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
|
/* minilogd.c
*
* A pale imitation of syslogd. Most notably, doesn't write anything
* anywhere except possibly back to syslogd.
*
*/
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <syslog.h>
#define __USE_BSD
#include <unistd.h>
#include <sys/poll.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#define MAX_BUF_LINES 10000
#define BUF_LINE_SIZE 8192
static int we_own_log=0;
static char **buffer=NULL;
static int buflines=0;
int debug;
int recvsock;
void alarm_handler(int x) {
alarm(0);
close(recvsock);
recvsock = -1;
}
void freeBuffer() {
struct sockaddr_un addr;
int sock;
int x=0,conn;
bzero(&addr,sizeof(addr));
addr.sun_family = AF_LOCAL;
strncpy(addr.sun_path,_PATH_LOG,sizeof(addr.sun_path)-1);
/* wait for klogd to hit syslog */
sleep(2);
sock = socket(AF_LOCAL, SOCK_STREAM,0);
conn=connect(sock,(struct sockaddr *) &addr,sizeof(addr));
while (x<buflines) {
if (!conn) {
/*printf("to syslog: %s\n", buffer[x]);*/
write(sock,buffer[x],strlen(buffer[x])+1);
}
free(buffer[x]);
x++;
}
}
void cleanup(int exitcode) {
/* If we own the log, unlink it before trying to free our buffer.
* Otherwise, sending the buffer to /dev/log doesn't make much sense.... */
if (we_own_log) {
perror("wol");
unlink(_PATH_LOG);
}
/* Don't try to free buffer if we were called from a signal handler */
if (exitcode<=0) {
if (buffer) freeBuffer();
exit(exitcode);
} else
exit(exitcode+128);
}
void runDaemon(int sock) {
struct sockaddr_un addr;
int x,len,done=0;
socklen_t addrlen;
char *message;
struct stat s1,s2;
struct pollfd pfds;
daemon(0,-1);
/* try not to leave stale sockets lying around */
/* Hopefully, we won't actually get any of these */
signal(SIGHUP,cleanup);
signal(SIGINT,cleanup);
signal(SIGQUIT,cleanup);
signal(SIGILL,cleanup);
signal(SIGABRT,cleanup);
signal(SIGFPE,cleanup);
signal(SIGSEGV,cleanup);
signal(SIGPIPE,cleanup);
signal(SIGBUS,cleanup);
signal(SIGTERM,cleanup);
done = 0;
/* Get stat info on /dev/log so we can later check to make sure we
* still own it... */
if (stat(_PATH_LOG,&s1) != 0)
memset(&s1, '\0', sizeof(struct stat));
while (!done) {
pfds.fd = sock;
pfds.events = POLLIN|POLLPRI;
if ( ( (x=poll(&pfds,1,500))==-1) && errno !=EINTR) {
perror("poll");
cleanup(-1);
}
if ( (x>0) && pfds.revents & (POLLIN | POLLPRI)) {
message = calloc(BUF_LINE_SIZE,sizeof(char));
recvsock = accept(sock,(struct sockaddr *) &addr, &addrlen);
alarm(2);
signal(SIGALRM, alarm_handler);
len = read(recvsock,message,BUF_LINE_SIZE);
alarm(0);
close(recvsock);
if (len>0) {
/*printf("line recv'd: %s\n", message);*/
if (buflines < MAX_BUF_LINES) {
if (buffer)
buffer = realloc(buffer,(buflines+1)*sizeof(char *));
else
buffer = malloc(sizeof(char *));
message[strlen(message)]='\n';
buffer[buflines]=message;
buflines++;
}
}
else {
recvsock=-1;
}
}
if ( (x>0) && ( pfds.revents & (POLLHUP | POLLNVAL)) )
done = 1;
/* Check to see if syslogd's yanked our socket out from under us */
if ( (stat(_PATH_LOG,&s2)!=0) ||
(s1.st_ino != s2.st_ino ) || (s1.st_ctime != s2.st_ctime) ||
(s1.st_mtime != s2.st_mtime) ) { /*|| (s1.st_atime != s2.st_atime) ) {*/
done = 1;
we_own_log = 0;
/*printf("someone stole our %s\n", _PATH_LOG);
printf("st_ino: %d %d\n", s1.st_ino, s2.st_ino);
printf("st_ctime: %d %d\n", s1.st_ctime, s2.st_ctime);
printf("st_atime: %d %d\n", s1.st_atime, s2.st_atime);
printf("st_mtime: %d %d\n", s1.st_mtime, s2.st_mtime);*/
}
}
cleanup(0);
}
int main(int argc, char **argv) {
struct sockaddr_un addr;
int sock;
int pid;
/* option processing made simple... */
if (argc>1) debug=1;
/* just in case */
sock = open("/dev/null",O_RDWR);
dup2(sock,0);
dup2(sock,1);
dup2(sock,2);
bzero(&addr, sizeof(addr));
addr.sun_family = AF_LOCAL;
strncpy(addr.sun_path,_PATH_LOG,sizeof(addr.sun_path)-1);
sock = socket(AF_LOCAL, SOCK_STREAM,0);
unlink(_PATH_LOG);
/* Bind socket before forking, so we know if the server started */
if (!bind(sock,(struct sockaddr *) &addr, sizeof(addr))) {
we_own_log = 1;
listen(sock,5);
if ((pid=fork())==-1) {
perror("fork");
exit(3);
}
if (pid) {
exit(0);
} else {
/*printf("starting daemon...\n");*/
runDaemon(sock);
/* shouldn't get back here... */
exit(4);
}
} else {
exit(5);
}
}
/* vim: set ts=2 noet: */
|
