patch.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

/* patch - a program to apply diffs to original files */

/* $Id: patch.c,v 1.23 1997/07/05 10:32:23 eggert Exp $ */

/*
Copyright 1984, 1985, 1986, 1987, 1988 Larry Wall
Copyright 1989, 1990, 1991, 1992, 1993, 1997 Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; see the file COPYING.
If not, write to the Free Software Foundation,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#define XTERN
#include <common.h>
#undef XTERN
#define XTERN extern
#include <argmatch.h>
#include <backupfile.h>
#include <getopt.h>
#include <inp.h>
#include <pch.h>
#include <util.h>
#include <version.h>

#if HAVE_UTIME_H
# include <utime.h>
#endif
/* Some nonstandard hosts don't declare this structure even in <utime.h>.  */
#if ! HAVE_STRUCT_UTIMBUF
struct utimbuf
{
  time_t actime;
  time_t modtime;
};
#endif

/* Output stream state.  */
struct outstate
{
  FILE *ofp;
  int after_newline;
  int zero_output;
};

/* procedures */

static FILE *create_output_file PARAMS ((char const *));
static LINENUM locate_hunk PARAMS ((LINENUM));
static bool apply_hunk PARAMS ((struct outstate *, LINENUM));
static bool copy_till PARAMS ((struct outstate *, LINENUM));
static bool patch_match PARAMS ((LINENUM, LINENUM, LINENUM, LINENUM));
static bool similar PARAMS ((char const *, size_t, char const *, size_t));
static bool spew_output PARAMS ((struct outstate *));
static char const *make_temp PARAMS ((int));
static int numeric_string PARAMS ((char const *, int, char const *));
static void abort_hunk PARAMS ((void));
static void cleanup PARAMS ((void));
static void get_some_switches PARAMS ((void));
static void init_output PARAMS ((char const *, struct outstate *));
static void init_reject PARAMS ((char const *));
static void reinitialize_almost_everything PARAMS ((void));
static void usage PARAMS ((FILE *, int)) __attribute__((noreturn));

static int make_backups;
static int backup_if_mismatch;
static char const *version_control;
static int remove_empty_files;

/* TRUE if -R was specified on command line.  */
static int reverse_flag_specified;

/* how many input lines have been irretractably output */
static LINENUM last_frozen_line;

static char const *do_defines; /* symbol to patch using ifdef, ifndef, etc. */
static char const if_defined[] = "\n#ifdef %s\n";
static char const not_defined[] = "#ifndef %s\n";
static char const else_defined[] = "\n#else\n";
static char const end_defined[] = "\n#endif /* %s */\n";

static int Argc;
static char * const *Argv;

static FILE *rejfp;  /* reject file pointer */

static char const *patchname;
static char *rejname;
static char const * volatile TMPREJNAME;

static LINENUM last_offset;
static LINENUM maxfuzz = 2;

static char serrbuf[BUFSIZ];

char const program_name[] = "patch";

/* Apply a set of diffs as appropriate. */

int main PARAMS ((int, char **));

int
main(argc,argv)
int argc;
char **argv;
{
    char const *val;
    bool somefailed = FALSE;
    struct outstate outstate;

    init_time ();

    setbuf(stderr, serrbuf);

    bufsize = 8 * 1024;
    buf = xmalloc (bufsize);

    strippath = INT_MAX;

    posixly_correct = getenv ("POSIXLY_CORRECT") != 0;
    backup_if_mismatch = ! posixly_correct;
    patch_get = ((val = getenv ("PATCH_GET"))
		 ? numeric_string (val, 1, "PATCH_GET value")
		 : posixly_correct - 1);

    {
      char const *v = getenv ("SIMPLE_BACKUP_SUFFIX");
      if (v && *v)
	simple_backup_suffix = v;
    }

    version_control = getenv ("PATCH_VERSION_CONTROL");
    if (! version_control)
      version_control = getenv ("VERSION_CONTROL");

    /* Cons up the names of the global temporary files.
       Do this before `cleanup' can possibly be called (e.g. by `pfatal').  */
    TMPOUTNAME = make_temp ('o');
    TMPINNAME = make_temp ('i');
    TMPREJNAME = make_temp ('r');
    TMPPATNAME = make_temp ('p');

    /* parse switches */
    Argc = argc;
    Argv = argv;
    get_some_switches();

    if (make_backups | backup_if_mismatch)
      backup_type = get_version (version_control);

    init_output (outfile, &outstate);

