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	/* sync_log.c -- Cyrus synchonization logging functions
	*
	* Copyright (c) 1994-2008 Carnegie Mellon University. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. The name "Carnegie Mellon University" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For permission or any legal
	* details, please contact
	* Carnegie Mellon University
	* Center for Technology Transfer and Enterprise Creation
	* 4615 Forbes Avenue
	* Suite 302
	* Pittsburgh, PA 15213
	* (412) 268-7393, fax: (412) 268-7395
	* innovation@andrew.cmu.edu
	*
	* 4. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by Computing Services
	* at Carnegie Mellon University (http://www.cmu.edu/computing/)."
	*
	* CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
	* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
	* AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
	* FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
	* AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
	* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*
	* Original version written by David Carter <dpc22@cam.ac.uk>
	* Rewritten and integrated into Cyrus by Ken Murchison <ken@oceana.com>
	*/

	/* YYY Need better quoting for obscure filenames: use literals? */

	#include <config.h>

	#ifdef HAVE_UNISTD_H
	#include <unistd.h>
	#endif
	#include <stdarg.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <string.h>
	#include <syslog.h>
	#include <errno.h>

	#include "assert.h"
	#include "exitcodes.h"
	#include "sync_log.h"
	#include "global.h"
	#include "cyr_lock.h"
	#include "mailbox.h"
	#include "retry.h"
	#include "util.h"
	#include "xmalloc.h"
	#include "xstrlcpy.h"

	/* generated headers are not necessarily in current directory */
	#include "imap/imap_err.h"

	static int sync_log_suppressed = 0;
	static strarray_t *channels = NULL;
	static strarray_t *unsuppressable = NULL;

	EXPORTED void sync_log_init(void)
	{
	const char *conf;
	int i;


	/* sync_log_init() may be called more than once */
	if (channels) strarray_free(channels);

	conf = config_getstring(IMAPOPT_SYNC_LOG_CHANNELS);
	if (!conf) conf = "\"\"";
	channels = strarray_split(conf, " ", 0);
	/*
	* The sysadmin can specify "" in the value of sync_log_channels to
	* mean the default channel name - this will be useful for sysadmins
	* who want to start using a sync log channel for squatter but who
	* have been using the default sync log channel for sync_client.
	*/
	i = strarray_find(channels, "\"\"", 0);
	if (i >= 0)
	strarray_set(channels, i, NULL);

	strarray_free(unsuppressable);
	unsuppressable = NULL;
	conf = config_getstring(IMAPOPT_SYNC_LOG_UNSUPPRESSABLE_CHANNELS);
	if (conf)
	unsuppressable = strarray_split(conf, " ", 0);
	}

	EXPORTED void sync_log_suppress(void)
	{
	sync_log_suppressed = 1;
	}

	EXPORTED void sync_log_done(void)
	{
	strarray_free(channels);
	channels = NULL;

	strarray_free(unsuppressable);
	unsuppressable = NULL;
	}

	static char sync_log_fname(const char channel)
	{
	static char buf[MAX_MAILBOX_PATH];

	if (channel)
	snprintf(buf, MAX_MAILBOX_PATH,
	"%s/sync/%s/log", config_dir, channel);
	else
	snprintf(buf, MAX_MAILBOX_PATH,
	"%s/sync/log", config_dir);

	return buf;
	}

	static int sync_log_enabled(const char *channel)
	{
	if (!config_getswitch(IMAPOPT_SYNC_LOG))
	return 0; /* entire mechanism is disabled */
	if (!sync_log_suppressed)
	return 1; /* _suppress() wasn't called */
	if (unsuppressable && strarray_find(unsuppressable, channel, 0) >= 0)
	return 1; /* channel is unsuppressable */
	return 0; /* suppressed */
	}

	static void sync_log_base(const char channel, const char string)
	{
	int fd;
	struct stat sbuffile, sbuffd;
	int retries = 0;
	const char *fname;

	fname = sync_log_fname(channel);

	while (retries++ < SYNC_LOG_RETRIES) {
	fd = open(fname, O_WRONLY\|O_APPEND\|O_CREAT, 0640);
	if (fd < 0 && errno == ENOENT) {
	if (!cyrus_mkdir(fname, 0755)) {
	fd = open(fname, O_WRONLY\|O_APPEND\|O_CREAT, 0640);
	}
	}
	if (fd < 0) {
	syslog(LOG_ERR, "sync_log(): Unable to write to log file %s: %s",
	fname, strerror(errno));
	return;
	}

	if (lock_blocking(fd, fname) == -1) {
	syslog(LOG_ERR, "sync_log(): Failed to lock %s for %s: %m",
	fname, string);
	xclose(fd);
	return;
	}

