NetBSD/gnu/usr.bin/diff/sdiff.c

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/* SDIFF -- interactive merge front end to diff
Copyright (C) 1992, 1993 Free Software Foundation, Inc.
This file is part of GNU DIFF.
GNU DIFF 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.
GNU DIFF 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 GNU DIFF; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#ifndef lint
static char *rcsid = "$Id: sdiff.c,v 1.4 1993/09/29 21:37:12 jtc Exp $";
#endif
/* GNU SDIFF was written by Thomas Lord. */
#include "system.h"
#include <stdio.h>
#include <ctype.h>
#include <signal.h>
#include "getopt.h"
/* Size of chunks read from files which must be parsed into lines. */
#define SDIFF_BUFSIZE ((size_t) 65536)
/* Default name of the diff program */
#ifndef DIFF_PROGRAM
#define DIFF_PROGRAM "/usr/bin/diff"
#endif
/* Users' editor of nonchoice */
#ifndef DEFAULT_EDITOR
#define DEFAULT_EDITOR "ed"
#endif
extern char version_string[];
static char const *prog;
static char const *diffbin = DIFF_PROGRAM;
static char const *edbin = DEFAULT_EDITOR;
static char *tmpname;
static int volatile tmpmade;
static pid_t volatile diffpid;
struct line_filter;
static FILE *ck_fdopen PARAMS((int, char const *));
static FILE *ck_fopen PARAMS((char const *, char const *));
static RETSIGTYPE catchsig PARAMS((int));
static VOID *xmalloc PARAMS((size_t));
static char const *expand_name PARAMS((char *, int, char const *));
static int edit PARAMS((struct line_filter *, int, struct line_filter *, int, FILE*));
static int interact PARAMS((struct line_filter *, struct line_filter *, struct line_filter *, FILE*));
static int lf_snarf PARAMS((struct line_filter *, char *, size_t));
static int skip_white PARAMS((void));
static size_t ck_fread PARAMS((char *, size_t, FILE *));
static size_t lf_refill PARAMS((struct line_filter *));
static void checksigs PARAMS((void));
static void ck_fclose PARAMS((FILE *));
static void ck_fflush PARAMS((FILE *));
static void ck_fwrite PARAMS((char const *, size_t, FILE *));
static void cleanup PARAMS((void));
static void diffarg PARAMS((char const *));
static void execdiff PARAMS((int, char const *, char const *, char const *));
static void exiterr PARAMS((void));
static void fatal PARAMS((char const *));
static void flush_line PARAMS((void));
static void give_help PARAMS((void));
static void lf_copy PARAMS((struct line_filter *, int, FILE *));
static void lf_init PARAMS((struct line_filter *, FILE *));
static void lf_skip PARAMS((struct line_filter *, int));
static void perror_fatal PARAMS((char const *));
static void trapsigs PARAMS((void));
static void untrapsig PARAMS((int));
static void usage PARAMS((void));
/* this lossage until the gnu libc conquers the universe */
#define PVT_tmpdir "/tmp"
static char *private_tempnam PARAMS((char const *, char const *, int, size_t *));
static int diraccess PARAMS((char const *));
static int exists PARAMS((char const *));
/* Options: */
/* name of output file if -o spec'd */
static char *out_file;
/* do not print common lines if true, set by -s option */
static int suppress_common_flag;
static struct option const longopts[] =
{
{"ignore-blank-lines", 0, 0, 'B'},
{"speed-large-files", 0, 0, 'H'},
{"ignore-matching-lines", 1, 0, 'I'},
