summaryrefslogtreecommitdiff
path: root/lib/libalpm/dload.c
blob: cd3e47338a1a678ad476f5c683dc412a7d1845ab (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
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
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
/*
 *  dload.c
 *
 *  Copyright (c) 2006-2018 Pacman Development Team <pacman-dev@archlinux.org>
 *  Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.org>
 *
 *  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, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h> /* setsockopt, SO_KEEPALIVE */
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <signal.h>

#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h> /* IPPROTO_TCP */
#endif
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h> /* TCP_KEEPINTVL, TCP_KEEPIDLE */
#endif

#ifdef HAVE_LIBCURL
#include <curl/curl.h>
#endif

/* libalpm */
#include "dload.h"
#include "alpm_list.h"
#include "alpm.h"
#include "log.h"
#include "util.h"
#include "handle.h"

#ifdef HAVE_LIBCURL
static const char *get_filename(const char *url)
{
	char *filename = strrchr(url, '/');
	if(filename != NULL) {
		filename++;
	}
	return filename;
}

static char *get_fullpath(const char *path, const char *filename,
		const char *suffix)
{
	char *filepath;
	/* len = localpath len + filename len + suffix len + null */
	size_t len = strlen(path) + strlen(filename) + strlen(suffix) + 1;
	MALLOC(filepath, len, return NULL);
	snprintf(filepath, len, "%s%s%s", path, filename, suffix);

	return filepath;
}

static CURL *get_libcurl_handle(alpm_handle_t *handle)
{
	if(!handle->curl) {
		curl_global_init(CURL_GLOBAL_SSL);
		handle->curl = curl_easy_init();
	}
	return handle->curl;
}

enum {
	ABORT_SIGINT = 1,
	ABORT_OVER_MAXFILESIZE
};

static int dload_interrupted;
static void inthandler(int UNUSED signum)
{
	dload_interrupted = ABORT_SIGINT;
}

static int dload_progress_cb(void *file, curl_off_t dltotal, curl_off_t dlnow,
		curl_off_t UNUSED ultotal, curl_off_t UNUSED ulnow)
{
	struct dload_payload *payload = (struct dload_payload *)file;
	off_t current_size, total_size;

	/* avoid displaying progress bar for redirects with a body */
	if(payload->respcode >= 300) {
		return 0;
	}

	/* SIGINT sent, abort by alerting curl */
	if(dload_interrupted) {
		return 1;
	}

	current_size = payload->initial_size + dlnow;

	/* is our filesize still under any set limit? */
	if(payload->max_size && current_size > payload->max_size) {
		dload_interrupted = ABORT_OVER_MAXFILESIZE;
		return 1;
	}

	/* none of what follows matters if the front end has no callback */
	if(payload->handle->dlcb == NULL) {
		return 0;
	}

	total_size = payload->initial_size + dltotal;

	if(dltotal == 0 || payload->prevprogress == total_size) {
		return 0;
	}

	/* initialize the progress bar here to avoid displaying it when
	 * a repo is up to date and nothing gets downloaded.
	 * payload->handle->dlcb will receive the remote_name
	 * and the following arguments:
	 * 0, -1: download initialized
	 * 0, 0: non-download event
	 * x {x>0}, x: download complete
	 * x {x>0, x<y}, y {y > 0}: download progress, expected total is known */
	if(!payload->cb_initialized) {
		payload->handle->dlcb(payload->remote_name, 0, -1);
		payload->cb_initialized = 1;
	}
	if(payload->prevprogress == current_size) {
		payload->handle->dlcb(payload->remote_name, 0, 0);
	} else {
	/* do NOT include initial_size since it wasn't part of the package's
	 * download_size (nor included in the total download size callback) */
		payload->handle->dlcb(payload->remote_name, dlnow, dltotal);
	}

	payload->prevprogress = current_size;

	return 0;
}

static int curl_gethost(const char *url, char *buffer, size_t buf_len)
{
	size_t hostlen;
	char *p, *q;

	if(strncmp(url, "file://", 7) == 0) {
		p = _("disk");
		hostlen = strlen(p);
	} else {
		p = strstr(url, "//");
		if(!p) {
			return 1;
		}
		p += 2; /* jump over the found // */
		hostlen = strcspn(p, "/");

