[151] | 1 | #include <stdio.h> |
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| 2 | #include <stdlib.h> |
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| 3 | #include <string.h> |
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| 4 | #include <sys/socket.h> |
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| 5 | #include <arpa/inet.h> |
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| 6 | #include <netdb.h> |
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| 7 | #include <unistd.h> |
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| 8 | #include <signal.h> |
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| 9 | #include <errno.h> |
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| 10 | #include <sys/wait.h> |
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| 11 | #include <sys/stat.h> |
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| 12 | #include <stdarg.h> |
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| 13 | #include <syslog.h> |
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| 14 | |
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| 15 | /* Buffer size, in bytes, used for copying in the Cat() function. */ |
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| 16 | const size_t BUF_SIZE = 10240; |
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| 17 | |
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| 18 | /* Typedef for a signal handler function. */ |
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| 19 | typedef void (*signal_handler_t) (int); |
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| 20 | |
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| 21 | /* Prototypes for functions in this file. */ |
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| 22 | void ParseArgs (int argc, char *argv[], struct in_addr *ra, |
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| 23 | unsigned short *rp, struct in_addr *la, unsigned short *lp); |
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| 24 | void Initialise (void); |
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| 25 | void sig_child (int signo); |
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| 26 | int CreateServerSocket (struct in_addr addr, unsigned short port); |
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| 27 | void Daemonise (void); |
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| 28 | void MainLoop (int listen_fd, struct in_addr rem_addr, |
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| 29 | unsigned short rem_port); |
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| 30 | void Proxy (int server_fd, int client_fd); |
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| 31 | int AcceptClientConnection (int listen_fd); |
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| 32 | int ConnectToServer (struct in_addr addr, unsigned short port); |
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| 33 | void Cat (int in_fd, int out_fd); |
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| 34 | int NameToAddr (const char *name, struct in_addr *p_inaddr); |
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| 35 | int NameToPort (const char *name, unsigned short *port, const char *proto); |
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| 36 | #ifdef __GNUC__ |
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| 37 | void quit (const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); |
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| 38 | void pbomb (const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); |
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| 39 | void hbomb (const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); |
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| 40 | #else |
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| 41 | void quit (const char *fmt, ...); |
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| 42 | void pbomb (const char *fmt, ...); |
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| 43 | void hbomb (const char *fmt, ...); |
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| 44 | #endif |
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| 45 | void set_signal_handler (int signum, signal_handler_t sig_handler_func); |
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| 46 | |
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| 47 | /* Global variables */ |
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| 48 | char g_program_name[100]; /* Initialised from argv[0] in ParseArgs() */ |
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| 49 | |
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| 50 | int |
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| 51 | main (int argc, char *argv[]) |
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| 52 | { |
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| 53 | struct in_addr remote_addr, local_addr; |
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| 54 | unsigned short remote_port, local_port; |
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| 55 | int listen_fd; |
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| 56 | |
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| 57 | ParseArgs (argc, argv, &remote_addr, &remote_port, &local_addr, |
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| 58 | &local_port); |
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| 59 | |
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| 60 | Initialise (); |
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| 61 | |
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| 62 | /* Create server socket before becoming a daemon so there is still a |
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| 63 | * chance to print an error message. */ |
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| 64 | listen_fd = CreateServerSocket (local_addr, local_port); |
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| 65 | if (listen_fd < 0) |
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| 66 | pbomb ("Unable to create server socket"); |
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| 67 | |
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| 68 | Daemonise (); |
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| 69 | |
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| 70 | MainLoop (listen_fd, remote_addr, remote_port); /* never returns */ |
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| 71 | |
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| 72 | exit (EXIT_SUCCESS); |
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| 73 | } |
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| 74 | |
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| 75 | /* ParseArgs(): Parse the command line arguments to extract the remote and |
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| 76 | * * local adresses and port numbers, ra, rp, la & lp. Exit the program |
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| 77 | * * gracefully upon error. |
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| 78 | * */ |
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| 79 | void |