{"ignore-all-space", 0, 0, 'W'}, /* swap W and w for historical reasons */
{"text", 0, 0, 'a'},
{"ignore-space-change", 0, 0, 'b'},
{"minimal", 0, 0, 'd'},
{"ignore-case", 0, 0, 'i'},
{"left-column", 0, 0, 'l'},
{"output", 1, 0, 'o'},
{"suppress-common-lines", 0, 0, 's'},
{"expand-tabs", 0, 0, 't'},
{"width", 1, 0, 'w'},
{"version", 0, 0, 'v'},
{0, 0, 0, 0}
};
/* prints usage message and quits */
static void
usage ()
{
fprintf (stderr, "Usage: %s [options] from-file to-file\n", prog);
fprintf (stderr, "Options:\n\
[-abBdHilstv] [-I regexp] [-o outfile] [-w columns]\n\
[--text] [--minimal] [--speed-large-files] [--expand-tabs]\n\
[--ignore-case] [--ignore-matching-lines=regexp]\n\
[--ignore-space-change] [--ignore-blank-lines] [--ignore-all-space]\n\
[--suppress-common-lines] [--left-column] [--output=outfile]\n\
[--version] [--width=columns]\n");
exit (2);
}
static void
cleanup ()
{
if (0 < diffpid)
kill (diffpid, SIGPIPE);
if (tmpmade)
unlink (tmpname);
}
static void
exiterr ()
{
cleanup ();
untrapsig (0);
checksigs ();
exit (2);
}
static void
fatal (msg)
char const *msg;
{
fprintf (stderr, "%s: %s\n", prog, msg);
exiterr ();
}
static void
perror_fatal (msg)
char const *msg;
{
int e = errno;
checksigs ();
fprintf (stderr, "%s: ", prog);
errno = e;
perror (msg);
exiterr ();
}
/* malloc freely or DIE! */
static VOID *
xmalloc (size)
size_t size;
{
VOID *r = (VOID *) malloc (size);
if (!r)
fatal ("virtual memory exhausted");
return r;
}
static FILE *
ck_fopen (fname, type)
char const *fname, *type;
{
FILE *r = fopen (fname, type);
if (!r)
perror_fatal (fname);
return r;
}
static FILE *
ck_fdopen (fd, type)
int fd;
char const *type;
{
FILE *r = fdopen (fd, type);
if (!r)
perror_fatal ("fdopen");
return r;
}
static void
ck_fclose (f)
FILE *f;
{
if (fclose (f))
perror_fatal ("input/output error");
}
static size_t
ck_fread (buf, size, f)
char *buf;
size_t size;
FILE *f;
{
size_t r = fread (buf, sizeof (char), size, f);
if (r == 0 && ferror (f))
perror_fatal ("input error");
return r;
}
static void
ck_fwrite (buf, size, f)
char const *buf;
size_t size;
FILE *f;
{
if (fwrite (buf, sizeof (char), size, f) != size)
perror_fatal ("output error");
}
static void
ck_fflush (f)
FILE *f;
{
if (fflush (f) != 0)
perror_fatal ("output error");
}
#if !HAVE_MEMCHR
char *
memchr (s, c, n)
char const *s;
int c;
size_t n;
{
unsigned char const *p = (unsigned char const *) s, *lim = p + n;
for (; p < lim; p++)
if (*p == c)
return (char *) p;
return 0;
}
#endif
#ifndef HAVE_WAITPID
/* Emulate waitpid well enough for sdiff, which has at most two children. */
static pid_t
waitpid (pid, stat_loc, options)
pid_t pid;
int *stat_loc;
int options;
{
static int ostatus;
static pid_t opid;
int npid, status;
if (pid == opid)
{
opid = 0;
status = ostatus;
}
else
while ((npid = wait (&status)) != pid)
{
if (npid < 0)
return npid;
opid = npid;
ostatus = status;
}
*stat_loc = status;
return pid;
}
#endif
static char const *
expand_name (name, isdir, other_name)
char *name;
int isdir;
char const *other_name;
{
if (strcmp (name, "-") == 0)
fatal ("cannot interactively merge standard input");
if (!isdir)
return name;
else
{
/* Yield NAME/BASE, where BASE is OTHER_NAME's basename. */
char const
*p = strrchr (other_name, '/'),
