/*	$OpenBSD: util.c,v 1.40 2015/07/26 14:32:19 millert Exp $	*/

/*
 * patch - a program to apply diffs to original files
 * 
 * Copyright 1986, Larry Wall
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following condition is met:
 * 1. Redistributions of source code must retain the above copyright notice,
 * this condition and the following disclaimer.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 * 
 * -C option added in 1998, original code by Marc Espie, based on FreeBSD
 * behaviour
 */

#include <sys/stat.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "util.h"
#include "backupfile.h"
#include "pathnames.h"

/* Rename a file, copying it if necessary. */

int
move_file(const char *from, const char *to)
{
	int	fromfd;
	ssize_t	i;

	/* to stdout? */

	if (strEQ(to, "-")) {
#ifdef DEBUGGING
		if (debug & 4)
			say("Moving %s to stdout.\n", from);
#endif
		fromfd = open(from, O_RDONLY);
		if (fromfd < 0)
			pfatal("internal error, can't reopen %s", from);
		while ((i = read(fromfd, buf, sizeof buf)) > 0)
			if (write(STDOUT_FILENO, buf, i) != i)
				pfatal("write failed");
		close(fromfd);
		return 0;
	}
	if (backup_file(to) < 0) {
		say("Can't backup %s, output is in %s: %s\n", to, from,
		    strerror(errno));
		return -1;
	}
#ifdef DEBUGGING
	if (debug & 4)
		say("Moving %s to %s.\n", from, to);
#endif
	if (rename(from, to) < 0) {
		if (errno != EXDEV || copy_file(from, to) < 0) {
			say("Can't create %s, output is in %s: %s\n",
			    to, from, strerror(errno));
			return -1;
		}
	}
	return 0;
}

/* Backup the original file.  */

int
backup_file(const char *orig)
{
	struct stat	filestat;
	char		bakname[PATH_MAX], *s, *simplename;
	dev_t		orig_device;
	ino_t		orig_inode;

	if (backup_type == none || stat(orig, &filestat) != 0)
		return 0;			/* nothing to do */
	orig_device = filestat.st_dev;
	orig_inode = filestat.st_ino;

	if (origprae) {
		if (strlcpy(bakname, origprae, sizeof(bakname)) >= sizeof(bakname) ||
		    strlcat(bakname, orig, sizeof(bakname)) >= sizeof(bakname))
			fatal("filename %s too long for buffer\n", origprae);
	} else {
		if ((s = find_backup_file_name(orig)) == NULL)
			fatal("out of memory\n");
		if (strlcpy(bakname, s, sizeof(bakname)) >= sizeof(bakname))
			fatal("filename %s too long for buffer\n", s);
		free(s);
	}

	if ((simplename = strrchr(bakname, '/')) != NULL)
		simplename = simplename + 1;
	else
		simplename = bakname;

	/*
	 * Find a backup name that is not the same file. Change the
	 * first lowercase char into uppercase; if that isn't
	 * sufficient, chop off the first char and try again.
	 */
	while (stat(bakname, &filestat) == 0 &&
	    orig_device == filestat.st_dev && orig_inode == filestat.st_ino) {
		/* Skip initial non-lowercase chars.  */
		for (s = simplename; *s && !islower((unsigned char)*s); s++)
			;
		if (*s)
			*s = toupper((unsigned char)*s);
		else
			memmove(simplename, simplename + 1,
			    strlen(simplename + 1) + 1);
	}
#ifdef DEBUGGING
	if (debug & 4)
		say("Moving %s to %s.\n", orig, bakname);
#endif
	if (rename(orig, bakname) < 0) {
		if (errno != EXDEV || copy_file(orig, bakname) < 0)
			return -1;
	}
	return 0;
}

/*
 * Copy a file.
 */
int
copy_file(const char *from, const char *to)
{
	int	tofd, fromfd;
	ssize_t	i;

	tofd = open(to, O_CREAT|O_TRUNC|O_WRONLY, 0666);
	if (tofd < 0)
		return -1;
	fromfd = open(from, O_RDONLY, 0);
	if (fromfd < 0)
		pfatal("internal error, can't reopen %s", from);
	while ((i = read(fromfd, buf, sizeof buf)) > 0)
		if (write(tofd, buf, i) != i)
			pfatal("write to %s failed", to);
	close(fromfd);
	close(tofd);
	return 0;
}

/*
 * Allocate a unique area for a string.
 */
char *
savestr(const char *s)
{
	char	*rv;

	if (!s)
		s = "Oops";
	rv = strdup(s);
	if (rv == NULL) {
		if (using_plan_a)
			out_of_mem = true;
		else
			fatal("out of memory\n");
	}
	return rv;
}

/*
 * Allocate a unique area for a string.  Call fatal if out of memory.
 */
char *
xstrdup(const char *s)
{
	char	*rv;

	if (!s)
		s = "Oops";
	rv = strdup(s);
	if (rv == NULL)
		fatal("out of memory\n");
	return rv;
}