	/* Check that the file wasn't renamed after it was opened above */
	if ((fstat(fd, &sbuffd) == 0) &&
	(stat(fname, &sbuffile) == 0) &&
	(sbuffd.st_ino == sbuffile.st_ino))
	break;

	lock_unlock(fd, fname);
	xclose(fd);
	}
	if (retries >= SYNC_LOG_RETRIES) {
	xclose(fd);
	syslog(LOG_ERR,
	"sync_log(): Failed to lock %s for %s after %d attempts",
	fname, string, retries);
	return;
	}

	if (retry_write(fd, string, strlen(string)) < 0)
	syslog(LOG_ERR, "write() to %s failed: %s",
	fname, strerror(errno));

	(void)fsync(fd); /* paranoia */
	lock_unlock(fd, fname);
	xclose(fd);
	}

	static const char sync_quote_name(const char name)
	{
	static char buf[MAX_MAILBOX_BUFFER+3]; /* "x2 plus \0 */
	char c;
	int src;
	int dst = 0;
	int need_quote = 0;

	/* initial quote */
	buf[dst++] = '"';

	/* degenerate case - no name is the empty string, quote it */
	if (!name \|\| !*name) {
	need_quote = 1;
	goto end;
	}

	for (src = 0; name[src]; src++) {
	c = name[src];
	if ((c == '\r') \|\| (c == '\n'))
	fatal("Illegal line break in folder name", EC_IOERR);

	/* quoteable characters */
	if ((c == '\\') \|\| (c == '\"') \|\| (c == '{') \|\| (c == '}')) {
	need_quote = 1;
	buf[dst++] = '\\';
	}

	/* non-atom characters */
	else if ((c == ' ') \|\| (c == '\t') \|\| (c == '(') \|\| (c == ')')) {
	need_quote = 1;
	}

	buf[dst++] = c;

	if (dst > MAX_MAILBOX_BUFFER)
	fatal("word too long", EC_IOERR);
	}

	end:
	if (need_quote) {
	buf[dst++] = '\"';
	buf[dst] = '\0';
	return buf;
	}
	else {
	buf[dst] = '\0';
	return buf + 1; /* skip initial quote */
	}
	}

	#define BUFSIZE 4096

	static char va_format(const char fmt, va_list ap)
	{
	static char buf[BUFSIZE+1];
	size_t len;
	int ival;
	const char *sval;
	const char *p;

	for (len = 0, p = fmt; *p && len < BUFSIZE; p++) {
	if (*p != '%') {
	buf[len++] = *p;
	continue;
	}
	switch (*++p) {
	case 'd':
	ival = va_arg(ap, int);
	len += snprintf(buf+len, BUFSIZE-len, "%d", ival);
	break;
	case 's':
	sval = va_arg(ap, const char *);
	sval = sync_quote_name(sval);
	strlcpy(buf+len, sval, BUFSIZE-len);
	len += strlen(sval);
	break;
	default:
	buf[len++] = *p;
	break;
	}
	}

	if (buf[len-1] != '\n') buf[len++] = '\n';
	buf[len] = '\0';

	return buf;
	}

	EXPORTED void sync_log(const char *fmt, ...)
	{
	va_list ap;
	const char *val;
	int i;

	if (!channels) return;

	va_start(ap, fmt);
	val = va_format(fmt, ap);
	va_end(ap);

	for (i = 0 ; i < channels->count ; i++) {
	const char *channel = channels->data[i];
	if (sync_log_enabled(channel))
	sync_log_base(channel, val);
	}
	}