*base = p ? p+1 : other_name;
size_t namelen = strlen (name), baselen = strlen (base);
char *r = xmalloc (namelen + baselen + 2);
memcpy (r, name, namelen);
r[namelen] = '/';
memcpy (r + namelen + 1, base, baselen + 1);
return r;
}
}
struct line_filter {
FILE *infile;
char *bufpos;
char *buffer;
char *buflim;
};
static void
lf_init (lf, infile)
struct line_filter *lf;
FILE *infile;
{
lf->infile = infile;
lf->bufpos = lf->buffer = lf->buflim = xmalloc (SDIFF_BUFSIZE + 1);
lf->buflim[0] = '\n';
}
/* Fill an exhausted line_filter buffer from its INFILE */
static size_t
lf_refill (lf)
struct line_filter *lf;
{
size_t s = ck_fread (lf->buffer, SDIFF_BUFSIZE, lf->infile);
lf->bufpos = lf->buffer;
lf->buflim = lf->buffer + s;
lf->buflim[0] = '\n';
checksigs ();
return s;
}
/* Advance LINES on LF's infile, copying lines to OUTFILE */
static void
lf_copy (lf, lines, outfile)
struct line_filter *lf;
int lines;
FILE *outfile;
{
char *start = lf->bufpos;
while (lines)
{
lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
if (! lf->bufpos)
{
ck_fwrite (start, lf->buflim - start, outfile);
if (! lf_refill (lf))
return;
start = lf->bufpos;
}
else
{
--lines;
++lf->bufpos;
}
}
ck_fwrite (start, lf->bufpos - start, outfile);
}
/* Advance LINES on LF's infile without doing output */
static void
lf_skip (lf, lines)
struct line_filter *lf;
int lines;
{
while (lines)
{
lf->bufpos = (char *) memchr (lf->bufpos, '\n', lf->buflim - lf->bufpos);
if (! lf->bufpos)
{
if (! lf_refill (lf))
break;
}
else
{
--lines;
++lf->bufpos;
}
}
}
/* Snarf a line into a buffer. Return EOF if EOF, 0 if error, 1 if OK. */
static int
lf_snarf (lf, buffer, bufsize)
struct line_filter *lf;
char *buffer;
size_t bufsize;
{
char *start = lf->bufpos;
for (;;)
{
char *next = (char *) memchr (start, '\n', lf->buflim + 1 - start);
size_t s = next - start;
if (bufsize <= s)
return 0;
memcpy (buffer, start, s);
if (next < lf->buflim)
{
buffer[s] = 0;
lf->bufpos = next + 1;
return 1;
}
if (! lf_refill (lf))
return s ? 0 : EOF;
buffer += s;
bufsize -= s;
start = next;
}
}
int
main (argc, argv)
int argc;
char *argv[];
{
int opt;
int version_requested = 0;
char *editor = getenv ("EDITOR");
char *differ = getenv ("DIFF");
prog = argv[0];
if (editor)
edbin = editor;
if (differ)
diffbin = differ;
diffarg ("diff");
/* parse command line args */
while ((opt = getopt_long (argc, argv, "abBdHiI:lo:stvw:W", longopts, 0))
!= EOF)
{
switch (opt)
{
case 'a':
diffarg ("-a");
break;
case 'b':
diffarg ("-b");
break;
case 'B':
diffarg ("-B");
break;
case 'd':
diffarg ("-d");
break;
case 'H':
diffarg ("-H");
break;
case 'i':
diffarg ("-i");
break;
case 'I':
diffarg ("-I");
diffarg (optarg);
break;
case 'l':
diffarg ("--left-column");
break;
case 'o':
out_file = optarg;
break;
case 's':
suppress_common_flag = 1;
break;
case 't':
diffarg ("-t");
break;
case 'v':
version_requested = 1;
fprintf (stderr, "GNU sdiff version %s\n", version_string);
ck_fflush (stderr);
break;
case 'w':
diffarg ("-W");
diffarg (optarg);
break;
case 'W':
diffarg ("-w");
break;
default:
usage ();
}
}
/* check: did user just want version message? if so exit. */
if (version_requested && argc - optind == 0)
exit (0);
if (argc - optind != 2)
usage ();
if (! out_file)
/* easy case: diff does everything for us */
