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Diffstat (limited to 'src/master/trigger_server.c')
| -rw-r--r-- | src/master/trigger_server.c | 809 |
1 files changed, 809 insertions, 0 deletions
diff --git a/src/master/trigger_server.c b/src/master/trigger_server.c new file mode 100644 index 0000000..fa6114b --- /dev/null +++ b/src/master/trigger_server.c @@ -0,0 +1,809 @@ +/*++ +/* NAME +/* trigger_server 3 +/* SUMMARY +/* skeleton triggered mail subsystem +/* SYNOPSIS +/* #include <mail_server.h> +/* +/* NORETURN trigger_server_main(argc, argv, service, key, value, ...) +/* int argc; +/* char **argv; +/* void (*service)(char *buf, int len, char *service_name, char **argv); +/* int key; +/* DESCRIPTION +/* This module implements a skeleton for triggered +/* mail subsystems: mail subsystem programs that wake up on +/* client request and perform some activity without further +/* client interaction. This module supports local IPC via FIFOs +/* and via UNIX-domain sockets. The resulting program expects to be +/* run from the \fBmaster\fR process. +/* +/* trigger_server_main() is the skeleton entry point. It should be +/* called from the application main program. The skeleton does the +/* generic command-line options processing, initialization of +/* configurable parameters, and connection management. +/* The skeleton never returns. +/* +/* Arguments: +/* .IP "void (*service)(char *buf, int len, char *service_name, char **argv)" +/* A pointer to a function that is called by the skeleton each time +/* a client connects to the program's service port. The function is +/* run after the program has irrevocably dropped its privileges. +/* The buffer argument specifies the data read from the trigger port; +/* this data corresponds to one or more trigger requests. +/* The len argument specifies how much client data is available. +/* The maximal size of the buffer is specified via the +/* TRIGGER_BUF_SIZE manifest constant. +/* The service name argument corresponds to the service name in the +/* master.cf file. +/* The argv argument specifies command-line arguments left over +/* after options processing. +/* The \fBserver\fR argument provides the following information: +/* .PP +/* Optional arguments are specified as a null-terminated list +/* with macros that have zero or more arguments: +/* .IP "CA_MAIL_SERVER_INT_TABLE(CONFIG_INT_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_LONG_TABLE(CONFIG_LONG_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_STR_TABLE(CONFIG_STR_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_BOOL_TABLE(CONFIG_BOOL_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_TIME_TABLE(CONFIG_TIME_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_RAW_TABLE(CONFIG_RAW_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. Raw parameters are not subjected to $name +/* evaluation. +/* .IP "CA_MAIL_SERVER_NINT_TABLE(CONFIG_NINT_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_NBOOL_TABLE(CONFIG_NBOOL_TABLE *)" +/* A table with configurable parameters, to be loaded from the +/* global Postfix configuration file. Tables are loaded in the +/* order as specified, and multiple instances of the same type +/* are allowed. +/* .IP "CA_MAIL_SERVER_PRE_INIT(void *(char *service_name, char **argv))" +/* A pointer to a function that is called once +/* by the skeleton after it has read the global configuration file +/* and after it has processed command-line arguments, but before +/* the skeleton has optionally relinquished the process