar header");
63	typed->size = err = bb_strtou(ar.formatted.size, NULL, 10);
64	if (err == -1) bb_error_msg_and_die("invalid ar header");
65
66	/* long filenames have '/' as the first character */
67	if (ar.formatted.name[0] == '/') {
68#if ENABLE_FEATURE_AR_LONG_FILENAMES
69		unsigned long_offset;
70
71		if (ar.formatted.name[1] == '/') {
72			/* If the second char is a '/' then this entries data section
73			 * stores long filename for multiple entries, they are stored
74			 * in static variable long_names for use in future entries */
75			ar_long_name_size = typed->size;
76			ar_long_names = xmalloc(ar_long_name_size);
77			xread(archive_handle->src_fd, ar_long_names, ar_long_name_size);
78			archive_handle->offset += ar_long_name_size;
79			/* This ar entries data section only contained filenames for other records
80			 * they are stored in the static ar_long_names for future reference */
81			return get_header_ar(archive_handle); /* Return next header */
82		}
83
84		if (ar.formatted.name[1] == ' ') {
85			/* This is the index of symbols in the file for compilers */
86			data_skip(archive_handle);
87			archive_handle->offset += typed->size;
88			return get_header_ar(archive_handle); /* Return next header */
89		}
90
91		/* The number after the '/' indicates the offset in the ar data section
92		 * (saved in variable long_name) that conatains the real filename */
93		long_offset = atoi(&ar.formatted.name[1]);
94		if (long_offset >= ar_long_name_size) {
95			bb_error_msg_and_die("can't resolve long filename");
96		}
97		typed->name = xstrdup(ar_long_names + long_offset);
98#else
99		bb_error_msg_and_die("long filenames not supported");
100#endif
101	} else {
102		/* short filenames */
103		typed->name = xstrndup(ar.formatted.name, 16);
104	}
105
106	typed->name[strcspn(typed->name, " /")] = '\0';
107
108	if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
109		archive_handle->action_header(typed);
110		if (archive_handle->sub_archive) {
111			while (archive_handle->action_data_subarchive(archive_handle->sub_archive) == EXIT_SUCCESS)
112				/* repeat */;
113		} else {
114			archive_handle->action_data(archive_handle);
115		}
116	} else {
117		data_skip(archive_handle);
118	}
119
120	archive_handle->offset += typed->size;
121	/* Set the file pointer to the correct spot, we may have been reading a compressed file */
122	lseek(archive_handle->src_fd, archive_handle->offset, SEEK_SET);
123
124	return EXIT_SUCCESS;
125}
126