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
|
/* 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>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#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)
{
printf("usage: %s [-h] [-d DESTDIR] URL\n", program);
return eval;
}
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;
}
/* 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 = {
.argc = 5,
.argv = { "curl", "-L", "-f", "-o", partfile, NULL }
};
struct cmdarray wgetcmd = {
.argc = 3,
.argv = { "wget", "-O", partfile, NULL }
};
name = strrchr(url, '/');
if (name == NULL)
errx(1, "%s: no '/' in url", url);
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)
err(1, "%s", lockfile);
if (fcntl(lockfd, F_SETLK, &fl) < 0) {
int i;
printf("Waiting for %s ...\n", lockfile);
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);
}
}
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);
status = fork_exec(curlcmd.argv, 0);
/* CURLE_RANGE_ERROR (33)
The server does not support or accept range requests. */
if (status == 33)
unlink(partfile);
/* is we failed execute curl, then fallback to wget */
if (status == 201)
status = fork_exec(wgetcmd.argv, 1);
/* only rename completed downloads */
if (status == 0)
rename(partfile, outfile);
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;
}
}
/* 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 */
int main(int argc, char *argv[])
{
int opt;
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:
printf("Unknown option '%c'\n", opt);
return usage(1);
break;
}
}
argv += optind;
argc -= optind;
if (argc != 1)
return usage(203);
signal(SIGABRT, sighandler);
signal(SIGINT, sighandler);
signal(SIGQUIT, sighandler);
signal(SIGTERM, sighandler);
return fetch(argv[0], destdir);
}
|
