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rcsid[] and sccsid[] and copyright[] are essentially unmaintained (and
unmaintainable).  these days, people use source.  these id's do not provide
any benefit, and do hurt the small install media
(the 33,000 line diff is essentially mechanical)
ok with the idea millert, ok dms

/*	$OpenBSD: inp.c,v 1.35 2009/10/27 23:59:41 deraadt 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/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mman.h>

#include <ctype.h>
#include <libgen.h>
#include <limits.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "common.h"
#include "util.h"
#include "pch.h"
#include "inp.h"


/* Input-file-with-indexable-lines abstract type */

static off_t	i_size;		/* size of the input file */
static char	*i_womp;	/* plan a buffer for entire file */
static char	**i_ptr;	/* pointers to lines in i_womp */

static int	tifd = -1;	/* plan b virtual string array */
static char	*tibuf[2];	/* plan b buffers */
static LINENUM	tiline[2] = {-1, -1};	/* 1st line in each buffer */
static LINENUM	lines_per_buf;	/* how many lines per buffer */
static int	tireclen;	/* length of records in tmp file */

static bool	rev_in_string(const char *);
static bool	reallocate_lines(size_t *);

/* returns false if insufficient memory */
static bool	plan_a(const char *);

static void	plan_b(const char *);

/* New patch--prepare to edit another file. */

void
re_input(void)
{
	if (using_plan_a) {
		i_size = 0;
		free(i_ptr);
		i_ptr = NULL;
		if (i_womp != NULL) {
			munmap(i_womp, i_size);
			i_womp = NULL;
		}
	} else {
		using_plan_a = true;	/* maybe the next one is smaller */
		close(tifd);
		tifd = -1;
		free(tibuf[0]);
		free(tibuf[1]);
		tibuf[0] = tibuf[1] = NULL;
		tiline[0] = tiline[1] = -1;
		tireclen = 0;
	}
}

/* Construct the line index, somehow or other. */

void
scan_input(const char *filename)
{
	if (!plan_a(filename))
		plan_b(filename);
	if (verbose) {
		say("Patching file %s using Plan %s...\n", filename,
		    (using_plan_a ? "A" : "B"));
	}
}

static bool
reallocate_lines(size_t *lines_allocated)
{
	char	**p;
	size_t	new_size;

	new_size = *lines_allocated * 3 / 2;
	p = realloc(i_ptr, (new_size + 2) * sizeof(char *));
	if (p == NULL) {	/* shucks, it was a near thing */
		munmap(i_womp, i_size);
		i_womp = NULL;
		free(i_ptr);
		i_ptr = NULL;
		*lines_allocated = 0;
		return false;
	}
	*lines_allocated = new_size;
	i_ptr = p;
	return true;
}

/* Try keeping everything in memory. */

static bool
plan_a(const char *filename)
{
	int		ifd, statfailed;
	char		*p, *s, lbuf[MAXLINELEN];
	struct stat	filestat;
	off_t		i;
	ptrdiff_t	sz;
	size_t		iline, lines_allocated;

#ifdef DEBUGGING
	if (debug & 8)
		return false;
#endif

	if (filename == NULL || *filename == '\0')
		return false;

	statfailed = stat(filename, &filestat);
	if (statfailed && ok_to_create_file) {
		if (verbose)
			say("(Creating file %s...)\n", filename);

		/*
		 * in check_patch case, we still display `Creating file' even
		 * though we're not. The rule is that -C should be as similar
		 * to normal patch behavior as possible
		 */
		if (check_only)
			return true;
		makedirs(filename, true);
		close(creat(filename, 0666));
		statfailed = stat(filename, &filestat);
	}
	if (statfailed && check_only)
		fatal("%s not found, -C mode, can't probe further\n", filename);
	/* For nonexistent or read-only files, look for RCS or SCCS versions.  */
	if (statfailed ||
	    /* No one can write to it.  */
	    (filestat.st_mode & 0222) == 0 ||
	    /* I can't write to it.  */
	    ((filestat.st_mode & 0022) == 0 && filestat.st_uid != getuid())) {
		char	*cs = NULL, *filebase, *filedir;
		struct stat	cstat;

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

		/* Leave room in lbuf for the diff command.  */
		s = lbuf + 20;

