1 # include <errno.h> 2 # include "sendmail.h" 3 4 #ifndef DAEMON 5 SCCSID(@(#)daemon.c 3.45 01/16/83 (w/o daemon mode)); 6 #else 7 8 #include <sys/socket.h> 9 #include <netinet/in.h> 10 #include <netdb.h> 11 #include <wait.h> 12 13 SCCSID(@(#)daemon.c 3.45 01/16/83 (with daemon mode)); 14 15 /* 16 ** DAEMON.C -- routines to use when running as a daemon. 17 ** 18 ** This entire file is highly dependent on the 4.2 BSD 19 ** interprocess communication primitives. No attempt has 20 ** been made to make this file portable to Version 7, 21 ** Version 6, MPX files, etc. If you should try such a 22 ** thing yourself, I recommend chucking the entire file 23 ** and starting from scratch. Basic semantics are: 24 ** 25 ** getrequests() 26 ** Opens a port and initiates a connection. 27 ** Returns in a child. Must set InChannel and 28 ** OutChannel appropriately. 29 ** clrdaemon() 30 ** Close any open files associated with getting 31 ** the connection; this is used when running the queue, 32 ** etc., to avoid having extra file descriptors during 33 ** the queue run and to avoid confusing the network 34 ** code (if it cares). 35 ** makeconnection(host, port, outfile, infile) 36 ** Make a connection to the named host on the given 37 ** port. Set *outfile and *infile to the files 38 ** appropriate for communication. Returns zero on 39 ** success, else an exit status describing the 40 ** error. 41 ** 42 ** The semantics of both of these should be clean. 43 */ 44 /* 45 ** GETREQUESTS -- open mail IPC port and get requests. 46 ** 47 ** Parameters: 48 ** none. 49 ** 50 ** Returns: 51 ** none. 52 ** 53 ** Side Effects: 54 ** Waits until some interesting activity occurs. When 55 ** it does, a child is created to process it, and the 56 ** parent waits for completion. Return from this 57 ** routine is always in the child. The file pointers 58 ** "InChannel" and "OutChannel" should be set to point 59 ** to the communication channel. 60 */ 61 62 struct sockaddr_in SendmailAddress;/* internet address of sendmail */ 63 int DaemonSocket = -1; /* fd describing socket */ 64 int MaxConnections = 4; /* maximum simultaneous sendmails */ 65 66 getrequests() 67 { 68 int t; 69 union wait status; 70 int numconnections = 0; 71 register struct servent *sp; 72 73 /* 74 ** Set up the address for the mailer. 75 */ 76 77 sp = getservbyname("smtp", "tcp"); 78 if (sp == NULL) 79 { 80 syserr("server \"smtp\" unknown"); 81 goto severe; 82 } 83 SendmailAddress.sin_family = AF_INET; 84 SendmailAddress.sin_addr.s_addr = INADDR_ANY; 85 SendmailAddress.sin_port = sp->s_port; 86 87 /* 88 ** Try to actually open the connection. 89 */ 90 91 # ifdef DEBUG 92 if (tTd(15, 1)) 93 printf("getrequests: port 0x%x\n", SendmailAddress.sin_port); 94 # endif DEBUG 95 96 /* get a socket for the SMTP connection */ 97 DaemonSocket = socket(AF_INET, SOCK_STREAM, 0, 0); 98 if (DaemonSocket < 0) 99 { 100 /* probably another daemon already */ 101 syserr("getrequests: can't create socket"); 102 severe: 103 # ifdef LOG 104 if (LogLevel > 0) 105 syslog(LOG_SALERT, "cannot get connection"); 106 # endif LOG 107 finis(); 108 } 109 if (bind(DaemonSocket, &SendmailAddress, sizeof SendmailAddress, 0) < 0) 110 { 111 syserr("getrequests: cannot bind"); 112 (void) close(DaemonSocket); 113 goto severe; 114 } 115 listen(DaemonSocket, 10); 116 117 # ifdef DEBUG 118 if (tTd(15, 1)) 119 printf("getrequests: %d\n", DaemonSocket); 120 # endif DEBUG 121 122 for (;;) 123 { 124 /* wait for a connection */ 125 register int pid; 126 127 do 128 { 129 auto int lotherend; 130 struct sockaddr otherend; 131 132 errno = 0; 133 lotherend = sizeof otherend; 134 t = accept(DaemonSocket, &otherend, &lotherend, 0); 135 } while (t < 0 && errno == EINTR); 136 if (t < 0) 137 { 138 syserr("getrequests: accept"); 139 sleep(5); 140 continue; 141 } 142 143 /* 144 ** Create a subprocess to process the mail. 145 */ 146 147 # ifdef DEBUG 148 if (tTd(15, 2)) 149 printf("getrequests: forking (fd = %d)\n", t); 150 # endif DEBUG 151 152 pid = fork(); 153 if (pid < 0) 154 { 155 syserr("daemon: cannot fork"); 156 sleep(10); 157 (void) close(t); 158 continue; 159 } 160 161 if (pid == 0) 162 { 163 /* 164 ** CHILD -- return to caller. 