		/* there might be a user:pass@ on the URL. hide it. avoid using memrchr()
		 * for portability concerns. */
		q = p + hostlen;
		while(--q > p) {
			if(*q == '@') {
				break;
			}
		}
		if(*q == '@' && p != q) {
			hostlen -= q - p + 1;
			p = q + 1;
		}
	}

	if(hostlen > buf_len - 1) {
		/* buffer overflow imminent */
		return 1;
	}
	memcpy(buffer, p, hostlen);
	buffer[hostlen] = '\0';

	return 0;
}

static int utimes_long(const char *path, long seconds)
{
	if(seconds != -1) {
		struct timeval tv[2];
		memset(&tv, 0, sizeof(tv));
		tv[0].tv_sec = tv[1].tv_sec = seconds;
		return utimes(path, tv);
	}
	return 0;
}

/* prefix to avoid possible future clash with getumask(3) */
static mode_t _getumask(void)
{
	mode_t mask = umask(0);
	umask(mask);
	return mask;
}

static size_t dload_parseheader_cb(void *ptr, size_t size, size_t nmemb, void *user)
{
	size_t realsize = size * nmemb;
	const char *fptr, *endptr = NULL;
	const char * const cd_header = "Content-Disposition:";
	const char * const fn_key = "filename=";
	struct dload_payload *payload = (struct dload_payload *)user;
	long respcode;

	if(_alpm_raw_ncmp(cd_header, ptr, strlen(cd_header)) == 0) {
		if((fptr = strstr(ptr, fn_key))) {
			fptr += strlen(fn_key);

			/* find the end of the field, which is either a semi-colon, or the end of
			 * the data. As per curl_easy_setopt(3), we cannot count on headers being
			 * null terminated, so we look for the closing \r\n */
			endptr = fptr + strcspn(fptr, ";\r\n") - 1;

			/* remove quotes */
			if(*fptr == '"' && *endptr == '"') {
				fptr++;
				endptr--;
			}

			STRNDUP(payload->content_disp_name, fptr, endptr - fptr + 1,
					RET_ERR(payload->handle, ALPM_ERR_MEMORY, realsize));
		}
	}

	curl_easy_getinfo(payload->handle->curl, CURLINFO_RESPONSE_CODE, &respcode);
	if(payload->respcode != respcode) {
		payload->respcode = respcode;
	}

	return realsize;
}

static void curl_set_handle_opts(struct dload_payload *payload,
		CURL *curl, char *error_buffer)
{
	alpm_handle_t *handle = payload->handle;
	const char *useragent = getenv("HTTP_USER_AGENT");
	struct stat st;

	/* the curl_easy handle is initialized with the alpm handle, so we only need
	 * to reset the handle's parameters for each time it's used. */
	curl_easy_reset(curl);
	curl_easy_setopt(curl, CURLOPT_URL, payload->fileurl);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, error_buffer);
	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 10L);
	curl_easy_setopt(curl, CURLOPT_FILETIME, 1L);
	curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 0L);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
	curl_easy_setopt(curl, CURLOPT_XFERINFOFUNCTION, dload_progress_cb);
	curl_easy_setopt(curl, CURLOPT_XFERINFODATA, (void *)payload);
	if(!handle->disable_dl_timeout) {
		curl_easy_setopt(curl, CURLOPT_LOW_SPEED_LIMIT, 1L);
		curl_easy_setopt(curl, CURLOPT_LOW_SPEED_TIME, 10L);
	}
	curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, dload_parseheader_cb);
	curl_easy_setopt(curl, CURLOPT_HEADERDATA, (void *)payload);
	curl_easy_setopt(curl, CURLOPT_NETRC, CURL_NETRC_OPTIONAL);
	curl_easy_setopt(curl, CURLOPT_TCP_KEEPALIVE, 1L);
	curl_easy_setopt(curl, CURLOPT_TCP_KEEPIDLE, 60L);
	curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);
	curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);

