Mercurial > dropbear
view svr-main.c @ 69:59d16db56e9f
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author | Matt Johnston <matt@ucc.asn.au> |
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date | Thu, 12 Aug 2004 15:41:36 +0000 |
parents | dcc43965928f |
children | ac96bc733e71 |
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/* * Dropbear - a SSH2 server * * Copyright (c) 2002,2003 Matt Johnston * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #include "includes.h" #include "dbutil.h" #include "session.h" #include "buffer.h" #include "signkey.h" #include "runopts.h" static int listensockets(int *sock, int sockcount, int *maxfd); static void sigchld_handler(int dummy); static void sigsegv_handler(int); static void sigintterm_handler(int fish); static int childpipes[MAX_UNAUTH_CLIENTS]; #if defined(DBMULTI_dropbear) || !defined(DROPBEAR_MULTI) #if defined(DBMULTI_dropbear) && defined(DROPBEAR_MULTI) int dropbear_main(int argc, char ** argv) #else int main(int argc, char ** argv) #endif { fd_set fds; struct timeval seltimeout; unsigned int i, j; int val; int maxsock = -1; struct sockaddr_storage remoteaddr; int remoteaddrlen; int listensocks[MAX_LISTEN_ADDR]; int listensockcount = 0; FILE * pidfile; int childsock; pid_t childpid; int childpipe[2]; struct sigaction sa_chld; _dropbear_exit = svr_dropbear_exit; _dropbear_log = svr_dropbear_log; /* get commandline options */ svr_getopts(argc, argv); /* fork */ if (svr_opts.forkbg) { int closefds = 0; #ifndef DEBUG_TRACE if (!svr_opts.usingsyslog) { closefds = 1; } #endif if (daemon(0, closefds) < 0) { dropbear_exit("Failed to create background process: %s", strerror(errno)); } } #ifndef DISABLE_SYSLOG if (svr_opts.usingsyslog) { startsyslog(); } #endif /* should be done after syslog is working */ if (svr_opts.forkbg) { dropbear_log(LOG_INFO, "Running in background"); } else { dropbear_log(LOG_INFO, "Not forking"); } /* create a PID file so that we can be killed easily */ pidfile = fopen(DROPBEAR_PIDFILE, "w"); if (pidfile) { fprintf(pidfile, "%d\n", getpid()); fclose(pidfile); } /* set up cleanup handler */ if (signal(SIGINT, sigintterm_handler) == SIG_ERR || #ifndef DEBUG_VALGRIND signal(SIGTERM, sigintterm_handler) == SIG_ERR || #endif signal(SIGPIPE, SIG_IGN) == SIG_ERR) { dropbear_exit("signal() error"); } /* catch and reap zombie children */ sa_chld.sa_handler = sigchld_handler; sa_chld.sa_flags = SA_NOCLDSTOP; if (sigaction(SIGCHLD, &sa_chld, NULL) < 0) { dropbear_exit("signal() error"); } if (signal(SIGSEGV, sigsegv_handler) == SIG_ERR) { dropbear_exit("signal() error"); } /* sockets to identify pre-authenticated clients */ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) { childpipes[i] = -1; } /* Set up the listening sockets */ /* XXX XXX ports */ listensockcount = listensockets(listensocks, MAX_LISTEN_ADDR, &maxsock); if (listensockcount < 0) { dropbear_exit("No listening ports available."); } /* incoming connection select loop */ for(;;) { FD_ZERO(&fds); seltimeout.tv_sec = 60; seltimeout.tv_usec = 0; /* listening sockets */ for (i = 0; i < (unsigned int)listensockcount; i++) { FD_SET(listensocks[i], &fds); } /* pre-authentication clients */ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) { if (childpipes[i] >= 0) { FD_SET(childpipes[i], &fds); maxsock = MAX(maxsock, childpipes[i]); } } val = select(maxsock+1, &fds, NULL, NULL, &seltimeout); if (exitflag) { unlink(DROPBEAR_PIDFILE); dropbear_exit("Terminated by signal"); } if (val == 0) { /* timeout reached */ continue; } if (val < 0) { if (errno == EINTR) { continue; } dropbear_exit("Listening socket error"); } /* close fds which have been authed or closed - auth.c handles * closing the auth sockets on success */ for (i = 0; i < MAX_UNAUTH_CLIENTS; i++) { if (childpipes[i] >= 0 && FD_ISSET(childpipes[i], &fds)) { close(childpipes[i]); childpipes[i] = -1; } } /* handle each socket which has something to say */ for (i = 0; i < (unsigned int)listensockcount; i++) { if (!FD_ISSET(listensocks[i], &fds)) continue; /* child connection XXX - ip6 stuff here */ remoteaddrlen = sizeof(remoteaddr); childsock = accept(listensocks[i], (struct sockaddr*)&remoteaddr, &remoteaddrlen); if (childsock < 0) { /* accept failed */ continue; } /* check for max number of connections not authorised */ for (j = 0; j < MAX_UNAUTH_CLIENTS; j++) { if (childpipes[j] < 0) { break; } } if (j == MAX_UNAUTH_CLIENTS) { /* no free connections */ /* TODO - possibly log, though this would be an easy way * to fill logs/disk */ close(childsock); continue; } if (pipe(childpipe) < 0) { TRACE(("error creating child pipe")); close(childsock); continue; } if ((childpid = fork()) == 0) { /* child */ char * addrstring = NULL; #ifdef DEBUG_FORKGPROF extern void _start(void), etext(void); monstartup((u_long)&_start, (u_long)&etext); #endif /* DEBUG_FORKGPROF */ addrstring = getaddrstring(&remoteaddr, 1); dropbear_log(LOG_INFO, "Child connection from %s", addrstring); m_free(addrstring); if (setsid() < 0) { dropbear_exit("setsid: %s", strerror(errno)); } /* make sure we close sockets */ for (i = 0; i < (unsigned int)listensockcount; i++) { if (m_close(listensocks[i]) == DROPBEAR_FAILURE) { dropbear_exit("Couldn't close socket"); } } if (m_close(childpipe[0]) == DROPBEAR_FAILURE) { dropbear_exit("Couldn't close socket"); } /* start the session */ svr_session(childsock, childpipe[1], getaddrhostname(&remoteaddr)); /* don't return */ assert(0); } /* parent */ childpipes[j] = childpipe[0]; if (m_close(childpipe[1]) == DROPBEAR_FAILURE || m_close(childsock) == DROPBEAR_FAILURE) { dropbear_exit("Couldn't close socket"); } } } /* for(;;) loop */ /* don't reach here */ return -1; } #endif /* catch + reap zombie children */ static void sigchld_handler(int fish) { struct sigaction sa_chld; while(waitpid(-1, NULL, WNOHANG) > 0); sa_chld.sa_handler = sigchld_handler; sa_chld.sa_flags = SA_NOCLDSTOP; if (sigaction(SIGCHLD, &sa_chld, NULL) < 0) { dropbear_exit("signal() error"); } } /* catch any segvs */ static void sigsegv_handler(int fish) { fprintf(stderr, "Aiee, segfault! You should probably report " "this as a bug to the developer\n"); exit(EXIT_FAILURE); } /* catch ctrl-c or sigterm */ static void sigintterm_handler(int fish) { exitflag = 1; } /* Set up listening sockets for all the requested ports */ static int listensockets(int *sock, int sockcount, int *maxfd) { unsigned int i; char portstring[NI_MAXSERV]; char* errstring = NULL; unsigned int sockpos = 0; int nsock; for (i = 0; i < svr_opts.portcount; i++) { snprintf(portstring, sizeof(portstring), "%d", svr_opts.ports[i]); nsock = dropbear_listen(NULL, portstring, &sock[sockpos], sockcount - sockpos, &errstring, maxfd); if (nsock < 0) { dropbear_log(LOG_WARNING, "Failed listening on port %s: %s", portstring, errstring); m_free(errstring); continue; } sockpos += nsock; } return sockpos; }