/usr/src/gnu/usr.bin/cvs/diff/util.c

Bug Summary

File:	src/gnu/usr.bin/cvs/diff/util.c
Warning:	line 230, column 4 This function call is prohibited after a successful vfork

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name util.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/cvs/obj/diff -resource-dir /usr/local/lib/clang/13.0.0 -D HAVE_CONFIG_H -I . -I /usr/src/gnu/usr.bin/cvs/diff -I .. -I ../src -I /usr/src/gnu/usr.bin/cvs/lib -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/gnu/usr.bin/cvs/obj/diff -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/gnu/usr.bin/cvs/diff/util.c

1/* Support routines for GNU DIFF.
 Copyright (C) 1988, 1989, 1992, 1993, 1994, 1997, 1998 Free Software Foundation, Inc.

4This file is part of GNU DIFF.

6GNU DIFF is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 2, or (at your option)
9any later version.

11GNU DIFF is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14GNU General Public License for more details.

16*/

18#include "diff.h"

20#if __STDC__1
21#include <stdarg.h>
22#else
23#include <varargs.h>
24#endif

26#ifndef strerror
27extern char *strerror ();
28#endif

30/* Queue up one-line messages to be printed at the end,
 when -l is specified.  Each message is recorded with a `struct msg'.  */

33struct msg
34{
struct msg *next;
char const *format;
char const *arg1;
char const *arg2;
char const *arg3;
char const *arg4;
41};

43/* Head of the chain of queues messages.  */

45static struct msg *msg_chain;

47/* Tail of the chain of queues messages.  */

49static struct msg **msg_chain_end = &msg_chain;
50
51/* Use when a system call returns non-zero status.
 TEXT should normally be the file name.  */

54void
55perror_with_name (text)
   char const *text;
57{
int e = errno(*__errno());

if (callbacks && callbacks->error)
  (*callbacks->error) ("%s: %s", text, strerror (e));
else
  {
    fprintf (stderr(&__sF[2]), "%s: ", diff_program_name);
    errno(*__errno()) = e;
    perror (text);
  }
68}

70/* Use when a system call returns non-zero status and that is fatal.  */

72void
73pfatal_with_name (text)
   char const *text;
75{
int e = errno(*__errno());
print_message_queue ();
if (callbacks && callbacks->error)
  (*callbacks->error) ("%s: %s", text, strerror (e));
else
  {
    fprintf (stderr(&__sF[2]), "%s: ", diff_program_name);
    errno(*__errno()) = e;
    perror (text);
  }
DIFF_ABORT (2)longjmp(diff_abort_buf, 2);
87}

89/* Print an error message from the format-string FORMAT
 with args ARG1 and ARG2.  */

92void
93diff_error (format, arg, arg1)
   char const *format, *arg, *arg1;
95{
if (callbacks && callbacks->error)
  (*callbacks->error) (format, arg, arg1);
else
  {
    fprintf (stderr(&__sF[2]), "%s: ", diff_program_name);
    fprintf (stderr(&__sF[2]), format, arg, arg1);
    fprintf (stderr(&__sF[2]), "\n");
  }
104}

106/* Print an error message containing the string TEXT, then exit.  */

108void
109fatal (m)
   char const *m;
111{
print_message_queue ();
diff_error ("%s", m, 0);
DIFF_ABORT (2)longjmp(diff_abort_buf, 2);
115}
116
117/* Like printf, except if -l in effect then save the message and print later.
 This is used for things like "binary files differ" and "Only in ...".  */

120void
121message (format, arg1, arg2)
   char const *format, *arg1, *arg2;
123{
message5 (format, arg1, arg2, 0, 0);
125}

127void
128message5 (format, arg1, arg2, arg3, arg4)
   char const *format, *arg1, *arg2, *arg3, *arg4;
130{
if (paginate_flag)
  {
    struct msg *new = (struct msg *) xmalloc (sizeof (struct msg));
    new->format = format;
    new->arg1 = concat (arg1, "", "");
    new->arg2 = concat (arg2, "", "");
    new->arg3 = arg3 ? concat (arg3, "", "") : 0;
    new->arg4 = arg4 ? concat (arg4, "", "") : 0;
    new->next = 0;
    *msg_chain_end = new;
    msg_chain_end = &new->next;
  }
else
  {
    if (sdiff_help_sdiff)
write_output (" ", 1);
    printf_output (format, arg1, arg2, arg3, arg4);
  }
149}