	EXPORTED void sync_log_channel(const char channel, const char fmt, ...)
	{
	va_list ap;
	const char *val;

	va_start(ap, fmt);
	val = va_format(fmt, ap);
	va_end(ap);

	sync_log_base(channel, val);
	}

	/*
	* Read-side sync log code
	*/
	struct sync_log_reader
	{
	/*
	* This object works in three modes:
	*
	* - initialised with a sync log channel
	* - standard mode used by sync_client
	* - slr->log_file != NULL
	* - slr->work_file is the name of a rename()d
	* file that needs to be unlink()ed.
	*
	* - initialised with a saved file name
	* - used by the sync_client -f option
	* - slr->log_file = NULL
	* - slr->work_file is the file given us by the user
	* which it's important that we do not unlink()
	*
	* - initialised with a file descriptor
	* - slr->log_file = NULL
	* - slr->work_file = NULL
	* - slr->fd is a file descriptor, probably stdin,
	* and possibly a pipe
	* - we cannot unlink() anything even if we wanted to.
	*/
	char *log_file;
	char *work_file;
	int fd;
	int fd_is_ours;
	struct protstream *input;
	struct buf type;
	struct buf arg1;
	struct buf arg2;
	};

	static sync_log_reader_t *sync_log_reader_alloc(void)
	{
	sync_log_reader_t *slr = xzmalloc(sizeof(sync_log_reader_t));
	slr->fd = -1;
	return slr;
	}

	/*
	* Create a sync log reader object which will read from the given sync log
	* channel 'channel'. The channel may be NULL for the default channel.
	* Returns a new object which must be freed with sync_log_reader_free().
	* Does not return NULL.
	*/
	EXPORTED sync_log_reader_t sync_log_reader_create_with_channel(const char channel)
	{
	sync_log_reader_t *slr = sync_log_reader_alloc();
	struct buf buf = BUF_INITIALIZER;

	slr->log_file = xstrdup(sync_log_fname(channel));

	/* Create a work log filename. We will process this
	* first if it exists */
	buf_printf(&buf, "%s-run", slr->log_file);
	slr->work_file = buf_release(&buf);

	return slr;
	}

	/*
	* Create a sync log reader object which will read from the given file
	* 'filename'. Returns a new object which must be freed with
	* sync_log_reader_free(). Does not return NULL.
	*/
	EXPORTED sync_log_reader_t sync_log_reader_create_with_filename(const char filename)
	{
	sync_log_reader_t *slr = sync_log_reader_alloc();
	slr->work_file = xstrdup(filename);
	/* slr->log_file remain NULL, which matters later */
	return slr;
	}

	/*
	* Create a sync log reader object which will read from the given file
	* descriptor 'fd'. The file descriptor must be open for reading and
	* is not closed. Returns a new object which must be freed with
	* sync_log_reader_free(). Does not return NULL.
	*/
	EXPORTED sync_log_reader_t *sync_log_reader_create_with_fd(int fd)
	{
	sync_log_reader_t *slr = sync_log_reader_alloc();
	slr->fd = fd;
	slr->fd_is_ours = 0;
	/* slr->log_file remain NULL, which matters later */
	return slr;
	}

	/*
	* Free a sync log reader object.
	*/
	EXPORTED void sync_log_reader_free(sync_log_reader_t *slr)
	{
	if (!slr) return;
	if (slr->input) prot_free(slr->input);
	if (slr->fd_is_ours && slr->fd >= 0) close(slr->fd);
	free(slr->log_file);
	free(slr->work_file);
	buf_free(&slr->type);
	buf_free(&slr->arg1);
	buf_free(&slr->arg2);
	free(slr);
	}

	/*
	* Begin reading a sync log file. If the reader is reading from a
	* channel, rename the current log file so it will not be appended to by
	* the write side code, and open the file. Otherwise, just open the file
	* (note this is still necessary even when the reader is reading from a
	* file descriptor).
	*
	* When sync_log_reader_begin() returns success, you should loop calling
	* sync_log_reader_getitem() and handling the items, until it returns
	* EOF, and then call sync_log_reader_end().
	*
	* Returns zero on success, IMAP_AGAIN if reading from a channel and
	* there is no current log file, or an IMAP error code on failure.
	*/
	EXPORTED int sync_log_reader_begin(sync_log_reader_t *slr)
	{
	struct stat sbuf;
	int r;

	if (slr->input) {
	r = sync_log_reader_end(slr);
	if (r) return r;
	}

	if (stat(slr->work_file, &sbuf) == 0) {
	/* Existing work log file - process this first */
	syslog(LOG_NOTICE,
	"Reprocessing sync log file %s", slr->work_file);
	}
	else if (!slr->log_file) {
	syslog(LOG_ERR, "Failed to stat %s: %m",
	slr->log_file);
	return IMAP_IOERROR;
	}
	else {
	/* Check for sync_log file */
	if (stat(slr->log_file, &sbuf) < 0) {
	if (errno == ENOENT)
	return IMAP_AGAIN; /* no problem, try again later */
	syslog(LOG_ERR, "Failed to stat %s: %m",
	slr->log_file);
	return IMAP_IOERROR;
	}

