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strsignal.c
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1993-06-29
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/* Extended support for using signal values.
Copyright (C) 1992 Free Software Foundation, Inc.
Written by Fred Fish. fnf@cygnus.com
This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
Libiberty 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include "config.h"
#include <stdio.h>
#include <signal.h>
/* Routines imported from standard C runtime libraries. */
#ifdef __STDC__
#include <stddef.h>
extern void *malloc (size_t size); /* 4.10.3.3 */
extern void *memset (void *s, int c, size_t n); /* 4.11.6.1 */
#else /* !__STDC__ */
extern char *malloc (); /* Standard memory allocater */
extern char *memset ();
#endif /* __STDC__ */
#ifndef NULL
# ifdef __STDC__
# define NULL (void *) 0
# else
# define NULL 0
# endif
#endif
#ifndef MAX
# define MAX(a,b) ((a) > (b) ? (a) : (b))
#endif
/* Translation table for signal values.
Note that this table is generally only accessed when it is used at runtime
to initialize signal name and message tables that are indexed by signal
value.
Not all of these signals will exist on all systems. This table is the only
thing that should have to be updated as new signal numbers are introduced.
It's sort of ugly, but at least its portable. */
static struct signal_info
{
int value; /* The numeric value from <signal.h> */
char *name; /* The equivalent symbolic value */
char *msg; /* Short message about this value */
} signal_table[] =
{
#if defined (SIGHUP)
SIGHUP, "SIGHUP", "Hangup",
#endif
#if defined (SIGINT)
SIGINT, "SIGINT", "Interrupt",
#endif
#if defined (SIGQUIT)
SIGQUIT, "SIGQUIT", "Quit",
#endif
#if defined (SIGILL)
SIGILL, "SIGILL", "Illegal instruction",
#endif
#if defined (SIGTRAP)
SIGTRAP, "SIGTRAP", "Trace/breakpoint trap",
#endif
/* Put SIGIOT before SIGABRT, so that if SIGIOT==SIGABRT then SIGABRT
overrides SIGIOT. SIGABRT is in ANSI and POSIX.1, and SIGIOT isn't. */
#if defined (SIGIOT)
SIGIOT, "SIGIOT", "IOT trap",
#endif
#if defined (SIGABRT)
SIGABRT, "SIGABRT", "Aborted",
#endif
#if defined (SIGEMT)
SIGEMT, "SIGEMT", "Emulation trap",
#endif
#if defined (SIGFPE)
SIGFPE, "SIGFPE", "Arithmetic exception",
#endif
#if defined (SIGKILL)
SIGKILL, "SIGKILL", "Killed",
#endif
#if defined (SIGBUS)
SIGBUS, "SIGBUS", "Bus error",
#endif
#if defined (SIGSEGV)
SIGSEGV, "SIGSEGV", "Segmentation fault",
#endif
#if defined (SIGSYS)
SIGSYS, "SIGSYS", "Bad system call",
#endif
#if defined (SIGPIPE)
SIGPIPE, "SIGPIPE", "Broken pipe",
#endif
#if defined (SIGALRM)
SIGALRM, "SIGALRM", "Alarm clock",
#endif
#if defined (SIGTERM)
SIGTERM, "SIGTERM", "Terminated",
#endif
#if defined (SIGUSR1)
SIGUSR1, "SIGUSR1", "User defined signal 1",
#endif
#if defined (SIGUSR2)
SIGUSR2, "SIGUSR2", "User defined signal 2",
#endif
/* Put SIGCLD before SIGCHLD, so that if SIGCLD==SIGCHLD then SIGCHLD
overrides SIGCLD. SIGCHLD is in POXIX.1 */
#if defined (SIGCLD)
SIGCLD, "SIGCLD", "Child status changed",
#endif
#if defined (SIGCHLD)
SIGCHLD, "SIGCHLD", "Child status changed",
#endif
#if defined (SIGPWR)
SIGPWR, "SIGPWR", "Power fail/restart",
#endif
#if defined (SIGWINCH)
SIGWINCH, "SIGWINCH", "Window size changed",
#endif
#if defined (SIGURG)
SIGURG, "SIGURG", "Urgent I/O condition",
#endif
#if defined (SIGIO)
/* "I/O pending has also been suggested, but is misleading since the
signal only happens when the process has asked for it, not everytime
I/O is pending. */
SIGIO, "SIGIO", "I/O possible",
#endif
#if defined (SIGPOLL)
SIGPOLL, "SIGPOLL", "Pollable event occurred",
#endif
#if defined (SIGSTOP)
SIGSTOP, "SIGSTOP", "Stopped (signal)",
#endif
#if defined (SIGTSTP)
SIGTSTP, "SIGTSTP", "Stopped (user)",
#endif
#if defined (SIGCONT)
SIGCONT, "SIGCONT", "Continued",
#endif
#if defined (SIGTTIN)
SIGTTIN, "SIGTTIN", "Stopped (tty input)",
#endif
#if defined (SIGTTOU)
SIGTTOU, "SIGTTOU", "Stopped (tty output)",
#endif
#if defined (SIGVTALRM)
SIGVTALRM, "SIGVTALRM", "Virtual timer expired",
#endif
#if defined (SIGPROF)
SIGPROF, "SIGPROF", "Profiling timer expired",
#endif
#if defined (SIGXCPU)
SIGXCPU, "SIGXCPU", "CPU time limit exceeded",
#endif
#if defined (SIGXFSZ)
SIGXFSZ, "SIGXFSZ", "File size limit exceeded",
#endif
#if defined (SIGWIND)
SIGWIND, "SIGWIND", "SIGWIND",
#endif
#if defined (SIGPHONE)
SIGPHONE, "SIGPHONE", "SIGPHONE",
#endif
#if defined (SIGLOST)
SIGLOST, "SIGLOST", "Resource lost",
#endif
#if defined (SIGWAITING)
SIGWAITING, "SIGWAITING", "Process's LWPs are blocked",
#endif
#if defined (SIGLWP)
SIGLWP, "SIGLWP", "Signal LWP",
#endif
0, NULL, NULL
};
/* Translation table allocated and initialized at runtime. Indexed by the
signal value to find the equivalent symbolic value. */
static char **signal_names;
static int num_signal_names = 0;
/* Translation table allocated and initialized at runtime, if it does not
already exist in the host environment. Indexed by the signal value to find
the descriptive string.
