gnu/dist/diffutils/src/sdiff.c

   1 /*      $NetBSD: sdiff.c,v 1.1.1.1 2003/01/26 00:43:17 wiz Exp $        */
   2
   3 /* sdiff - side-by-side merge of file differences
   4
   5    Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 2001, 2002 Free
   6    Software Foundation, Inc.
   7
   8    This file is part of GNU DIFF.
   9
  10    GNU DIFF is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2, or (at your option)
  13    any later version.
  14
  15    GNU DIFF is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  18    See the GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; see the file COPYING.
  22    If not, write to the Free Software Foundation,
  23    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  24
  25 #include "system.h"
  26
  27 #include <c-stack.h>
  28 #include <dirname.h>
  29 #include <error.h>
  30 #include <exitfail.h>
  31 #include <freesoft.h>
  32 #include <getopt.h>
  33 #include <quotesys.h>
  34 #include <stdio.h>
  35 #include <xalloc.h>
  36
  37 static char const authorship_msgid[] = N_("Written by Thomas Lord.");
  38
  39 static char const copyright_string[] =
  40   "Copyright (C) 2002 Free Software Foundation, Inc.";
  41
  42 extern char const version_string[];
  43
  44 /* Size of chunks read from files which must be parsed into lines.  */
  45 #define SDIFF_BUFSIZE ((size_t) 65536)
  46
  47 char *program_name;
  48
  49 static char const *editor_program = DEFAULT_EDITOR_PROGRAM;
  50 static char const **diffargv;
  51
  52 static char * volatile tmpname;
  53 static FILE *tmp;
  54
  55 #if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
  56 static pid_t volatile diffpid;
  57 #endif
  58
  59 struct line_filter;
  60
  61 static RETSIGTYPE catchsig (int);
  62 static bool edit (struct line_filter *, char const *, lin, lin, struct line_filter *, char const *, lin, lin, FILE *);
  63 static bool interact (struct line_filter *, struct line_filter *, char const *, struct line_filter *, char const *, FILE *);
  64 static void checksigs (void);
  65 static void diffarg (char const *);
  66 static void fatal (char const *) __attribute__((noreturn));
  67 static void perror_fatal (char const *) __attribute__((noreturn));
  68 static void trapsigs (void);
  69 static void untrapsig (int);
  70
  71 #define NUM_SIGS (sizeof sigs / sizeof *sigs)
  72 static int const sigs[] = {
  73 #ifdef SIGHUP
  74        SIGHUP,
  75 #endif
  76 #ifdef SIGQUIT
  77        SIGQUIT,
  78 #endif
  79 #ifdef SIGTERM
  80        SIGTERM,
  81 #endif
  82 #ifdef SIGXCPU
  83        SIGXCPU,
  84 #endif
  85 #ifdef SIGXFSZ
  86        SIGXFSZ,
  87 #endif
  88        SIGINT,
  89        SIGPIPE
  90 };
  91 #define handler_index_of_SIGINT (NUM_SIGS - 2)
  92 #define handler_index_of_SIGPIPE (NUM_SIGS - 1)
  93
  94 #if HAVE_SIGACTION
  95   /* Prefer `sigaction' if available, since `signal' can lose signals.  */
  96   static struct sigaction initial_action[NUM_SIGS];
  97 # define initial_handler(i) (initial_action[i].sa_handler)
  98   static void signal_handler (int, RETSIGTYPE (*) (int));
  99 #else
 100   static RETSIGTYPE (*initial_action[NUM_SIGS]) ();
 101 # define initial_handler(i) (initial_action[i])
 102 # define signal_handler(sig, handler) signal (sig, handler)
 103 #endif
 104
 105 #if ! HAVE_SIGPROCMASK
 106 # define sigset_t int
 107 # define sigemptyset(s) (*(s) = 0)
 108 # ifndef sigmask
 109 #  define sigmask(sig) (1 << ((sig) - 1))
 110 # endif
 111 # define sigaddset(s, sig) (*(s) |= sigmask (sig))
 112 # ifndef SIG_BLOCK
 113 #  define SIG_BLOCK 0
 114 # endif
 115 # ifndef SIG_SETMASK
 116 #  define SIG_SETMASK (! SIG_BLOCK)
 117 # endif
 118 # define sigprocmask(how, n, o) \
 119     ((how) == SIG_BLOCK ? *(o) = sigblock (*(n)) : sigsetmask (*(n)))
 120 #endif
 121
 122 static bool diraccess (char const *);
 123 static int temporary_file (void);
 124
 125 /* Options: */
 126
 127 /* Name of output file if -o specified.  */
 128 static char const *output;
 129
 130 /* Do not print common lines.  */
 131 static bool suppress_common_lines;
 132
 133 /* Value for the long option that does not have single-letter equivalents.  */
 134 enum
 135 {
 136   DIFF_PROGRAM_OPTION = CHAR_MAX + 1,
 137   HELP_OPTION,
 138   STRIP_TRAILING_CR_OPTION
 139 };
 140
 141 static struct option const longopts[] =
 142 {
 143   {"diff-program", 1, 0, DIFF_PROGRAM_OPTION},
 144   {"expand-tabs", 0, 0, 't'},
 145   {"help", 0, 0, HELP_OPTION},
 146   {"ignore-all-space", 0, 0, 'W'}, /* swap W and w for historical reasons */