151/* Output all the messages that were saved up by calls to `message'.  */

153void
154print_message_queue ()
155{
struct msg *m;

for (m = msg_chain; m; m = m->next)
  printf_output (m->format, m->arg1, m->arg2, m->arg3, m->arg4);
160}
161
162/* Call before outputting the results of comparing files NAME0 and NAME1
 to set up OUTFILE, the stdio stream for the output to go to.

 Usually, OUTFILE is just stdout.  But when -l was specified
 we fork off a `pr' and make OUTFILE a pipe to it.
 `pr' then outputs to our stdout.  */

169static char const *current_name0;
170static char const *current_name1;
171static int current_depth;

173static int output_in_progress = 0;

175void
176setup_output (name0, name1, depth)
   char const *name0, *name1;
   int depth;
179{
current_name0 = name0;
current_name1 = name1;
current_depth = depth;
183}

185#if HAVE_FORK1 && defined (PR_PROGRAM"/usr/bin/pr")
186static pid_t pr_pid;
187#endif

189void
190begin_output ()
191{
char *name;

if (output_in_progress)
1
Assuming 'output_in_progress' is 0→
2
←
Taking false branch→
  return;
output_in_progress = 1;

/* Construct the header of this piece of diff.  */
name = xmalloc (strlen (current_name0) + strlen (current_name1)
  + strlen (switch_string) + 7);
/* Posix.2 section 4.17.6.1.1 specifies this format.  But there is a
   bug in the first printing (IEEE Std 1003.2-1992 p 251 l 3304):
   it says that we must print only the last component of the pathnames.
   This requirement is silly and does not match historical practice.  */
sprintf (name, "diff%s %s %s", switch_string, current_name0, current_name1);

if (paginate_flag && callbacks && callbacks->write_output)
3
←
Assuming 'paginate_flag' is not equal to 0→
4
←
Assuming 'callbacks' is null→
  fatal ("can't paginate when using library callbacks");

if (paginate_flag4.1
'paginate_flag' is not equal to 0
)
5
←
Taking true branch→
  {
    /* Make OUTFILE a pipe to a subsidiary `pr'.  */

214#ifdef PR_PROGRAM"/usr/bin/pr"

216# if HAVE_FORK1
    int pipes[2];

    if (pipe (pipes) != 0)
6
←
Assuming the condition is false→
7
←
Taking false branch→
pfatal_with_name ("pipe");

    fflush (stdout(&__sF[1]));

    pr_pid = vfork ();
    if (pr_pid7.1
'pr_pid' is >= 0
 < 0)
8
←
Taking false branch→
pfatal_with_name ("vfork");

    if (pr_pid8.1
'pr_pid' is equal to 0
 == 0)
9
←
Taking true branch→
{
 close (pipes[1]);
10
←
This function call is prohibited after a successful vfork
 if (pipes[0] != STDIN_FILENO0)
   {
     if (dup2 (pipes[0], STDIN_FILENO0) < 0)
pfatal_with_name ("dup2");
     close (pipes[0]);
   }

 execl (PR_PROGRAM"/usr/bin/pr", PR_PROGRAM"/usr/bin/pr", "-f", "-h", name, (char *)NULL((void *)0));
 pfatal_with_name (PR_PROGRAM"/usr/bin/pr");
}
    else
{
 close (pipes[0]);
 outfile = fdopen (pipes[1], "w");
 if (!outfile)
   pfatal_with_name ("fdopen");
}
248# else /* ! HAVE_FORK */
    char *command = xmalloc (4 * strlen (name) + strlen (PR_PROGRAM"/usr/bin/pr") + 10);
    char *p;
    char const *a = name;
    sprintf (command, "%s -f -h ", PR_PROGRAM"/usr/bin/pr");
    p = command + strlen (command);
    SYSTEM_QUOTE_ARG (p, a){ *(p)++ = '\''; for (; *(a); *(p)++ = *(a)++) if (*(a) == '\''
) { *(p)++ = '\''; *(p)++ = '\\'; *(p)++ = '\''; } *(p)++ = '\''
; };
    *p = 0;
    outfile = popen (command, "w");
    if (!outfile)
pfatal_with_name (command);
    free (command);
260# endif /* ! HAVE_FORK */
261#else
    fatal ("This port does not support the --paginate option to diff.");
263#endif
  }
else
  {