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| 80 | ParseArgs (int argc, char *argv[], struct in_addr *ra, unsigned short *rp, |
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| 81 | struct in_addr *la, unsigned short *lp) |
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| 82 | { |
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| 83 | /* |
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| 84 | * * argv[0] = program name |
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| 85 | * * argv[1] = remote_addr |
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| 86 | * * argv[2] = remote_port |
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| 87 | * * argv[3] = local_addr (optional) |
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| 88 | * * argv[4] = local_port (optional) |
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| 89 | * */ |
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| 90 | |
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| 91 | char *p = strrchr (argv[0], '/'); |
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| 92 | |
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| 93 | strncpy (g_program_name, (p == NULL) ? argv[0] : p + 1, |
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| 94 | sizeof (g_program_name) - 1); |
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| 95 | |
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| 96 | if ((argc < 3) || (argc > 5)) |
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| 97 | { |
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| 98 | fprintf (stderr, |
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| 99 | "usage: %s remote_addr remote_port [local_addr] [local_port]\n", |
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| 100 | argv[0]); |
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| 101 | exit (EXIT_FAILURE); |
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| 102 | } |
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| 103 | |
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| 104 | if (NameToAddr (argv[1], ra)) |
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| 105 | hbomb ("Unable to resolve \"%s\" to an ip address", argv[1]); |
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| 106 | |
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| 107 | if (NameToPort (argv[2], rp, "tcp")) |
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| 108 | quit ("Unable to resolve \"%s\" to a port number", argv[2]); |
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| 109 | |
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| 110 | if (argc < 4) |
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| 111 | la->s_addr = htonl (INADDR_ANY); |
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| 112 | else if (NameToAddr (argv[3], la)) |
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| 113 | hbomb ("Unable to resolve \"%s\" to an ip address", argv[3]); |
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| 114 | |
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| 115 | if (argc < 5) |
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| 116 | memcpy (lp, rp, sizeof (*lp)); |
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| 117 | else if (NameToPort (argv[4], lp, "tcp")) |
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| 118 | quit ("Unable to resolve \"%s\" to a port number", argv[4]); |
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| 119 | } |
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| 120 | |
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| 121 | /* Initialise(): Setup syslog, signal handlers, and other intialisation. |
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| 122 | * */ |
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| 123 | void |
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| 124 | Initialise (void) |
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| 125 | { |
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| 126 | openlog (g_program_name, LOG_PID, LOG_USER); |
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| 127 | syslog (LOG_INFO, "%s started", g_program_name); |
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| 128 | |
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| 129 | chdir ("/"); /* Change working directory to the root. */ |
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| 130 | |
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| 131 | umask (0); /* Clear our file mode creation mask */ |
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| 132 | |
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| 133 | set_signal_handler (SIGCHLD, sig_child); |
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| 134 | |
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| 135 | signal (SIGPIPE, SIG_IGN); |
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| 136 | } |
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| 137 | |
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| 138 | /* sig_child(): Handles SIGCHLD from exiting child processes. |
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| 139 | * */ |
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| 140 | void |
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| 141 | sig_child (int signo) |
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| 142 | { |
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| 143 | pid_t pid; |
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| 144 | |
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| 145 | (void) signo; /* suppress compiler warning */ |
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| 146 | |
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| 147 | for (;;) |
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| 148 | { |
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| 149 | pid = waitpid (WAIT_ANY, NULL, WNOHANG); |
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| 150 | |
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| 151 | if (pid > 0) |
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| 152 | syslog (LOG_INFO, "Caught SIGCHLD from pid %d", pid); |
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| 153 | else |
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| 154 | break; |
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| 155 | } |
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| 156 | |
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| 157 | if ((pid < 0) && (errno != ECHILD)) |
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| 158 | syslog (LOG_ERR, "waitpid(): %m"), exit (EXIT_FAILURE); |
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| 159 | |
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| 160 | return; |
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| 161 | } |
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| 162 | |
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| 163 | /* CreateServerSocket(): Create a socket, bind it to the specified address |