 147   {"ignore-blank-lines", 0, 0, 'B'},
 148   {"ignore-case", 0, 0, 'i'},
 149   {"ignore-matching-lines", 1, 0, 'I'},
 150   {"ignore-space-change", 0, 0, 'b'},
 151   {"ignore-tab-expansion", 0, 0, 'E'},
 152   {"left-column", 0, 0, 'l'},
 153   {"minimal", 0, 0, 'd'},
 154   {"output", 1, 0, 'o'},
 155   {"speed-large-files", 0, 0, 'H'},
 156   {"strip-trailing-cr", 0, 0, STRIP_TRAILING_CR_OPTION},
 157   {"suppress-common-lines", 0, 0, 's'},
 158   {"text", 0, 0, 'a'},
 159   {"version", 0, 0, 'v'},
 160   {"width", 1, 0, 'w'},
 161   {0, 0, 0, 0}
 162 };
 163
 164 static void try_help (char const *, char const *) __attribute__((noreturn));
 165 static void
 166 try_help (char const *reason_msgid, char const *operand)
 167 {
 168   if (reason_msgid)
 169     error (0, 0, _(reason_msgid), operand);
 170   error (EXIT_TROUBLE, 0, _("Try `%s --help' for more information."),
 171          program_name);
 172   abort ();
 173 }
 174
 175 static void
 176 check_stdout (void)
 177 {
 178   if (ferror (stdout))
 179     fatal ("write failed");
 180   else if (fclose (stdout) != 0)
 181     perror_fatal (_("standard output"));
 182 }
 183
 184 static char const * const option_help_msgid[] = {
 185   N_("-o FILE  --output=FILE  Operate interactively, sending output to FILE."),
 186   "",
 187   N_("-i  --ignore-case  Consider upper- and lower-case to be the same."),
 188   N_("-E  --ignore-tab-expansion  Ignore changes due to tab expansion."),
 189   N_("-b  --ignore-space-change  Ignore changes in the amount of white space."),
 190   N_("-W  --ignore-all-space  Ignore all white space."),
 191   N_("-B  --ignore-blank-lines  Ignore changes whose lines are all blank."),
 192   N_("-I RE  --ignore-matching-lines=RE  Ignore changes whose lines all match RE."),
 193   N_("--strip-trailing-cr  Strip trailing carriage return on input."),
 194   N_("-a  --text  Treat all files as text."),
 195   "",
 196   N_("-w NUM  --width=NUM  Output at most NUM (default 130) columns per line."),
 197   N_("-l  --left-column  Output only the left column of common lines."),
 198   N_("-s  --suppress-common-lines  Do not output common lines."),
 199   "",
 200   N_("-t  --expand-tabs  Expand tabs to spaces in output."),
 201   "",
 202   N_("-d  --minimal  Try hard to find a smaller set of changes."),
 203   N_("-H  --speed-large-files  Assume large files and many scattered small changes."),
 204   N_("--diff-program=PROGRAM  Use PROGRAM to compare files."),
 205   "",
 206   N_("-v  --version  Output version info."),
 207   N_("--help  Output this help."),
 208   0
 209 };
 210
 211 static void
 212 usage (void)
 213 {
 214   char const * const *p;
 215
 216   printf (_("Usage: %s [OPTION]... FILE1 FILE2\n"), program_name);
 217   printf ("%s\n\n", _("Side-by-side merge of file differences."));
 218   for (p = option_help_msgid;  *p;  p++)
 219     if (**p)
 220       printf ("  %s\n", _(*p));
 221     else
 222       putchar ('\n');
 223   printf ("\n%s\n\n%s\n",
 224           _("If a FILE is `-', read standard input."),
 225           _("Report bugs to <bug-gnu-utils@gnu.org>."));
 226 }
 227
 228 static void
 229 cleanup (void)
 230 {
 231 #if HAVE_WORKING_FORK || HAVE_WORKING_VFORK
 232   if (0 < diffpid)
 233     kill (diffpid, SIGPIPE);
 234 #endif
 235   if (tmpname)
 236     unlink (tmpname);
 237 }
 238
 239 static void exiterr (void) __attribute__((noreturn));
 240 static void
 241 exiterr (void)
 242 {
 243   cleanup ();
 244   untrapsig (0);
 245   checksigs ();
 246   exit (EXIT_TROUBLE);
 247 }
 248
 249 static void
 250 fatal (char const *msgid)
 251 {
 252   error (0, 0, "%s", _(msgid));
 253   exiterr ();
 254 }
 255
 256 static void
 257 perror_fatal (char const *msg)
 258 {
 259   int e = errno;
 260   checksigs ();
 261   error (0, e, "%s", msg);
 262   exiterr ();
 263 }
 264
 265 static void
 266 check_child_status (int werrno, int wstatus, int max_ok_status,
 267                     char const *subsidiary_program)
 268 {
 269   int status = (! werrno && WIFEXITED (wstatus)
 270                 ? WEXITSTATUS (wstatus)
 271                 : INT_MAX);
 272
 273   if (max_ok_status < status)
 274     {
 275       error (0, werrno,
 276              _(status == 126
 277                ? "subsidiary program `%s' could not be invoked"
 278                : status == 127
 279                ? "subsidiary program `%s' not found"
 280                : status == INT_MAX
 281                ? "subsidiary program `%s' failed"
