1 # include <errno.h> 2 # include "sendmail.h" 3 4 #ifndef DAEMON 5 SCCSID(@(#)daemon.c 3.33 11/20/82 (w/o daemon mode)); 6 #else 7 8 # include <sys/socket.h> 9 # include <net/in.h> 10 # include <wait.h> 11 12 SCCSID(@(#)daemon.c 3.33 11/20/82 (with daemon mode)); 13 14 /* 15 ** DAEMON.C -- routines to use when running as a daemon. 16 ** 17 ** This entire file is highly dependent on the 4.2 BSD 18 ** interprocess communication primitives. No attempt has 19 ** been made to make this file portable to Version 7, 20 ** Version 6, MPX files, etc. If you should try such a 21 ** thing yourself, I recommend chucking the entire file 22 ** and starting from scratch. Basic semantics are: 23 ** 24 ** getrequests() 25 ** Opens a port and initiates a connection. 26 ** Returns in a child. Must set InChannel and 27 ** OutChannel appropriately. 28 ** makeconnection(host, port, outfile, infile) 29 ** Make a connection to the named host on the given 30 ** port. Set *outfile and *infile to the files 31 ** appropriate for communication. Returns zero on 32 ** success, else an exit status describing the 33 ** error. 34 ** 35 ** The semantics of both of these should be clean. 36 */ 37 /* 38 ** GETREQUESTS -- open mail IPC port and get requests. 39 ** 40 ** Parameters: 41 ** none. 42 ** 43 ** Returns: 44 ** none. 45 ** 46 ** Side Effects: 47 ** Waits until some interesting activity occurs. When 48 ** it does, a child is created to process it, and the 49 ** parent waits for completion. Return from this 50 ** routine is always in the child. 51 */ 52 53 # define MAXCONNS 4 /* maximum simultaneous sendmails */ 54 55 getrequests() 56 { 57 union wait status; 58 int numconnections = 0; 59 60 for (;;) 61 { 62 register int pid; 63 register int port; 64 65 /* 66 ** Wait for a connection. 67 */ 68 69 while ((port = getconnection()) < 0) 70 { 71 # ifdef LOG 72 if (LogLevel > 0) 73 syslog(LOG_SALERT, "cannot get connection"); 74 # endif LOG 75 finis(); 76 } 77 78 /* 79 ** Create a subprocess to process the mail. 80 */ 81 82 # ifdef DEBUG 83 if (tTd(15, 2)) 84 printf("getrequests: forking (port = %d)\n", port); 85 # endif DEBUG 86 87 pid = fork(); 88 if (pid < 0) 89 { 90 syserr("daemon: cannot fork"); 91 sleep(10); 92 (void) close(port); 93 continue; 94 } 95 96 if (pid == 0) 97 { 98 /* 99 ** CHILD -- return to caller. 100 ** Verify calling user id if possible here. 101 */ 102 103 InChannel = fdopen(port, "r"); 104 OutChannel = fdopen(port, "w"); 105 # ifdef DEBUG 106 if (tTd(15, 2)) 107 printf("getreq: returning\n"); 108 # endif DEBUG 109 # ifdef LOG 110 if (LogLevel > 11) 111 syslog(LOG_DEBUG, "connected, pid=%d", getpid()); 112 # endif LOG 113 return; 114 } 115 116 /* 117 ** PARENT -- wait for child to terminate. 118 ** Perhaps we should allow concurrent processing? 119 */ 120 121 # ifdef DEBUG 122 if (tTd(15, 2)) 123 { 124 sleep(2); 125 printf("getreq: parent waiting\n"); 126 } 127 # endif DEBUG 128 129 /* close the port so that others will hang (for a while) */ 130 (void) close(port); 131 132 /* pick up old zombies; implement load limiting */ 133 numconnections++; 134 while (wait3(&status, numconnections < MAXCONNS ? WNOHANG : 0, 0) > 0) 135 numconnections--; 136 } 137 } 138 /* 139 ** GETCONNECTION -- make a connection with the outside world 140 ** 141 ** This routine is horribly contorted to try to get around a bunch 142 ** of 4.1a IPC bugs. There appears to be nothing we can do to make 143 ** it "right" -- the code to interrupt accepts just doesn't work 144 ** right. However, this is an attempt to minimize the probablity 145 ** of problems. 