	_alpm_log(handle, ALPM_LOG_DEBUG, "url: %s\n", payload->fileurl);

	if(payload->max_size) {
		_alpm_log(handle, ALPM_LOG_DEBUG, "maxsize: %jd\n",
				(intmax_t)payload->max_size);
		curl_easy_setopt(curl, CURLOPT_MAXFILESIZE_LARGE,
				(curl_off_t)payload->max_size);
	}

	if(useragent != NULL) {
		curl_easy_setopt(curl, CURLOPT_USERAGENT, useragent);
	}

	if(!payload->allow_resume && !payload->force && payload->destfile_name &&
			stat(payload->destfile_name, &st) == 0) {
		/* start from scratch, but only download if our local is out of date. */
		curl_easy_setopt(curl, CURLOPT_TIMECONDITION, CURL_TIMECOND_IFMODSINCE);
		curl_easy_setopt(curl, CURLOPT_TIMEVALUE, (long)st.st_mtime);
		_alpm_log(handle, ALPM_LOG_DEBUG,
				"using time condition: %ld\n", (long)st.st_mtime);
	} else if(stat(payload->tempfile_name, &st) == 0 && payload->allow_resume) {
		/* a previous partial download exists, resume from end of file. */
		payload->tempfile_openmode = "ab";
		curl_easy_setopt(curl, CURLOPT_RESUME_FROM_LARGE, (curl_off_t)st.st_size);
		_alpm_log(handle, ALPM_LOG_DEBUG,
				"tempfile found, attempting continuation from %jd bytes\n",
				(intmax_t)st.st_size);
		payload->initial_size = st.st_size;
	}
}

static void mask_signal(int signum, void (*handler)(int),
		struct sigaction *origaction)
{
	struct sigaction newaction;

	newaction.sa_handler = handler;
	sigemptyset(&newaction.sa_mask);
	newaction.sa_flags = 0;

	sigaction(signum, NULL, origaction);
	sigaction(signum, &newaction, NULL);
}

static void unmask_signal(int signum, struct sigaction *sa)
{
	sigaction(signum, sa, NULL);
}

static FILE *create_tempfile(struct dload_payload *payload, const char *localpath)
{
	int fd;
	FILE *fp;
	char *randpath;
	size_t len;

	/* create a random filename, which is opened with O_EXCL */
	len = strlen(localpath) + 14 + 1;
	MALLOC(randpath, len, RET_ERR(payload->handle, ALPM_ERR_MEMORY, NULL));
	snprintf(randpath, len, "%salpmtmp.XXXXXX", localpath);
	if((fd = mkstemp(randpath)) == -1 ||
			fchmod(fd, ~(_getumask()) & 0666) ||
			!(fp = fdopen(fd, payload->tempfile_openmode))) {
		unlink(randpath);
		close(fd);
		_alpm_log(payload->handle, ALPM_LOG_ERROR,
				_("failed to create temporary file for download\n"));
		free(randpath);
		return NULL;
	}
	/* fp now points to our alpmtmp.XXXXXX */
	free(payload->tempfile_name);
	payload->tempfile_name = randpath;
	free(payload->remote_name);
	STRDUP(payload->remote_name, strrchr(randpath, '/') + 1,
			fclose(fp); RET_ERR(payload->handle, ALPM_ERR_MEMORY, NULL));

	return fp;
}

/* RFC1123 states applications should support this length */
#define HOSTNAME_SIZE 256

static int curl_download_internal(struct dload_payload *payload,
		const char *localpath, char **final_file, const char **final_url)
{
	int ret = -1;
	FILE *localf = NULL;
	char *effective_url;
	char hostname[HOSTNAME_SIZE];
	char error_buffer[CURL_ERROR_SIZE] = {0};
	struct stat st;
	long timecond, remote_time = -1;
	double remote_size, bytes_dl;
	struct sigaction orig_sig_pipe, orig_sig_int;
	/* shortcut to our handle within the payload */
	alpm_handle_t *handle = payload->handle;
	CURL *curl = get_libcurl_handle(handle);
	handle->pm_errno = ALPM_ERR_OK;

	/* make sure these are NULL */
	FREE(payload->tempfile_name);
	FREE(payload->destfile_name);
	FREE(payload->content_disp_name);

	payload->tempfile_openmode = "wb";
	if(!payload->remote_name) {
		STRDUP(payload->remote_name, get_filename(payload->fileurl),
				RET_ERR(handle, ALPM_ERR_MEMORY, -1));
	}
	if(curl_gethost(payload->fileurl, hostname, sizeof(hostname)) != 0) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("url '%s' is invalid\n"), payload->fileurl);
		RET_ERR(handle, ALPM_ERR_SERVER_BAD_URL, -1);
	}