 282                : "subsidiary program `%s' failed (exit status %d)"),
 283              subsidiary_program, status);
 284       exiterr ();
 285     }
 286 }
 287
 288 static FILE *
 289 ck_fopen (char const *fname, char const *type)
 290 {
 291   FILE *r = fopen (fname, type);
 292   if (! r)
 293     perror_fatal (fname);
 294   return r;
 295 }
 296
 297 static void
 298 ck_fclose (FILE *f)
 299 {
 300   if (fclose (f))
 301     perror_fatal ("fclose");
 302 }
 303
 304 static size_t
 305 ck_fread (char *buf, size_t size, FILE *f)
 306 {
 307   size_t r = fread (buf, sizeof (char), size, f);
 308   if (r == 0 && ferror (f))
 309     perror_fatal (_("read failed"));
 310   return r;
 311 }
 312
 313 static void
 314 ck_fwrite (char const *buf, size_t size, FILE *f)
 315 {
 316   if (fwrite (buf, sizeof (char), size, f) != size)
 317     perror_fatal (_("write failed"));
 318 }
 319
 320 static void
 321 ck_fflush (FILE *f)
 322 {
 323   if (fflush (f) != 0)
 324     perror_fatal (_("write failed"));
 325 }
 326
 327 static char const *
 328 expand_name (char *name, bool is_dir, char const *other_name)
 329 {
 330   if (strcmp (name, "-") == 0)
 331     fatal ("cannot interactively merge standard input");
 332   if (! is_dir)
 333     return name;
 334   else
 335     {
 336       /* Yield NAME/BASE, where BASE is OTHER_NAME's basename.  */
 337       char const *base = base_name (other_name);
 338       size_t namelen = strlen (name), baselen = strlen (base);
 339       bool insert_slash = *base_name (name) && name[namelen - 1] != '/';
 340       char *r = xmalloc (namelen + insert_slash + baselen + 1);
 341       memcpy (r, name, namelen);
 342       r[namelen] = '/';
 343       memcpy (r + namelen + insert_slash, base, baselen + 1);
 344       return r;
 345     }
 346 }
 347
 348
 349 \f
 350 struct line_filter {
 351   FILE *infile;
 352   char *bufpos;
 353   char *buffer;
 354   char *buflim;
 355 };
 356
 357 static void
 358 lf_init (struct line_filter *lf, FILE *infile)
 359 {
 360   lf->infile = infile;
 361   lf->bufpos = lf->buffer = lf->buflim = xmalloc (SDIFF_BUFSIZE + 1);
 362   lf->buflim[0] = '\n';
 363 }
 364
 365 /* Fill an exhausted line_filter buffer from its INFILE */
 366 static size_t
 367 lf_refill (struct line_filter *lf)
 368 {
 369   size_t s = ck_fread (lf->buffer, SDIFF_BUFSIZE, lf->infile);
 370   lf->bufpos = lf->buffer;
 371   lf->buflim = lf->buffer + s;
 372   lf->buflim[0] = '\n';
 373   checksigs ();
 374   return s;
 375 }
 376
 377 /* Advance LINES on LF's infile, copying lines to OUTFILE */
 378 static void
 379 lf_copy (struct line_filter *lf, lin lines, FILE *outfile)
 380 {
 381   char *start = lf->bufpos;
 382
 383   while (lines)
 384     {
 385       lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
 386       if (! lf->bufpos)
 387         {
 388           ck_fwrite (start, lf->buflim - start, outfile);
 389           if (! lf_refill (lf))
 390             return;
 391           start = lf->bufpos;
 392         }
 393       else
 394         {
 395           --lines;
 396           ++lf->bufpos;
 397         }
 398     }
 399
 400   ck_fwrite (start, lf->bufpos - start, outfile);
 401 }
 402
 403 /* Advance LINES on LF's infile without doing output */
 404 static void
 405 lf_skip (struct line_filter *lf, lin lines)
 406 {
 407   while (lines)
 408     {
 409       lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
 410       if (! lf->bufpos)
 411         {
 412           if (! lf_refill (lf))
 413             break;
 414         }
 415       else
 416         {
 417           --lines;
 418           ++lf->bufpos;
 419         }
 420     }
 421 }
 422
 423 /* Snarf a line into a buffer.  Return EOF if EOF, 0 if error, 1 if OK.  */
 424 static int
 425 lf_snarf (struct line_filter *lf, char *buffer, size_t bufsize)
 426 {
 427   for (;;)
 428     {
 429       char *start = lf->bufpos;
 430       char *next = (char *) memchr (start, '\n', lf->buflim + 1 - start);
 431       size_t s = next - start;
 432       if (bufsize <= s)
 433         return 0;
 434       memcpy (buffer, start, s);
 435       if (next < lf->buflim)
 436         {
 437           buffer[s] = 0;
 438           lf->bufpos = next + 1;
 439           return 1;
 440         }
 441       if (! lf_refill (lf))
 442         return s ? 0 : EOF;
 443       buffer += s;
 444       bufsize -= s;
 445     }
 446 }
 447
 448 \f
 449
 450 int
 451 main (int argc, char *argv[])
 452 {
 453   int opt;
 454   char const *prog;