    /* Make sure we clean up in case of disaster.  */
    set_signals(0);

    for (
	open_patch_file (patchname);
	there_is_another_patch();
	reinitialize_almost_everything()
    ) {					/* for each patch in patch file */
      int hunk = 0;
      int failed = 0;
      int mismatch = 0;
      char *outname = outfile ? outfile : inname;

      if (!skip_rest_of_patch)
	get_input_file (inname, outname);

      if (diff_type == ED_DIFF) {
	outstate.zero_output = 0;
	if (! dry_run)
	  {
	    do_ed_script (outstate.ofp);
	    if (! outfile)
	      {
		struct stat statbuf;
		if (stat (TMPOUTNAME, &statbuf) != 0)
		  pfatal ("%s", TMPOUTNAME);
		outstate.zero_output = statbuf.st_size == 0;
	      }
	  }
      } else {
	int got_hunk;
	int apply_anyway = 0;

	/* initialize the patched file */
	if (! skip_rest_of_patch && ! outfile)
	  init_output (TMPOUTNAME, &outstate);

	/* initialize reject file */
	init_reject(TMPREJNAME);

	/* find out where all the lines are */
	if (!skip_rest_of_patch)
	    scan_input (inname);

	/* from here on, open no standard i/o files, because malloc */
	/* might misfire and we can't catch it easily */

	/* apply each hunk of patch */
	while (0 < (got_hunk = another_hunk (diff_type, reverse))) {
	    LINENUM where = 0; /* Pacify `gcc -Wall'.  */
	    LINENUM newwhere;
	    LINENUM fuzz = 0;
	    LINENUM prefix_context = pch_prefix_context ();
	    LINENUM suffix_context = pch_suffix_context ();
	    LINENUM context = (prefix_context < suffix_context
			       ? suffix_context : prefix_context);
	    LINENUM mymaxfuzz = (maxfuzz < context ? maxfuzz : context);
	    hunk++;
	    if (!skip_rest_of_patch) {
		do {
		    where = locate_hunk(fuzz);
		    if (! where || fuzz || last_offset)
		      mismatch = 1;
		    if (hunk == 1 && ! where && ! (force | apply_anyway)
			&& reverse == reverse_flag_specified) {
						/* dwim for reversed patch? */
			if (!pch_swap()) {
			    say (
"Not enough memory to try swapped hunk!  Assuming unswapped.\n");
			    continue;
			}
			/* Try again.  */
			where = locate_hunk (fuzz);
			if (where
			    && (ok_to_reverse
				("%s patch detected!",
				 (reverse
				  ? "Unreversed"
				  : "Reversed (or previously applied)"))))
			  reverse ^= 1;
			else
			  {
			    /* Put it back to normal.  */
			    if (! pch_swap ())
			      fatal ("lost hunk on alloc error!");
			    if (where)
			      {
				apply_anyway = 1;
				fuzz--; /* Undo `++fuzz' below.  */
				where = 0;
			      }
			  }
		    }
		} while (!skip_rest_of_patch && !where
			 && ++fuzz <= mymaxfuzz);

		if (skip_rest_of_patch) {		/* just got decided */
		  if (outstate.ofp && ! outfile)
		    {
		      fclose (outstate.ofp);
		      outstate.ofp = 0;
		    }
		}
	    }

	    newwhere = pch_newfirst() + last_offset;
	    if (skip_rest_of_patch) {
		abort_hunk();
		failed++;
		if (verbosity == VERBOSE)
		    say ("Hunk #%d ignored at %ld.\n", hunk, newwhere);
	    }
	    else if (!where
		     || (where == 1 && pch_says_nonexistent (reverse)
			 && instat.st_size)) {
		if (where)
		  say ("Patch attempted to create file `%s', which already exists.\n", inname);
		abort_hunk();
		failed++;
		if (verbosity != SILENT)
		    say ("Hunk #%d FAILED at %ld.\n", hunk, newwhere);
	    }
	    else if (! apply_hunk (&outstate, where)) {
		abort_hunk ();
		failed++;
		if (verbosity != SILENT)
		    say ("Hunk #%d FAILED at %ld.\n", hunk, newwhere);
	    } else {
		if (verbosity == VERBOSE
		    || (verbosity != SILENT && (fuzz || last_offset))) {
		    say ("Hunk #%d succeeded at %ld", hunk, newwhere);
		    if (fuzz)
			say (" with fuzz %ld", fuzz);
		    if (last_offset)
			say (" (offset %ld line%s)",
			    last_offset, last_offset==1?"":"s");
		    say (".\n");
		}
	    }
	}

	if (got_hunk < 0  &&  using_plan_a) {
	    if (outfile)
	      fatal ("out of memory using Plan A");
	    say ("\n\nRan out of memory using Plan A -- trying again...\n\n");
	    if (outstate.ofp)
	      {
		fclose (outstate.ofp);
		outstate.ofp = 0;
	      }
	    fclose (rejfp);
	    continue;
	}