	/* Move sync_log to our work file */
	if (rename(slr->log_file, slr->work_file) < 0) {
	syslog(LOG_ERR, "Rename %s -> %s failed: %m",
	slr->log_file, slr->work_file);
	return IMAP_IOERROR;
	}
	}

	if (slr->fd < 0) {
	int fd = open(slr->work_file, O_RDWR, 0);
	if (fd < 0) {
	syslog(LOG_ERR, "Failed to open %s: %m", slr->work_file);
	return IMAP_IOERROR;
	}

	if (lock_blocking(fd, slr->work_file) < 0) {
	syslog(LOG_ERR, "Failed to lock %s: %m", slr->work_file);
	close(fd);
	return IMAP_IOERROR;
	}

	slr->fd = fd;
	slr->fd_is_ours = 1;

	/* we can unlock immediately, since we have serialised
	* any process which held the lock over the rename. All
	* future attempts to lock this inode will stat and notice
	* the rename, so they won't write any more */
	lock_unlock(slr->fd, slr->work_file);
	}

	slr->input = prot_new(slr->fd, /write/0);

	return 0;
	}

	EXPORTED const char sync_log_reader_get_file_name(const sync_log_reader_t slr)
	{
	return slr->work_file;
	}

	/*
	* Finish reading a sync log file. Closes the file (and, if the reader
	* is reading from a channel, unlinks the work file and prepares for the
	* next file). Returns 0 on success or an IMAP error code on failure.
	*/
	EXPORTED int sync_log_reader_end(sync_log_reader_t *slr)
	{
	if (!slr->input)
	return 0;

	if (slr->input) {
	prot_free(slr->input);
	slr->input = NULL;
	}

	if (slr->fd_is_ours && slr->fd >= 0) {
	lock_unlock(slr->fd, slr->work_file);
	close(slr->fd);
	slr->fd = -1;
	}

	if (slr->log_file) {
	/* We were initialised with a sync log channel, whose
	* log file we rename()d to the work file. Now that
	* we've done with the work file we can unlink it.
	* Further checks at this point are just paranoia. */
	if (slr->work_file && unlink(slr->work_file) < 0) {
	syslog(LOG_ERR, "Unlink %s failed: %m", slr->work_file);
	return IMAP_IOERROR;
	}
	}

	return 0;
	}

	/*
	* Read a single log item from a sync log file. The item will be
	* returned as three constant strings. The first string is the type of
	* the item (e.g. "MAILBOX") and is always capitalised. The second and
	* third strings are arguments.
	*
	* Returns 0 on success, EOF when the end of the file is reached, or an
	* IMAP error code on failure.
	*/
	EXPORTED int sync_log_reader_getitem(sync_log_reader_t *slr,
	const char *args[3])
	{
	int c;
	const char *arg1s = NULL;
	const char *arg2s = NULL;

	if (!slr->input)
	return EOF;

	for (;;) {
	if ((c = getword(slr->input, &slr->type)) == EOF)
	return EOF;

	/* Ignore blank lines */
	if (c == '\r') c = prot_getc(slr->input);
	if (c == '\n')
	continue;

	if (c != ' ') {
	syslog(LOG_ERR, "Invalid input");
	eatline(slr->input, c);
	continue;
	}

	if ((c = getastring(slr->input, 0, &slr->arg1)) == EOF) return EOF;
	arg1s = slr->arg1.s;

	arg2s = NULL;
	if (c == ' ') {
	if ((c = getastring(slr->input, 0, &slr->arg2)) == EOF) return EOF;
	arg2s = slr->arg2.s;
	}

	if (c == '\r') c = prot_getc(slr->input);
	if (c != '\n') {
	syslog(LOG_ERR, "Garbage at end of input line");
	eatline(slr->input, c);
	continue;
	}

	break;
	}

	ucase(slr->type.s);
	args[0] = slr->type.s;
	args[1] = arg1s;
	args[2] = arg2s;
	return 0;
	}

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