	if(payload->remote_name && strlen(payload->remote_name) > 0 &&
			strcmp(payload->remote_name, ".sig") != 0) {
		payload->destfile_name = get_fullpath(localpath, payload->remote_name, "");
		payload->tempfile_name = get_fullpath(localpath, payload->remote_name, ".part");
		if(!payload->destfile_name || !payload->tempfile_name) {
			goto cleanup;
		}
	} else {
		/* URL doesn't contain a filename, so make a tempfile. We can't support
		 * resuming this kind of download; partial transfers will be destroyed */
		payload->unlink_on_fail = 1;

		localf = create_tempfile(payload, localpath);
		if(localf == NULL) {
			goto cleanup;
		}
	}

	curl_set_handle_opts(payload, curl, error_buffer);

	if(localf == NULL) {
		localf = fopen(payload->tempfile_name, payload->tempfile_openmode);
		if(localf == NULL) {
			handle->pm_errno = ALPM_ERR_RETRIEVE;
			_alpm_log(handle, ALPM_LOG_ERROR,
					_("could not open file %s: %s\n"),
					payload->tempfile_name, strerror(errno));
			goto cleanup;
		}
	}

	_alpm_log(handle, ALPM_LOG_DEBUG,
			"opened tempfile for download: %s (%s)\n", payload->tempfile_name,
			payload->tempfile_openmode);

	curl_easy_setopt(curl, CURLOPT_WRITEDATA, localf);

	/* Ignore any SIGPIPE signals. With libcurl, these shouldn't be happening,
	 * but better safe than sorry. Store the old signal handler first. */
	mask_signal(SIGPIPE, SIG_IGN, &orig_sig_pipe);
	mask_signal(SIGINT, &inthandler, &orig_sig_int);

	/* perform transfer */
	payload->curlerr = curl_easy_perform(curl);
	_alpm_log(handle, ALPM_LOG_DEBUG, "curl returned error %d from transfer\n",
			payload->curlerr);

	/* disconnect relationships from the curl handle for things that might go out
	 * of scope, but could still be touched on connection teardown. This really
	 * only applies to FTP transfers. */
	curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, (char *)NULL);

	/* was it a success? */
	switch(payload->curlerr) {
		case CURLE_OK:
			/* get http/ftp response code */
			_alpm_log(handle, ALPM_LOG_DEBUG, "response code: %ld\n", payload->respcode);
			if(payload->respcode >= 400) {
				payload->unlink_on_fail = 1;
				if(!payload->errors_ok) {
					/* non-translated message is same as libcurl */
					snprintf(error_buffer, sizeof(error_buffer),
							"The requested URL returned error: %ld", payload->respcode);
					_alpm_log(handle, ALPM_LOG_ERROR,
							_("failed retrieving file '%s' from %s : %s\n"),
							payload->remote_name, hostname, error_buffer);
				}
				goto cleanup;
			}
			break;
		case CURLE_ABORTED_BY_CALLBACK:
			/* handle the interrupt accordingly */
			if(dload_interrupted == ABORT_OVER_MAXFILESIZE) {
				payload->curlerr = CURLE_FILESIZE_EXCEEDED;
				payload->unlink_on_fail = 1;
				handle->pm_errno = ALPM_ERR_LIBCURL;
				_alpm_log(handle, ALPM_LOG_ERROR,
						_("failed retrieving file '%s' from %s : expected download size exceeded\n"),
						payload->remote_name, hostname);
			}
			goto cleanup;
		default:
			/* delete zero length downloads */
			if(fstat(fileno(localf), &st) == 0 && st.st_size == 0) {
				payload->unlink_on_fail = 1;
			}
			if(!payload->errors_ok) {
				handle->pm_errno = ALPM_ERR_LIBCURL;
				_alpm_log(handle, ALPM_LOG_ERROR,
						_("failed retrieving file '%s' from %s : %s\n"),
						payload->remote_name, hostname, error_buffer);
			} else {
				_alpm_log(handle, ALPM_LOG_DEBUG,
						"failed retrieving file '%s' from %s : %s\n",
						payload->remote_name, hostname, error_buffer);
			}
			goto cleanup;
	}