    /* If -l was not specified, output the diff straight to `stdout'.  */

    /* If handling multiple files (because scanning a directory),
print which files the following output is about.  */
    if (current_depth > 0)
printf_output ("%s\n", name);
  }

free (name);

/* A special header is needed at the beginning of context output.  */
switch (output_style)
  {
  case OUTPUT_CONTEXT:
    print_context_header (files, 0);
    break;

  case OUTPUT_UNIFIED:
    print_context_header (files, 1);
    break;

  default:
    break;
  }
292}

294/* Call after the end of output of diffs for one file.
 If -l was given, close OUTFILE and get rid of the `pr' subfork.  */

297void
298finish_output ()
299{
if (paginate_flag && outfile != 0 && outfile != stdout(&__sF[1]))
  {
302#ifdef PR_PROGRAM"/usr/bin/pr"
    int wstatus;
    if (ferror (outfile)(!__isthreaded ? (((outfile)->_flags & 0x0040) != 0) :
 (ferror)(outfile)))
fatal ("write error");
306# if ! HAVE_FORK1
    wstatus = pclose (outfile);
308# else /* HAVE_FORK */
    if (fclose (outfile) != 0)
pfatal_with_name ("write error");
    if (waitpid (pr_pid, &wstatus, 0) < 0)
pfatal_with_name ("waitpid");
313# endif /* HAVE_FORK */
    if (wstatus != 0)
fatal ("subsidiary pr failed");
316#else
    fatal ("internal error in finish_output");
318#endif
  }

output_in_progress = 0;
322}

324/* Write something to the output file.  */

326void
327write_output (text, len)
   char const *text;
   size_t len;
330{
if (callbacks && callbacks->write_output)
  (*callbacks->write_output) (text, len);
else if (len == 1)
  putc (*text, outfile)(!__isthreaded ? __sputc(*text, outfile) : (putc)(*text, outfile
));
else
  fwrite (text, sizeof (char), len, outfile);
337}

339/* Printf something to the output file.  */

341#if __STDC__1
342#define VA_START(args, lastarg)__builtin_va_start(args, lastarg) va_start(args, lastarg)__builtin_va_start(args, lastarg)
343#else /* ! __STDC__ */
344#define VA_START(args, lastarg)__builtin_va_start(args, lastarg) va_start(args)
345#endif /* __STDC__ */

347void
348#if __STDC__1
349printf_output (const char *format, ...)
350#else
351printf_output (format, va_alist)
   char const *format;
   va_dcl
354#endif
355{
va_list args;

VA_START (args, format)__builtin_va_start(args, format);
if (callbacks && callbacks->write_output)
  {
    /* We implement our own limited printf-like functionality (%s, %d,
and %c only).  Callers who want something fancier can use
sprintf.  */
    const char *p = format;
    char *q;
    char *str;
    int num;
    int ch;
    char buf[100];

    while ((q = strchr (p, '%')) != NULL((void *)0))
{
 static const char msg[] =
   "\ninternal error: bad % in printf_output\n";
 (*callbacks->write_output) (p, q - p);

 switch (q[1])
   {
   case 's':
     str = va_arg (args, char *)__builtin_va_arg(args, char *);
     (*callbacks->write_output) (str, strlen (str));
     break;
   case 'd':
     num = va_arg (args, int)__builtin_va_arg(args, int);
     sprintf (buf, "%d", num);
     (*callbacks->write_output) (buf, strlen (buf));
     break;
   case 'c':
     ch = va_arg (args, int)__builtin_va_arg(args, int);
     buf[0] = ch;
     (*callbacks->write_output) (buf, 1);
     break;
   default:
     (*callbacks->write_output) (msg, sizeof (msg) - 1);
     /* Don't just keep going, because q + 1 might point to the
 terminating '\0'.  */
     goto out;
   }
 p = q + 2;
}
    (*callbacks->write_output) (p, strlen (p));
  }
else
  vfprintf (outfile, format, args);
out:
va_end (args)__builtin_va_end(args);
407}

