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author | Sergey Poznyakoff <gray@gnu.org.ua> | 2007-04-20 09:09:46 +0000 |
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committer | Sergey Poznyakoff <gray@gnu.org.ua> | 2007-04-20 09:09:46 +0000 |
commit | f0992a40ee322ea27371ed6b81dce893cb8cd4d8 (patch) | |
tree | 8f216ae0aab3d309178816df14f4a8d31c2caf8f /src | |
parent | 5d78549a3171c8d058f1485e5cbc6f3d74770c9a (diff) | |
download | mailfromd-f0992a40ee322ea27371ed6b81dce893cb8cd4d8.tar.gz mailfromd-f0992a40ee322ea27371ed6b81dce893cb8cd4d8.tar.bz2 |
Implement asyncronous syslog
git-svn-id: file:///svnroot/mailfromd/trunk@1368 7a8a7f39-df28-0410-adc6-e0d955640f24
Diffstat (limited to 'src')
-rw-r--r-- | src/Makefile.am | 10 | ||||
-rw-r--r-- | src/mailfromd.h | 9 | ||||
-rw-r--r-- | src/main.c | 40 | ||||
-rw-r--r-- | src/syslog_async.c | 409 | ||||
-rw-r--r-- | src/syslog_async.h | 122 |
5 files changed, 585 insertions, 5 deletions
diff --git a/src/Makefile.am b/src/Makefile.am index c090a170..dee8e0a2 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -58,15 +58,19 @@ mailfromd_SOURCES = \ rate.c\ $(M4_FILES:.m4=.c) +mailfromd_LDADD = $(LDADD) $(SYSLOG_LIBS) +EXTRA_LIBRARIES=libsyslog_async.a +noinst_LIBRARIES=@BUILD_SYSLOG_ASYNC@ +libsyslog_async_a_SOURCES=syslog_async.c syslog_async.h + mtasim_SOURCES = mtasim.c mtasim_LDADD = $(LDADD) $(READLINE_LIBS) -noinst_HEADERS = mailfromd.h mu_dbm.h builtin.h dns.h spf.h drivers.c -EXTRA_DIST = gram.h snarf.m4 init.m4 $(M4_FILES) builtin.h builtin.def mf-status.mfi status.mfi mfstat.awk status.mfh optab.opc optab.oph opcode.awk opcodes node-type.h node-tab.c drv.awk +noinst_HEADERS = mailfromd.h mu_dbm.h builtin.h dns.h spf.h drivers.c +EXTRA_DIST = gram.h snarf.m4 init.m4 $(M4_FILES) builtin.h builtin.def mf-status.mfi status.mfi mfstat.awk status.mfh optab.opc optab.oph opcode.awk opcodes node-type.h node-tab.c drv.awk $(SYSLOG_ASYNC) BUILT_SOURCES=$(M4_FILES:.m4=.c) builtin.h mf-status.c optab.c optab.h node-type.h node-tab.c AM_CPPFLAGS=-DSYSCONFDIR=\"$(sysconfdir)\"\ - -DDATAROOTDIR=\"$(datarootdir)\"\ -DDEFAULT_STATE_DIR=\"$(DEFAULT_STATE_DIR)\"\ -DDEFAULT_SOCKET=\"$(DEFAULT_SOCKET)\"\ -DDEFAULT_VERSION_INCLUDE_DIR=\"$(incdir)\"\ diff --git a/src/mailfromd.h b/src/mailfromd.h index 23574182..973c94ae 100644 --- a/src/mailfromd.h +++ b/src/mailfromd.h @@ -223,7 +223,14 @@ mf_status getmxip(char *ipstr, mxbuf_t mxbuf); } while (0) #define debug6(lev,fmt,x1,x2,x3,x4,x5,x6) \ do { __DBG(lev) __debug6(fmt,x1,x2,x3,x4,x5,x6); } while(0) - + + +/* Syslog flavor */ +#ifdef USE_SYSLOG_ASYNC +# include <syslog_async.h> +#endif + + void debug_log(char *fmt, ...); void enable_module_trace(char *name); @@ -111,7 +111,9 @@ time_t response_timeout = 30; int syslog_printer (int prio, const char *fmt, va_list ap) { -#ifdef HAVE_VSYSLOG +#ifdef USE_SYSLOG_ASYNC + vsyslog_async (prio, fmt, ap); +#elif HAVE_VSYSLOG vsyslog (prio, fmt, ap); #else char buf[128]; @@ -121,6 +123,32 @@ syslog_printer (int prio, const char *fmt, va_list ap) return 0; } +#ifdef USE_SYSLOG_ASYNC +void +mf_gacopyz_syslog_async_log_printer(int level, char *fmt, va_list ap) +{ + switch (level) { + case SMI_LOG_DEBUG: + level = LOG_DEBUG; + break; + case SMI_LOG_INFO: + level = LOG_INFO; + break; + case SMI_LOG_WARN: + level = LOG_WARNING; + break; + case SMI_LOG_ERR: + level = LOG_ERR; + break; + + case SMI_LOG_FATAL: + default: + level = LOG_EMERG; + } + vsyslog_async(level, fmt, ap); +} +#endif + int syslog_error_printer (const char *fmt, va_list ap) { @@ -1744,6 +1772,11 @@ mailfromd_show_defaults() printf("statedir: %s\n", DEFAULT_STATE_DIR); printf("socket: %s\n", DEFAULT_SOCKET); printf("pidfile: %s\n", DEFAULT_PIDFILE); +#ifdef USE_SYSLOG_ASYNC + printf("syslog: non-blocking\n"); +#else + printf("syslog: blocking\n"); +#endif printf("database format: "); #if defined WITH_GDBM printf("GDBM"); @@ -1822,7 +1855,12 @@ main(int argc, char **argv) /* Set up default values */ if (!log_to_stderr) { +#ifdef USE_SYSLOG_ASYNC + openlog_async(syslog_tag, LOG_PID, log_facility); + gacopyz_set_logger (mf_gacopyz_syslog_async_log_printer); +#else openlog(syslog_tag, LOG_PID, log_facility); +#endif mu_error_set_print(syslog_error_printer); } else gacopyz_set_logger (gacopyz_stderr_log_printer); diff --git a/src/syslog_async.c b/src/syslog_async.c new file mode 100644 index 00000000..431e834f --- /dev/null +++ b/src/syslog_async.c @@ -0,0 +1,409 @@ +/* syslog_async is Copyright (c) 2007 Simon Kelley + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 dated June, 1991. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. +*/ + +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <sys/file.h> +#include <sys/syslog.h> + +#include <sys/uio.h> +#include <sys/wait.h> +#include <netdb.h> +#include <string.h> +#include <time.h> +#include <unistd.h> +#include <errno.h> +#include <stdarg.h> +#include <stdlib.h> +#include <paths.h> +#include <stdio.h> +#include <ctype.h> + +#include "syslog_async.h" + +/* From RFC 3164 */ +#define MAX_MESSAGE 1024 + +#define DEF_BACKLOG 5 +#define DEF_DELAY 1000 /* doesn't come into effect until backlog > 10 */ + +static int log_fac = LOG_USER; +static int log_opts = LOG_ODELAY; +static const char *log_tag = "syslog"; +static int log_mask = 0xff; +static int log_backlog = DEF_BACKLOG; +static int log_delay = DEF_DELAY; + +static int log_fd = -1; +static int entries_alloced = 0; +static int entries_lost = 0; +static int connection_good = 1; + +struct log_entry { + int offset, length; + struct log_entry *next; + char payload[MAX_MESSAGE]; +}; + +static struct log_entry *entries = NULL; +static struct log_entry *free_entries = NULL; + +static int mksock(int type) +{ + int flags; + int fd = socket(AF_UNIX, type, 0); + + if (fd != -1) + { + if ((flags = fcntl(fd, F_GETFL)) == -1 || + fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1 || + (flags = fcntl(fd, F_GETFD)) == -1 || + fcntl(fd, F_SETFD, flags | FD_CLOEXEC) == -1) + { + close(fd); + fd = -1; + } + } + return fd; +} + +void openlog_async(const char *ident, int option, int facility) +{ + if (ident) + log_tag = ident; + + log_opts = option; + + if (facility != 0 && (facility &~ LOG_FACMASK) == 0) + log_fac = facility; + + if (log_opts & LOG_NDELAY) + log_fd = mksock(SOCK_DGRAM); +} + +int setlogmask_async(int mask) +{ + int old = log_mask; + + if (mask != 0) + log_mask = mask; + + return old; +} + +void tunelog_async(int backlog, int delay) +{ + /* we need at least one buffer, and the + delay calculations overflow for more than 99 */ + if (backlog < 1) + backlog = 1; + else if (backlog > 99) + backlog = 99; + + /* don't lose existing buffers */ + if (backlog < entries_alloced) + log_backlog = entries_alloced; + else + log_backlog = backlog; + + if (delay < 0) + log_delay = 0; + else if (delay > 1000) + log_delay = 1000; + else + log_delay = delay; +} + +void closelog_async(void) +{ + /* maybe last chance to flush */ + log_write_async(); + + if (log_fd != -1) + { + close(log_fd); + log_fd = -1; + } + + /* restore defaults */ + log_fac = LOG_USER; + log_opts = LOG_ODELAY; + log_tag = "syslog"; + log_mask = 0xff; + + log_delay = DEF_DELAY; + + if (entries_alloced < DEF_BACKLOG) + log_backlog = entries_alloced; + else + log_backlog = DEF_BACKLOG; +} + +int log_fd_async(void) +{ + if (!entries || !connection_good) + return -1; + + return log_fd; +} + +void log_write_async(void) +{ + ssize_t rc; + int fd, tried_stream = 0; + struct log_entry *tmp; + + while (entries) + { + if (log_fd == -1 && + (log_fd = mksock(SOCK_DGRAM)) == -1) + goto fail; + + connection_good = 1; + + if ((rc = send(log_fd, + entries->payload + entries->offset, + entries->length, + MSG_NOSIGNAL)) != -1) + { + entries->length -= rc; + entries->offset += rc; + connection_good = 1; + + if (entries->length == 0) + goto free; + + continue; + } + + if (errno == EINTR) + continue; + + if (errno == EAGAIN) + return; + + /* *BSD, returns this instead of blocking? */ + if (errno == ENOBUFS) + { + connection_good = 0; + return; + } + + /* A stream socket closed at the other end goes into EPIPE + forever, close and re-open. */ + if (errno == EPIPE) + goto reopen_stream; + + if (errno == ECONNREFUSED || + errno == ENOTCONN || + errno == EDESTADDRREQ || + errno == ECONNRESET) + { + /* socket went (syslogd down?), try and reconnect. If we fail, + stop trying until the next call to my_syslog() + ECONNREFUSED -> connection went down + ENOTCONN -> nobody listening + (ECONNRESET, EDESTADDRREQ are *BSD equivalents) */ + + struct sockaddr_un logaddr; + + logaddr.sun_family = AF_LOCAL; + strncpy(logaddr.sun_path, _PATH_LOG, sizeof(logaddr.sun_path)); + + /* Got connection back? try again. */ + if (connect(log_fd, (struct sockaddr *)&logaddr, sizeof(logaddr)) != -1) + continue; + + /* errors from connect which mean we should keep trying */ + if (errno == ENOENT || + errno == EALREADY || + errno == ECONNREFUSED || + errno == EISCONN || + errno == EINTR || + errno == EAGAIN) + { + /* try again on next syslog() call */ + connection_good = 0; + return; + } + + /* we start with a SOCK_DGRAM socket, but syslog may want SOCK_STREAM */ + if (!tried_stream && errno == EPROTOTYPE) + { + reopen_stream: + tried_stream = 1; + close(log_fd); + if ((log_fd = mksock(SOCK_STREAM)) != -1) + continue; + } + } + + fail: + tried_stream = 0; + + /* give up - try to write to console if we've been asked + take care not to block in open() or write() */ + if ((log_opts & LOG_CONS) && + (fd = open(_PATH_CONSOLE, O_WRONLY | O_NONBLOCK, 0)) != -1) + { + char *start = strchr(entries->payload, '>') + 1; + int flags = fcntl(fd, F_GETFL); + + if (flags != -1) + fcntl(fd, F_SETFL, flags | O_NONBLOCK); + + entries->length -= start - entries->payload; + /* move down to remove the tag, and make room for the \r\n */ + memmove(entries->payload, start, entries->length); + entries->payload[entries->length - 1] = '\r'; + entries->payload[entries->length] = '\n'; + write(fd, entries->payload, entries->length + 1); + close(fd); + } + + free: + tmp = entries; + entries = tmp->next; + tmp->next = free_entries; + free_entries = tmp; + + if (entries_lost != 0) + { + int e = entries_lost; + entries_lost = 0; /* avoid wild recursion */ + syslog_async(LOG_WARNING, "async_syslog overflow: %d log entries lost", e); + } + continue; + } +} + +void syslog_async(int priority, const char *format, ...) +{ + va_list ap; + + va_start(ap, format); + vsyslog_async(priority, format, ap); + va_end(ap); +} + +void vsyslog_async(int priority, const char *format, va_list ap) +{ + struct log_entry *entry; + time_t time_now; + char *p, *q, *r; + size_t len; + + if (!