summaryrefslogtreecommitdiff
path: root/src/archive.c
blob: 4005bf174bf6cd7935cfe4df20f758e0716cd1d3 (plain) (blame)
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
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
/* archive.c - Alpine Package Keeper (APK)
 *
 * Copyright (C) 2005-2008 Natanael Copa <n@tanael.org>
 * Copyright (C) 2008 Timo Teräs <timo.teras@iki.fi>
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation. See http://www.gnu.org/ for details.
 */

#include <stdio.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <utime.h>
#include <malloc.h>
#include <string.h>
#include <unistd.h>
#include <sysexits.h>
#include <sys/wait.h>
#include <limits.h>

#include "apk_defines.h"
#include "apk_archive.h"

struct tar_header {
	/* ustar header, Posix 1003.1 */
	char name[100];     /*   0-99 */
	char mode[8];       /* 100-107 */
	char uid[8];        /* 108-115 */
	char gid[8];        /* 116-123 */
	char size[12];      /* 124-135 */
	char mtime[12];     /* 136-147 */
	char chksum[8];     /* 148-155 */
	char typeflag;      /* 156-156 */
	char linkname[100]; /* 157-256 */
	char magic[8];      /* 257-264 */
	char uname[32];     /* 265-296 */
	char gname[32];     /* 297-328 */
	char devmajor[8];   /* 329-336 */
	char devminor[8];   /* 337-344 */
	char prefix[155];   /* 345-499 */
	char padding[12];   /* 500-512 */
};

struct apk_tar_digest_info {
	char id[4];
	uint16_t nid;
	uint16_t size;
	char digest[];
};

#define GET_OCTAL(s)	get_octal(s, sizeof(s))
#define PUT_OCTAL(s,v)	put_octal(s, sizeof(s), v)

static int get_octal(char *s, size_t l)
{
	apk_blob_t b = APK_BLOB_PTR_LEN(s, l);
	return apk_blob_pull_uint(&b, 8);
}

static void put_octal(char *s, size_t l, size_t value)
{
	char *ptr = &s[l - 1];

	*(ptr--) = '\0';
	while (value != 0 && ptr >= s) {
		*(ptr--) = '0' + (value % 8);
		value /= 8;
	}
	while (ptr >= s)
		*(ptr--) = '0';
}

struct apk_tar_entry_istream {
	struct apk_istream is;
	struct apk_istream *tar_is;
	size_t bytes_left;
	EVP_MD_CTX mdctx;
	struct apk_checksum *csum;
};

static ssize_t tar_entry_read(void *stream, void *ptr, size_t size)
{
	struct apk_tar_entry_istream *teis =
		container_of(stream, struct apk_tar_entry_istream, is);
	ssize_t r;

	if (size > teis->bytes_left)
		size = teis->bytes_left;
	r = teis->tar_is->read(teis->tar_is, ptr, size);
	if (r < 0)
		return r;

	teis->bytes_left -= r;
	if (teis->csum == NULL)
		return r;

	EVP_DigestUpdate(&teis->mdctx, ptr, r);
	if (teis->bytes_left == 0) {
		teis->csum->type = EVP_MD_CTX_size(&teis->mdctx);
		EVP_DigestFinal_ex(&teis->mdctx, teis->csum->data, NULL);
	}
	return r;
}

static void tar_entry_close(void *stream)
{
}

int apk_tar_parse(struct apk_istream *is, apk_archive_entry_parser parser,
		  void *ctx)
{
	struct apk_file_info entry;
	struct apk_tar_entry_istream teis = {
		.is.read = tar_entry_read,
		.is.close = tar_entry_close,
		.tar_is = is,
	};
	struct tar_header buf;
	struct apk_tar_digest_info *di;
	unsigned long offset = 0;
	int end = 0, r;
	size_t toskip;