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| 164 | * * and port, and set it to listen for client connections. Returns <0 on |
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| 165 | * * failure to bind, bombs on error otherwise, returns the fd of the new |
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| 166 | * * socket on success. |
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| 167 | * */ |
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| 168 | int |
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| 169 | CreateServerSocket (struct in_addr addr, unsigned short port) |
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| 170 | { |
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| 171 | int err, fd; |
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| 172 | const int on = 1; |
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| 173 | struct sockaddr_in sa; |
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| 174 | |
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| 175 | /* Create a socket and get its descriptor. */ |
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| 176 | fd = socket (AF_INET, SOCK_STREAM, 0); |
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| 177 | if (fd < 0) |
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| 178 | syslog (LOG_ERR, "socket(): %m"), exit (EXIT_FAILURE); |
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| 179 | |
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| 180 | /* Set SO_REUSEADDR socket option */ |
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| 181 | if (setsockopt (fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on)) < 0) |
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| 182 | syslog (LOG_ERR, "setsockopt(fd%d, SO_REUSEADDR): %m", fd); |
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| 183 | |
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| 184 | /* Load a sa structure with the specified address and port */ |
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| 185 | sa.sin_family = AF_INET; |
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| 186 | sa.sin_port = htons (port); |
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| 187 | sa.sin_addr = addr; |
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| 188 | memset (sa.sin_zero, 0, sizeof (sa.sin_zero)); |
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| 189 | |
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| 190 | /* Bind our socket to the address and port specified */ |
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| 191 | err = bind (fd, (struct sockaddr *) &sa, sizeof (sa)); |
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| 192 | if (err < 0) |
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| 193 | { |
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| 194 | syslog (LOG_ERR, "bind(): %m"); |
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| 195 | return err; |
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| 196 | } |
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| 197 | |
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| 198 | /* Tell socket to listen and queue up to 5 incoming connections. */ |
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| 199 | if (listen (fd, 5) < 0) |
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| 200 | syslog (LOG_ERR, "listen(): %m"), exit (EXIT_FAILURE); |
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| 201 | |
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| 202 | return fd; |
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| 203 | } |
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| 204 | |
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| 205 | /* Daemonise(): Put the program in the background, set PPID=1, create a new |
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| 206 | * * session and process group, without a controlling tty. |
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| 207 | * */ |
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| 208 | void |
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| 209 | Daemonise (void) |
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| 210 | { |
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| 211 | pid_t pid; |
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| 212 | |
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| 213 | /* Close stdin, stdout & stderr */ |
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| 214 | /* TODO: open /dev/null and dup the fd to stdin, stdout & stderr |
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| 215 | * close(STDIN_FILENO); |
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| 216 | * close(STDOUT_FILENO); |
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| 217 | * close(STDERR_FILENO); |
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| 218 | * */ |
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| 219 | |
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| 220 | syslog (LOG_INFO, "%s daemonising", g_program_name); |
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| 221 | |
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| 222 | /* Fork the process to put it in the background. */ |
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| 223 | |
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| 224 | pid = fork (); |
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| 225 | if (pid == -1) |
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| 226 | syslog (LOG_ERR, "fork(): %m"), exit (EXIT_FAILURE); |
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| 227 | |
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| 228 | /* parent terminates here, so shell thinks the command is done. */ |
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| 229 | if (pid) |
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| 230 | exit (0); |
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| 231 | |
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| 232 | syslog (LOG_INFO, "%s in background", g_program_name); |
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| 233 | |
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| 234 | /* 1st child continues to run in the background with PPID=1 */ |
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| 235 | |
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| 236 | /* Become leader of a new session and a new process group, |
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| 237 | * with no controlling tty. */ |
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| 238 | setsid (); |
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| 239 | |
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| 240 | /* Fork again to guarantee the process will not be able to aquire a |
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| 241 | * controlling tty. */ |
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| 242 | |
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| 243 | /*signal (SIGHUP, SIG_IGN); *//* required according to Stevens' UNP2 p333 */ |
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| 244 | |
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| 245 | pid = fork (); |