execdiff (suppress_common_flag, "-y", argv[optind], argv[optind + 1]);
else
{
FILE *left, *right, *out, *diffout;
int diff_fds[2];
int interact_ok;
pid_t pid;
struct line_filter lfilt;
struct line_filter rfilt;
struct line_filter diff_filt;
int leftdir = diraccess (argv[optind]);
int rightdir = diraccess (argv[optind + 1]);
if (leftdir && rightdir)
fatal ("both files to be compared are directories");
left = ck_fopen (expand_name (argv[optind], leftdir, argv[optind + 1]), "r");
;
right = ck_fopen (expand_name (argv[optind + 1], rightdir, argv[optind]), "r");
out = ck_fopen (out_file, "w");
if (pipe (diff_fds))
perror_fatal ("pipe");
trapsigs ();
diffpid = pid = vfork ();
if (pid == 0)
{
signal (SIGINT, SIG_IGN); /* in case user interrupts editor */
signal (SIGPIPE, SIG_DFL);
close (diff_fds[0]);
if (diff_fds[1] != STDOUT_FILENO)
{
dup2 (diff_fds[1], STDOUT_FILENO);
close (diff_fds[1]);
}
execdiff (0, "--sdiff-merge-assist", argv[optind], argv[optind + 1]);
}
if (pid < 0)
perror_fatal ("fork failed");
close (diff_fds[1]);
diffout = ck_fdopen (diff_fds[0], "r");
lf_init (&diff_filt, diffout);
lf_init (&lfilt, left);
lf_init (&rfilt, right);
interact_ok = interact (&diff_filt, &lfilt, &rfilt, out);
ck_fclose (diffout);
ck_fclose (left);
ck_fclose (right);
ck_fclose (out);
{
int wstatus;
while (waitpid (pid, &wstatus, 0) < 0)
if (errno == EINTR)
checksigs ();
else
perror_fatal ("wait failed");
diffpid = 0;
if (tmpmade)
{
unlink (tmpname);
tmpmade = 0;
}
if (! interact_ok)
exiterr ();
if (! (WIFEXITED (wstatus) && WEXITSTATUS (wstatus) < 2))
fatal ("Subsidiary diff failed");
untrapsig (0);
checksigs ();
exit (WEXITSTATUS (wstatus));
}
}
return 0; /* Fool -Wall . . . */
}
static char const **diffargv;
static void
diffarg (a)
char const *a;
{
static unsigned diffargs, diffargsmax;
if (diffargs == diffargsmax)
{
if (! diffargsmax)
{
diffargv = (char const **) xmalloc (sizeof (char));
diffargsmax = 8;
}
diffargsmax *= 2;
diffargv = (char const **) realloc (diffargv,
diffargsmax * sizeof (char const *));
if (! diffargv)
fatal ("out of memory");
}
diffargv[diffargs++] = a;
}
static void
execdiff (differences_only, option, file1, file2)
int differences_only;
char const *option, *file1, *file2;
{
if (differences_only)
diffarg ("--suppress-common-lines");
diffarg (option);
diffarg ("--");
diffarg (file1);
diffarg (file2);
diffarg (0);
execvp (diffbin, (char **) diffargv);
write (STDERR_FILENO, diffbin, strlen (diffbin));
write (STDERR_FILENO, ": not found\n", 12);
_exit (2);
}
/* Signal handling */
#define NUM_SIGS (sizeof (sigs) / sizeof (*sigs))
static int const sigs[] = {
#ifdef SIGHUP
SIGHUP,
#endif
#ifdef SIGQUIT
SIGQUIT,
#endif
#ifdef SIGTERM
SIGTERM,
#endif
#ifdef SIGXCPU
SIGXCPU,
#endif
#ifdef SIGXFSZ
SIGXFSZ,
#endif
SIGINT,
SIGPIPE
};
/* Prefer `sigaction' if it is available, since `signal' can lose signals. */
#if HAVE_SIGACTION
static struct sigaction initial_action[NUM_SIGS];
#define initial_handler(i) (initial_action[i].sa_handler)
#else
static RETSIGTYPE (*initial_action[NUM_SIGS]) ();
#define initial_handler(i) (initial_action[i])
#endif
static int volatile ignore_SIGINT;
static int volatile signal_received;
static int sigs_trapped;
static RETSIGTYPE
catchsig (s)
int s;
{
