/*
* $OpenBSD: util.c,v 1.32 2006/03/11 19:41:30 otto Exp $
* $DragonFly: src/usr.bin/patch/util.c,v 1.9 2007/09/29 23:11:10 swildner Exp $
* $NetBSD: util.c,v 1.30 2021/05/25 11:25:59 cjep 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/cdefs.h>
__RCSID("$NetBSD: util.c,v 1.30 2021/05/25 11:25:59 cjep Exp $");

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

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.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, bufsz)) > 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[MAXPATHLEN], *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, bufsz)) > 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;
}

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

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

/*
* 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, bufsz)) > 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))
               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;
}

/*
* Takes the name returned by fetchname and looks in RCS/SCCS directories
* for a checked in version.
*/
char *
checked_in(char *file)
{
       char            *filebase, *filedir, tmpbuf[MAXPATHLEN];
       struct stat     filestat;

       filebase = basename(file);
       filedir = dirname(file);

#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 file;

       return NULL;
}

void
version(void)
{
       printf("Patch version 2.0-12u9-NetBSD\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);
}

void *
pch_realloc(void *ptr, size_t number, size_t size)
{
       if (number > SIZE_MAX / size) {
               errno = EOVERFLOW;
               return NULL;
       }
       return realloc(ptr, number * size);
}