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| 246 | if (pid == -1) |
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| 247 | syslog (LOG_ERR, "fork(): %m"), exit (EXIT_FAILURE); |
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| 248 | |
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| 249 | if (pid) /* 1st child terminates */ |
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| 250 | exit (0); |
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| 251 | |
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| 252 | /* 2nd child continues, no longer a session or group leader */ |
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| 253 | |
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| 254 | syslog (LOG_INFO, "%s daemonised", g_program_name); |
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| 255 | } |
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| 256 | |
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| 257 | /* MainLoop(): Classic concurrent server model. Wait for a client to connect, |
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| 258 | * * fork a child process to do the business with the client, parent process |
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| 259 | * * continues to wait for the next connection. This function does not return. |
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| 260 | * */ |
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| 261 | void |
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| 262 | MainLoop (int listen_fd, struct in_addr rem_addr, unsigned short rem_port) |
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| 263 | { |
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| 264 | int server_fd, client_fd; |
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| 265 | pid_t child_pid; |
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| 266 | |
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| 267 | for (;;) |
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| 268 | { |
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| 269 | client_fd = AcceptClientConnection (listen_fd); |
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| 270 | |
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| 271 | child_pid = fork (); |
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| 272 | if (child_pid == -1) |
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| 273 | syslog (LOG_ERR, "fork(): %m"), exit (EXIT_FAILURE); |
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| 274 | |
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| 275 | if (child_pid) /* parent */ |
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| 276 | { |
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| 277 | close (client_fd); |
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| 278 | |
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| 279 | syslog (LOG_INFO, "Forked child pid %d to deal with client", |
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| 280 | child_pid); |
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| 281 | |
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| 282 | continue; |
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| 283 | } |
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| 284 | else /* child */ |
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| 285 | { |
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| 286 | close (listen_fd); |
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| 287 | |
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| 288 | server_fd = ConnectToServer (rem_addr, rem_port); |
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| 289 | |
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| 290 | Proxy (server_fd, client_fd); |
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| 291 | |
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| 292 | syslog (LOG_INFO, "exiting"); |
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| 293 | _exit (0); |
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| 294 | } |
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| 295 | } |
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| 296 | } |
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| 297 | |
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| 298 | /* Proxy(): Copies data between server_fd and client_fd in both directions |
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| 299 | * * until one or other peer closes their connection. |
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| 300 | * */ |
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| 301 | void |
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| 302 | Proxy (int server_fd, int client_fd) |
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| 303 | { |
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| 304 | pid_t helper_pid; |
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| 305 | |
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| 306 | syslog (LOG_INFO, "Proxy(fd%d, fd%d)", server_fd, client_fd); |
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| 307 | |
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| 308 | signal (SIGCHLD, SIG_IGN); |
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| 309 | |
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| 310 | helper_pid = fork (); |
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| 311 | if (helper_pid == -1) |
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| 312 | syslog (LOG_ERR, "fork(): %m"), exit (EXIT_FAILURE); |
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| 313 | |
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| 314 | if (helper_pid) /* parent */ |
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| 315 | { |
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| 316 | syslog (LOG_INFO, "Forked child pid %d to help with proxying", |
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| 317 | helper_pid); |
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| 318 | |
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| 319 | Cat (server_fd, client_fd); |
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| 320 | |
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| 321 | shutdown (client_fd, 1); |
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| 322 | close (server_fd); |
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| 323 | close (client_fd); |
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| 324 | |
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| 325 | wait (0); /* wait for helper to exit */ |
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| 326 | } |
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| 327 | else /* child (helper) */ |
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| 328 | { |
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| 329 | Cat (client_fd, server_fd); |
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| 330 | |
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| 331 | shutdown (server_fd, 1); |
