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
|
/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) many different people. If you wrote this, please
* acknowledge your work.
*
* 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 <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "libbb.h"
extern FILE *gz_open(FILE *compressed_file, int *pid)
{
int unzip_pipe[2];
if (pipe(unzip_pipe)!=0) {
error_msg("pipe error");
return(NULL);
}
if ((*pid = fork()) == -1) {
error_msg("fork failed");
return(NULL);
}
if (*pid==0) {
/* child process */
close(unzip_pipe[0]);
unzip(compressed_file, fdopen(unzip_pipe[1], "w"));
fflush(NULL);
fclose(compressed_file);
close(unzip_pipe[1]);
exit(EXIT_SUCCESS);
}
close(unzip_pipe[1]);
if (unzip_pipe[0] == -1) {
error_msg("gzip stream init failed");
}
return(fdopen(unzip_pipe[0], "r"));
}
/* gz_open implementation using gunzip and a vfork/exec -- dodges OOM killer */
extern FILE *gzvopen(FILE *compressed_file, int *pid)
{
int unzip_pipe[2];
off_t floc;
int cfile;
/* create a new file descriptor for the input stream
* (it *must* be associated with a file)
* and seek to the same position in that fd as the stream.
*/
cfile = dup(fileno(compressed_file));
floc = ftello(compressed_file);
lseek(cfile, floc, SEEK_SET);
/* create the pipe */
if (pipe(unzip_pipe)!=0) {
error_msg("gzvopen(): pipe error");
return(NULL);
}
*pid = vfork();
if (*pid < 0) {
error_msg("gzvopen(): fork failed");
return(NULL);
}
if (*pid==0) {
/* child process - reads STDIN, writes to pipe */
/* close unused read end of pipe */
close(unzip_pipe[0]);
/* connect child's stdout to the pipe write end */
dup2(unzip_pipe[1], 1);
/* connect child's stdin to the fd passed in to us */
dup2(cfile, 0);
/* execute the gunzip utility */
execlp("gunzip","gunzip",NULL);
/* if we get here, we had a failure - since we are
* using vfork(), we cannot call exit(), must call _exit().
*/
_exit(-1);
}
/* Parent process is executing here */
/* we have no more need of the duplicate fd */
close(cfile);
/* close the write end of the pipe */
close(unzip_pipe[1]);
/* return the read end of the pipe as a FILE */
return(fdopen(unzip_pipe[0], "r"));
}
extern void gzvclose(int gunzip_pid)
{
if (kill(gunzip_pid, SIGTERM) == -1) {
perror("gzvclose()");
fprintf(stderr,"%s: unable to kill gunzip pid.\n",
__FUNCTION__);
}
if (waitpid(gunzip_pid, NULL, 0) == -1) {
fprintf(stderr,"%s: unable to wait on gunzip pid.\n",
__FUNCTION__);
}
}
|