(log_mask & LOG_MASK(LOG_PRI(priority))) || (priority &~ (LOG_PRIMASK|LOG_FACMASK))) + return; + + if ((entry = free_entries)) + free_entries = entry->next; + else if (entries_alloced < log_backlog && (entry = malloc(sizeof(struct log_entry)))) + entries_alloced++; + + if (!entry) + entries_lost++; + else + { + /* add to end of list, consumed from the start */ + entry->next = NULL; + if (!entries) + entries = entry; + else + { + struct log_entry *tmp; + for (tmp = entries; tmp->next; tmp = tmp->next); + tmp->next = entry; + } + + time(&time_now); + p = entry->payload; + p += sprintf(p, "<%d>", priority | log_fac); + + q = p; + + if (log_opts & LOG_PID) + p += sprintf(p, "%.15s %s[%d]: ", ctime(&time_now) + 4, log_tag, getpid()); + else + p += sprintf(p, "%.15s %s: ", ctime(&time_now) + 4, log_tag); + + len = p - entry->payload; + len += vsnprintf(p, MAX_MESSAGE - len, format, ap) + 1; /* include zero-terminator */ + entry->length = len > MAX_MESSAGE ? MAX_MESSAGE : len; + + /* remove trailing '\n's passed to us. */ + for (r = &entry->payload[entry->length - 2]; r >= entry->payload; r--) + if (*r == '\n') + entry->length--; + else + break; + + entry->offset = 0; + + if (log_opts & LOG_PERROR) + { + ssize_t rc, s = entry->length - (q - entry->payload); + /* replace terminator with \n */ + entry->payload[entry->length - 1] = '\n'; + + while (s != 0) + if ((rc = write(STDERR_FILENO, q, s)) != -1) + { + s -= rc; + q += rc; + continue; + } + else if (errno == EINTR) + continue; + else + break; + } + entry->payload[entry->length - 1] = 0; + } + + /* almost always, logging won't block, so try and write this now, + to save collecting too many log messages during a select loop. */ + log_write_async(); + + /* Since we're doing things asynchronously, we + can now generate log lines very fast. With a small buffer (desirable), + that means it can overflow the log-buffer very quickly. + To avoid this, we delay here, the delay growing exponentially + with queue length. Delay is limited to 1 second, by default + but can be tuned for less if needed. Note that for a responsive + syslog, the log-line we just created will have been writen by the + call the log_write_async() above, so that this doesn't delay at all. */ + if (entries && log_delay != 0) + { + struct timespec waiter; + int d; + + for (d = 1,entry = entries; entry->next; entry = entry->next) + { + d *= 2; + if (d >= log_delay) /* limit to 999ms */ + { + d = log_delay - 1; + break; + } + } + + waiter.tv_sec = 0; + waiter.tv_nsec = d * 1000000; /* 1 ms */ + nanosleep(&waiter, NULL); + + /* try and write again */ + log_write_async(); + } +} + diff --git a/src/syslog_async.h b/src/syslog_async.h new file mode 100644 index 00000000..ba6ae766 --- /dev/null +++ b/src/syslog_async.h @@ -0,0 +1,122 @@ +/* syslog_async is Copyright (c) 2007 Simon Kelley + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 dated June, 1991. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. +*/ + +#ifndef _SYSLOG_ASYNC_H +#define _SYSLOG_ASYNC_H 1 + +#include <syslog.h> +#include <stdarg.h> + +/* Syslog_async is a non-blocking replacement for the + POSIX-standard syslog() system call. Instead of blocking, + log-lines are buffered in memory. The buffer size is limited + and if the buffer overflows log lines are lost. When lines are + lost this fact is logged with a message of the form: + + async_syslog overflow: 5 log entries lost + + In order to limit the probability of buffer overflow + short delays are added to syslog_async() calls when the + queue is getting full. The delay added is strictly + bounded and tunable. + + The API is very close to the standard syslog(), with an + additional call the tune buffer parameters and a couple + of calls into the event loop. + + The code has been tested under Linux and BSD, and with both + the syslog and syslog-ng log daemons. +*/ + + +/* + openlog_async(), closelog_async() and setlogmask_async() are + identical to the POSIX equivalents. +*/ + +void openlog_async(const char *ident, int option, int facility); +void closelog_async(void); +int setlogmask_async(int mask); + + + +/* + syslog_async() and vsyslog_async() are identical to syslog() and vsyslog() + except for their blocking behaviour. The formatting is done using printf(), + so the additional format operator %m is available only if the system + printf() provides it. (GNU printf() does.) +*/ + +void syslog_async(int priority, const char *format, ...); +void vsyslog_async(int priority, const char *format, va_list ap); + + + +/* + log_fd_async() and log_write_async() are the interface between the library + and the daemon event loop. + + log_fd_async() returns a file descriptor which the library needs to write, + or -1 if no write is queued. log_write_async() does the write. + + The result of log_fd_async() is only valid until [v]syslog_async() or + log_write_async() is called, so it should be called each time around the + event loop, just before the call to select() or poll(). + + A typical event loop looks like this: + + while (1) + { + int log_fd; + fd_set read_set, write_set; + + FD_ZERO(&read_set); + FD_ZERO(&write_set); + + ...other stuff.. + + if ((log_fd = log_fd_async()) != -1) + FD_SET(log_fd, &write_set); + + select(..., &read_set, &write_set, ...); + + if (log_fd != -1 && FD_ISSET(log_fd, &write)) + log_write_async(); + + + ...other stuff.... + } +*/ + +int log_fd_async(void); +void log_write_async(void); + + + +/* + tunelog_async() tunes the log-line buffer. Backlog is the limit + on the number of queued log-lines. These are stored in malloc'ed memory + and each line is stored in a fixed-size buffer which is just over 1K bytes. + The library maintains a buffer pool to avoid heap fragmentation. Delay + is the upper bound on the time taken to run syslog_async, in milliseconds. + This delay is added when syslog is busy in order to reduce the probability + of buffer overflow. Backlog is constrained between 1 and 99 and delay + between 1 millisecond and 1000 millisconds. The default for backlog + is 5 and for delay 1000. Note that delay is calculated from queue size as + 2^queue_size (in milliseconds) therefore the maximum delay for the default + queue size is 64ms. Setting delay to zero is allowed, and inhibits the delay + completely. +*/ + +void tunelog_async(int backlog, int delay); + +#endif |