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| 332 | |
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| 333 | syslog (LOG_INFO, "exiting"); |
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| 334 | exit (0); /* helper exits here */ |
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| 335 | } |
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| 336 | } |
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| 337 | |
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| 338 | /* AcceptClientConnection(): waits for a tcp connect to the socket listen_fd, |
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| 339 | * * which must already be bound and set to listen on a local port. Bombs on |
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| 340 | * * error, returns the fd of the new socket on success. |
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| 341 | * */ |
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| 342 | int |
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| 343 | AcceptClientConnection (int listen_fd) |
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| 344 | { |
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| 345 | int newfd; |
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| 346 | struct sockaddr_in sa; |
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| 347 | socklen_t socklen; |
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| 348 | |
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| 349 | syslog (LOG_INFO, "AcceptClientConnection(fd%d)", listen_fd); |
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| 350 | |
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| 351 | /* Accept the connection and create a new socket for it. */ |
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| 352 | socklen = sizeof (sa); |
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| 353 | memset (&sa, 0, socklen); |
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| 354 | do |
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| 355 | { |
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| 356 | newfd = accept (listen_fd, (struct sockaddr *) &sa, &socklen); |
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| 357 | } |
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| 358 | while ((newfd < 0) && (errno == EINTR)); |
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| 359 | |
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| 360 | syslog (LOG_INFO, "Accepted client connection on new socket fd%d", newfd); |
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| 361 | |
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| 362 | if (newfd < 0) |
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| 363 | syslog (LOG_ERR, "accept(): %m"), exit (EXIT_FAILURE); |
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| 364 | |
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| 365 | if (socklen != sizeof (sa)) |
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| 366 | syslog (LOG_ERR, "accept() screwed up!"), exit (EXIT_FAILURE); |
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| 367 | |
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| 368 | return (newfd); |
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| 369 | } |
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| 370 | |
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| 371 | /* ConnectToServer(): attempts a tcp connect to the server specified by addr |
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| 372 | * * and port. Bombs on failure to connect, returns the fd of the new socket |
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| 373 | * * on success. |
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| 374 | * */ |
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| 375 | int |
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| 376 | ConnectToServer (struct in_addr addr, unsigned short port) |
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| 377 | { |
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| 378 | /* TODO: have a timeout for connect() - see Unix socket FAQ 6.2 */ |
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| 379 | |
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| 380 | int fd, err; |
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| 381 | struct sockaddr_in sa; |
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| 382 | |
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| 383 | /* Create a socket and get its descriptor. */ |
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| 384 | fd = socket (AF_INET, SOCK_STREAM, 0); |
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| 385 | if (fd < 0) |
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| 386 | syslog (LOG_ERR, "socket(): %m"), exit (EXIT_FAILURE); |
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| 387 | |
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| 388 | sa.sin_family = AF_INET; |
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| 389 | sa.sin_port = htons (port); |
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| 390 | sa.sin_addr = addr; |
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| 391 | memset (sa.sin_zero, 0, sizeof (sa.sin_zero)); |
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| 392 | |
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| 393 | err = connect (fd, (struct sockaddr *) &sa, sizeof (sa)); |
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| 394 | if (err < 0) |
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| 395 | { |
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| 396 | syslog (LOG_ERR, "Unable to connect socket fd%d to server: %m", fd); |
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| 397 | exit (EXIT_FAILURE); |
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| 398 | } |
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| 399 | |
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| 400 | syslog (LOG_INFO, "Connected socket fd%d to server", fd); |
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| 401 | |
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| 402 | return fd; |
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| 403 | } |
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| 404 | |
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| 405 | /* Cat(): read data from in_fd and write it to out_fd until the connection is |
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| 406 | * * closed by one of the peers. Data is copied using a dynamically allocated |
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| 407 | * * buffer. |
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| 408 | * */ |
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| 409 | void |
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| 410 | Cat (int in_fd, int out_fd) |
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| 411 | { |
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| 412 | unsigned char *const buf = malloc (BUF_SIZE); |
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| 413 | int bytes_rcvd, bytes_sent = 0, i; |
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| 414 | |
