1 /* miniudpserv: something like an inetd for the "make check" target of utftpd */
2
3 /*
4 * Copyright (C) 1999 Uwe Ohse
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21 #include "config.h"
22 #include <sys/types.h>
23 #include <sys/ioctl.h>
24 #include <sys/stat.h>
25 #include <signal.h>
26 #include <fcntl.h>
27
28 #include <sys/socket.h>
29 #include <netinet/in.h>
30 #include <netdb.h>
31 #ifdef HAVE_ARPA_INET_H
32 #include <arpa/inet.h>
33 #endif
34
35 #include <syslog.h>
36 #include <errno.h>
37 #include <string.h>
38 #include <stdlib.h>
39 #include <unistd.h>
40 #include "uogetopt.h"
41 #include "timselsysdep.h"
42 #include "nonblock.h"
43 #include "str2num.h"
44 #include "uostr.h"
45 #include "uoio.h"
46 #include "cdb.h"
47 #include "sys/wait.h"
48 #include "str_ulong.h"
49
50 #ifndef errno
51 extern int errno;
52 #endif
53
54 int peer;
55 int nullfd;
56
57 static char *argv0;
58
59 static uogetopt_t myopts[] =
60 {
61 {0, 0, 0, 0, 0, 0, 0}
62 };
63
64 static void
usage(void)65 usage(void)
66 {write(2,argv0,strlen(argv0));write(2,": use the --help option for usage infomation\n",47); _exit(1); }
67
68 static int
eat(int fd)69 eat(int fd)
70 {
71 char buf[1];
72 recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *) 0, 0);
73 return 0;
74 }
75
76 int
main(int argc,char ** argv)77 main (int argc, char **argv)
78 {
79 unsigned long ul;
80 fd_set set;
81 struct sockaddr_in s_in;
82
83 #ifdef HAVE_LIBEFENCE
84 /* hack around efence :-) */
85 {int fd,fd2;void *waste;
86 if (-1==(fd=open("/dev/null",O_WRONLY))) _exit(1);
87 if (-1==(fd2=dup(2))) _exit(1);
88 if (-1==(dup2(fd,2))) _exit(1);
89 waste=malloc(1);
90 if (-1==(dup2(fd2,2))) _exit(1);
91 close(fd); close(fd2);
92 }
93 #endif
94
95 argv0 = strrchr (argv[0], '/');
96 if (!argv0++)
97 argv0 = argv[0];
98 nullfd = open ("/dev/null", O_RDWR);
99 if (nullfd == -1) { syslog (LOG_ERR, "cannot open /dev/null: %s", strerror (errno)); _exit (1); }
100 uogetopt ("miniudpserv", PACKAGE, VERSION, &argc, argv, uogetopt_out, 0, myopts, "usage: miniudpserv host port program ...");
101 if (argc<4) usage();
102
103 openlog ("miniudpserv", LOG_PID | LOG_NDELAY, LOG_DAEMON);
104
105 memset (&s_in, 0, sizeof (s_in));
106 s_in.sin_family = AF_INET;
107 if (0 == inet_aton (argv[1], &s_in.sin_addr)) { syslog (LOG_ERR, "%s: not a valid in_addr", argv[1]); _exit (1); }
108 if (-1 == str2ulong (argv[2], &ul, 0) || ul == 0 || ul > 65535)
109 { syslog (LOG_ERR, "%s: not a valid port number", argv[2]); _exit (1); }
110 s_in.sin_port = htons (((short) ul));
111
112 peer = socket (AF_INET, SOCK_DGRAM, 0);
113 if (peer < 0) { syslog (LOG_ERR, "socket: %s", strerror (errno)); _exit (1); }
114 if (bind (peer, (struct sockaddr *) &s_in, sizeof (s_in)) < 0) { syslog (LOG_ERR, "bind: %s", strerror (errno)); _exit (1); }
115
116 FD_ZERO(&set);
117 while (1) {
118 char buf[1];
119 pid_t pid;
120 socklen_t len;
121 len = sizeof(s_in);
122 FD_SET(peer,&set);
123 if (-1==select(peer+1,&set,0,0,0)) { syslog(LOG_ERR,"select: %s",strerror(errno)); _exit(1); }
124 #ifdef MSG_PEEK
125 if (recvfrom(peer, buf, sizeof(buf), MSG_PEEK, (struct sockaddr *) & s_in, &len) < 0) {
126 /* uh? */
127 syslog(LOG_WARNING,"recvfrom(MSG_PEEK): %s",strerror(errno));
128 continue;
129 }
130 syslog(LOG_INFO,"packet from %s",inet_ntoa(s_in.sin_addr));
131 #endif
132 pid=fork();
133 if (pid==-1) {
134 syslog(LOG_ERR,"cannot fork: %s",strerror(errno));
135 eat(peer);
136 } else if (pid==0) {
137 /* child */
138 if (dup2(peer,0) != 0) { syslog(LOG_ERR,"cannot dup2 socket->stdin: %s",strerror(errno)); _exit(1); }
139 argv+=3;
140 execvp(*argv,argv);
141 syslog(LOG_ERR,"execvp %s: %s",*argv,strerror(errno));
142 eat(peer);
143 _exit(1);
144 } else {
145 waitpid(pid,0,0);
146 }
147 }
148 _exit (0);
149 }
150