	/* retrieve info about the state of the transfer */
	curl_easy_getinfo(curl, CURLINFO_FILETIME, &remote_time);
	curl_easy_getinfo(curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &remote_size);
	curl_easy_getinfo(curl, CURLINFO_SIZE_DOWNLOAD, &bytes_dl);
	curl_easy_getinfo(curl, CURLINFO_CONDITION_UNMET, &timecond);
	curl_easy_getinfo(curl, CURLINFO_EFFECTIVE_URL, &effective_url);

	if(final_url != NULL) {
		*final_url = effective_url;
	}

	/* time condition was met and we didn't download anything. we need to
	 * clean up the 0 byte .part file that's left behind. */
	if(timecond == 1 && DOUBLE_EQ(bytes_dl, 0)) {
		_alpm_log(handle, ALPM_LOG_DEBUG, "file met time condition\n");
		ret = 1;
		unlink(payload->tempfile_name);
		goto cleanup;
	}

	/* remote_size isn't necessarily the full size of the file, just what the
	 * server reported as remaining to download. compare it to what curl reported
	 * as actually being transferred during curl_easy_perform() */
	if(!DOUBLE_EQ(remote_size, -1) && !DOUBLE_EQ(bytes_dl, -1) &&
			!DOUBLE_EQ(bytes_dl, remote_size)) {
		handle->pm_errno = ALPM_ERR_RETRIEVE;
		_alpm_log(handle, ALPM_LOG_ERROR, _("%s appears to be truncated: %jd/%jd bytes\n"),
				payload->remote_name, (intmax_t)bytes_dl, (intmax_t)remote_size);
		goto cleanup;
	}

	if(payload->trust_remote_name) {
		if(payload->content_disp_name) {
			/* content-disposition header has a better name for our file */
			free(payload->destfile_name);
			payload->destfile_name = get_fullpath(localpath, payload->content_disp_name, "");
		} else {
			const char *effective_filename = strrchr(effective_url, '/');
			if(effective_filename && strlen(effective_filename) > 2) {
				effective_filename++;

				/* if destfile was never set, we wrote to a tempfile. even if destfile is
				 * set, we may have followed some redirects and the effective url may
				 * have a better suggestion as to what to name our file. in either case,
				 * refactor destfile to this newly derived name. */
				if(!payload->destfile_name || strcmp(effective_filename,
							strrchr(payload->destfile_name, '/') + 1) != 0) {
					free(payload->destfile_name);
					payload->destfile_name = get_fullpath(localpath, effective_filename, "");
				}
			}
		}
	}

	ret = 0;

cleanup:
	if(localf != NULL) {
		fclose(localf);
		utimes_long(payload->tempfile_name, remote_time);
	}

	if(ret == 0) {
		const char *realname = payload->tempfile_name;
		if(payload->destfile_name) {
			realname = payload->destfile_name;
			if(rename(payload->tempfile_name, payload->destfile_name)) {
				_alpm_log(handle, ALPM_LOG_ERROR, _("could not rename %s to %s (%s)\n"),
						payload->tempfile_name, payload->destfile_name, strerror(errno));
				ret = -1;
			}
		}
		if(ret != -1 && final_file) {
			STRDUP(*final_file, strrchr(realname, '/') + 1,
					RET_ERR(handle, ALPM_ERR_MEMORY, -1));
		}
	}

	if((ret == -1 || dload_interrupted) && payload->unlink_on_fail &&
			payload->tempfile_name) {
		unlink(payload->tempfile_name);
	}

	/* restore the old signal handlers */
	unmask_signal(SIGINT, &orig_sig_int);
	unmask_signal(SIGPIPE, &orig_sig_pipe);
	/* if we were interrupted, trip the old handler */
	if(dload_interrupted) {
		raise(SIGINT);
	}

	return ret;
}
#endif

/** Download a file given by a URL to a local directory.
 * Does not overwrite an existing file if the download fails.
 * @param payload the payload context
 * @param localpath the directory to save the file in
 * @param final_file the real name of the downloaded file (may be NULL)
 * @return 0 on success, -1 on error (pm_errno is set accordingly if errors_ok == 0)
 */
int _alpm_download(struct dload_payload *payload, const char *localpath,
		char **final_file, const char **final_url)
{
	alpm_handle_t *handle = payload->handle;