409/* Flush the output file.  */

411void
412flush_output ()
413{
if (callbacks && callbacks->flush_output)
  (*callbacks->flush_output) ();
else
  fflush (outfile);
418}
419
420/* Compare two lines (typically one from each input file)
 according to the command line options.
 For efficiency, this is invoked only when the lines do not match exactly
 but an option like -i might cause us to ignore the difference.
 Return nonzero if the lines differ.  */

426int
427line_cmp (s1, s2)
   char const *s1, *s2;
429{
register unsigned char const *t1 = (unsigned char const *) s1;
register unsigned char const *t2 = (unsigned char const *) s2;

while (1)
  {
    register unsigned char c1 = *t1++;
    register unsigned char c2 = *t2++;

    /* Test for exact char equality first, since it's a common case.  */
    if (c1 != c2)
{
 /* Ignore horizontal white space if -b or -w is specified.  */

 if (ignore_all_space_flag)
   {
     /* For -w, just skip past any white space.  */
     while (ISSPACE (c1)(1 && isspace (c1)) && c1 != '\n') c1 = *t1++;
     while (ISSPACE (c2)(1 && isspace (c2)) && c2 != '\n') c2 = *t2++;
   }
 else if (ignore_space_change_flag)
   {
     /* For -b, advance past any sequence of white space in line 1
 and consider it just one Space, or nothing at all
 if it is at the end of the line.  */
     if (ISSPACE (c1)(1 && isspace (c1)))
{
  while (c1 != '\n')
    {
      c1 = *t1++;
      if (! ISSPACE (c1)(1 && isspace (c1)))
	{
	  --t1;
	  c1 = ' ';
	  break;
	}
    }
}

     /* Likewise for line 2.  */
     if (ISSPACE (c2)(1 && isspace (c2)))
{
  while (c2 != '\n')
    {
      c2 = *t2++;
      if (! ISSPACE (c2)(1 && isspace (c2)))
	{
	  --t2;
	  c2 = ' ';
	  break;
	}
    }
}

     if (c1 != c2)
{
  /* If we went too far when doing the simple test
     for equality, go back to the first non-white-space
     character in both sides and try again.  */
  if (c2 == ' ' && c1 != '\n'
      && (unsigned char const *) s1 + 1 < t1
      && ISSPACE(t1[-2])(1 && isspace (t1[-2])))
    {
      --t1;
      continue;
    }
  if (c1 == ' ' && c2 != '\n'
      && (unsigned char const *) s2 + 1 < t2
      && ISSPACE(t2[-2])(1 && isspace (t2[-2])))
    {
      --t2;
      continue;
    }
}
   }

 /* Lowercase all letters if -i is specified.  */

 if (ignore_case_flag)
   {
     if (ISUPPER (c1)(1 && isupper (c1)))
c1 = tolower (c1);
     if (ISUPPER (c2)(1 && isupper (c2)))
c2 = tolower (c2);
   }

 if (c1 != c2)
   break;
}
    if (c1 == '\n')
return 0;
  }

return (1);
523}
524
525/* Find the consecutive changes at the start of the script START.
 Return the last link before the first gap.  */

528struct change *
529find_change (start)
   struct change *start;
531{
return start;
533}

535struct change *
536find_reverse_change (start)
   struct change *start;
538{
return start;
540}
541
542/* Divide SCRIPT into pieces by calling HUNKFUN and
 print each piece with PRINTFUN.
 Both functions take one arg, an edit script.

 HUNKFUN is called with the tail of the script
 and returns the last link that belongs together with the start
 of the tail.