privileges. +/* .sp +/* Only the last instance of this parameter type is remembered. +/* .IP "CA_MAIL_SERVER_POST_INIT(void *(char *service_name, char **argv))" +/* A pointer to a function that is called once +/* by the skeleton after it has optionally relinquished the process +/* privileges, but before servicing client connection requests. +/* .sp +/* Only the last instance of this parameter type is remembered. +/* .IP "CA_MAIL_SERVER_LOOP(int *(char *service_name, char **argv))" +/* A pointer to function that is executed from +/* within the event loop, whenever an I/O or timer event has happened, +/* or whenever nothing has happened for a specified amount of time. +/* The result value of the function specifies how long to wait until +/* the next event. Specify -1 to wait for "as long as it takes". +/* .sp +/* Only the last instance of this parameter type is remembered. +/* .IP "CA_MAIL_SERVER_EXIT(void *(char *service_name, char **argv))" +/* A pointer to function that is executed immediately before normal +/* process termination. +/* .sp +/* Only the last instance of this parameter type is remembered. +/* .IP "CA_MAIL_SERVER_PRE_ACCEPT(void *(char *service_name, char **argv))" +/* Function to be executed prior to accepting a new request. +/* .sp +/* Only the last instance of this parameter type is remembered. +/* .IP "CA_MAIL_SERVER_IN_FLOW_DELAY(none)" +/* Pause $in_flow_delay seconds when no "mail flow control token" +/* is available. A token is consumed for each connection request. +/* .IP CA_MAIL_SERVER_SOLITARY +/* This service must be configured with process limit of 1. +/* .IP CA_MAIL_SERVER_UNLIMITED +/* This service must be configured with process limit of 0. +/* .IP CA_MAIL_SERVER_PRIVILEGED +/* This service must be configured as privileged. +/* .IP "CA_MAIL_SERVER_WATCHDOG(int *)" +/* Override the default 1000s watchdog timeout. The value is +/* used after command-line and main.cf file processing. +/* .IP "CA_MAIL_SERVER_BOUNCE_INIT(const char *, const char **)" +/* Initialize the DSN filter for the bounce/defer service +/* clients with the specified map source and map names. +/* .PP +/* The var_use_limit variable limits the number of clients that +/* a server can service before it commits suicide. +/* This value is taken from the global \fBmain.cf\fR configuration +/* file. Setting \fBvar_use_limit\fR to zero disables the client limit. +/* +/* The var_idle_limit variable limits the time that a service +/* receives no client connection requests before it commits suicide. +/* This value is taken from the global \fBmain.cf\fR configuration +/* file. Setting \fBvar_use_limit\fR to zero disables the idle limit. +/* DIAGNOSTICS +/* Problems and transactions are logged to \fBsyslogd\fR(8) +/* or \fBpostlogd\fR(8). +/* BUGS +/* Works with FIFO-based services only. +/* SEE ALSO +/* master(8), master process +/* postlogd(8), Postfix logging +/* syslogd(8), system logging +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/* +/* Wietse Venema +/* Google, Inc. +/* 111 8th Avenue +/* New York, NY 10011, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <sys/socket.h> +#include <unistd.h> +#include <signal.h> +#include <stdlib.h> +#include <limits.h> +#include <string.h> +#include <errno.h> +#include <fcntl.h> +#include <stdarg.h> +#ifdef STRCASECMP_IN_STRINGS_H +#include <strings.h> +#endif +#include <time.h> + +/* Utility library. */ + +#include <msg.h> +#include <msg_vstream.h> +#include <chroot_uid.h> +#include <vstring.h> +#include <vstream.h> +#include <msg_vstream.h> +#include <mymalloc.h> +#include <events.h> +#include <iostuff.h> +#include <stringops.h> +#include <sane_accept.h> +#include <myflock.h> +#include <safe_open.h> +#include <listen.h> +#include <watchdog.h> +#include <split_at.h> + +/* Global library. */ + +#include <mail_params.h> +#include <mail_task.h> +#include <debug_process.h> +#include <mail_conf.h> +#include <mail_dict.h> +#include <resolve_local.h> +#include <mail_flow.h> +#include <mail_version.h> +#include <bounce.h> +#include <maillog_client.h> + +/* Process manager. */ + +#include "master_proto.h" + +/* Application-specific */ + +#include "mail_server.h" + + /* + * Global state. + */ +static int use_count; + +static TRIGGER_SERVER_FN trigger_server_service; +static char *trigger_server_name; +static char **trigger_server_argv; +static void (*trigger_server_accept) (int, void *); +static void (*trigger_server_onexit) (char *, char **); +static void (*trigger_server_pre_accept) (char *, char **); +static VSTREAM *trigger_server_lock; +static int trigger_server_in_flow_delay; +static unsigned trigger_server_generation; +static int trigger_server_watchdog = 1000; + +/* trigger_server_exit - normal termination */ + +static NORETURN trigger_server_exit(void) +{ + if (trigger_server_onexit) + trigger_server_onexit(trigger_server_name, trigger_server_argv); + exit(0); +} + +/* trigger_server_abort - terminate after abnormal master exit */ + +static void trigger_server_abort(int unused_event, void *unused_context) +{ + if (msg_verbose) + msg_info("master disconnect -- exiting"); + trigger_server_exit(); +} + +/* trigger_server_timeout - idle time exceeded */ + +static void trigger_server_timeout(int unused_event, void *unused_context) +{ + if (msg_verbose) + msg_info("idle timeout -- exiting"); + trigger_server_exit(); +} + +/* trigger_server_wakeup - wake up application */ + +static void trigger_server_wakeup(int fd) +{ + char buf[TRIGGER_BUF_SIZE]; + ssize_t len; + + /* + * Commit suicide when the master process disconnected from us. Don't + * drop the already accepted client request after "postfix reload"; that + * would be rude. + */ + if (master_notify(var_pid, trigger_server_generation, MASTER_STAT_TAKEN) < 0) + /* void */ ; + if (trigger_server_in_flow_delay && mail_flow_get(1) < 0) + doze(var_in_flow_delay * 1000000); + if ((len = read(fd, buf, sizeof(buf))) >= 0) + trigger_server_service(buf, len, trigger_server_name, + trigger_server_argv); + if (master_notify(var_pid, trigger_server_generation, MASTER_STAT_AVAIL) < 0) + trigger_server_abort(EVENT_NULL_TYPE, EVENT_NULL_CONTEXT); + if (var_idle_limit > 0) + event_request_timer(trigger_server_timeout, (void *) 0, var_idle_limit); + /* Avoid integer wrap-around in a persistent process. */ + if (use_count < INT_MAX) + use_count++; +} + +/* trigger_server_accept_fifo - accept fifo client request */ + +static void trigger_server_accept_fifo(int unused_event, void *context) +{ + const char *myname = "trigger_server_accept_fifo"; + int listen_fd = CAST_ANY_PTR_TO_INT(context); + + if (trigger_server_lock != 0 + && myflock(vstream_fileno(trigger_server_lock), INTERNAL_LOCK, + MYFLOCK_OP_NONE) < 0) + msg_fatal("select unlock: %m"); + + if (msg_verbose) + msg_info("%s: trigger arrived", myname); + + /* + * Read whatever the other side wrote into the FIFO. The FIFO read end is + * non-blocking so we won't get stuck when multiple processes wake up. + */ + if (trigger_server_pre_accept) + trigger_server_pre_accept(trigger_server_name, trigger_server_argv); + trigger_server_wakeup(listen_fd); +} + +/* trigger_server_accept_local - accept socket client request */ + +static void trigger_server_accept_local(int unused_event, void *context) +{ + const char *myname = "trigger_server_accept_local"; + int listen_fd = CAST_ANY_PTR_TO_INT(context); + int time_left = 0; + int fd; + + if (msg_verbose) + msg_info("%s: trigger arrived", myname); + + /* + * Read a message from a socket. Be prepared for accept() to fail because + * some other process already got the connection. The socket is + * non-blocking so we won't get stuck when multiple processes wake up. + * Don't get stuck when the client connects but sends no data. Restart + * the idle timer if this was a false alarm. + */ + if (var_idle_limit > 0) + time_left = event_cancel_timer(trigger_server_timeout, (void *) 0); + + if (trigger_server_pre_accept) + trigger_server_pre_accept(trigger_server_name, trigger_server_argv); + fd = LOCAL_ACCEPT(listen_fd); + if (trigger_server_lock != 0 + && myflock(vstream_fileno(trigger_server_lock), INTERNAL_LOCK, + MYFLOCK_OP_NONE) < 0) + msg_fatal("select unlock: %m"); + if (fd < 0) { + if (errno != EAGAIN) + msg_error("accept connection: %m"); + if (time_left >= 0) + event_request_timer(trigger_server_timeout, (void *) 0, time_left); + return; + } + close_on_exec(fd, CLOSE_ON_EXEC); + if (read_wait(fd, 10) == 0) + trigger_server_wakeup(fd); + else if (time_left >= 0) + event_request_timer(trigger_server_timeout, (void *) 0, time_left); + close(fd); +} + +#ifdef MASTER_XPORT_NAME_PASS + +/* trigger_server_accept_pass - accept descriptor */ + +static void trigger_server_accept_pass(int unused_event, void *context) +{ + const char *myname = "trigger_server_accept_pass"; + int listen_fd = CAST_ANY_PTR_TO_INT(context); + int time_left = 0; + int fd; + + if (msg_verbose) + msg_info("%s: trigger arrived", myname); + + /* + * Read a message from a socket. Be prepared for accept() to fail because + * some other process already got the connection. The socket is + * non-blocking so we won't get stuck when multiple processes wake up. + * Don't get stuck when the client connects but sends no data. Restart + * the idle timer if this was a false alarm. + */ + if (var_idle_limit > 0) + time_left = event_cancel_timer(trigger_server_timeout, (void *) 0); + + if (trigger_server_pre_accept) + trigger_server_pre_accept(trigger_server_name, trigger_server_argv); + fd = pass_accept(listen_fd); + if (trigger_server_lock != 0 + && myflock(vstream_fileno(trigger_server_lock), INTERNAL_LOCK, + MYFLOCK_OP_NONE) < 0) + msg_fatal("select unlock: %m"); + if (fd < 0) { + if (errno != EAGAIN) + msg_error("accept connection: %m"); + if (time_left >= 0) + event_request_timer(trigger_server_timeout, (void *) 0, time_left); + return; + } + close_on_exec(fd, CLOSE_ON_EXEC); + if (read_wait(fd, 10) == 0) + trigger_server_wakeup(fd); + else if (time_left >= 0) + event_request_timer(trigger_server_timeout, (void *) 0, time_left); + close(fd); +} + +#endif + +/* trigger_server_main - the real main program */ + +NORETURN trigger_server_main(int argc, char **argv, TRIGGER_SERVER_FN service,...) +{ + const char *myname = "trigger_server_main"; + char *root_dir = 0; + char *user_name = 0; + int debug_me = 0; + int daemon_mode = 1; + char *service_name = basename(argv[0]); + VSTREAM *stream = 0; + int delay; + int c; + int socket_count = 1; + int fd; + va_list ap; + MAIL_SERVER_INIT_FN pre_init = 0; + MAIL_SERVER_INIT_FN post_init = 0; + MAIL_SERVER_LOOP_FN loop = 0; + int