146 ** 147 ** Parameters: 148 ** none. 149 ** 150 ** Returns: 151 ** The port for mail traffic. 152 ** 153 ** Side Effects: 154 ** Waits for a connection. 155 */ 156 157 #define IPPORT_PLAYPORT 3055 /* random number */ 158 159 struct sockaddr_in SendmailAddress = { AF_INET, IPPORT_SMTP }; 160 161 getconnection() 162 { 163 register int s; 164 struct sockaddr otherend; 165 166 /* 167 ** Set up the address for the mailer. 168 */ 169 170 SendmailAddress.sin_addr.s_addr = 0; 171 SendmailAddress.sin_port = IPPORT_SMTP; 172 # ifdef DEBUG 173 if (tTd(15, 15)) 174 SendmailAddress.sin_port = IPPORT_PLAYPORT; 175 # endif DEBUG 176 SendmailAddress.sin_port = htons(SendmailAddress.sin_port); 177 178 /* 179 ** Try to actually open the connection. 180 */ 181 182 # ifdef DEBUG 183 if (tTd(15, 1)) 184 printf("getconnection\n"); 185 # endif DEBUG 186 187 for (;; sleep(15)) 188 { 189 int i; 190 191 /* get a socket for the SMTP connection */ 192 /* do loop is to avoid 4.1b kernel bug (?) */ 193 i = 60; 194 do 195 { 196 s = socket(SOCK_STREAM, 0, &SendmailAddress, SO_ACCEPTCONN); 197 if (s < 0) 198 sleep(10); 199 } while (--i > 0 && s < 0); 200 if (s < 0) 201 { 202 /* probably another daemon already */ 203 syserr("getconnection: can't create socket"); 204 return (-1); 205 } 206 207 # ifdef DEBUG 208 if (tTd(15, 1)) 209 printf("getconnection: %d\n", s); 210 # endif DEBUG 211 212 /* wait for a connection */ 213 do 214 { 215 errno = 0; 216 if (accept(s, &otherend) >= 0) 217 return (s); 218 } while (errno == EINTR); 219 syserr("getconnection: accept"); 220 sleep(5); 221 (void) close(s); 222 } 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 if ((SendmailAddress.sin_addr.s_addr = rhost(&host)) == -1) 278 return (EX_NOHOST); 279 if (port == 0) 280 port = IPPORT_SMTP; 281 SendmailAddress.sin_port = htons(port); 282 283 /* 284 ** Try to actually open the connection. 285 */ 286 287 # ifdef DEBUG 288 if (tTd(16, 1)) 289 printf("makeconnection (%s)\n", host); 290 # endif DEBUG 291 292 s = socket(SOCK_STREAM, 0, (struct sockaddr_in *) 0, 0); 293 if (s < 0) 294 { 295 syserr("makeconnection: no socket"); 296 goto failure; 297 } 298 299 # ifdef DEBUG 300 if (tTd(16, 1)) 301 printf("makeconnection: %d\n", s); 302 # endif DEBUG 303 (void) fflush(Xscript); /* for debugging */ 304 if (connect(s, &SendmailAddress) < 0) 305 { 306 /* failure, decide if temporary or not */ 307 failure: 308 switch (errno) 309 { 310 case EISCONN: 311 case ETIMEDOUT: 312 case EINPROGRESS: 313 case EALREADY: 314 case EADDRINUSE: 315 case ENETDOWN: 316 case ENETRESET: 317 case ENOBUFS: 318 case ECONNREFUSED: 319 /* there are others, I'm sure..... */ 320 return (EX_TEMPFAIL); 321 322 default: 323 return (EX_UNAVAILABLE); 324 } 325 } 326 327 /* connection ok, put it into canonical form */ 328 *outfile = fdopen(s, "w"); 329 *infile = fdopen(s, "r"); 330 331 return (0); 332 } 333 334 #endif DAEMON 335