#if ! HAVE_SIGACTION
signal (s, SIG_IGN);
#endif
if (! (s == SIGINT && ignore_SIGINT))
signal_received = s;
}
static void
trapsigs ()
{
int i;
#if HAVE_SIGACTION
struct sigaction catchaction;
bzero (&catchaction, sizeof (catchaction));
catchaction.sa_handler = catchsig;
#ifdef SA_INTERRUPT
/* Non-Posix BSD-style systems like SunOS 4.1.x need this
so that `read' calls are interrupted properly. */
catchaction.sa_flags = SA_INTERRUPT;
#endif
sigemptyset (&catchaction.sa_mask);
for (i = 0; i < NUM_SIGS; i++)
sigaddset (&catchaction.sa_mask, sigs[i]);
for (i = 0; i < NUM_SIGS; i++)
{
sigaction (sigs[i], 0, &initial_action[i]);
if (initial_handler (i) != SIG_IGN
&& sigaction (sigs[i], &catchaction, 0) != 0)
fatal ("signal error");
}
#else /* ! HAVE_SIGACTION */
for (i = 0; i < NUM_SIGS; i++)
{
initial_action[i] = signal (sigs[i], SIG_IGN);
if (initial_handler (i) != SIG_IGN
&& signal (sigs[i], catchsig) != SIG_IGN)
fatal ("signal error");
}
#endif /* ! HAVE_SIGACTION */
sigs_trapped = 1;
}
/* Untrap signal S, or all trapped signals if S is zero. */
static void
untrapsig (s)
int s;
{
int i;
if (sigs_trapped)
for (i = 0; i < NUM_SIGS; i++)
if ((!s || sigs[i] == s) && initial_handler (i) != SIG_IGN)
#if HAVE_SIGACTION
sigaction (sigs[i], &initial_action[i], 0);
#else
signal (sigs[i], initial_action[i]);
#endif
}
/* Exit if a signal has been received. */
static void
checksigs ()
{
int s = signal_received;
if (s)
{
cleanup ();
/* Yield an exit status indicating that a signal was received. */
untrapsig (s);
kill (getpid (), s);
/* That didn't work, so exit with error status. */
exit (2);
}
}
static void
give_help ()
{
fprintf (stderr,"l:\tuse the left version\n");
fprintf (stderr,"r:\tuse the right version\n");
fprintf (stderr,"e l:\tedit then use the left version\n");
fprintf (stderr,"e r:\tedit then use the right version\n");
fprintf (stderr,"e b:\tedit then use the left and right versions concatenated\n");
fprintf (stderr,"e:\tedit a new version\n");
fprintf (stderr,"s:\tsilently include common lines\n");
fprintf (stderr,"v:\tverbosely include common lines\n");
fprintf (stderr,"q:\tquit\n");
}
static int
skip_white ()
{
int c;
while (isspace (c = getchar ()) && c != '\n')
checksigs ();
if (ferror (stdin))
perror_fatal ("input error");
return c;
}
static void
flush_line ()
{
int c;
while ((c = getchar ()) != '\n' && c != EOF)
;
if (ferror (stdin))
perror_fatal ("input error");
}
/* interpret an edit command */
static int
edit (left, lenl, right, lenr, outfile)
struct line_filter *left;
int lenl;
struct line_filter *right;
int lenr;
FILE *outfile;
{
for (;;)
{
int cmd0, cmd1;
int gotcmd = 0;
cmd1 = 0; /* Pacify `gcc -W'. */
while (!gotcmd)
{
if (putchar ('%') != '%')
perror_fatal ("output error");
ck_fflush (stdout);
cmd0 = skip_white ();
switch (cmd0)
{
case 'l': case 'r': case 's': case 'v': case 'q':
if (skip_white () != '\n')
{
give_help ();
flush_line ();
continue;
}
gotcmd = 1;
break;
case 'e':
cmd1 = skip_white ();
switch (cmd1)
{
case 'l': case 'r': case 'b':
if (skip_white () != '\n')
{
give_help ();
flush_line ();
continue;
}
gotcmd = 1;
break;
case '\n':
gotcmd = 1;
break;
default:
give_help ();
flush_line ();
continue;
}
break;
case EOF:
if (feof (stdin))
{
gotcmd = 1;
cmd0 = 'q';
break;
}
/* falls through */