/*
 * Vanilla terminal output (buffered).
 */
void
say(const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	vfprintf(stdout, fmt, ap);
	va_end(ap);
	fflush(stdout);
}

/*
 * Terminal output, pun intended.
 */
void
fatal(const char *fmt, ...)
{
	va_list	ap;

	va_start(ap, fmt);
	fprintf(stderr, "patch: **** ");
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	my_exit(2);
}

/*
 * Say something from patch, something from the system, then silence . . .
 */
void
pfatal(const char *fmt, ...)
{
	va_list	ap;
	int	errnum = errno;

	fprintf(stderr, "patch: **** ");
	va_start(ap, fmt);
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	fprintf(stderr, ": %s\n", strerror(errnum));
	my_exit(2);
}

/*
 * Get a response from the user via /dev/tty
 */
void
ask(const char *fmt, ...)
{
	va_list	ap;
	ssize_t	nr;
	static	int ttyfd = -1;

	va_start(ap, fmt);
	vfprintf(stdout, fmt, ap);
	va_end(ap);
	fflush(stdout);
	if (ttyfd < 0)
		ttyfd = open(_PATH_TTY, O_RDONLY);
	if (ttyfd >= 0) {
		if ((nr = read(ttyfd, buf, sizeof(buf))) > 0 &&
		    buf[nr - 1] == '\n')
			buf[nr - 1] = '\0';
	}
	if (ttyfd < 0 || nr <= 0) {
		/* no tty or error reading, pretend user entered 'return' */
		putchar('\n');
		buf[0] = '\0';
	}
}

/*
 * How to handle certain events when not in a critical region.
 */
void
set_signals(int reset)
{
	static sig_t	hupval, intval;

	if (!reset) {
		hupval = signal(SIGHUP, SIG_IGN);
		if (hupval != SIG_IGN)
			hupval = (sig_t) my_exit;
		intval = signal(SIGINT, SIG_IGN);
		if (intval != SIG_IGN)
			intval = (sig_t) my_exit;
	}
	signal(SIGHUP, hupval);
	signal(SIGINT, intval);
}

/*
 * How to handle certain events when in a critical region.
 */
void
ignore_signals(void)
{
	signal(SIGHUP, SIG_IGN);
	signal(SIGINT, SIG_IGN);
}

/*
 * Make sure we'll have the directories to create a file. If `striplast' is
 * true, ignore the last element of `filename'.
 */

void
makedirs(const char *filename, bool striplast)
{
	char	*tmpbuf;

	if ((tmpbuf = strdup(filename)) == NULL)
		fatal("out of memory\n");

	if (striplast) {
		char	*s = strrchr(tmpbuf, '/');
		if (s == NULL) {
			free(tmpbuf);
			return;	/* nothing to be done */
		}
		*s = '\0';
	}
	if (mkpath(tmpbuf) != 0)
		pfatal("creation of %s failed", tmpbuf);
	free(tmpbuf);
}

/*
 * Make filenames more reasonable.
 */
char *
fetchname(const char *at, bool *exists, int strip_leading)
{
	char		*fullname, *name, *t;
	int		sleading, tab;
	struct stat	filestat;

	if (at == NULL || *at == '\0')
		return NULL;
	while (isspace((unsigned char)*at))
		at++;
#ifdef DEBUGGING
	if (debug & 128)
		say("fetchname %s %d\n", at, strip_leading);
#endif
	/* So files can be created by diffing against /dev/null.  */
	if (strnEQ(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
		return NULL;
	name = fullname = t = savestr(at);

	tab = strchr(t, '\t') != NULL;
	/* Strip off up to `strip_leading' path components and NUL terminate. */
	for (sleading = strip_leading; *t != '\0' && ((tab && *t != '\t') ||
	    !isspace((unsigned char)*t)); t++) {
		if (t[0] == '/' && t[1] != '/' && t[1] != '\0')
			if (--sleading >= 0)
				name = t + 1;
	}
	*t = '\0';

	/*
	 * If no -p option was given (957 is the default value!), we were
	 * given a relative pathname, and the leading directories that we
	 * just stripped off all exist, put them back on.
	 */
	if (strip_leading == 957 && name != fullname && *fullname != '/') {
		name[-1] = '\0';
		if (stat(fullname, &filestat) == 0 && S_ISDIR(filestat.st_mode)) {
			name[-1] = '/';
			name = fullname;
		}
	}
	name = savestr(name);
	free(fullname);

	*exists = stat(name, &filestat) == 0;
	return name;
}

void
version(void)
{
	fprintf(stderr, "Patch version 2.0-12u8-OpenBSD\n");
	my_exit(EXIT_SUCCESS);
}

/*
 * Exit with cleanup.
 */
void
my_exit(int status)
{
	unlink(TMPINNAME);
	if (!toutkeep)
		unlink(TMPOUTNAME);
	if (!trejkeep)
		unlink(TMPREJNAME);
	unlink(TMPPATNAME);
	exit(status);
}