 455
 456   exit_failure = EXIT_TROUBLE;
 457   initialize_main (&argc, &argv);
 458   program_name = argv[0];
 459   setlocale (LC_ALL, "");
 460   bindtextdomain (PACKAGE, LOCALEDIR);
 461   textdomain (PACKAGE);
 462   c_stack_action (c_stack_die);
 463
 464   prog = getenv ("EDITOR");
 465   if (prog)
 466     editor_program = prog;
 467
 468   diffarg (DEFAULT_DIFF_PROGRAM);
 469
 470   /* parse command line args */
 471   while ((opt = getopt_long (argc, argv, "abBdHiI:lo:stvw:W", longopts, 0))
 472          != -1)
 473     {
 474       switch (opt)
 475         {
 476         case 'a':
 477           diffarg ("-a");
 478           break;
 479
 480         case 'b':
 481           diffarg ("-b");
 482           break;
 483
 484         case 'B':
 485           diffarg ("-B");
 486           break;
 487
 488         case 'd':
 489           diffarg ("-d");
 490           break;
 491
 492         case 'E':
 493           diffarg ("-E");
 494           break;
 495
 496         case 'H':
 497           diffarg ("-H");
 498           break;
 499
 500         case 'i':
 501           diffarg ("-i");
 502           break;
 503
 504         case 'I':
 505           diffarg ("-I");
 506           diffarg (optarg);
 507           break;
 508
 509         case 'l':
 510           diffarg ("--left-column");
 511           break;
 512
 513         case 'o':
 514           output = optarg;
 515           break;
 516
 517         case 's':
 518           suppress_common_lines = 1;
 519           break;
 520
 521         case 't':
 522           diffarg ("-t");
 523           break;
 524
 525         case 'v':
 526           printf ("sdiff %s\n%s\n\n%s\n\n%s\n",
 527                   version_string, copyright_string,
 528                   _(free_software_msgid), _(authorship_msgid));
 529           check_stdout ();
 530           return EXIT_SUCCESS;
 531
 532         case 'w':
 533           diffarg ("-W");
 534           diffarg (optarg);
 535           break;
 536
 537         case 'W':
 538           diffarg ("-w");
 539           break;
 540
 541         case DIFF_PROGRAM_OPTION:
 542           diffargv[0] = optarg;
 543           break;
 544
 545         case HELP_OPTION:
 546           usage ();
 547           check_stdout ();
 548           return EXIT_SUCCESS;
 549
 550         case STRIP_TRAILING_CR_OPTION:
 551           diffarg ("--strip-trailing-cr");
 552           break;
 553
 554         default:
 555           try_help (0, 0);
 556         }
 557     }
 558
 559   if (argc - optind != 2)
 560     {
 561       if (argc - optind < 2)
 562         try_help ("missing operand after `%s'", argv[argc - 1]);
 563       else
 564         try_help ("extra operand `%s'", argv[optind + 2]);
 565     }
 566
 567   if (! output)
 568     {
 569       /* easy case: diff does everything for us */
 570       if (suppress_common_lines)
 571         diffarg ("--suppress-common-lines");
 572       diffarg ("-y");
 573       diffarg ("--");
 574       diffarg (argv[optind]);
 575       diffarg (argv[optind + 1]);
 576       diffarg (0);
 577       execvp (diffargv[0], (char **) diffargv);
 578       perror_fatal (diffargv[0]);
 579     }
 580   else
 581     {
 582       char const *lname, *rname;
 583       FILE *left, *right, *out, *diffout;
 584       bool interact_ok;
 585       struct line_filter lfilt;
 586       struct line_filter rfilt;
 587       struct line_filter diff_filt;
 588       bool leftdir = diraccess (argv[optind]);
 589       bool rightdir = diraccess (argv[optind + 1]);
 590
 591       if (leftdir & rightdir)
 592         fatal ("both files to be compared are directories");
 593
 594       lname = expand_name (argv[optind], leftdir, argv[optind + 1]);
 595       left = ck_fopen (lname, "r");
 596       rname = expand_name (argv[optind + 1], rightdir, argv[optind]);
 597       right = ck_fopen (rname, "r");
 598       out = ck_fopen (output, "w");
 599
 600       diffarg ("--sdiff-merge-assist");
 601       diffarg ("--");
 602       diffarg (argv[optind]);
 603       diffarg (argv[optind + 1]);
 604       diffarg (0);
 605
 606       trapsigs ();
 607
 608 #if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
 609       {
 610         size_t cmdsize = 1;
 611         char *p, *command;
 612         int i;
 613
 614         for (i = 0;  diffargv[i];  i++)
 615           cmdsize += quote_system_arg (0, diffargv[i]) + 1;
 616         command = p = xmalloc (cmdsize);
 617         for (i = 0;  diffargv[i];  i++)
 618           {
