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/*
* Copyright (c) 1987, 1989 University of Maryland
* Department of Computer Science. All rights reserved.
* Permission to copy for any purpose is hereby granted
* so long as this copyright notice remains intact.
*/
/*
* Print an error message with an optional system error number, and
* optionally quit.
*
*/
#include <stdio.h>
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "types.h" /* for HAVE_VPRINTF */
#include "error.h"
#include "tempfile.h"
extern char *ProgName; /* program name from argv[0] */
#include <errno.h>
#ifndef errno
extern int errno;
#endif
static FILE *trap_file; /* error diversion file, if any */
static void (*trap_fn)(int, const char *); /* trap function */
static char *trap_buf; /* buffer for trapped error strings */
static int trap_size; /* size of trap_buf */
#ifndef KPATHSEA
extern char *malloc(), *realloc();
#endif
#if !defined (HAVE_STRERROR) && !defined (strerror)
static char *
strerror (int errnum)
{
extern char *sys_errlist[];
extern int sys_nerr;
return 0 < errnum && errnum <= sys_nerr
? sys_errlist[errnum] : "Unknown system error";
}
#endif /* not HAVE_STRERROR && not strerror */
/*
* Read a trapped error into trap_buf.
* Return a pointer to the (NUL-terminated) text.
* If something goes wrong, return something else printable.
*/
static const char *
readback(void)
{
int nbytes = ftell(trap_file) + 1;
if (nbytes > trap_size) {
if (trap_buf == NULL)
trap_buf = malloc((unsigned)nbytes);
else
trap_buf = realloc(trap_buf, (unsigned)nbytes);
if (trap_buf == NULL) {
trap_size = 0;
return ("Ouch! Lost error text: out of memory?");
}
}
rewind(trap_file); /* now can read */
nbytes = fread(trap_buf, 1, nbytes, trap_file);
if (nbytes < 0)
return ("Ouch! Trouble reading error text!");
trap_buf[nbytes] = 0;
return (trap_buf);
}
/*
* Print an error message to the error output (either stderr, or
* if trapping errors, to the error trap file). We precede this
* with the program's name and an optional string (a0), then use
* the format and variable argument list, then append an optional
* Unix error string. Finally, if errors are being trapped, we
* pass the error text and the quit flag to the trap function.
*
* In the interest of `look and feel', if errors are being trapped,
* the program name is omitted.
*/
static void
verror(int quit, const char *a0, const char *fmt, va_list l, int e)
{
register FILE *fp = trap_file;
/* print to the trap file, if any, else stderr */
if ((fp = trap_file) != NULL)
rewind(fp); /* now can write */
else {
fp = stderr;
(void) fflush(fp);
}
if (trap_file == NULL)
(void) fprintf(fp, "%s: ", ProgName);
if (a0)
(void) fprintf(fp, "%s", a0);
(void) vfprintf(fp, fmt, l);
if (e)
(void) fprintf(fp, ": %s", strerror(e));
(void) putc('\n', fp);
(void) fflush(fp);
if (trap_file != NULL)
(*trap_fn)(quit, readback());
if (quit)
exit(quit);
}
/*
* Print an error message and optionally quit.
*/
void
error(int quit, int e, const char *fmt, ...)
{
va_list l;
va_start(l, fmt);
if (e < 0)
e = errno;
verror(quit, NULL, fmt, l, e);
va_end(l);
}
/*
* Panic (print to stderr and abort).
*/
void
panic(const char *fmt, ...)
{
va_list l;
va_start(l, fmt);
verror(0, "panic: ", fmt, l, 0);
va_end(l);
abort();
}
/*
* Enable error trapping: register the function fn as the trapper.
* If fn is NULL, stop trapping.
*/
void
SetErrorTrap(void (*fn)(int, const char *))
{
int tempfd;
char fname[BUFSIZ];
/* shut down any existing error trap */
if (trap_file) {
(void) fclose(trap_file);
trap_file = NULL;
}
if ((trap_fn = fn) == NULL)
return;
/* begin trapping */
if ((tempfd = MakeRWTempFile(fname)) < 0)
error(1, -1, "cannot create temporary file %s", fname);
if (trap_size == 0) {
trap_buf = malloc((unsigned)(trap_size = 1000));
if (trap_buf == 0)
error(1, -1,
"cannot get space for error buffer");
}
if ((trap_file = fdopen(tempfd, "r+")) == NULL)
error(1, -1, "cannot get stdio file for error trap");
}
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