#define try(f, a1, a2, a3) \
	(snprintf(s, sizeof lbuf - 20, f, a1, a2, a3), stat(s, &cstat) == 0)

		if (try("%s/RCS/%s%s", filedir, filebase, RCSSUFFIX) ||
		    try("%s/RCS/%s%s", filedir, filebase, "") ||
		    try("%s/%s%s", filedir, filebase, RCSSUFFIX)) {
			snprintf(buf, sizeof buf, CHECKOUT, filename);
			snprintf(lbuf, sizeof lbuf, RCSDIFF, filename);
			cs = "RCS";
		} else if (try("%s/SCCS/%s%s", filedir, SCCSPREFIX, filebase) ||
		    try("%s/%s%s", filedir, SCCSPREFIX, filebase)) {
			snprintf(buf, sizeof buf, GET, s);
			snprintf(lbuf, sizeof lbuf, SCCSDIFF, s, filename);
			cs = "SCCS";
		} else if (statfailed)
			fatal("can't find %s\n", filename);
		/*
		 * else we can't write to it but it's not under a version
		 * control system, so just proceed.
		 */
		if (cs) {
			if (!statfailed) {
				if ((filestat.st_mode & 0222) != 0)
					/* The owner can write to it.  */
					fatal("file %s seems to be locked "
					    "by somebody else under %s\n",
					    filename, cs);
				/*
				 * It might be checked out unlocked.  See if
				 * it's safe to check out the default version
				 * locked.
				 */
				if (verbose)
					say("Comparing file %s to default "
					    "%s version...\n",
					    filename, cs);
				if (system(lbuf))
					fatal("can't check out file %s: "
					    "differs from default %s version\n",
					    filename, cs);
			}
			if (verbose)
				say("Checking out file %s from %s...\n",
				    filename, cs);
			if (system(buf) || stat(filename, &filestat))
				fatal("can't check out file %s from %s\n",
				    filename, cs);
		}
	}
	filemode = filestat.st_mode;
	if (!S_ISREG(filemode))
		fatal("%s is not a normal file--can't patch\n", filename);
	i_size = filestat.st_size;
	if (out_of_mem) {
		set_hunkmax();	/* make sure dynamic arrays are allocated */
		out_of_mem = false;
		return false;	/* force plan b because plan a bombed */
	}
	if (i_size > SIZE_MAX) {
		say("block too large to mmap\n");
		return false;
	}
	if ((ifd = open(filename, O_RDONLY)) < 0)
		pfatal("can't open file %s", filename);

	i_womp = mmap(NULL, i_size, PROT_READ, MAP_PRIVATE, ifd, 0);
	if (i_womp == MAP_FAILED) {
		perror("mmap failed");
		i_womp = NULL;
		close(ifd);
		return false;
	}

	close(ifd);
	if (i_size)
		madvise(i_womp, i_size, MADV_SEQUENTIAL);

	/* estimate the number of lines */
	lines_allocated = i_size / 25;
	if (lines_allocated < 100)
		lines_allocated = 100;

	if (!reallocate_lines(&lines_allocated))
		return false;

	/* now scan the buffer and build pointer array */
	iline = 1;
	i_ptr[iline] = i_womp;
	/* test for NUL too, to maintain the behavior of the original code */
	for (s = i_womp, i = 0; i < i_size && *s != '\0'; s++, i++) {
		if (*s == '\n') {
			if (iline == lines_allocated) {
				if (!reallocate_lines(&lines_allocated))
					return false;
			}
			/* these are NOT NUL terminated */
			i_ptr[++iline] = s + 1;
		}
	}
	/* if the last line contains no EOL, append one */
	if (i_size > 0 && i_womp[i_size - 1] != '\n') {
		last_line_missing_eol = true;
		/* fix last line */
		sz = s - i_ptr[iline];
		p = malloc(sz + 1);
		if (p == NULL) {
			free(i_ptr);
			i_ptr = NULL;
			munmap(i_womp, i_size);
			i_womp = NULL;
			return false;
		}

		memcpy(p, i_ptr[iline], sz);
		p[sz] = '\n';
		i_ptr[iline] = p;
		/* count the extra line and make it point to some valid mem */
		i_ptr[++iline] = "";
	} else
		last_line_missing_eol = false;

	input_lines = iline - 1;

	/* now check for revision, if any */

	if (revision != NULL) {
		if (!rev_in_string(i_womp)) {
			if (force) {
				if (verbose)
					say("Warning: this file doesn't appear "
					    "to be the %s version--patching anyway.\n",
					    revision);
			} else if (batch) {
				fatal("this file doesn't appear to be the "
				    "%s version--aborting.\n",
				    revision);
			} else {
				ask("This file doesn't appear to be the "
				    "%s version--patch anyway? [n] ",
				    revision);
				if (*buf != 'y')
					fatal("aborted\n");
			}
		} else if (verbose)
			say("Good.  This file appears to be the %s version.\n",
			    revision);
	}
	return true;		/* plan a will work */
}