 619             p += quote_system_arg (p, diffargv[i]);
 620             *p++ = ' ';
 621           }
 622         p[-1] = 0;
 623         errno = 0;
 624         diffout = popen (command, "r");
 625         if (! diffout)
 626           perror_fatal (command);
 627         free (command);
 628       }
 629 #else
 630       {
 631         int diff_fds[2];
 632 # if HAVE_WORKING_VFORK
 633         sigset_t procmask;
 634         sigset_t blocked;
 635 # endif
 636
 637         if (pipe (diff_fds) != 0)
 638           perror_fatal ("pipe");
 639
 640 # if HAVE_WORKING_VFORK
 641         /* Block SIGINT and SIGPIPE.  */
 642         sigemptyset (&blocked);
 643         sigaddset (&blocked, SIGINT);
 644         sigaddset (&blocked, SIGPIPE);
 645         sigprocmask (SIG_BLOCK, &blocked, &procmask);
 646 # endif
 647         diffpid = vfork ();
 648         if (diffpid < 0)
 649           perror_fatal ("fork");
 650         if (! diffpid)
 651           {
 652             /* Alter the child's SIGINT and SIGPIPE handlers;
 653                this may munge the parent.
 654                The child ignores SIGINT in case the user interrupts the editor.
 655                The child does not ignore SIGPIPE, even if the parent does.  */
 656             if (initial_handler (handler_index_of_SIGINT) != SIG_IGN)
 657               signal_handler (SIGINT, SIG_IGN);
 658             signal_handler (SIGPIPE, SIG_DFL);
 659 # if HAVE_WORKING_VFORK
 660             /* Stop blocking SIGINT and SIGPIPE in the child.  */
 661             sigprocmask (SIG_SETMASK, &procmask, 0);
 662 # endif
 663             close (diff_fds[0]);
 664             if (diff_fds[1] != STDOUT_FILENO)
 665               {
 666                 dup2 (diff_fds[1], STDOUT_FILENO);
 667                 close (diff_fds[1]);
 668               }
 669
 670             execvp (diffargv[0], (char **) diffargv);
 671             _exit (errno == ENOEXEC ? 126 : 127);
 672           }
 673
 674 # if HAVE_WORKING_VFORK
 675         /* Restore the parent's SIGINT and SIGPIPE behavior.  */
 676         if (initial_handler (handler_index_of_SIGINT) != SIG_IGN)
 677           signal_handler (SIGINT, catchsig);
 678         if (initial_handler (handler_index_of_SIGPIPE) != SIG_IGN)
 679           signal_handler (SIGPIPE, catchsig);
 680         else
 681           signal_handler (SIGPIPE, SIG_IGN);
 682
 683         /* Stop blocking SIGINT and SIGPIPE in the parent.  */
 684         sigprocmask (SIG_SETMASK, &procmask, 0);
 685 # endif
 686
 687         close (diff_fds[1]);
 688         diffout = fdopen (diff_fds[0], "r");
 689         if (! diffout)
 690           perror_fatal ("fdopen");
 691       }
 692 #endif
 693
 694       lf_init (&diff_filt, diffout);
 695       lf_init (&lfilt, left);
 696       lf_init (&rfilt, right);
 697
 698       interact_ok = interact (&diff_filt, &lfilt, lname, &rfilt, rname, out);
 699
 700       ck_fclose (left);
 701       ck_fclose (right);
 702       ck_fclose (out);
 703
 704       {
 705         int wstatus;
 706         int werrno = 0;
 707
 708 #if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
 709         wstatus = pclose (diffout);
 710         if (wstatus == -1)
 711           werrno = errno;
 712 #else
 713         ck_fclose (diffout);
 714         while (waitpid (diffpid, &wstatus, 0) < 0)
 715           if (errno == EINTR)
 716             checksigs ();
 717           else
 718             perror_fatal ("waitpid");
 719         diffpid = 0;
 720 #endif
 721
 722         if (tmpname)
 723           {
 724             unlink (tmpname);
 725             tmpname = 0;
 726           }
 727
 728         if (! interact_ok)
 729           exiterr ();
 730
 731         check_child_status (werrno, wstatus, EXIT_FAILURE, diffargv[0]);
 732         untrapsig (0);
 733         checksigs ();
 734         exit (WEXITSTATUS (wstatus));
 735       }
 736     }
 737   return EXIT_SUCCESS;                  /* Fool `-Wall'.  */
 738 }
 739
 740 static void
 741 diffarg (char const *a)
 742 {
 743   static size_t diffargs, diffarglim;
 744
 745   if (diffargs == diffarglim)
 746     {
 747       if (! diffarglim)
 748         diffarglim = 16;
 749       else if (PTRDIFF_MAX / (2 * sizeof *diffargv) <= diffarglim)
 750         xalloc_die ();
 751       else
 752         diffarglim *= 2;
 753       diffargv = xrealloc (diffargv, diffarglim * sizeof *diffargv);
 754     }
 755   diffargv[diffargs++] = a;
 756 }
 757
 758 \f
 759
 760
 761 /* Signal handling */
 762