default:
flush_line ();
/* falls through */
case '\n':
give_help ();
continue;
}
}
switch (cmd0)
{
case 'l':
lf_copy (left, lenl, outfile);
lf_skip (right, lenr);
return 1;
case 'r':
lf_copy (right, lenr, outfile);
lf_skip (left, lenl);
return 1;
case 's':
suppress_common_flag = 1;
break;
case 'v':
suppress_common_flag = 0;
break;
case 'q':
return 0;
case 'e':
if (! tmpname && ! (tmpname = private_tempnam (0, "sdiff", 1, 0)))
perror_fatal ("temporary file name");
tmpmade = 1;
{
FILE *tmp = ck_fopen (tmpname, "w+");
if (cmd1 == 'l' || cmd1 == 'b')
lf_copy (left, lenl, tmp);
else
lf_skip (left, lenl);
if (cmd1 == 'r' || cmd1 == 'b')
lf_copy (right, lenr, tmp);
else
lf_skip (right, lenr);
ck_fflush (tmp);
{
pid_t pid;
int wstatus;
ignore_SIGINT = 1;
checksigs ();
pid = vfork ();
if (pid == 0)
{
char const *argv[3];
int i = 0;
argv[i++] = edbin;
argv[i++] = tmpname;
argv[i++] = 0;
execvp (edbin, (char **) argv);
write (STDERR_FILENO, edbin, strlen (edbin));
write (STDERR_FILENO, ": not found\n", 12);
_exit (1);
}
if (pid < 0)
perror_fatal ("fork failed");
while (waitpid (pid, &wstatus, 0) < 0)
if (errno == EINTR)
checksigs ();
else
perror_fatal ("wait failed");
ignore_SIGINT = 0;
if (! (WIFEXITED (wstatus) && WEXITSTATUS (wstatus) < 1))
fatal ("Subsidiary editor failed");
}
if (fseek (tmp, 0L, SEEK_SET) != 0)
perror_fatal ("fseek");
{
/* SDIFF_BUFSIZE is too big for a local var
in some compilers, so we allocate it dynamically. */
char *buf = xmalloc (SDIFF_BUFSIZE);
size_t size;
while ((size = ck_fread (buf, SDIFF_BUFSIZE, tmp)) != 0)
{
checksigs ();
ck_fwrite (buf, size, outfile);
}
ck_fclose (tmp);
free (buf);
}
return 1;
}
default:
give_help ();
break;
}
}
}
/* Alternately reveal bursts of diff output and handle user commands. */
static int
interact (diff, left, right, outfile)
struct line_filter *diff;
struct line_filter *left;
struct line_filter *right;
FILE *outfile;
{
for (;;)
{
char diff_help[256];
int snarfed = lf_snarf (diff, diff_help, sizeof (diff_help));
if (snarfed <= 0)
return snarfed;
checksigs ();
switch (diff_help[0])
{
case ' ':
puts (diff_help + 1);
break;
case 'i':
{
int lenl = atoi (diff_help + 1), lenr, lenmax;
char *p = strchr (diff_help, ',');
if (!p)
fatal (diff_help);
lenr = atoi (p + 1);
lenmax = max (lenl, lenr);
if (suppress_common_flag)
lf_skip (diff, lenmax);
else
lf_copy (diff, lenmax, stdout);
lf_copy (left, lenl, outfile);
lf_skip (right, lenr);
break;
}
case 'c':
{
int lenl = atoi (diff_help + 1), lenr;
char *p = strchr (diff_help, ',');
if (!p)
fatal (diff_help);
lenr = atoi (p + 1);
lf_copy (diff, max (lenl, lenr), stdout);
if (! edit (left, lenl, right, lenr, outfile))
return 0;
break;
}
default:
fatal (diff_help);
break;
}
}
}
/* temporary lossage: this is torn from gnu libc */
/* Return nonzero if DIR is an existing directory. */
static int
diraccess (dir)
char const *dir;
{
struct stat buf;
return stat (dir, &buf) == 0 && S_ISDIR (buf.st_mode);
}
/* Return nonzero if FILE exists. */
static int
exists (file)
char const *file;
{
struct stat buf;
return stat (file, &buf) == 0;
}
/* These are the characters used in temporary filenames. */
static char const letters[] =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
/* Generate a temporary filename.
