/*	$OpenBSD: util.c,v 1.18 2003/07/25 02:12:45 millert Exp $	*/

#ifndef lint
static const char     rcsid[] = "$OpenBSD: util.c,v 1.18 2003/07/25 02:12:45 millert Exp $";
#endif /* not lint */

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

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

#include "EXTERN.h"
#include "common.h"
#include "INTERN.h"
#include "util.h"
#include "backupfile.h"


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

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

	/* 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(char *orig)
{
	char	bakname[MAXPATHLEN], *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(*s); s++)
			;
		if (*s)
			*s = toupper(*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(char *from, char *to)
{
	int	tofd, fromfd, 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(char *s)
{
	char	*rv, *t;

	if (!s)
		s = "Oops";
	t = s;
	while (*t++)
		;
	rv = malloc((size_t) (t - s));
	if (rv == NULL) {
		if (using_plan_a)
			out_of_mem = TRUE;
		else
			fatal("out of memory\n");
	} else {
		t = rv;
		while ((*t++ = *s++))
			;
	}
	return rv;
}

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

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

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

	va_start(ap, fmt);
	fprintf(stderr, "patch: **** ");
	vfprintf(stderr, fmt, ap);
	va_end(ap);
	my_exit(1);
}

/*
 * Say something from patch, something from the system, then silence . . .
 */
void
pfatal(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(1);
}

/*
 * Get a response from the user, somehow or other.
 */
void
ask(char *fmt, ...)
{
	va_list	ap;
	int	ttyfd, r;
	bool	tty2 = isatty(2);

	va_start(ap, fmt);
	vsnprintf(buf, sizeof buf, fmt, ap);
	va_end(ap);
	fflush(stderr);
	write(2, buf, strlen(buf));
	if (tty2) {
		/* might be redirected to a file */
		r = read(2, buf, sizeof buf);
	} else if (isatty(1)) {	/* this may be new file output */
		fflush(stdout);
		write(1, buf, strlen(buf));
		r = read(1, buf, sizeof buf);
	} else if ((ttyfd = open(_PATH_TTY, O_RDWR)) >= 0 && isatty(ttyfd)) {
		/* might be deleted or unwriteable */
		write(ttyfd, buf, strlen(buf));
		r = read(ttyfd, buf, sizeof buf);
		close(ttyfd);
	} else if (isatty(0)) {	/* this is probably patch input */
		fflush(stdin);
		write(0, buf, strlen(buf));
		r = read(0, buf, sizeof buf);
	} else {		/* no terminal at all--default it */
		buf[0] = '\n';
		r = 1;
	}
	if (r <= 0)
		buf[0] = 0;
	else
		buf[r] = '\0';
	if (!tty2)
		say(buf);
}

/*
 * 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(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)
			return;	/* nothing to be done */
		*s = '\0';
	}
	strlcpy(buf, "/bin/mkdir -p ", sizeof buf);
	if (strlcat(buf, tmpbuf, sizeof(buf)) >= sizeof(buf))
		fatal("buffer too small to hold %.20s...\n", tmpbuf);

	if (system(buf))
		pfatal("%.40s failed", buf);
}

/*
 * Make filenames more reasonable.
 */
char *
fetchname(char *at, int strip_leading, int assume_exists)
{
	char	*fullname, *name, *t, tmpbuf[200];
	int	sleading = strip_leading;

	if (!at || *at == '\0')
		return NULL;
	while (isspace(*at))
		at++;
#ifdef DEBUGGING
	if (debug & 128)
		say("fetchname %s %d %d\n", at, strip_leading, assume_exists);
#endif
	if (strnEQ(at, "/dev/null", 9))	/* so files can be created by diffing */
		return NULL;	/* against /dev/null. */
	name = fullname = t = savestr(at);

	/* Strip off up to `sleading' leading slashes and null terminate.  */
	for (; *t && !isspace(*t); t++)
		if (*t == '/')
			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);

	if (stat(name, &filestat) && !assume_exists) {
		char	*filebase = basename(name);
		char	*filedir = dirname(name);

#define try(f, a1, a2, a3) \
	(snprintf(tmpbuf, sizeof tmpbuf, f, a1, a2, a3), stat(tmpbuf, &filestat) == 0)

		if (try("%s/RCS/%s%s", filedir, filebase, RCSSUFFIX) ||
		    try("%s/RCS/%s%s", filedir, filebase, "") ||
		    try("%s/%s%s", filedir, filebase, RCSSUFFIX) ||
		    try("%s/SCCS/%s%s", filedir, SCCSPREFIX, filebase) ||
		    try("%s/%s%s", filedir, SCCSPREFIX, filebase))
			return name;
		free(name);
		name = NULL;
	}
	return name;
}

void
version(void)
{
	fprintf(stderr, "Patch version 2.0-12u8-OpenBSD\n");
	my_exit(0);
}

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