 763 static bool volatile ignore_SIGINT;
 764 static int volatile signal_received;
 765 static bool sigs_trapped;
 766
 767 static RETSIGTYPE
 768 catchsig (int s)
 769 {
 770 #if ! HAVE_SIGACTION
 771   signal (s, SIG_IGN);
 772 #endif
 773   if (! (s == SIGINT && ignore_SIGINT))
 774     signal_received = s;
 775 }
 776
 777 #if HAVE_SIGACTION
 778 static struct sigaction catchaction;
 779
 780 static void
 781 signal_handler (int sig, RETSIGTYPE (*handler) (int))
 782 {
 783   catchaction.sa_handler = handler;
 784   sigaction (sig, &catchaction, 0);
 785 }
 786 #endif
 787
 788 static void
 789 trapsigs (void)
 790 {
 791   int i;
 792
 793 #if HAVE_SIGACTION
 794   catchaction.sa_flags = SA_RESTART;
 795   sigemptyset (&catchaction.sa_mask);
 796   for (i = 0;  i < NUM_SIGS;  i++)
 797     sigaddset (&catchaction.sa_mask, sigs[i]);
 798 #endif
 799
 800   for (i = 0;  i < NUM_SIGS;  i++)
 801     {
 802 #if HAVE_SIGACTION
 803       sigaction (sigs[i], 0, &initial_action[i]);
 804 #else
 805       initial_action[i] = signal (sigs[i], SIG_IGN);
 806 #endif
 807       if (initial_handler (i) != SIG_IGN)
 808         signal_handler (sigs[i], catchsig);
 809     }
 810
 811 #ifdef SIGCHLD
 812   /* System V fork+wait does not work if SIGCHLD is ignored.  */
 813   signal (SIGCHLD, SIG_DFL);
 814 #endif
 815
 816   sigs_trapped = 1;
 817 }
 818
 819 /* Untrap signal S, or all trapped signals if S is zero.  */
 820 static void
 821 untrapsig (int s)
 822 {
 823   int i;
 824
 825   if (sigs_trapped)
 826     for (i = 0;  i < NUM_SIGS;  i++)
 827       if ((! s || sigs[i] == s)  &&  initial_handler (i) != SIG_IGN)
 828 #if HAVE_SIGACTION
 829           sigaction (sigs[i], &initial_action[i], 0);
 830 #else
 831           signal (sigs[i], initial_action[i]);
 832 #endif
 833 }
 834
 835 /* Exit if a signal has been received.  */
 836 static void
 837 checksigs (void)
 838 {
 839   int s = signal_received;
 840   if (s)
 841     {
 842       cleanup ();
 843
 844       /* Yield an exit status indicating that a signal was received.  */
 845       untrapsig (s);
 846       kill (getpid (), s);
 847
 848       /* That didn't work, so exit with error status.  */
 849       exit (EXIT_TROUBLE);
 850     }
 851 }
 852
 853 \f
 854 static void
 855 give_help (void)
 856 {
 857   fprintf (stderr, "%s", _("\
 858 ed:\tEdit then use both versions, each decorated with a header.\n\
 859 eb:\tEdit then use both versions.\n\
 860 el:\tEdit then use the left version.\n\
 861 er:\tEdit then use the right version.\n\
 862 e:\tEdit a new version.\n\
 863 l:\tUse the left version.\n\
 864 r:\tUse the right version.\n\
 865 s:\tSilently include common lines.\n\
 866 v:\tVerbosely include common lines.\n\
 867 q:\tQuit.\n\
 868 "));
 869 }
 870
 871 static int
 872 skip_white (void)
 873 {
 874   int c;
 875   for (;;)
 876     {
 877       c = getchar ();
 878       if (! ISSPACE (c) || c == '\n')
 879         break;
 880       checksigs ();
 881     }
 882   if (ferror (stdin))
 883     perror_fatal (_("read failed"));
 884   return c;
 885 }
 886
 887 static void
 888 flush_line (void)
 889 {
 890   int c;
 891   while ((c = getchar ()) != '\n' && c != EOF)
 892     continue;
 893   if (ferror (stdin))
 894     perror_fatal (_("read failed"));
 895 }
 896
 897
 898 /* interpret an edit command */
 899 static bool
 900 edit (struct line_filter *left, char const *lname, lin lline, lin llen,
 901       struct line_filter *right, char const *rname, lin rline, lin rlen,
 902       FILE *outfile)
 903 {
 904   for (;;)
 905     {
 906       int cmd0, cmd1;
 907       bool gotcmd = 0;
 908
 909       cmd1 = 0; /* Pacify `gcc -W'.  */
 910
 911       while (! gotcmd)
 912         {
 913           if (putchar ('%') != '%')
 914             perror_fatal (_("write failed"));
 915           ck_fflush (stdout);
 916
 917           cmd0 = skip_white ();
 918           switch (cmd0)
 919             {
 920             case 'l': case 'r': case 's': case 'v': case 'q':
 921               if (skip_white () != '\n')
 922                 {
 923                   give_help ();
 924                   flush_line ();
 925                   continue;
 926                 }
 927               gotcmd = 1;
 928               break;
 929
 930             case 'e':
 931               cmd1 = skip_white ();
 932               switch (cmd1)
 933                 {
 934                 case 'b': case 'd': case 'l': case 'r':
 935                   if (skip_white () != '\n')
 936                     {