	di = (struct apk_tar_digest_info *) &buf.linkname[3];
	EVP_MD_CTX_init(&teis.mdctx);
	memset(&entry, 0, sizeof(entry));
	while ((r = is->read(is, &buf, 512)) == 512) {
		offset += 512;
		if (buf.name[0] == '\0') {
			if (end)
				break;
			end++;
			continue;
		}

		entry = (struct apk_file_info){
			.size  = GET_OCTAL(buf.size),
			.uid   = GET_OCTAL(buf.uid),
			.gid   = GET_OCTAL(buf.gid),
			.mode  = GET_OCTAL(buf.mode) & 07777,
			.mtime = GET_OCTAL(buf.mtime),
			.name  = entry.name,
			.uname = buf.uname,
			.gname = buf.gname,
			.device = makedev(GET_OCTAL(buf.devmajor),
					  GET_OCTAL(buf.devminor)),
		};

		switch (buf.typeflag) {
		case 'L':
			if (entry.name != NULL)
				free(entry.name);
			entry.name = malloc(entry.size+1);
			is->read(is, entry.name, entry.size);
			entry.name[entry.size] = 0;
			offset += entry.size;
			entry.size = 0;
			break;
		case '0':
		case '7': /* regular file */
			entry.mode |= S_IFREG;
			if (memcmp(di->id, "APK2", 4) == 0 &&
			    di->size <= sizeof(entry.csum.data)) {
				entry.csum.type = di->size;
				memcpy(entry.csum.data, di->digest, di->size);
				teis.csum = NULL;
			} else {
				teis.csum = &entry.csum;
			}
			break;
		case '1': /* hard link */
			entry.mode |= S_IFREG;
			entry.link_target = buf.linkname;
			break;
		case '2': /* symbolic link */
			entry.mode |= S_IFLNK;
			entry.link_target = buf.linkname;
			break;
		case '3': /* char device */
			entry.mode |= S_IFCHR;
			break;
		case '4': /* block device */
			entry.mode |= S_IFBLK;
			break;
		case '5': /* directory */
			entry.mode |= S_IFDIR;
			break;
		default:
			break;
		}

		teis.bytes_left = entry.size;
		if (entry.mode & S_IFMT) {
			if (entry.name == NULL)
				entry.name = strdup(buf.name);

			/* callback parser function */
			EVP_DigestInit_ex(&teis.mdctx, apk_default_checksum(), NULL);
			r = parser(ctx, &entry, &teis.is);
			free(entry.name);
			if (r != 0)
				goto err;

			entry.name = NULL;
		}

		offset += entry.size - teis.bytes_left;
		toskip = teis.bytes_left;
		if ((offset + toskip) & 511)
			toskip += 512 - ((offset + toskip) & 511);
		offset += toskip;
		if (toskip != 0)
			is->read(is, NULL, toskip);
	}
	EVP_MD_CTX_cleanup(&teis.mdctx);

	/* Read remaining end-of-archive records, to ensure we read all of
	 * the file. The underlying istream is likely doing checksumming. */
	if (r == 512) {
		while ((r = is->read(is, &buf, 512)) == 512) {
			if (buf.name[0] != 0)
				return -EBADMSG;
		}
	}

	/* Check that there was no partial record */
	if (r > 0)
		r = -EBADMSG;

	return r;

err:
	EVP_MD_CTX_cleanup(&teis.mdctx);
	return r;
}

int apk_tar_write_entry(struct apk_ostream *os, const struct apk_file_info *ae, char *data)
{
	struct tar_header buf;

	memset(&buf, 0, sizeof(buf));
	if (ae != NULL) {
		const unsigned char *src;
	        int chksum, i;

		if (S_ISREG(ae->mode))
			buf.typeflag = '0';
		else
			return -1;

		if (ae->name != NULL)
			strncpy(buf.name, ae->name, sizeof(buf.name));

		strncpy(buf.uname, ae->uname ?: "root", sizeof(buf.uname));
		strncpy(buf.gname, ae->gname ?: "root", sizeof(buf.gname));