/* Keep (virtually) nothing in memory. */

static void
plan_b(const char *filename)
{
	FILE	*ifp;
	size_t	i = 0, j, maxlen = 1;
	char	*p;
	bool	found_revision = (revision == NULL);

	using_plan_a = false;
	if ((ifp = fopen(filename, "r")) == NULL)
		pfatal("can't open file %s", filename);
	(void) unlink(TMPINNAME);
	if ((tifd = open(TMPINNAME, O_EXCL | O_CREAT | O_WRONLY, 0666)) < 0)
		pfatal("can't open file %s", TMPINNAME);
	while (fgets(buf, sizeof buf, ifp) != NULL) {
		if (revision != NULL && !found_revision && rev_in_string(buf))
			found_revision = true;
		if ((i = strlen(buf)) > maxlen)
			maxlen = i;	/* find longest line */
	}
	last_line_missing_eol = i > 0 && buf[i - 1] != '\n';
	if (last_line_missing_eol && maxlen == i)
		maxlen++;

	if (revision != NULL) {
		if (!found_revision) {
			if (force) {
				if (verbose)
					say("Warning: this file doesn't appear "
					    "to be the %s version--patching anyway.\n",
					    revision);
			} else if (batch) {
				fatal("this file doesn't appear to be the "
				    "%s version--aborting.\n",
				    revision);
			} else {
				ask("This file doesn't appear to be the %s "
				    "version--patch anyway? [n] ",
				    revision);
				if (*buf != 'y')
					fatal("aborted\n");
			}
		} else if (verbose)
			say("Good.  This file appears to be the %s version.\n",
			    revision);
	}
	fseek(ifp, 0L, SEEK_SET);	/* rewind file */
	lines_per_buf = BUFFERSIZE / maxlen;
	tireclen = maxlen;
	tibuf[0] = malloc(BUFFERSIZE + 1);
	if (tibuf[0] == NULL)
		fatal("out of memory\n");
	tibuf[1] = malloc(BUFFERSIZE + 1);
	if (tibuf[1] == NULL)
		fatal("out of memory\n");
	for (i = 1;; i++) {
		p = tibuf[0] + maxlen * (i % lines_per_buf);
		if (i % lines_per_buf == 0)	/* new block */
			if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
				pfatal("can't write temp file");
		if (fgets(p, maxlen + 1, ifp) == NULL) {
			input_lines = i - 1;
			if (i % lines_per_buf != 0)
				if (write(tifd, tibuf[0], BUFFERSIZE) < BUFFERSIZE)
					pfatal("can't write temp file");
			break;
		}
		j = strlen(p);
		/* These are '\n' terminated strings, so no need to add a NUL */
		if (j == 0 || p[j - 1] != '\n')
			p[j] = '\n';
	}
	fclose(ifp);
	close(tifd);
	if ((tifd = open(TMPINNAME, O_RDONLY)) < 0)
		pfatal("can't reopen file %s", TMPINNAME);
}

/*
 * Fetch a line from the input file, \n terminated, not necessarily \0.
 */
char *
ifetch(LINENUM line, int whichbuf)
{
	if (line < 1 || line > input_lines) {
		if (warn_on_invalid_line) {
			say("No such line %ld in input file, ignoring\n", line);
			warn_on_invalid_line = false;
		}
		return NULL;
	}
	if (using_plan_a)
		return i_ptr[line];
	else {
		LINENUM	offline = line % lines_per_buf;
		LINENUM	baseline = line - offline;

		if (tiline[0] == baseline)
			whichbuf = 0;
		else if (tiline[1] == baseline)
			whichbuf = 1;
		else {
			tiline[whichbuf] = baseline;

			if (lseek(tifd, (off_t) (baseline / lines_per_buf *
			    BUFFERSIZE), SEEK_SET) < 0)
				pfatal("cannot seek in the temporary input file");

			if (read(tifd, tibuf[whichbuf], BUFFERSIZE) < 0)
				pfatal("error reading tmp file %s", TMPINNAME);
		}
		return tibuf[whichbuf] + (tireclen * offline);
	}
}

/*
 * True if the string argument contains the revision number we want.
 */
static bool
rev_in_string(const char *string)
{
	const char	*s;
	size_t		patlen;

	if (revision == NULL)
		return true;
	patlen = strlen(revision);
	if (strnEQ(string, revision, patlen) && isspace(string[patlen]))
		return true;
	for (s = string; *s; s++) {
		if (isspace(*s) && strnEQ(s + 1, revision, patlen) &&
		    isspace(s[patlen + 1])) {
			return true;
		}
	}
	return false;
}