1 # include <errno.h> 2 # include "sendmail.h" 3 4 #ifndef DAEMON 5 SCCSID(@(#)daemon.c 3.31 10/13/82 (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 3.31 10/13/82 (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 ** Parameters: 142 ** none. 143 ** 144 ** Returns: 145 ** The port for mail traffic. 146 ** 147 ** Side Effects: 148 ** Waits for a connection. 149 */ 150 151 #define IPPORT_PLAYPORT 3055 /* random number */ 152 153 struct sockaddr_in SendmailAddress = { AF_INET, IPPORT_SMTP }; 154 155 getconnection() 156 { 157 register int s; 158 struct sockaddr otherend; 159 160 /* 161 ** Set up the address for the mailer. 162 */ 163 164 SendmailAddress.sin_addr.s_addr = 0; 165 SendmailAddress.sin_port = IPPORT_SMTP; 166 # ifdef DEBUG 167 if (tTd(15, 15)) 168 SendmailAddress.sin_port = IPPORT_PLAYPORT; 169 # endif DEBUG 170 SendmailAddress.sin_port = htons(SendmailAddress.sin_port); 171 172 /* 173 ** Try to actually open the connection. 174 */ 175 176 # ifdef DEBUG 177 if (tTd(15, 1)) 178 printf("getconnection\n"); 179 # endif DEBUG 180 181 for (;;) 182 { 183 int i; 184 185 /* get a socket for the SMTP connection */ 186 /* do loop is to avoid 4.1b kernel bug (?) */ 187 i = 50; 188 do 189 { 190 s = socket(SOCK_STREAM, 0, &SendmailAddress, SO_ACCEPTCONN); 191 if (s < 0) 192 sleep(5); 193 } while (--i > 0 && s < 0); 194 if (s < 0) 195 { 196 /* probably another daemon already */ 197 syserr("getconnection: can't create socket"); 198 return (-1); 199 } 200 201 # ifdef DEBUG 202 if (tTd(15, 1)) 203 printf("getconnection: %d\n", s); 204 # endif DEBUG 205 206 /* wait for a connection */ 207 /* contorted code is due to a 4.1a kernel bug */ 208 errno = 0; 209 if (accept(s, &otherend) >= 0) 210 return (s); 211 (void) close(s); 212 if (errno != EINTR) 213 syserr("getconnection: accept"); 214 sleep(5); 215 } 216 } 217 /* 218 ** MAKECONNECTION -- make a connection to an SMTP socket on another machine. 219 ** 220 ** Parameters: 221 ** host -- the name of the host. 222 ** port -- the port number to connect to. 223 ** outfile -- a pointer to a place to put the outfile 224 ** descriptor. 225 ** infile -- ditto for infile. 226 ** 227 ** Returns: 228 ** An exit code telling whether the connection could be 229 ** made and if not why not. 230 ** 231 ** Side Effects: 232 ** none. 233 */ 234 235 makeconnection(host, port, outfile, infile) 236 char *host; 237 u_short port; 238 FILE **outfile; 239 FILE **infile; 240 { 241 register int s; 242 243 /* 244 ** Set up the address for the mailer. 245 */ 246 247 if ((SendmailAddress.sin_addr.s_addr = rhost(&host)) == -1) 248 return (EX_NOHOST); 249 if (port == 0) 250 port = IPPORT_SMTP; 251 SendmailAddress.sin_port = htons(port); 252 253 /* 254 ** Try to actually open the connection. 255 */ 256 257 # ifdef DEBUG 258 if (tTd(16, 1)) 259 printf("makeconnection (%s)\n", host); 260 # endif DEBUG 261 262 s = socket(SOCK_STREAM, 0, (struct sockaddr_in *) 0, 0); 263 if (s < 0) 264 { 265 syserr("makeconnection: no socket"); 266 goto failure; 267 } 268 269 # ifdef DEBUG 270 if (tTd(16, 1)) 271 printf("makeconnection: %d\n", s); 272 # endif DEBUG 273 (void) fflush(Xscript); /* for debugging */ 274 if (connect(s, &SendmailAddress) < 0) 275 { 276 /* failure, decide if temporary or not */ 277 failure: 278 switch (errno) 279 { 280 case EISCONN: 281 case ETIMEDOUT: 282 case EINPROGRESS: 283 case EALREADY: 284 case EADDRINUSE: 285 case ENETDOWN: 286 case ENETRESET: 287 case ENOBUFS: 288 case ECONNREFUSED: 289 /* there are others, I'm sure..... */ 290 return (EX_TEMPFAIL); 291 292 default: 293 return (EX_UNAVAILABLE); 294 } 295 } 296 297 /* connection ok, put it into canonical form */ 298 *outfile = fdopen(s, "w"); 299 *infile = fdopen(s, "r"); 300 301 return (0); 302 } 303 304 #endif DAEMON 305