	if(handle->fetchcb == NULL) {
#ifdef HAVE_LIBCURL
		return curl_download_internal(payload, localpath, final_file, final_url);
#else
		/* work around unused warnings when building without libcurl */
		(void)final_file;
		(void)final_url;
		RET_ERR(handle, ALPM_ERR_EXTERNAL_DOWNLOAD, -1);
#endif
	} else {
		int ret = handle->fetchcb(payload->fileurl, localpath, payload->force);
		if(ret == -1 && !payload->errors_ok) {
			RET_ERR(handle, ALPM_ERR_EXTERNAL_DOWNLOAD, -1);
		}
		return ret;
	}
}

static char *filecache_find_url(alpm_handle_t *handle, const char *url)
{
	const char *filebase = strrchr(url, '/');

	if(filebase == NULL) {
		return NULL;
	}

	filebase++;
	if(*filebase == '\0') {
		return NULL;
	}

	return _alpm_filecache_find(handle, filebase);
}

/** Fetch a remote pkg. */
char SYMEXPORT *alpm_fetch_pkgurl(alpm_handle_t *handle, const char *url)
{
	char *filepath;
	const char *cachedir, *final_pkg_url = NULL;
	char *final_file = NULL;
	struct dload_payload payload;
	int ret = 0;

	CHECK_HANDLE(handle, return NULL);
	ASSERT(url, RET_ERR(handle, ALPM_ERR_WRONG_ARGS, NULL));

	/* find a valid cache dir to download to */
	cachedir = _alpm_filecache_setup(handle);

	memset(&payload, 0, sizeof(struct dload_payload));

	/* attempt to find the file in our pkgcache */
	filepath = filecache_find_url(handle, url);
	if(filepath == NULL) {
		STRDUP(payload.fileurl, url, RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
		payload.allow_resume = 1;
		payload.handle = handle;
		payload.trust_remote_name = 1;

		/* download the file */
		ret = _alpm_download(&payload, cachedir, &final_file, &final_pkg_url);
		_alpm_dload_payload_reset(&payload);
		if(ret == -1) {
			_alpm_log(handle, ALPM_LOG_WARNING, _("failed to download %s\n"), url);
			free(final_file);
			return NULL;
		}
		_alpm_log(handle, ALPM_LOG_DEBUG, "successfully downloaded %s\n", url);
	}

	/* attempt to download the signature */
	if(ret == 0 && final_pkg_url && (handle->siglevel & ALPM_SIG_PACKAGE)) {
		char *sig_filepath, *sig_final_file = NULL;
		size_t len;

		len = strlen(final_pkg_url) + 5;
		MALLOC(payload.fileurl, len, free(final_file); RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
		snprintf(payload.fileurl, len, "%s.sig", final_pkg_url);

		sig_filepath = filecache_find_url(handle, payload.fileurl);
		if(sig_filepath == NULL) {
			payload.handle = handle;
			payload.trust_remote_name = 1;
			payload.force = 1;
			payload.errors_ok = (handle->siglevel & ALPM_SIG_PACKAGE_OPTIONAL);

			/* set hard upper limit of 16KiB */
			payload.max_size = 16 * 1024;

			ret = _alpm_download(&payload, cachedir, &sig_final_file, NULL);
			if(ret == -1 && !payload.errors_ok) {
				_alpm_log(handle, ALPM_LOG_WARNING,
						_("failed to download %s\n"), payload.fileurl);
				/* Warn now, but don't return NULL. We will fail later during package
				 * load time. */
			} else if(ret == 0) {
				_alpm_log(handle, ALPM_LOG_DEBUG,
						"successfully downloaded %s\n", payload.fileurl);
			}
			FREE(sig_final_file);
		}
		free(sig_filepath);
		_alpm_dload_payload_reset(&payload);
	}

	/* we should be able to find the file the second time around */
	if(filepath == NULL) {
		filepath = _alpm_filecache_find(handle, final_file);
	}
	free(final_file);

	return filepath;
}

void _alpm_dload_payload_reset(struct dload_payload *payload)
{
	ASSERT(payload, return);

	FREE(payload->remote_name);
	FREE(payload->tempfile_name);
	FREE(payload->destfile_name);
	FREE(payload->content_disp_name);
	FREE(payload->fileurl);
	memset(payload, '\0', sizeof(*payload));
}

void _alpm_dload_payload_reset_for_retry(struct dload_payload *payload)
{
	ASSERT(payload, return);

	FREE(payload->fileurl);
	payload->initial_size += payload->prevprogress;
	payload->prevprogress = 0;
	payload->unlink_on_fail = 0;
	payload->cb_initialized = 0;
}