summaryrefslogtreecommitdiff
path: root/archival/ar.c
blob: 89c43b43d466131e78ce594ce0b7794e0202bb64 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
/* vi: set sw=4 ts=4: */
/*
 * Mini ar implementation for busybox 
 *
 * Copyright (C) 2000 by Glenn McGrath
 * Written by Glenn McGrath <bug1@optushome.com.au> 1 June 2000
 * 		
 * Based in part on BusyBox tar, Debian dpkg-deb and GNU ar.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <unistd.h>
#include "busybox.h"

typedef struct ar_headers_s {
	char *name;
	off_t size;
	uid_t uid;
	gid_t gid;
	mode_t mode;
	time_t mtime;
	off_t offset;
	struct ar_headers_s *next;
} ar_headers_t;

/*
 * return the headerL_t struct for the filename descriptor
 */
extern ar_headers_t get_ar_headers(int srcFd)
{
	typedef struct raw_ar_header_s {	/* Byte Offset */
		char name[16];	/*  0-15 */
		char date[12];	/* 16-27 */
		char uid[6];	
		char gid[6];	/* 28-39 */
		char mode[8];	/* 40-47 */
		char size[10];	/* 48-57 */
		char fmag[2];	/* 58-59 */
	} raw_ar_header_t;

	raw_ar_header_t raw_ar_header;

	ar_headers_t *head, *entry;
	char ar_magic[8];
	char *long_name=NULL;
	
	head = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
	entry = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
	
	/* check ar magic */
	if (full_read(srcFd, ar_magic, 8) != 8) {
		error_msg_and_die("cannot read magic");
	}

	if (strncmp(ar_magic,"!<arch>",7) != 0) {
		error_msg_and_die("invalid magic");
	}

	while (full_read(srcFd, (char *) &raw_ar_header, 60)==60) {
		/* check the end of header markers are valid */
		if ((raw_ar_header.fmag[0]!='`') || (raw_ar_header.fmag[1]!='\n')) {
			char newline;
			if (raw_ar_header.fmag[1]!='`') {
				break;
			}
			/* some version of ar, have an extra '\n' after each entry */
			read(srcFd, &newline, 1);
			if (newline!='\n') {
				break;
			}
			/* fix up the header, we started reading 1 byte too early due to a '\n' */
			memmove((char *) &raw_ar_header, (char *)&raw_ar_header+1, 59);
			/* dont worry about adding the last '\n', we dont need it now */
		}
		
		entry->size = (off_t) atoi(raw_ar_header.size);
		/* long filenames have '/' as the first character */
		if (raw_ar_header.name[0] == '/') {
			if (raw_ar_header.name[1] == '/') {
				/* multiple long filenames are stored as data in one entry */
				long_name = (char *) xrealloc(long_name, entry->size);
				full_read(srcFd, long_name, entry->size);
				continue;
			}
			else {
				/* The number after the '/' indicates the offset in the ar data section
					(saved in variable long_name) that conatains the real filename */
				const int long_name_offset = (int) atoi((char *) &raw_ar_header.name[1]);
				entry->name = xmalloc(strlen(&long_name[long_name_offset]));
				strcpy(entry->name, &long_name[long_name_offset]);
			}
		}
		else {
			/* short filenames */
			entry->name = xmalloc(16);
			strncpy(entry->name, raw_ar_header.name, 16);
		}
		entry->name[strcspn(entry->name, " /")]='\0';

		/* convert the rest of the now valid char header to its typed struct */	
		parse_mode(raw_ar_header.mode, &entry->mode);
		entry->mtime = atoi(raw_ar_header.date);
		entry->uid = atoi(raw_ar_header.uid);
		entry->gid = atoi(raw_ar_header.gid);
		entry->offset = lseek(srcFd, 0, SEEK_CUR);

		/* add this entries header to our combined list */
		entry->next = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
		*entry->next = *head;
		*head = *entry;
		lseek(srcFd, (off_t) entry->size, SEEK_CUR);
	}
	return(*head);
}

extern int ar_main(int argc, char **argv)
{
	const int preserve_date = 1;	/* preserve original dates */
	const int verbose = 2;		/* be verbose */
	const int display = 4;		/* display contents */
	const int extract_to_file = 8;	/* extract contents of archive */
	const int extract_to_stdout = 16;	/* extract to stdout */

	int funct = 0, opt=0;
	int srcFd=0, dstFd=0;

	ar_headers_t head, *extract_list=NULL;

	extract_list = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));

	while ((opt = getopt(argc, argv, "ovtpx")) != -1) {
		switch (opt) {
		case 'o':
			funct |= preserve_date;
			break;
		case 'v':
			funct |= verbose;
			break;
		case 't':
			funct |= display;
			break;
		case 'p':
			funct |= extract_to_stdout;
			break;
		case 'x':
			funct |= extract_to_file;
			break;
		default:
			show_usage();
		}
	}
 
	/* check the src filename was specified */
	if (optind == argc)
		show_usage();
	
	if ( (srcFd = open(argv[optind], O_RDONLY)) < 0)
		error_msg_and_die("Cannot read %s", argv[optind]);

	optind++;	
	head = get_ar_headers(srcFd);

	/* find files to extract or display */
	/* search through argv and build extract list */
	for (;optind<argc; optind++) {
		ar_headers_t *ar_entry;
		ar_entry = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
		ar_entry = &head;
		while (ar_entry->next != NULL) {
			if (strcmp(argv[optind], ar_entry->name) == 0) {
				ar_headers_t *tmp;
				tmp = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
				*tmp = *extract_list;
				*extract_list = *ar_entry;
				extract_list->next = tmp;
				break;					
			}
			ar_entry=ar_entry->next;
		}
	}

	/* if individual files not found extract all files */	
	if (extract_list->next==NULL) {
		extract_list = &head;
	}
	
	/* find files to extract or display */	
	while (extract_list->next != NULL) {
		if (funct & extract_to_file) {
			dstFd = open(extract_list->name, O_WRONLY | O_CREAT, extract_list->mode);				
		}
		else if (funct & extract_to_stdout) {
			dstFd = fileno(stdout);
		}
		if ((funct & extract_to_file) || (funct & extract_to_stdout)) {
			lseek(srcFd, extract_list->offset, SEEK_SET);
			copy_file_chunk(srcFd, dstFd, (off_t) extract_list->size);			
		}
		if (funct & verbose) {
			printf("%s %d/%d %8d %s ", mode_string(extract_list->mode), 
				extract_list->uid, extract_list->gid,
				(int) extract_list->size, time_string(extract_list->mtime));
		}
		if ((funct & display) || (funct & verbose)){
			printf("%s\n", extract_list->name);
		}
		extract_list=extract_list->next;
	}
	return EXIT_SUCCESS;
}