X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/06d823120f122fb9a9f0c291ad5b882efb17d199..1a0391391c65a147b7eee692421c4876ff97553e:/fw.c diff --git a/fw.c b/fw.c index e5537fc..a53d515 100644 --- a/fw.c +++ b/fw.c @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: fw.c,v 1.5 1999/10/22 22:47:50 mdw Exp $ + * $Id: fw.c,v 1.12 2002/01/13 14:49:17 mdw Exp $ * * Port forwarding thingy * @@ -29,6 +29,28 @@ /*----- Revision history --------------------------------------------------* * * $Log: fw.c,v $ + * Revision 1.12 2002/01/13 14:49:17 mdw + * Track @dstr_vputf@ change. + * + * Revision 1.11 2001/02/03 20:33:26 mdw + * Fix flags to be unsigned. + * + * Revision 1.10 2001/02/03 20:30:03 mdw + * Support re-reading config files on SIGHUP. + * + * Revision 1.9 2001/01/20 11:55:17 mdw + * Handle select errors more robustly. + * + * Revision 1.8 2000/03/23 23:19:19 mdw + * Fix changed options in parser table. + * + * Revision 1.7 2000/03/23 00:37:33 mdw + * Add option to change user and group after initialization. Naughtily + * reassign short equivalents of --grammar and --options. + * + * Revision 1.6 1999/12/22 15:44:10 mdw + * Make syslog a separate option, and do it better. + * * Revision 1.5 1999/10/22 22:47:50 mdw * Grammar changes. Also, don't enable SIGINT if it's currently ignored. * @@ -52,6 +74,7 @@ #include "config.h" +#include #include #include #include @@ -64,6 +87,9 @@ #include #include +#include +#include + #include #include #include @@ -87,8 +113,14 @@ sel_state *sel; /* Multiplexor for nonblocking I/O */ /*----- Static variables --------------------------------------------------*/ +typedef struct conffile { + struct conffile *next; + char *name; +} conffile; + static unsigned flags = 0; /* Global state flags */ static unsigned active = 0; /* Number of active things */ +static conffile *conffiles = 0; /* List of configuration files */ #define FW_SYSLOG 1u #define FW_QUIET 2u @@ -120,10 +152,9 @@ void fw_log(time_t t, const char *fmt, ...) t = time(0); tm = localtime(&t); DENSURE(&d, 64); - d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S", tm); - DPUTC(&d, ' '); + d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S ", tm); va_start(ap, fmt); - dstr_vputf(&d, fmt, ap); + dstr_vputf(&d, fmt, &ap); va_end(ap); if (flags & FW_SYSLOG) syslog(LOG_NOTICE, "%s", d.buf); @@ -174,14 +205,72 @@ static void fw_exit(void) static void fw_tidy(int n, void *p) { - const char *sn = "unexpected signal (bug!)"; - if (n == SIGTERM) - sn = "SIGTERM"; - else if (n == SIGINT) - sn = "SIGINT"; - - fw_log(-1, "closing down on %s", sn); - fw_exit(); + const char *sn = 0; + switch (n) { + case SIGTERM: sn = "SIGTERM"; break; + case SIGINT: sn = "SIGINT"; break; + default: abort(); + } + + fw_log(-1, "closing down gracefully on %s", sn); + source_killall(); +} + +/* --- @fw_die@ --- * + * + * Arguments: @int n@ = signal number + * @void *p@ = an uninteresting argument + * + * Returns: --- + * + * Use: Handles various signals and causes an abrupt shutdown. + */ + +static void fw_die(int n, void *p) +{ + const char *sn = 0; + switch (n) { + case SIGQUIT: sn = "SIGQUIT"; break; + default: abort(); + } + + fw_log(-1, "closing down abruptly on %s", sn); + source_killall(); + endpt_killall(); +} + +/* --- @fw_reload@ --- * + * + * Arguments: @int n@ = a signal number + * @void *p@ = an uninteresting argument + * + * Returns: --- + * + * Use: Handles a hangup signal by re-reading configuration files. + */ + +static void fw_reload(int n, void *p) +{ + FILE *fp; + scanner sc; + conffile *cf; + + assert(n == SIGHUP); + if (!conffiles) { + fw_log(-1, "no configuration files to reload: ignoring SIGHUP"); + return; + } + fw_log(-1, "reloading configuration files..."); + source_killall(); + scan_create(&sc); + for (cf = conffiles; cf; cf = cf->next) { + if ((fp = fopen(cf->name, "r")) == 0) + fw_log(-1, "error loading `%s': %s", cf->name, strerror(errno)); + else + scan_add(&sc, scan_file(fp, cf->name, 0)); + } + conf_parse(&sc); + fw_log(-1, "... reload completed OK"); } /* --- Standard GNU help options --- */ @@ -193,7 +282,7 @@ static void version(FILE *fp) static void usage(FILE *fp) { - pquis(fp, "Usage: $ [-db] [-f file] [config statements...]\n"); + pquis(fp, "Usage: $ [-dql] [-f file] [config statements...]\n"); } static void help(FILE *fp) @@ -206,15 +295,19 @@ An excessively full-featured port-forwarder, which subsumes large chunks\n\ of the functionality of inetd, netcat, and normal cat. Options available\n\ are:\n\ \n\ --h, --help Display this help message.\n\ --v, --version Display the program's version number.\n\ --u, --usage Display a terse usage summary.\n\ +-h, --help Display this help message.\n\ +-v, --version Display the program's version number.\n\ +-u, --usage Display a terse usage summary.\n\ \n\ --g, --grammar Show a summary of the configuration language.\n\ --o, --options Show a summary of the source and target options.\n\ +-G, --grammar Show a summary of the configuration language.\n\ +-O, --options Show a summary of the source and target options.\n\ \n\ --f, --file=FILE Read configuration from a file.\n\ --d, --daemon Fork into background after initializing.\n\ +-f, --file=FILE Read configuration from a file.\n\ +-q, --quiet Don't emit any logging information.\n\ +-d, --daemon Fork into background after initializing.\n\ +-l, --syslog Send log output to the system logger.\n\ +-s, --setuid=USER Change uid to USER after initializing sources.\n\ +-g, --setgid=GRP Change gid to GRP after initializing sources.\n\ \n\ Configuration may be supplied in one or more configuration files, or on\n\ the command line (or both). If no `-f' option is present, and no\n\ @@ -338,14 +431,16 @@ int main(int argc, char *argv[]) { unsigned f = 0; sel_state sst; - sig s_term, s_int; + sig s_term, s_quit, s_int, s_hup; scanner sc; + uid_t drop = -1; + gid_t dropg = -1; + conffile *cf, **cff = &conffiles; - enum { - f_bogus = 1, - f_file = 2, - f_fork = 8 - }; +#define f_bogus 1u +#define f_file 2u +#define f_syslog 4u +#define f_fork 8u /* --- Initialize things --- */ @@ -360,20 +455,6 @@ int main(int argc, char *argv[]) fattr_init(&fattr_global); scan_create(&sc); - /* --- Set up some signal handlers --- * - * - * Don't enable @SIGINT@ if the caller already disabled it. - */ - - { - struct sigaction sa; - - sig_add(&s_term, SIGTERM, fw_tidy, 0); - sigaction(SIGINT, 0, &sa); - if (sa.sa_handler != SIG_IGN) - sig_add(&s_int, SIGINT, fw_tidy, 0); - } - atexit(fw_exit); /* --- Parse command line options --- */ @@ -389,21 +470,27 @@ int main(int argc, char *argv[]) /* --- Other help options --- */ - { "grammar", 0, 0, 'g' }, - { "options", 0, 0, 'o' }, + { "grammar", 0, 0, 'G' }, + { "options", 0, 0, 'O' }, /* --- Other useful arguments --- */ { "file", OPTF_ARGREQ, 