		PUT_OCTAL(buf.size, ae->size);
		PUT_OCTAL(buf.uid, ae->uid);
		PUT_OCTAL(buf.gid, ae->gid);
		PUT_OCTAL(buf.mode, ae->mode & 07777);
		PUT_OCTAL(buf.mtime, ae->mtime ?: time(NULL));

		/* Checksum */
		strcpy(buf.magic, "ustar  ");
		memset(buf.chksum, ' ', sizeof(buf.chksum));
		src = (const unsigned char *) &buf;
		for (i = chksum = 0; i < sizeof(buf); i++)
			chksum += src[i];
	        put_octal(buf.chksum, sizeof(buf.chksum)-1, chksum);
	}

	if (os->write(os, &buf, sizeof(buf)) != sizeof(buf))
		return -1;

	if (ae == NULL) {
		/* End-of-archive is two empty headers */
		if (os->write(os, &buf, sizeof(buf)) != sizeof(buf))
			return -1;
	} else if (data != NULL) {
		if (os->write(os, data, ae->size) != ae->size)
			return -1;
		if (apk_tar_write_padding(os, ae) != 0)
			return -1;
	}

	return 0;
}

int apk_tar_write_padding(struct apk_ostream *os, const struct apk_file_info *ae)
{
	static char padding[512];
	int pad;

	pad = 512 - (ae->size & 511);
	if (pad != 512 &&
	    os->write(os, padding, pad) != pad)
		return -1;

	return 0;
}

int apk_archive_entry_extract(const struct apk_file_info *ae,
			      struct apk_istream *is,
			      const char *fn, apk_progress_cb cb,
			      void *cb_ctx)
{
	struct utimbuf utb;
	int r = -1, fd;

	if (fn == NULL)
		fn = ae->name;

	/* BIG HONKING FIXME */
	unlink(fn);

	switch (ae->mode & S_IFMT) {
	case S_IFDIR:
		r = mkdir(fn, ae->mode & 07777);
		if (r < 0 && errno == EEXIST)
			r = 0;
		break;
	case S_IFREG:
		if (ae->link_target == NULL) {
			fd = open(fn, O_WRONLY | O_CREAT, ae->mode & 07777);
			if (fd < 0) {
				r = -1;
				break;
			}
			if (apk_istream_splice(is, fd, ae->size, cb, cb_ctx)
			    == ae->size)
				r = 0;
			close(fd);
		} else {
			char link_target[PATH_MAX];
			snprintf(link_target, sizeof(link_target),
				 "%s.apk-new", ae->link_target);
			r = link(link_target, fn);
		}
		break;
	case S_IFLNK:
		r = symlink(ae->link_target, fn);
		break;
	case S_IFSOCK:
	case S_IFBLK:
	case S_IFCHR:
	case S_IFIFO:
		r = mknod(fn, ae->mode & 07777, ae->device);
		break;
	}
	if (r == 0) {
		if (!S_ISLNK(ae->mode))
			r = chown(fn, ae->uid, ae->gid);
		else
			r = lchown(fn, ae->uid, ae->gid);
		if (r < 0) {
			apk_error("Failed to set ownership on %s: %s",
				  fn, strerror(errno));
			return -errno;
		}

		/* chown resets suid bit so we need set it again */
		if (ae->mode & 07000) {
			r = chmod(fn, ae->mode & 07777);
			if (r < 0) {
				apk_error("Failed to set file permissions "
					  "on %s: %s",
					  fn, strerror(errno));
				return -errno;
			}
		}

		if (!S_ISLNK(ae->mode)) {
			/* preserve modification time */
			utb.actime = utb.modtime = ae->mtime;
			r = utime(fn, &utb);
			if (r < 0) {
				apk_error("Failed to preserve modification time on %s: %s",
					fn, strerror(errno));
				return -errno;
			}
		}
	} else {
		apk_error("Failed to extract %s: %s", ae->name, strerror(errno));
		return -errno;
	}
	return 0;
}