/*
 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000-2002  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * 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.
 */

/*
 * Portions Copyright (c) 1987, 1993
 *      The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* $Id: file.c,v 1.51 2007/06/19 23:47:18 tbox Exp $ */

/*! \file */

#include <config.h>

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <time.h>		/* Required for utimes on some platforms. */
#include <unistd.h>		/* Required for mkstemp on NetBSD. */


#include <sys/stat.h>
#include <sys/time.h>

#include <isc/dir.h>
#include <isc/file.h>
#include <isc/random.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/util.h>

#include "errno2result.h"

/*
 * XXXDCL As the API for accessing file statistics undoubtedly gets expanded,
 * it might be good to provide a mechanism that allows for the results
 * of a previous stat() to be used again without having to do another stat,
 * such as perl's mechanism of using "_" in place of a file name to indicate
 * that the results of the last stat should be used.  But then you get into
 * annoying MP issues.   BTW, Win32 has stat().
 */
static isc_result_t
file_stats(const char *file, struct stat *stats) {
	isc_result_t result = ISC_R_SUCCESS;

	REQUIRE(file != NULL);
	REQUIRE(stats != NULL);

	if (stat(file, stats) != 0)
		result = isc__errno2result(errno);

	return (result);
}

isc_result_t
isc_file_getmodtime(const char *file, isc_time_t *time) {
	isc_result_t result;
	struct stat stats;

	REQUIRE(file != NULL);
	REQUIRE(time != NULL);

	result = file_stats(file, &stats);

	if (result == ISC_R_SUCCESS)
		/*
		 * XXXDCL some operating systems provide nanoseconds, too,
		 * such as BSD/OS via st_mtimespec.
		 */
		isc_time_set(time, stats.st_mtime, 0);

	return (result);
}

isc_result_t
isc_file_settime(const char *file, isc_time_t *time) {
	struct timeval times[2];

	REQUIRE(file != NULL && time != NULL);

	/*
	 * tv_sec is at least a 32 bit quantity on all platforms we're
	 * dealing with, but it is signed on most (all?) of them,
	 * so we need to make sure the high bit isn't set.  This unfortunately
	 * loses when either:
	 *   * tv_sec becomes a signed 64 bit integer but long is 32 bits
	 *	and isc_time_seconds > LONG_MAX, or
	 *   * isc_time_seconds is changed to be > 32 bits but long is 32 bits
	 *      and isc_time_seconds has at least 33 significant bits.
	 */
	times[0].tv_sec = times[1].tv_sec = (long)isc_time_seconds(time);

	/*
	 * Here is the real check for the high bit being set.
	 */
	if ((times[0].tv_sec &
	     (1ULL << (sizeof(times[0].tv_sec) * CHAR_BIT - 1))) != 0)
		return (ISC_R_RANGE);

	/*
	 * isc_time_nanoseconds guarantees a value that divided by 1000 will
	 * fit into the minimum possible size tv_usec field.  Unfortunately,
	 * we don't know what that type is so can't cast directly ... but
	 * we can at least cast to signed so the IRIX compiler shuts up.
	 */
	times[0].tv_usec = times[1].tv_usec =
		(isc_int32_t)(isc_time_nanoseconds(time) / 1000);

	if (utimes(file, times) < 0)
		return (isc__errno2result(errno));

	return (ISC_R_SUCCESS);
}

#undef TEMPLATE
#define TEMPLATE "tmp-XXXXXXXXXX" /*%< 14 characters. */

isc_result_t
isc_file_mktemplate(const char *path, char *buf, size_t buflen) {
	return (isc_file_template(path, TEMPLATE, buf, buflen));
}

isc_result_t
isc_file_template(const char *path, const char *templet, char *buf,
			size_t buflen) {
	char *s;

	REQUIRE(path != NULL);
	REQUIRE(templet != NULL);
	REQUIRE(buf != NULL);

	s = strrchr(templet, '/');
	if (s != NULL)
		templet = s + 1;

	s = strrchr(path, '/');

	if (s != NULL) {
		if ((s - path + 1 + strlen(templet) + 1) > buflen)
			return (ISC_R_NOSPACE);

		strncpy(buf, path, s - path + 1);
		buf[s - path + 1] = '\0';
		strcat(buf, templet);
	} else {
		if ((strlen(templet) + 1) > buflen)
			return (ISC_R_NOSPACE);

		strcpy(buf, templet);
	}

	return (ISC_R_SUCCESS);
}

static char alphnum[] =
	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

isc_result_t
isc_file_renameunique(const char *file, char *templet) {
	char *x;
	char *cp;
	isc_uint32_t which;

	REQUIRE(file != NULL);
	REQUIRE(templet != NULL);

	cp = templet;
	while (*cp != '\0')
		cp++;
	if (cp == templet)
		return (ISC_R_FAILURE);

	x = cp--;
	while (cp >= templet && *cp == 'X') {
		isc_random_get(&which);
		*cp = alphnum[which % (sizeof(alphnum) - 1)];
		x = cp--;
	}
	while (link(file, templet) == -1) {
		if (errno != EEXIST)
			return (isc__errno2result(errno));
		for (cp = x;;) {
			char *t;
			if (*cp == '\0')
				return (ISC_R_FAILURE);
			t = strchr(alphnum, *cp);
			if (t == NULL || *++t == '\0')
				*cp++ = alphnum[0];
			else {
				*cp = *t;
				break;
			}
		}
	}
	(void)unlink(file);
	return (ISC_R_SUCCESS);
}


isc_result_t
isc_file_openunique(char *templet, FILE **fp) {
	int fd;
	FILE *f;
	isc_result_t result = ISC_R_SUCCESS;
	char *x;
	char *cp;
	isc_uint32_t which;
	int mode;

