/*-
 * 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.
 * 
 * patch - a program to apply diffs to original files
 *
 * -C option added in 1998, original code by Marc Espie, based on FreeBSD
 * behaviour
 *
 * $OpenBSD: util.c,v 1.35 2010/07/24 01:10:12 ray Exp $
 */

#include <sys/stat.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.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, buf_size)) > 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 */
        /*
         * If the user used zero prefixes or suffixes, then
         * he doesn't want backups.  Yet we have to remove
         * orig to break possible hardlinks.
         */
        if ((origprae && *origprae == 0) || *simple_backup_suffix == 0) {
                unlink(orig);
                return 0;
        }
        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, buf_size)) > 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 = 0;
        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, buf_size)) > 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 = my_exit;
                intval = signal(SIGINT, SIG_IGN);
                if (intval != SIG_IGN)
                        intval = 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)) {
                *exists = true;
                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)
{
        printf("patch 2.0-12u11 FreeBSD\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);
}