key; + char buf[TRIGGER_BUF_SIZE]; + ssize_t len; + char *transport = 0; + char *lock_path; + VSTRING *why; + int alone = 0; + int zerolimit = 0; + WATCHDOG *watchdog; + char *oname_val; + char *oname; + char *oval; + const char *err; + char *generation; + int msg_vstream_needed = 0; + const char *dsn_filter_title; + const char **dsn_filter_maps; + + /* + * Process environment options as early as we can. + */ + if (getenv(CONF_ENV_VERB)) + msg_verbose = 1; + if (getenv(CONF_ENV_DEBUG)) + debug_me = 1; + + /* + * Don't die when a process goes away unexpectedly. + */ + signal(SIGPIPE, SIG_IGN); + + /* + * Don't die for frivolous reasons. + */ +#ifdef SIGXFSZ + signal(SIGXFSZ, SIG_IGN); +#endif + + /* + * May need this every now and then. + */ + var_procname = mystrdup(basename(argv[0])); + set_mail_conf_str(VAR_PROCNAME, var_procname); + + /* + * Initialize logging and exit handler. Do the syslog first, so that its + * initialization completes before we enter the optional chroot jail. + */ + maillog_client_init(mail_task(var_procname), MAILLOG_CLIENT_FLAG_NONE); + if (msg_verbose) + msg_info("daemon started"); + + /* + * Check the Postfix library version as soon as we enable logging. + */ + MAIL_VERSION_CHECK; + + /* + * Initialize from the configuration file. Allow command-line options to + * override compiled-in defaults or configured parameter values. + */ + mail_conf_suck(); + + /* + * After database open error, continue execution with reduced + * functionality. + */ + dict_allow_surrogate = 1; + + /* + * Pick up policy settings from master process. Shut up error messages to + * stderr, because no-one is going to see them. + */ + opterr = 0; + while ((c = GETOPT(argc, argv, "cdDi:lm:n:o:s:St:uvVz")) > 0) { + switch (c) { + case 'c': + root_dir = "setme"; + break; + case 'd': + daemon_mode = 0; + break; + case 'D': + debug_me = 1; + break; + case 'i': + mail_conf_update(VAR_MAX_IDLE, optarg); + break; + case 'l': + alone = 1; + break; + case 'm': + mail_conf_update(VAR_MAX_USE, optarg); + break; + case 'n': + service_name = optarg; + break; + case 'o': + oname_val = mystrdup(optarg); + if ((err = split_nameval(oname_val, &oname, &oval)) != 0) + msg_fatal("invalid \"-o %s\" option value: %s", optarg, err); + mail_conf_update(oname, oval); + myfree(oname_val); + break; + case 's': + if ((socket_count = atoi(optarg)) <= 0) + msg_fatal("invalid socket_count: %s", optarg); + break; + case 'S': + stream = VSTREAM_IN; + break; + case 't': + transport = optarg; + break; + case 'u': + user_name = "setme"; + break; + case 'v': + msg_verbose++; + break; + case 'V': + if (++msg_vstream_needed == 1) + msg_vstream_init(mail_task(var_procname), VSTREAM_ERR); + break; + case 'z': + zerolimit = 1; + break; + default: + msg_fatal("invalid option: %c", optopt); + break; + } + } + set_mail_conf_str(VAR_SERVNAME, service_name); + + /* + * Initialize generic parameters and re-initialize logging in case of a + * non-default program name or logging destination. + */ + mail_params_init(); + maillog_client_init(mail_task(var_procname), MAILLOG_CLIENT_FLAG_NONE); + + /* + * Register higher-level dictionaries and initialize the support for + * dynamically-loaded dictionarles. + */ + mail_dict_init(); + + /* + * If not connected to stdin, stdin must not be a terminal. + */ + if (daemon_mode && stream == 0 && isatty(STDIN_FILENO)) { + msg_vstream_init(var_procname, VSTREAM_ERR); + msg_fatal("do not run this command by hand"); + } + + /* + * Application-specific initialization. + */ + va_start(ap, service); + while ((key = va_arg(ap, int)) != 0) { + switch (key) { + case MAIL_SERVER_INT_TABLE: + get_mail_conf_int_table(va_arg(ap, CONFIG_INT_TABLE *)); + break; + case MAIL_SERVER_LONG_TABLE: + get_mail_conf_long_table(va_arg(ap, CONFIG_LONG_TABLE *)); + break; + case MAIL_SERVER_STR_TABLE: + get_mail_conf_str_table(va_arg(ap, CONFIG_STR_TABLE *)); + break; + case MAIL_SERVER_BOOL_TABLE: + get_mail_conf_bool_table(va_arg(ap, CONFIG_BOOL_TABLE *)); + break; + case MAIL_SERVER_TIME_TABLE: + get_mail_conf_time_table(va_arg(ap, CONFIG_TIME_TABLE *)); + break; + case MAIL_SERVER_RAW_TABLE: + get_mail_conf_raw_table(va_arg(ap, CONFIG_RAW_TABLE *)); + break; + case MAIL_SERVER_NINT_TABLE: + get_mail_conf_nint_table(va_arg(ap, CONFIG_NINT_TABLE *)); + break; + case MAIL_SERVER_NBOOL_TABLE: + get_mail_conf_nbool_table(va_arg(ap, CONFIG_NBOOL_TABLE *)); + break; + case MAIL_SERVER_PRE_INIT: + pre_init = va_arg(ap, MAIL_SERVER_INIT_FN); + break; + case MAIL_SERVER_POST_INIT: + post_init = va_arg(ap, MAIL_SERVER_INIT_FN); + break; + case MAIL_SERVER_LOOP: + loop = va_arg(ap, MAIL_SERVER_LOOP_FN); + break; + case MAIL_SERVER_EXIT: + trigger_server_onexit = va_arg(ap, MAIL_SERVER_EXIT_FN); + break; + case MAIL_SERVER_PRE_ACCEPT: + trigger_server_pre_accept = va_arg(ap, MAIL_SERVER_ACCEPT_FN); + break; + case MAIL_SERVER_IN_FLOW_DELAY: + trigger_server_in_flow_delay = 1; + break; + case MAIL_SERVER_SOLITARY: + if (stream == 0 && !alone) + msg_fatal("service %s requires a process limit of 1", + service_name); + break; + case MAIL_SERVER_UNLIMITED: + if (stream == 0 && !zerolimit) + msg_fatal("service %s requires a process limit of 0", + service_name); + break; + case MAIL_SERVER_PRIVILEGED: + if (user_name) + msg_fatal("service %s requires privileged operation", + service_name); + break; + case MAIL_SERVER_WATCHDOG: + trigger_server_watchdog = *va_arg(ap, int *); + break; + case MAIL_SERVER_BOUNCE_INIT: + dsn_filter_title = va_arg(ap, const char *); + dsn_filter_maps = va_arg(ap, const char **); + bounce_client_init(dsn_filter_title, *dsn_filter_maps); + break; + default: + msg_panic("%s: unknown argument type: %d", myname, key); + } + } + va_end(ap); + + if (root_dir) + root_dir = var_queue_dir; + if (user_name) + user_name = var_mail_owner; + + /* + * Can options be required? + * + * XXX Initially this code was implemented with UNIX-domain sockets, but + * Solaris <= 2.5 UNIX-domain sockets misbehave hopelessly when the + * client disconnects before the server has accepted the connection. + * Symptom: the server accept() fails with EPIPE or EPROTO, but the + * socket stays readable, so that the program goes into a wasteful loop. + * + * The initial fix was to use FIFOs, but those turn out to have their own + * problems, witness the workarounds in the fifo_listen() routine. + * Therefore we support both FIFOs and UNIX-domain sockets, so that the + * user can choose whatever works best. + * + * Well, I give up. Solaris UNIX-domain sockets still don't work properly, + * so it will have to limp along with a streams-specific alternative. + */ + if (stream == 0) { + if (transport == 0) + msg_fatal("no transport type specified"); + if (strcasecmp(transport, MASTER_XPORT_NAME_UNIX) == 0) + trigger_server_accept = trigger_server_accept_local; + else if (strcasecmp(transport, MASTER_XPORT_NAME_FIFO) == 0) + trigger_server_accept = trigger_server_accept_fifo; +#ifdef MASTER_XPORT_NAME_PASS + else if (strcasecmp(transport, MASTER_XPORT_NAME_PASS) == 0) + trigger_server_accept = trigger_server_accept_pass; +#endif + else + msg_fatal("unsupported transport type: %s", transport); + } + + /* + * Retrieve process generation from environment. + */ + if ((generation = getenv(MASTER_GEN_NAME)) != 0) { + if (!alldig(generation)) + msg_fatal("bad generation: %s", generation); + OCTAL_TO_UNSIGNED(trigger_server_generation, generation); + if (msg_verbose) + msg_info("process generation: %s (%o)", + generation, trigger_server_generation); + } + + /* + * Optionally start the debugger on ourself. + */ + if (debug_me) + debug_process(); + + /* + * Traditionally, BSD select() can't handle multiple processes selecting + * on the same socket, and wakes up every process in select(). See TCP/IP + * Illustrated volume 2 page 532. We avoid select() collisions with an + * external lock file. + */ + if (stream == 0 && !alone) { + lock_path = concatenate(DEF_PID_DIR, "/", transport, + ".", service_name, (char *) 0); + why = vstring_alloc(1); + if ((trigger_server_lock = safe_open(lock_path, O_CREAT | O_RDWR, 0600, + (struct stat *) 0, -1, -1, why)) == 0) + msg_fatal("open lock file %s: %s", lock_path, vstring_str(why)); + close_on_exec(vstream_fileno(trigger_server_lock), CLOSE_ON_EXEC); + myfree(lock_path); + vstring_free(why); + } + + /* + * Set up call-back info. + */ + trigger_server_service = service; + trigger_server_name = service_name; + trigger_server_argv = argv + optind; + + /* + * Run pre-jail initialization. + */ + if (chdir(var_queue_dir) < 0) + msg_fatal("chdir(\"%s\"): %m", var_queue_dir); + if (pre_init) + pre_init(trigger_server_name, trigger_server_argv); + + /* + * Optionally, restrict the damage that this process can do. + */ + resolve_local_init(); + tzset(); + chroot_uid(root_dir, user_name); + + /* + * Run post-jail initialization. + */ + if (post_init) + post_init(trigger_server_name, trigger_server_argv); + + /* + * Are we running as a one-shot server with the client connection on + * standard input? + */ + if (stream != 0) { + if ((len = read(vstream_fileno(stream), buf, sizeof(buf))) <= 0) + msg_fatal("read: %m"); + service(buf, len, trigger_server_name, trigger_server_argv); + vstream_fflush(stream); + trigger_server_exit(); + } + + /* + * Running as a semi-resident server. Service connection requests. + * Terminate when we have serviced a sufficient number of clients, when + * no-one has been talking to us for a configurable amount of time, or + * when the master process terminated abnormally. + */ + if (var_idle_limit > 0) + event_request_timer(trigger_server_timeout, (void *) 0, var_idle_limit); + for (fd = MASTER_LISTEN_FD; fd < MASTER_LISTEN_FD + socket_count; fd++) { + event_enable_read(fd, trigger_server_accept, CAST_INT_TO_VOID_PTR(fd)); + close_on_exec(fd, CLOSE_ON_EXEC); + } + event_enable_read(MASTER_STATUS_FD, trigger_server_abort, (void *) 0); + close_on_exec(MASTER_STATUS_FD, CLOSE_ON_EXEC); + close_on_exec(MASTER_FLOW_READ, CLOSE_ON_EXEC); + close_on_exec(MASTER_FLOW_WRITE, CLOSE_ON_EXEC); + watchdog = watchdog_create(trigger_server_watchdog, + (WATCHDOG_FN) 0, (void *) 0); + + /* + * The event loop, at last. + */ + while (var_use_limit == 0 || use_count < var_use_limit) { + if (trigger_server_lock != 0) { + watchdog_stop(watchdog); + if (myflock(vstream_fileno(trigger_server_lock), INTERNAL_LOCK, + MYFLOCK_OP_EXCLUSIVE) < 0) + msg_fatal("select lock: %m"); + } + watchdog_start(watchdog); + delay = loop ? loop(trigger_server_name, trigger_server_argv) : -1; + event_loop(delay); + } + trigger_server_exit(); +} |