	REQUIRE(templet != NULL);
	REQUIRE(fp != NULL && *fp == NULL);

	cp = templet;
	while (*cp != '\0')
		cp++;
	if (cp == templet)
		return (ISC_R_FAILURE);

	x = cp--;
	while (cp >= templet && *cp == 'X') {
		isc_random_get(&which);
		*cp = alphnum[which % (sizeof(alphnum) - 1)];
		x = cp--;
	}

	mode = S_IWUSR|S_IRUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;

	while ((fd = open(templet, O_RDWR|O_CREAT|O_EXCL, mode)) == -1) {
		if (errno != EEXIST)
			return (isc__errno2result(errno));
		for (cp = x;;) {
			char *t;
			if (*cp == '\0')
				return (ISC_R_FAILURE);
			t = strchr(alphnum, *cp);
			if (t == NULL || *++t == '\0')
				*cp++ = alphnum[0];
			else {
				*cp = *t;
				break;
			}
		}
	}
	f = fdopen(fd, "w+");
	if (f == NULL) {
		result = isc__errno2result(errno);
		(void)remove(templet);
		(void)close(fd);
	} else
		*fp = f;

	return (result);
}

isc_result_t
isc_file_remove(const char *filename) {
	int r;

	REQUIRE(filename != NULL);

	r = unlink(filename);
	if (r == 0)
		return (ISC_R_SUCCESS);
	else
		return (isc__errno2result(errno));
}

isc_result_t
isc_file_rename(const char *oldname, const char *newname) {
	int r;

	REQUIRE(oldname != NULL);
	REQUIRE(newname != NULL);

	r = rename(oldname, newname);
	if (r == 0)
		return (ISC_R_SUCCESS);
	else
		return (isc__errno2result(errno));
}

isc_boolean_t
isc_file_exists(const char *pathname) {
	struct stat stats;

	REQUIRE(pathname != NULL);

	return (ISC_TF(file_stats(pathname, &stats) == ISC_R_SUCCESS));
}

isc_boolean_t
isc_file_isabsolute(const char *filename) {
	REQUIRE(filename != NULL);
	return (ISC_TF(filename[0] == '/'));
}

isc_boolean_t
isc_file_iscurrentdir(const char *filename) {
	REQUIRE(filename != NULL);
	return (ISC_TF(filename[0] == '.' && filename[1] == '\0'));
}

isc_boolean_t
isc_file_ischdiridempotent(const char *filename) {
	REQUIRE(filename != NULL);
	if (isc_file_isabsolute(filename))
		return (ISC_TRUE);
	if (isc_file_iscurrentdir(filename))
		return (ISC_TRUE);
	return (ISC_FALSE);
}

const char *
isc_file_basename(const char *filename) {
	char *s;

	REQUIRE(filename != NULL);

	s = strrchr(filename, '/');
	if (s == NULL)
		return (filename);

	return (s + 1);
}

isc_result_t
isc_file_progname(const char *filename, char *buf, size_t buflen) {
	const char *base;
	size_t len;

	REQUIRE(filename != NULL);
	REQUIRE(buf != NULL);

	base = isc_file_basename(filename);
	len = strlen(base) + 1;

	if (len > buflen)
		return (ISC_R_NOSPACE);
	memcpy(buf, base, len);

	return (ISC_R_SUCCESS);
}

/*
 * Put the absolute name of the current directory into 'dirname', which is
 * a buffer of at least 'length' characters.  End the string with the 
 * appropriate path separator, such that the final product could be
 * concatenated with a relative pathname to make a valid pathname string.
 */
static isc_result_t
dir_current(char *dirname, size_t length) {
	char *cwd;
	isc_result_t result = ISC_R_SUCCESS;

	REQUIRE(dirname != NULL);
	REQUIRE(length > 0U);

	cwd = getcwd(dirname, length);

	if (cwd == NULL) {
		if (errno == ERANGE)
			result = ISC_R_NOSPACE;
		else
			result = isc__errno2result(errno);
	} else {
		if (strlen(dirname) + 1 == length)
			result = ISC_R_NOSPACE;
		else if (dirname[1] != '\0')
			strcat(dirname, "/");
	}

	return (result);
}

isc_result_t
isc_file_absolutepath(const char *filename, char *path, size_t pathlen) {
	isc_result_t result;
	result = dir_current(path, pathlen);
	if (result != ISC_R_SUCCESS)
		return (result);
	if (strlen(path) + strlen(filename) + 1 > pathlen)
		return (ISC_R_NOSPACE);
	strcat(path, filename);
	return (ISC_R_SUCCESS);
}

isc_result_t
isc_file_truncate(const char *filename, isc_offset_t size) {
	isc_result_t result = ISC_R_SUCCESS;

	if (truncate(filename, size) < 0) 
		result = isc__errno2result(errno);
	return (result);
}