165 ** Verify calling user id if possible here. 166 */ 167 168 (void) close(DaemonSocket); 169 InChannel = fdopen(t, "r"); 170 OutChannel = fdopen(t, "w"); 171 # ifdef DEBUG 172 if (tTd(15, 2)) 173 printf("getreq: returning\n"); 174 # endif DEBUG 175 # ifdef LOG 176 if (LogLevel > 11) 177 syslog(LOG_DEBUG, "connected, pid=%d", getpid()); 178 # endif LOG 179 return; 180 } 181 182 /* 183 ** PARENT -- wait for child to terminate. 184 ** Perhaps we should allow concurrent processing? 185 */ 186 187 # ifdef DEBUG 188 if (tTd(15, 2)) 189 { 190 sleep(2); 191 printf("getreq: parent waiting\n"); 192 } 193 # endif DEBUG 194 195 /* close the port so that others will hang (for a while) */ 196 (void) close(t); 197 198 /* pick up old zombies; implement load limiting */ 199 numconnections++; 200 while (wait3(&status, numconnections < MaxConnections ? WNOHANG : 0, 0) > 0) 201 numconnections--; 202 } 203 /*NOTREACHED*/ 204 } 205 /* 206 ** CLRDAEMON -- reset the daemon connection 207 ** 208 ** Parameters: 209 ** none. 210 ** 211 ** Returns: 212 ** none. 213 ** 214 ** Side Effects: 215 ** releases any resources used by the passive daemon. 216 */ 217 218 clrdaemon() 219 { 220 if (DaemonSocket >= 0) 221 (void) close(DaemonSocket); 222 DaemonSocket = -1; 223 } 224 /* 225 ** MAKECONNECTION -- make a connection to an SMTP socket on another machine. 226 ** 227 ** Parameters: 228 ** host -- the name of the host. 229 ** port -- the port number to connect to. 230 ** outfile -- a pointer to a place to put the outfile 231 ** descriptor. 232 ** infile -- ditto for infile. 233 ** 234 ** Returns: 235 ** An exit code telling whether the connection could be 236 ** made and if not why not. 237 ** 238 ** Side Effects: 239 ** none. 240 */ 241 242 makeconnection(host, port, outfile, infile) 243 char *host; 244 u_short port; 245 FILE **outfile; 246 FILE **infile; 247 { 248 register int s; 249 250 /* 251 ** Set up the address for the mailer. 252 ** Accept "[a.b.c.d]" syntax for host name. 253 */ 254 255 if (host[0] == '[') 256 { 257 long hid = 0; 258 int i, j; 259 register char *p = host; 260 261 for (i = 3; i >= 0 && *p != ']' && *p != '\0'; i--) 262 { 263 j = 0; 264 while (isdigit(*++p)) 265 j = j * 10 + (*p - '0'); 266 if (*p != (i == 0 ? ']' : '.') || j > 255 || j < 0) 267 break; 268 hid |= j << ((3 - i) * 8); 269 } 270 if (i >= 0 || *p != ']' || *++p != '\0') 271 { 272 usrerr("Invalid numeric domain spec \"%s\"", host); 273 return (EX_NOHOST); 274 } 275 SendmailAddress.sin_addr.s_addr = hid; 276 } 277 else 278 { 279 register struct hostent *hp = gethostbyname(host); 280 281 if (hp == 0) 282 return (EX_NOHOST); 283 bmove(hp->h_addr, (char *) &SendmailAddress.sin_addr, hp->h_length); 284 } 285 286 /* 287 ** Determine the port number. 288 */ 289 290 if (port != 0) 291 SendmailAddress.sin_port = htons(port); 292 else 293 { 294 register struct servent *sp = getservbyname("smtp", "tcp"); 295 296 if (sp == NULL) 297 { 298 syserr("makeconnection: server \"smtp\" unknown"); 299 return (EX_OSFILE); 300 } 301 SendmailAddress.sin_port = sp->s_port; 302 } 303 304 /* 305 ** Try to actually open the connection. 306 */ 307 308 # ifdef DEBUG 309 if (tTd(16, 1)) 310 printf("makeconnection (%s)\n", host); 311 # endif DEBUG 312 313 s = socket(AF_INET, SOCK_STREAM, 0, 0); 314 if (s < 0) 315 { 316 syserr("makeconnection: no socket"); 317 goto failure; 318 } 319 320 # ifdef DEBUG 321 if (tTd(16, 1)) 322 printf("makeconnection: %d\n", s); 323 # endif DEBUG 324 (void) fflush(CurEnv->e_xfp); /* for debugging */ 325 SendmailAddress.sin_family = AF_INET; 326 bind(s, &SendmailAddress, sizeof SendmailAddress, 0); 327 if (connect(s, &SendmailAddress, sizeof SendmailAddress, 0) < 0) 328 { 329 /* failure, decide if temporary or not */ 330 failure: 331 switch (errno) 332 { 333 case EISCONN: 334 case ETIMEDOUT: 335 case EINPROGRESS: 336 case EALREADY: 337 case EADDRINUSE: 338 case EHOSTDOWN: 339 case ENETDOWN: 340 case ENETRESET: 341 case ENOBUFS: 342 case ECONNREFUSED: 343 case EHOSTUNREACH: 344 case ENETUNREACH: 345 /* there are others, I'm sure..... */ 346 return (EX_TEMPFAIL); 347 348 default: 349 return (EX_UNAVAILABLE); 350 } 351 } 352 353 /* connection ok, put it into canonical form */ 354 *outfile = fdopen(s, "w"); 355 *infile = fdopen(s, "r"); 356 357 return (EX_OK); 358 } 359 360 #endif DAEMON 361