	/* finish spewing out the new file */
	if (!skip_rest_of_patch)
	  {
	    assert (hunk);
	    if (! spew_output (&outstate))
	      {
		say ("Skipping patch.\n");
		skip_rest_of_patch = TRUE;
	      }
	  }
      }

      /* and put the output where desired */
      ignore_signals ();
      if (! skip_rest_of_patch && ! outfile) {
	  if (outstate.zero_output
	      && (remove_empty_files
		  || (pch_says_nonexistent (reverse ^ 1) == 2
		      && ! posixly_correct)))
	    {
	      if (verbosity == VERBOSE)
		say ("Removing file `%s'%s.\n", outname,
		     dry_run ? " and any empty ancestor directories" : "");
	      if (! dry_run)
		{
		  move_file ((char *) 0, outname, (mode_t) 0,
			     (make_backups
			      || (backup_if_mismatch && (mismatch | failed))));
		  removedirs (outname);
		}
	    }
	  else
	    {
	      if (! outstate.zero_output
		  && pch_says_nonexistent (reverse ^ 1))
		{
		  mismatch = 1;
		  if (verbosity != SILENT)
		    say ("File `%s' is not empty after patch, as expected.\n",
			 outname);
		}

	      if (! dry_run)
		{
		  time_t t;

		  move_file (TMPOUTNAME, outname, instat.st_mode,
			     (make_backups
			      || (backup_if_mismatch && (mismatch | failed))));

		  if ((set_time | set_utc)
		      && (t = pch_timestamp (reverse ^ 1)) != (time_t) -1)
		    {
		      struct utimbuf utimbuf;
		      utimbuf.actime = utimbuf.modtime = t;

		      if (! force && ! inerrno
			  && ! pch_says_nonexistent (reverse)
			  && (t = pch_timestamp (reverse)) != (time_t) -1
			  && t != instat.st_mtime)
			say ("not setting time of file `%s' (time mismatch)\n",
			     outname);
		      else if (! force && (mismatch | failed))
			say ("not setting time of file `%s' (contents mismatch)\n",
			     outname);
		      else if (utime (outname, &utimbuf) != 0)
			pfatal ("can't set timestamp on file `%s'", outname);
		    }

		  if (! inerrno && chmod (outname, instat.st_mode) != 0)
		    pfatal ("can't set permissions on file `%s'", outname);
		}
	    }
      }
      if (diff_type != ED_DIFF) {
	if (fclose (rejfp) != 0)
	    write_fatal ();
	if (failed) {
	    somefailed = TRUE;
	    say ("%d out of %d hunk%s %s", failed, hunk, "s" + (hunk == 1),
		 skip_rest_of_patch ? "ignored" : "FAILED");
	    if (outname) {
		char *rej = rejname;
		if (!rejname) {
		    rej = xmalloc (strlen (outname) + 5);
		    strcpy (rej, outname);
		    addext (rej, ".rej", '#');
		}
		say (" -- saving rejects to %s", rej);
		if (! dry_run)
		  {
		    move_file (TMPREJNAME, rej, instat.st_mode, FALSE);
		    if (! inerrno
			&& (chmod (rej, (instat.st_mode
					 & ~(S_IXUSR|S_IXGRP|S_IXOTH)))
			    != 0))
		      pfatal ("can't set permissions on file `%s'", rej);
		  }
		if (!rejname)
		    free (rej);
	    }
	    say ("\n");
	}
      }
      set_signals (1);
    }
    if (outstate.ofp && (ferror (outstate.ofp) || fclose (outstate.ofp) != 0))
      write_fatal ();
    cleanup ();
    if (somefailed)
      exit (1);
    return 0;
}

/* Prepare to find the next patch to do in the patch file. */

static void
reinitialize_almost_everything()