 937                       give_help ();
 938                       flush_line ();
 939                       continue;
 940                     }
 941                   gotcmd = 1;
 942                   break;
 943                 case '\n':
 944                   gotcmd = 1;
 945                   break;
 946                 default:
 947                   give_help ();
 948                   flush_line ();
 949                   continue;
 950                 }
 951               break;
 952
 953             case EOF:
 954               if (feof (stdin))
 955                 {
 956                   gotcmd = 1;
 957                   cmd0 = 'q';
 958                   break;
 959                 }
 960               /* Fall through.  */
 961             default:
 962               flush_line ();
 963               /* Fall through.  */
 964             case '\n':
 965               give_help ();
 966               continue;
 967             }
 968         }
 969
 970       switch (cmd0)
 971         {
 972         case 'l':
 973           lf_copy (left, llen, outfile);
 974           lf_skip (right, rlen);
 975           return 1;
 976         case 'r':
 977           lf_copy (right, rlen, outfile);
 978           lf_skip (left, llen);
 979           return 1;
 980         case 's':
 981           suppress_common_lines = 1;
 982           break;
 983         case 'v':
 984           suppress_common_lines = 0;
 985           break;
 986         case 'q':
 987           return 0;
 988         case 'e':
 989           {
 990             int fd;
 991
 992             if (tmpname)
 993               tmp = fopen (tmpname, "w");
 994             else
 995               {
 996                 if ((fd = temporary_file ()) < 0)
 997                   perror_fatal ("mkstemp");
 998                 tmp = fdopen (fd, "w");
 999               }
1000
1001             if (! tmp)
1002               perror_fatal (tmpname);
1003
1004             switch (cmd1)
1005               {
1006               case 'd':
1007                 if (llen)
1008                   {
1009                     if (llen == 1)
1010                       fprintf (tmp, "--- %s %ld\n", lname, (long) lline);
1011                     else
1012                       fprintf (tmp, "--- %s %ld,%ld\n", lname,
1013                                (long) lline, (long) (lline + llen - 1));
1014                   }
1015                 /* Fall through.  */
1016               case 'b': case 'l':
1017                 lf_copy (left, llen, tmp);
1018                 break;
1019
1020               default:
1021                 lf_skip (left, llen);
1022                 break;
1023               }
1024
1025             switch (cmd1)
1026               {
1027               case 'd':
1028                 if (rlen)
1029                   {
1030                     if (rlen == 1)
1031                       fprintf (tmp, "+++ %s %ld\n", rname, (long) rline);
1032                     else
1033                       fprintf (tmp, "+++ %s %ld,%ld\n", rname,
1034                                (long) rline, (long) (rline + rlen - 1));
1035                   }
1036                 /* Fall through.  */
1037               case 'b': case 'r':
1038                 lf_copy (right, rlen, tmp);
1039                 break;
1040
1041               default:
1042                 lf_skip (right, rlen);
1043                 break;
1044               }
1045
1046             ck_fclose (tmp);
1047
1048             {
1049               int wstatus;
1050               int werrno = 0;
1051               ignore_SIGINT = 1;
1052               checksigs ();
1053
1054               {
1055 #if ! (HAVE_WORKING_FORK || HAVE_WORKING_VFORK)
1056                 char *command =
1057                   xmalloc (quote_system_arg (0, editor_program)
1058                            + 1 + strlen (tmpname) + 1);
1059                 sprintf (command + quote_system_arg (command, editor_program),
1060                          " %s", tmpname);
1061                 wstatus = system (command);
1062                 if (wstatus == -1)
1063                   werrno = errno;
1064                 free (command);
1065 #else
1066                 pid_t pid;
1067
1068                 pid = vfork ();
1069                 if (pid == 0)
1070                   {
1071                     char const *argv[3];
1072                     int i = 0;
1073
1074                     argv[i++] = editor_program;
1075                     argv[i++] = tmpname;
1076                     argv[i] = 0;