0, 'f' }, { "fork", 0, 0, 'd' }, { "daemon", 0, 0, 'd' }, + { "syslog", 0, 0, 'l' }, + { "log", 0, 0, 'l' }, { "quiet", 0, 0, 'q' }, + { "setuid", OPTF_ARGREQ, 0, 's' }, + { "uid", OPTF_ARGREQ, 0, 's' }, + { "setgid", OPTF_ARGREQ, 0, 'g' }, + { "gid", OPTF_ARGREQ, 0, 'g' }, /* --- Magic terminator --- */ { 0, 0, 0, 0 } }; - int i = mdwopt(argc, argv, "+hvu go f:d", opts, 0, 0, 0); + int i = mdwopt(argc, argv, "+hvu GO f:dls:g:", opts, 0, 0, 0); if (i < 0) break; @@ -420,11 +507,11 @@ int main(int argc, char *argv[]) usage(stdout); exit(0); break; - case 'g': + case 'G': grammar(stdout); exit(0); break; - case 'o': + case 'O': options(stdout); exit(0); break; @@ -435,6 +522,10 @@ int main(int argc, char *argv[]) FILE *fp; if ((fp = fopen(optarg, "r")) == 0) die(1, "couldn't open file `%s': %s", optarg, strerror(errno)); + cf = CREATE(conffile); + cf->name = optarg; + *cff = cf; + cff = &cf->next; scan_add(&sc, scan_file(fp, optarg, 0)); } f |= f_file; @@ -442,9 +533,38 @@ int main(int argc, char *argv[]) case 'd': f |= f_fork; break; + case 'l': + f |= f_syslog; + break; case 'q': flags |= FW_QUIET; break; + case 's': + if (isdigit((unsigned char )optarg[0])) { + char *q; + drop = strtol(optarg, &q, 0); + if (*q) + die(1, "bad uid `%s'", optarg); + } else { + struct passwd *pw = getpwnam(optarg); + if (!pw) + die(1, "unknown user `%s'", optarg); + drop = pw->pw_uid; + } + break; + case 'g': + if (isdigit((unsigned char )optarg[0])) { + char *q; + dropg = strtol(optarg, &q, 0); + if (*q) + die(1, "bad gid `%s'", optarg); + } else { + struct group *gr = getgrnam(optarg); + if (!gr) + die(1, "unknown group `%s'", optarg); + dropg = gr->gr_gid; + } + break; default: f |= f_bogus; break; @@ -455,6 +575,7 @@ int main(int argc, char *argv[]) usage(stderr); exit(1); } + *cff = 0; /* --- Deal with the remaining arguments --- */ @@ -474,6 +595,34 @@ int main(int argc, char *argv[]) conf_parse(&sc); + /* --- Set up some signal handlers --- * + * + * Don't enable @SIGINT@ if the caller already disabled it. + */ + + { + struct sigaction sa; + + sig_add(&s_term, SIGTERM, fw_tidy, 0); + sig_add(&s_quit, SIGQUIT, fw_die, 0); + sigaction(SIGINT, 0, &sa); + if (sa.sa_handler != SIG_IGN) + sig_add(&s_int, SIGINT, fw_tidy, 0); + sig_add(&s_hup, SIGHUP, fw_reload, 0); + } + + /* --- Drop privileges --- */ + +#ifdef HAVE_SETGROUPS + if ((dropg != -1 && (setgid(dropg) || setgroups(1, &dropg))) || + (drop != -1 && setuid(drop))) + die(1, "couldn't drop privileges: %s", strerror(errno)); +#else + if ((dropg != -1 && setgid(dropg)) || + (drop != -1 && setuid(drop))) + die(1, "couldn't drop privileges: %s", strerror(errno)); +#endif + /* --- Fork into the background --- */ if (f & f_fork) { @@ -492,7 +641,9 @@ int main(int argc, char *argv[]) kid = fork(); if (kid != 0) _exit(0); + } + if (f & f_syslog) { flags |= FW_SYSLOG; openlog(QUIS, 0, LOG_DAEMON); } @@ -502,8 +653,23 @@ int main(int argc, char *argv[]) if (!(flags & FW_SET)) moan("nothing to do!"); signal(SIGPIPE, SIG_IGN); - while (active) - sel_select(sel); + + { + int selerr = 0; + while (active) { + if (!sel_select(sel)) + selerr = 0; + else if (errno != EINTR && errno != EAGAIN) { + fw_log(-1, "error from select: %s", strerror(errno)); + selerr++; + if (selerr > 8) { + fw_log(-1, "too many consecutive select errors: bailing out"); + exit(EXIT_FAILURE); + } + } + } + } + return (0); }