abuild-fetch.c 4.85 KB
Newer Older
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
/* MIT license

Copyright (C) 2015 Natanael Copa <ncopa@alpinelinux.org>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

*/


#include <sys/wait.h>

#include <err.h>
29
#include <errno.h>
30
#include <fcntl.h>
31
#include <limits.h>
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static char *program;
static char lockfile[PATH_MAX] = "";

struct cmdarray {
	size_t argc;
	char *argv[32];
};

void add_opt(struct cmdarray *cmd, char *opt)
{
	cmd->argv[cmd->argc++] = opt;
	cmd->argv[cmd->argc] = NULL;
}

int usage(int eval)
{
53
	printf("usage: %s [-h] [-d DESTDIR] URL\n", program);
54 55 56
	return eval;
}

57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78
int fork_exec(char *argv[], int showerr)
{
	int r = 202;
	int status = 0;
	pid_t childpid = fork();
	if (childpid < 0 )
		err(200, "fork");

	if (childpid == 0) {
		execvp(argv[0], argv);
		if (showerr)
			warn("%s", argv[0]);
		_exit(201);
	}

	/* wait for curl/wget and get the exit code */
	wait(&status);
	if (WIFEXITED(status))
		r = WEXITSTATUS(status);
	return r;
}

79 80 81 82 83 84 85 86 87 88 89 90 91
/* create or wait for an NFS-safe lockfile and fetch url with curl or wget */
int fetch(char *url, const char *destdir)
{
	int lockfd, status=0;
	char outfile[PATH_MAX], partfile[PATH_MAX];
	char *name, *p;
	struct flock fl = {
		.l_type = F_WRLCK,
		.l_whence = SEEK_SET,
		.l_start = 1,
		.l_len = 0,
	};
	struct cmdarray curlcmd = {
92 93
		.argc = 5,
		.argv = { "curl", "-L", "-f", "-o", partfile, NULL }
94 95 96 97 98 99 100 101
	};
	struct cmdarray wgetcmd = {
		.argc = 3,
		.argv = { "wget", "-O", partfile, NULL }
	};

	name = strrchr(url, '/');
	if (name == NULL)
102
		errx(1, "%s: no '/' in url", url);
103 104 105 106 107 108 109 110 111 112 113 114 115 116 117
	p = strstr(url, "::");
	if (p != NULL) {
		name = url;
		*p = '\0';
		url = p + 2;
	} else {
		name++;
	}

	snprintf(outfile, sizeof(outfile), "%s/%s", destdir, name);
	snprintf(lockfile, sizeof(lockfile), "%s.lock", outfile);
	snprintf(partfile, sizeof(partfile), "%s.part", outfile);

	lockfd = open(lockfile, O_WRONLY|O_CREAT, 0660);
	if (lockfd < 0)
118
		err(1, "%s", lockfile);
119 120

	if (fcntl(lockfd, F_SETLK, &fl) < 0) {
121
		int i;
122
		printf("Waiting for %s ...\n", lockfile);
123 124 125 126 127 128 129 130
		for (i=0; i<10; i++) {
			int r = fcntl(lockfd, F_SETLKW, &fl);
			if (r == 0)
				break;
			if (r == -1 && errno != ESTALE)
				err(1, "fcntl(F_SETLKW)");
			sleep(1);
		}
131 132 133 134 135 136 137 138 139 140 141 142 143 144 145
	}

	if (access(outfile, F_OK) == 0)
		goto fetch_done;

	if (access(partfile, F_OK) == 0) {
		printf("Partial download found. Trying to resume.\n");
		add_opt(&curlcmd, "-C");
		add_opt(&curlcmd, "-");
		add_opt(&wgetcmd, "-c");
	}

	add_opt(&curlcmd, url);
	add_opt(&wgetcmd, url);

146
	status = fork_exec(curlcmd.argv, 0);
147

148 149 150 151
	/* CURLE_RANGE_ERROR (33)
	   The server does not support or accept range requests. */
	if (status == 33)
		unlink(partfile);
152

153 154 155
	/* is we failed execute curl, then fallback to wget */
	if (status == 201)
		status = fork_exec(wgetcmd.argv, 1);
156

157
	/* only rename completed downloads */
158 159
	if (status == 0)
		rename(partfile, outfile);
160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182

fetch_done:
	unlink(lockfile);
	close(lockfd);
	lockfile[0] = '\0';
	return status;
}

void sighandler(int sig)
{
	switch(sig) {
	case SIGABRT:
	case SIGINT:
	case SIGQUIT:
	case SIGTERM:
		unlink(lockfile);
		exit(0);
		break;
	default:
		break;
	}
}

183 184 185 186 187 188
/* exit codes get passed through from curl/wget (so we can check in abuild
   whether the server does not support resuming). Additional exit codes:
   200: fork failed
   201: curl/wget could not be started
   202: curl/wget did not terminate normally
   203: usage displayed */
189 190
int main(int argc, char *argv[])
{
191
	int opt;
192 193 194 195 196 197 198 199 200 201 202 203
	char *destdir = "/var/cache/distfiles";

	program = argv[0];
	while ((opt = getopt(argc, argv, "hd:")) != -1) {
		switch (opt) {
		case 'h':
			return usage(0);
			break;
		case 'd':
			destdir = optarg;
			break;
		default:
Jonathan Neuschäfer's avatar
Jonathan Neuschäfer committed
204
			printf("Unknown option '%c'\n", opt);
205 206 207 208 209 210 211 212
			return usage(1);
			break;
		}
	}

	argv += optind;
	argc -= optind;

213 214
	if (argc != 1)
		return usage(203);
215 216 217 218 219 220

	signal(SIGABRT, sighandler);
	signal(SIGINT, sighandler);
	signal(SIGQUIT, sighandler);
	signal(SIGTERM, sighandler);

221
	return fetch(argv[0], destdir);
222
}