 PRINTFUN takes a subscript which belongs together (with a null
 link at the end) and prints it.  */

553void
554print_script (script, hunkfun, printfun)
   struct change *script;
   struct change * (*hunkfun) PARAMS((struct change *))(struct change *);
   void (*printfun) PARAMS((struct change *))(struct change *);
558{
struct change *next = script;

while (next)
  {
    struct change *this, *end;

    /* Find a set of changes that belong together.  */
    this = next;
    end = (*hunkfun) (next);

    /* Disconnect them from the rest of the changes,
making them a hunk, and remember the rest for next iteration.  */
    next = end->link;
    end->link = 0;
573#ifdef DEBUG
    debug_script (this);
575#endif

    /* Print this hunk.  */
    (*printfun) (this);

    /* Reconnect the script so it will all be freed properly.  */
    end->link = next;
  }
583}
584
585/* Print the text of a single line LINE,
 flagging it with the characters in LINE_FLAG (which say whether
 the line is inserted, deleted, changed, etc.).  */

589void
590print_1_line (line_flag, line)
   char const *line_flag;
   char const * const *line;
593{
char const *text = line[0], *limit = line[1]; /* Help the compiler.  */
char const *flag_format = 0;

/* If -T was specified, use a Tab between the line-flag and the text.
   Otherwise use a Space (as Unix diff does).
   Print neither space nor tab if line-flags are empty.  */

if (line_flag && *line_flag)
  {
    flag_format = tab_align_flag ? "%s\t" : "%s ";
    printf_output (flag_format, line_flag);
  }

output_1_line (text, limit, flag_format, line_flag);

if ((!line_flag || line_flag[0]) && limit[-1] != '\n')
  printf_output ("\n\\ No newline at end of file\n");
611}

613/* Output a line from TEXT up to LIMIT.  Without -t, output verbatim.
 With -t, expand white space characters to spaces, and if FLAG_FORMAT
 is nonzero, output it with argument LINE_FLAG after every
 internal carriage return, so that tab stops continue to line up.  */

618void
619output_1_line (text, limit, flag_format, line_flag)
   char const *text, *limit, *flag_format, *line_flag;
621{
if (!tab_expand_flag)
  write_output (text, limit - text);
else
  {
    register unsigned char c;
    register char const *t = text;
    register unsigned column = 0;
    /* CC is used to avoid taking the address of the register
       variable C.  */
    char cc;

    while (t < limit)
switch ((c = *t++))
 {
 case '\t':
   {
     unsigned spaces = TAB_WIDTH8 - column % TAB_WIDTH8;
     column += spaces;
     do
write_output (" ", 1);
     while (--spaces);
   }
   break;

 case '\r':
   write_output ("\r", 1);
   if (flag_format && t < limit && *t != '\n')
     printf_output (flag_format, line_flag);
   column = 0;
   break;

 case '\b':
   if (column == 0)
     continue;
   column--;
   write_output ("\b", 1);
   break;

 default:
   if (ISPRINT (c)(1 && isprint (c)))
     column++;
   cc = c;
   write_output (&cc, 1);
   break;
 }
  }
668}

670int
671change_letter (inserts, deletes)
   int inserts, deletes;
673{
if (!inserts)
  return 'd';
else if (!deletes)
  return 'a';
else
  return 'c';
680}
681
682/* Translate an internal line number (an index into diff's table of lines)
 into an actual line number in the input file.
 The internal line number is LNUM.  FILE points to the data on the file.

 Internal line numbers count from 0 starting after the prefix.
 Actual line numbers count from 1 within the entire file.  */

689int
690translate_line_number (file, lnum)
   struct file_data const *file;
   int lnum;
693{
return lnum + file->prefix_lines + 1;
695}

697void
698translate_range (file, a, b, aptr, bptr)
   struct file_data const *file;
   int a, b;
   int *aptr, *bptr;
702{
*aptr = translate_line_number (file, a - 1) + 1;
*bptr = translate_line_number (file, b + 1) - 1;
705}

707/* Print a pair of line numbers with SEPCHAR, translated for file FILE.
 If the two numbers are identical, print just one number.