1077
1078                     execvp (editor_program, (char **) argv);
1079                     _exit (errno == ENOEXEC ? 126 : 127);
1080                   }
1081
1082                 if (pid < 0)
1083                   perror_fatal ("fork");
1084
1085                 while (waitpid (pid, &wstatus, 0) < 0)
1086                   if (errno == EINTR)
1087                     checksigs ();
1088                   else
1089                     perror_fatal ("waitpid");
1090 #endif
1091               }
1092
1093               ignore_SIGINT = 0;
1094               check_child_status (werrno, wstatus, EXIT_SUCCESS,
1095                                   editor_program);
1096             }
1097
1098             {
1099               char buf[SDIFF_BUFSIZE];
1100               size_t size;
1101               tmp = ck_fopen (tmpname, "r");
1102               while ((size = ck_fread (buf, SDIFF_BUFSIZE, tmp)) != 0)
1103                 {
1104                   checksigs ();
1105                   ck_fwrite (buf, size, outfile);
1106                 }
1107               ck_fclose (tmp);
1108             }
1109             return 1;
1110           }
1111         default:
1112           give_help ();
1113           break;
1114         }
1115     }
1116 }
1117
1118 \f
1119
1120 /* Alternately reveal bursts of diff output and handle user commands.  */
1121 static bool
1122 interact (struct line_filter *diff,
1123           struct line_filter *left, char const *lname,
1124           struct line_filter *right, char const *rname,
1125           FILE *outfile)
1126 {
1127   lin lline = 1, rline = 1;
1128
1129   for (;;)
1130     {
1131       char diff_help[256];
1132       int snarfed = lf_snarf (diff, diff_help, sizeof diff_help);
1133
1134       if (snarfed <= 0)
1135         return snarfed != 0;
1136
1137       checksigs ();
1138
1139       if (diff_help[0] == ' ')
1140         puts (diff_help + 1);
1141       else
1142         {
1143           char *numend;
1144           uintmax_t val;
1145           lin llen, rlen, lenmax;
1146           errno = 0;
1147           llen = val = strtoumax (diff_help + 1, &numend, 10);
1148           if (llen < 0 || llen != val || errno || *numend != ',')
1149             fatal (diff_help);
1150           rlen = val = strtoumax (numend + 1, &numend, 10);
1151           if (rlen < 0 || rlen != val || errno || *numend)
1152             fatal (diff_help);
1153
1154           lenmax = MAX (llen, rlen);
1155
1156           switch (diff_help[0])
1157             {
1158             case 'i':
1159               if (suppress_common_lines)
1160                 lf_skip (diff, lenmax);
1161               else
1162                 lf_copy (diff, lenmax, stdout);
1163
1164               lf_copy (left, llen, outfile);
1165               lf_skip (right, rlen);
1166               break;
1167
1168             case 'c':
1169               lf_copy (diff, lenmax, stdout);
1170               if (! edit (left, lname, lline, llen,
1171                           right, rname, rline, rlen,
1172                           outfile))
1173                 return 0;
1174               break;
1175
1176             default:
1177               fatal (diff_help);
1178             }
1179
1180           lline += llen;
1181           rline += rlen;
1182         }
1183     }
1184 }
1185
1186 /* Return nonzero if DIR is an existing directory.  */
1187 static bool
1188 diraccess (char const *dir)
1189 {
1190   struct stat buf;
1191   return stat (dir, &buf) == 0 && S_ISDIR (buf.st_mode);
1192 }
1193
1194 #ifndef P_tmpdir
1195 # define P_tmpdir "/tmp"
1196 #endif
1197 #ifndef TMPDIR_ENV
1198 # define TMPDIR_ENV "TMPDIR"
1199 #endif
1200
1201 /* Open a temporary file and return its file descriptor.  Put into
1202    tmpname the address of a newly allocated buffer that holds the
1203    file's name.  Use the prefix "sdiff".  */
1204 static int
1205 temporary_file (void)
1206 {
1207   char const *tmpdir = getenv (TMPDIR_ENV);
1208   char const *dir = tmpdir ? tmpdir : P_tmpdir;
1209   char *buf = xmalloc (strlen (dir) + 1 + 5 + 6 + 1);
1210   int fd;
1211   int e;
1212   sigset_t procmask;
1213   sigset_t blocked;
1214   sprintf (buf, "%s/sdiffXXXXXX", dir);
1215   sigemptyset (&blocked);
1216   sigaddset (&blocked, SIGINT);
1217   sigprocmask (SIG_BLOCK, &blocked, &procmask);
1218   fd = mkstemp (buf);
1219   e = errno;
1220   if (0 <= fd)
1221     tmpname = buf;
1222   sigprocmask (SIG_SETMASK, &procmask, 0);
1223   errno = e;
1224   return fd;
1225 }