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| 415 | syslog (LOG_INFO, "Cat(fd%d, fd%d)", in_fd, out_fd); |
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| 416 | |
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| 417 | if (buf == NULL) |
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| 418 | syslog (LOG_ERR, "malloc(): %m"), exit (EXIT_FAILURE); |
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| 419 | |
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| 420 | do |
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| 421 | { |
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| 422 | bytes_rcvd = recv (in_fd, buf, BUF_SIZE, 0); |
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| 423 | |
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| 424 | for (i = 0; i < bytes_rcvd; i += bytes_sent) |
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| 425 | { |
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| 426 | bytes_sent = send (out_fd, buf + i, bytes_rcvd - i, 0); |
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| 427 | |
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| 428 | if (bytes_sent < 0) |
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| 429 | break; |
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| 430 | } |
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| 431 | |
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| 432 | } |
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| 433 | while ((bytes_rcvd > 0) && (bytes_sent > 0)); |
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| 434 | |
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| 435 | if ((bytes_rcvd < 0) && (errno != ECONNRESET)) |
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| 436 | syslog (LOG_ERR, "recv(): %m"), exit (EXIT_FAILURE); |
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| 437 | |
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| 438 | if ((bytes_sent < 0) && (errno != EPIPE)) |
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| 439 | syslog (LOG_ERR, "send(): %m"), exit (EXIT_FAILURE); |
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| 440 | |
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| 441 | free (buf); |
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| 442 | } |
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| 443 | |
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| 444 | /* NameToAddress(): Convert name to an ip address. Returns 0 on success, |
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| 445 | * * -1 on failure. |
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| 446 | * */ |
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| 447 | int |
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| 448 | NameToAddr (const char *name, struct in_addr *p_inaddr) |
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| 449 | { |
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| 450 | struct hostent *he; |
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| 451 | |
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| 452 | /* First, attempt to convert from string ip format */ |
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| 453 | /* TODO: use inet_aton() instead */ |
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| 454 | p_inaddr->s_addr = inet_addr (name); |
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| 455 | if (p_inaddr->s_addr != -1U) /* Success */ |
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| 456 | return 0; |
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| 457 | |
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| 458 | /* Next, attempt to read from /etc/hosts or do a DNS lookup */ |
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| 459 | he = gethostbyname (name); |
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| 460 | if (he != NULL) /* Success */ |
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| 461 | { |
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| 462 | memcpy (p_inaddr, he->h_addr, sizeof (struct in_addr)); |
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| 463 | return 0; |
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| 464 | } |
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| 465 | |
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| 466 | return -1; /* Failed to resolve name to an ip address */ |
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| 467 | } |
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| 468 | |
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| 469 | /* NameToPort(): Convert name to a port number. Name can either be a port |
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| 470 | * * name (in which case proto must also be set to either "tcp" or "udp") or |
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| 471 | * * name can be the ascii representation of the port number. Returns 0 on |
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| 472 | * * success, -1 on failure. |
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| 473 | * */ |
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| 474 | int |
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| 475 | NameToPort (const char *name, unsigned short *port, const char *proto) |
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| 476 | { |
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| 477 | unsigned long lport; |
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| 478 | char *errpos; |
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| 479 | struct servent *se; |
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| 480 | |
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| 481 | /* First, attempt to convert string to integer */ |
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| 482 | lport = strtoul (name, &errpos, 0); |
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| 483 | if ((*errpos == 0) && (lport <= 65535)) /* Success */ |
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| 484 | { |
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| 485 | *port = lport; |
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| 486 | return 0; |
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| 487 | } |
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| 488 | |
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| 489 | /* Next, attempt to read the string from /etc/services */ |
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| 490 | se = getservbyname (name, proto); |
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| 491 | if (se != NULL) /* Success */ |
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| 492 | { |
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| 493 | *port = ntohs (se->s_port); |
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| 494 | return 0; |
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| 495 | } |
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| 496 | |
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| 497 | return -1; /* Failed to resolve port name to a number */ |