 Args A and B are internal line numbers.
 We print the translated (real) line numbers.  */

713void
714print_number_range (sepchar, file, a, b)
   int sepchar;
   struct file_data *file;
   int a, b;
718{
int trans_a, trans_b;
translate_range (file, a, b, &trans_a, &trans_b);

/* Note: we can have B < A in the case of a range of no lines.
   In this case, we should print the line number before the range,
   which is B.  */
if (trans_b > trans_a)
  printf_output ("%d%c%d", trans_a, sepchar, trans_b);
else
  printf_output ("%d", trans_b);
729}
730
731/* Look at a hunk of edit script and report the range of lines in each file
 that it applies to.  HUNK is the start of the hunk, which is a chain
 of `struct change'.  The first and last line numbers of file 0 are stored in
 *FIRST0 and *LAST0, and likewise for file 1 in *FIRST1 and *LAST1.
 Note that these are internal line numbers that count from 0.

 If no lines from file 0 are deleted, then FIRST0 is LAST0+1.

 Also set *DELETES nonzero if any lines of file 0 are deleted
 and set *INSERTS nonzero if any lines of file 1 are inserted.
 If only ignorable lines are inserted or deleted, both are
 set to 0.  */

744void
745analyze_hunk (hunk, first0, last0, first1, last1, deletes, inserts)
   struct change *hunk;
   int *first0, *last0, *first1, *last1;
   int *deletes, *inserts;
749{
int l0, l1, show_from, show_to;
int i;
int trivial = ignore_blank_lines_flag || ignore_regexp_list;
struct change *next;

show_from = show_to = 0;

*first0 = hunk->line0;
*first1 = hunk->line1;

next = hunk;
do
  {
    l0 = next->line0 + next->deleted - 1;
    l1 = next->line1 + next->inserted - 1;
    show_from += next->deleted;
    show_to += next->inserted;

    for (i = next->line0; i <= l0 && trivial; i++)
if (!ignore_blank_lines_flag || files[0].linbuf[i][0] != '\n')
 {
   struct regexp_list *r;
   char const *line = files[0].linbuf[i];
   int len = files[0].linbuf[i + 1] - line;

   for (r = ignore_regexp_list; r; r = r->next)
     if (0 <= re_search (&r->buf, line, len, 0, len, 0))
break;	/* Found a match.  Ignore this line.  */
   /* If we got all the way through the regexp list without
      finding a match, then it's nontrivial.  */
   if (!r)
     trivial = 0;
 }

    for (i = next->line1; i <= l1 && trivial; i++)
if (!ignore_blank_lines_flag || files[1].linbuf[i][0] != '\n')
 {
   struct regexp_list *r;
   char const *line = files[1].linbuf[i];
   int len = files[1].linbuf[i + 1] - line;

   for (r = ignore_regexp_list; r; r = r->next)
     if (0 <= re_search (&r->buf, line, len, 0, len, 0))
break;	/* Found a match.  Ignore this line.  */
   /* If we got all the way through the regexp list without
      finding a match, then it's nontrivial.  */
   if (!r)
     trivial = 0;
 }
  }
while ((next = next->link) != 0);

*last0 = l0;
*last1 = l1;

/* If all inserted or deleted lines are ignorable,
   tell the caller to ignore this hunk.  */

if (trivial)
  show_from = show_to = 0;

*deletes = show_from;
*inserts = show_to;
813}
814
815/* Concatenate three strings, returning a newly malloc'd string.  */

817char *
818concat (s1, s2, s3)
   char const *s1, *s2, *s3;
820{
size_t len = strlen (s1) + strlen (s2) + strlen (s3);
char *new = xmalloc (len + 1);
sprintf (new, "%s%s%s", s1, s2, s3);
return new;
825}

827/* Yield the newly malloc'd pathname
 of the file in DIR whose filename is FILE.  */

830char *
831dir_file_pathname (dir, file)
   char const *dir, *file;
833{
char const *p = filename_lastdirchar (dir)strrchr (dir, '/');
return concat (dir, "/" + (p && !p[1]), file);
836}
837
838void
839debug_script (sp)
   struct change *sp;
841{
fflush (stdout(&__sF[1]));
for (; sp; sp = sp->link)
  fprintf (stderr(&__sF[2]), "%3d %3d delete %d insert %d\n",
    sp->line0, sp->line1, sp->deleted, sp->inserted);
fflush (stderr(&__sF[2]));
847}