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
|
/*
VTun - Virtual Tunnel over TCP/IP network.
Copyright (C) 1998-2016 Maxim Krasnyansky <max_mk@yahoo.com>
VTun has been derived from VPPP package by Maxim Krasnyansky.
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.
*/
/*
* $Id: lock.c,v 1.6.2.3 2016/10/01 21:27:51 mtbishop Exp $
*/
#include "config.h"
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/time.h>
#include <syslog.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include "vtun.h"
#include "linkfd.h"
#include "lib.h"
#include "lock.h"
#include <time.h>
int create_lock(char * file)
{
char tmp_file[255], str[20];
int fd, pid, ret;
pid = getpid();
ret = 0;
/* Create temp file */
sprintf(tmp_file, "%s_%d_tmp\n", file, pid);
if( (fd = open(tmp_file, O_WRONLY|O_CREAT|O_TRUNC, 0644)) < 0 ){
vtun_syslog(LOG_ERR, "Can't create temp lock file %s", file);
return -1;
}
pid = sprintf(str, "%d\n", pid);
if( write(fd, str, pid) == pid ){
/* Create lock file */
if( link(tmp_file, file) < 0 ){
/* Oops, already locked */
ret = -1;
}
} else {
vtun_syslog(LOG_ERR, "Can't write to %s", tmp_file);
ret = -1;
}
close(fd);
/* Remove temp file */
unlink(tmp_file);
return ret;
}
pid_t read_lock(char * file)
{
char str[20];
int fd, pid;
/* Read PID from existing lock */
if( (fd = open(file, O_RDONLY)) < 0)
return -1;
pid = read(fd,str,sizeof(str));
close(fd);
if( pid <= 0 )
return -1;
str[sizeof(str)-1]='\0';
pid = strtol(str, NULL, 10);
if( !pid || errno == ERANGE ){
/* Broken lock file */
if( unlink(file) < 0 )
vtun_syslog(LOG_ERR, "Unable to remove broken lock %s", file);
return -1;
}
/* Check if process is still alive */
if( kill(pid, 0) < 0 && errno == ESRCH ){
/* Process is dead. Remove stale lock. */
if( unlink(file) < 0 )
vtun_syslog(LOG_ERR, "Unable to remove stale lock %s", file);
return -1;
}
return pid;
}
int lock_host(struct vtun_host * host)
{
char lock_file[255];
struct timespec tm;
int pid, i;
if( host->multi == VTUN_MULTI_ALLOW )
return 0;
sprintf(lock_file, "%s/%s", VTUN_LOCK_DIR, host->host);
/* Check if lock already exists. */
if( (pid = read_lock(lock_file)) > 0 ){
/* Old process is alive */
switch( host->multi ){
case VTUN_MULTI_KILL:
vtun_syslog(LOG_INFO, "Killing old connection (process %d)", pid);
if( kill(pid, SIGTERM) < 0 && errno != ESRCH ){
vtun_syslog(LOG_ERR, "Can't kill process %d. %s",pid,strerror(errno));
return -1;
}
/* Give it a time(up to 5 secs) to terminate */
for(i=0; i < 10 && !kill(pid, 0); i++ ){
tm.tv_sec = 0; tm.tv_nsec = 500000000;
nanosleep(&tm, NULL);
}
/* Make sure it's dead */
if( !kill(pid, SIGKILL) ){
vtun_syslog(LOG_ERR, "Process %d ignored TERM, killed with KILL", pid);
/* Remove lock */
if( unlink(lock_file) < 0 )
vtun_syslog(LOG_ERR, "Unable to remove lock %s", lock_file);
}
break;
case VTUN_MULTI_DENY:
return -1;
}
}
return create_lock(lock_file);
}
void unlock_host(struct vtun_host *host)
{
char lock_file[255];
if( host->multi == VTUN_MULTI_ALLOW )
return;
sprintf(lock_file, "%s/%s", VTUN_LOCK_DIR, host->host);
if( unlink(lock_file) < 0 )
vtun_syslog(LOG_ERR, "Unable to remove lock %s", lock_file);
}
|