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| 498 | } |
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| 499 | |
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| 500 | /* quit(), pbomb(), hbomb(): Print an error message to stderr and syslog, then |
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| 501 | * * exit the program. pbomb() and hbomb() additionally include the string |
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| 502 | * * representation of errno and h_errno respectively. |
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| 503 | * */ |
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| 504 | void |
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| 505 | quit (const char *fmt, ...) /* quit with msg */ |
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| 506 | { |
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| 507 | va_list ap; |
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| 508 | |
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| 509 | fflush (stdout); |
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| 510 | |
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| 511 | fprintf (stderr, "%s: ", g_program_name); |
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| 512 | |
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| 513 | va_start (ap, fmt); |
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| 514 | vfprintf (stderr, fmt, ap); |
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| 515 | va_end (ap); |
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| 516 | |
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| 517 | fputc ('\n', stderr); |
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| 518 | |
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| 519 | syslog (LOG_ERR, "I quit!"); |
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| 520 | |
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| 521 | exit (EXIT_FAILURE); |
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| 522 | } |
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| 523 | |
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| 524 | void |
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| 525 | pbomb (const char *fmt, ...) /* bomb with perror */ |
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| 526 | { |
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| 527 | va_list ap; |
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| 528 | int errno_save = errno; |
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| 529 | char buf[100]; |
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| 530 | |
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| 531 | fflush (stdout); |
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| 532 | |
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| 533 | fprintf (stderr, "%s: ", g_program_name); |
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| 534 | |
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| 535 | va_start (ap, fmt); |
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| 536 | vsnprintf (buf, sizeof (buf), fmt, ap); |
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| 537 | va_end (ap); |
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| 538 | |
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| 539 | errno = errno_save; |
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| 540 | perror (buf); |
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| 541 | |
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| 542 | syslog (LOG_ERR, "Bang!: %s: %m", buf); |
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| 543 | |
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| 544 | exit (EXIT_FAILURE); |
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| 545 | } |
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| 546 | |
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| 547 | void |
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| 548 | hbomb (const char *fmt, ...) /* bomb with herror */ |
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| 549 | { |
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| 550 | va_list ap; |
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| 551 | int h_errno_save = h_errno; |
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| 552 | char buf[100]; |
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| 553 | |
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| 554 | fflush (stdout); |
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| 555 | |
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| 556 | fprintf (stderr, "%s: ", g_program_name); |
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| 557 | |
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| 558 | va_start (ap, fmt); |
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| 559 | vsnprintf (buf, sizeof (buf), fmt, ap); |
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| 560 | va_end (ap); |
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| 561 | |
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| 562 | h_errno = h_errno_save; |
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| 563 | herror (buf); |
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| 564 | |
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| 565 | syslog (LOG_ERR, "Bang!: %s: %s", buf, hstrerror (h_errno)); |
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| 566 | |
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| 567 | exit (EXIT_FAILURE); |
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| 568 | } |
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| 569 | |
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| 570 | /* set_signal_handler(): Sets a signal handler function. Similar to signal() |
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| 571 | * * but this method is more portable between platforms. |
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| 572 | * */ |
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| 573 | void |
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| 574 | set_signal_handler (int signum, signal_handler_t sa_handler_func) |
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| 575 | { |
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| 576 | struct sigaction act; |
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| 577 | |
---|
| 578 | act.sa_handler = sa_handler_func; |
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| 579 | sigemptyset (&(act.sa_mask)); |
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| 580 | act.sa_flags = 0; |
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| 581 | |
---|
| 582 | if (sigaction (signum, &act, NULL) < 0) |
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| 583 | { |
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| 584 | syslog (LOG_ERR, "Error setting handler for signal %d: %m", signum); |
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| 585 | exit (EXIT_FAILURE); |
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| 586 | } |
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| 587 | } |
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