1 # include <errno.h> 2 # include "sendmail.h" 3 4 #ifndef DAEMON 5 SCCSID(@(#)daemon.c 3.32 10/22/82 (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 3.32 10/22/82 (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 */ 253 254 if ((SendmailAddress.sin_addr.s_addr = rhost(&host)) == -1) 255 return (EX_NOHOST); 256 if (port == 0) 257 port = IPPORT_SMTP; 258 SendmailAddress.sin_port = htons(port); 259 260 /* 261 ** Try to actually open the connection. 262 */ 263 264 # ifdef DEBUG 265 if (tTd(16, 1)) 266 printf("makeconnection (%s)\n", host); 267 # endif DEBUG 268 269 s = socket(SOCK_STREAM, 0, (struct sockaddr_in *) 0, 0); 270 if (s < 0) 271 { 272 syserr("makeconnection: no socket"); 273 goto failure; 274 } 275 276 # ifdef DEBUG 277 if (tTd(16, 1)) 278 printf("makeconnection: %d\n", s); 279 # endif DEBUG 280 (void) fflush(Xscript); /* for debugging */ 281 if (connect(s, &SendmailAddress) < 0) 282 { 283 /* failure, decide if temporary or not */ 284 failure: 285 switch (errno) 286 { 287 case EISCONN: 288 case ETIMEDOUT: 289 case EINPROGRESS: 290 case EALREADY: 291 case EADDRINUSE: 292 case ENETDOWN: 293 case ENETRESET: 294 case ENOBUFS: 295 case ECONNREFUSED: 296 /* there are others, I'm sure..... */ 297 return (EX_TEMPFAIL); 298 299 default: 300 return (EX_UNAVAILABLE); 301 } 302 } 303 304 /* connection ok, put it into canonical form */ 305 *outfile = fdopen(s, "w"); 306 *infile = fdopen(s, "r"); 307 308 return (0); 309 } 310 311 #endif DAEMON 312