If DIR_SEARCH is nonzero, DIR and PFX are used as
described for tempnam. If not, a temporary filename
in P_tmpdir with no special prefix is generated. If LENPTR
is not 0, *LENPTR is set the to length (including the
terminating '\0') of the resultant filename, which is returned.
This goes through a cyclic pattern of all possible filenames
consisting of five decimal digits of the current pid and three
of the characters in `letters'. Data for tempnam and tmpnam
is kept separate, but when tempnam is using P_tmpdir and no
prefix (i.e, it is identical to tmpnam), the same data is used.
Each potential filename is tested for an already-existing file of
the same name, and no name of an existing file will be returned.
When the cycle reaches its end (12345ZZZ), 0 is returned. */
static char *
private_tempnam (dir, pfx, dir_search, lenptr)
char const *dir;
char const *pfx;
int dir_search;
size_t *lenptr;
{
static char const tmpdir[] = PVT_tmpdir;
static struct
{
char buf[3];
char *s;
size_t i;
} infos[2], *info;
static char *buf;
static size_t bufsize = 1;
static pid_t oldpid = 0;
pid_t pid = getpid ();
register size_t len, plen;
if (dir_search)
{
register char const *d = getenv ("TMPDIR");
if (d && !diraccess (d))
d = 0;
if (!d && dir && diraccess (dir))
d = dir;
if (!d && diraccess (tmpdir))
d = tmpdir;
if (!d && diraccess ("/tmp"))
d = "/tmp";
if (!d)
{
errno = ENOENT;
return 0;
}
dir = d;
}
else
dir = tmpdir;
if (pfx && *pfx)
{
plen = strlen (pfx);
if (plen > 5)
plen = 5;
}
else
plen = 0;
if (dir != tmpdir && !strcmp (dir, tmpdir))
dir = tmpdir;
info = &infos[(plen == 0 && dir == tmpdir) ? 1 : 0];
if (pid != oldpid)
{
oldpid = pid;
info->buf[0] = info->buf[1] = info->buf[2] = '0';
info->s = &info->buf[0];
info->i = 0;
}
len = strlen (dir) + 1 + plen + 8;
if (bufsize <= len)
{
do
{
bufsize *= 2;
}
while (bufsize <= len);
if (buf)
free (buf);
buf = xmalloc (bufsize);
}
for (;;)
{
*info->s = letters[info->i];
sprintf (buf, "%s/%.*s%.5lu%.3s", dir, (int) plen, pfx,
(unsigned long) pid % 100000, info->buf);
if (!exists (buf))
break;
++info->i;
if (info->i > sizeof (letters) - 1)
{
info->i = 0;
if (info->s == &info->buf[2])
{
errno = EEXIST;
return 0;
}
++info->s;
}
}
if (lenptr)
*lenptr = len;
return buf;
}