We don't export it for use in other modules because even though it has the
same name, it differs from other implementations in that it is dynamically
initialized rather than statically initialized. */
#ifdef NEED_sys_siglist
static int sys_nsig;
static char **sys_siglist;
#else
static int sys_nsig = NSIG;
#ifdef __STDC__
extern const char * const sys_siglist[];
#else
extern char *sys_siglist[];
#endif
#endif
/*
NAME
init_signal_tables -- initialize the name and message tables
SYNOPSIS
static void init_signal_tables ();
DESCRIPTION
Using the signal_table, which is initialized at compile time, generate
the signal_names and the sys_siglist (if needed) tables, which are
indexed at runtime by a specific signal value.
BUGS
The initialization of the tables may fail under low memory conditions,
in which case we don't do anything particularly useful, but we don't
bomb either. Who knows, it might succeed at a later point if we free
some memory in the meantime. In any case, the other routines know
how to deal with lack of a table after trying to initialize it. This
may or may not be considered to be a bug, that we don't specifically
warn about this particular failure mode.
*/
static void
init_signal_tables ()
{
struct signal_info *eip;
int nbytes;
/* If we haven't already scanned the signal_table once to find the maximum
signal value, then go find it now. */
if (num_signal_names == 0)
{
for (eip = signal_table; eip -> name != NULL; eip++)
{
if (eip -> value >= num_signal_names)
{
num_signal_names = eip -> value + 1;
}
}
}
/* Now attempt to allocate the signal_names table, zero it out, and then
initialize it from the statically initialized signal_table. */
if (signal_names == NULL)
{
nbytes = num_signal_names * sizeof (char *);
if ((signal_names = (char **) malloc (nbytes)) != NULL)
{
memset (signal_names, 0, nbytes);
for (eip = signal_table; eip -> name != NULL; eip++)
{
signal_names[eip -> value] = eip -> name;
}
}
}
#ifdef NEED_sys_siglist
/* Now attempt to allocate the sys_siglist table, zero it out, and then
initialize it from the statically initialized signal_table. */
if (sys_siglist == NULL)
{
nbytes = num_signal_names * sizeof (char *);
if ((sys_siglist = (char **) malloc (nbytes)) != NULL)
{
memset (sys_siglist, 0, nbytes);
sys_nsig = num_signal_names;
for (eip = signal_table; eip -> name != NULL; eip++)
{
sys_siglist[eip -> value] = eip -> msg;
}
}
}
#endif
}
/*
NAME
signo_max -- return the max signo value
SYNOPSIS
int signo_max ();
DESCRIPTION
Returns the maximum signo value for which a corresponding symbolic
name or message is available. Note that in the case where
we use the sys_siglist supplied by the system, it is possible for
there to be more symbolic names than messages, or vice versa.
In fact, the manual page for psignal(3b) explicitly warns that one
should check the size of the table (NSIG) before indexing it,
since new signal codes may be added to the system before they are
added to the table. Thus NSIG might be smaller than value
implied by the largest signo value defined in <signal.h>.
We return the maximum value that can be used to obtain a meaningful
symbolic name or message.
*/
int
signo_max ()
{
int maxsize;
if (signal_names == NULL)
{
init_signal_tables ();
}
maxsize = MAX (sys_nsig, num_signal_names);
return (maxsize - 1);
}
/*
NAME
strsignal -- map a signal number to a signal message string
SYNOPSIS
char *strsignal (int signo)
DESCRIPTION
Maps an signal number to an signal message string, the contents of
which are implementation defined. On systems which have the external
variable sys_siglist, these strings will be the same as the ones used
by psignal().
If the supplied signal number is within the valid range of indices
for the sys_siglist, but no message is available for the particular
signal number, then returns the string "Signal NUM", where NUM is the
signal number.
If the supplied signal number is not a valid index into sys_siglist,
returns NULL.
The returned string is only guaranteed to be valid only until the
next call to strsignal.
*/
char *
strsignal (signo)
int signo;
{
char *msg;
static char buf[32];
#ifdef NEED_sys_siglist
if (signal_names == NULL)
{
init_signal_tables ();
}
#endif
if ((signo < 0) || (signo >= sys_nsig))
{
/* Out of range, just return NULL */
msg = NULL;
}
else if ((sys_siglist == NULL) || (sys_siglist[signo] == NULL))
{
/* In range, but no sys_siglist or no entry at this index. */
sprintf (buf, "Signal %d", signo);
msg = buf;
}
else
{
/* In range, and a valid message. Just return the message. */
msg = (char*)sys_siglist[signo];
}
return (msg);
}
/*
NAME
strsigno -- map an signal number to a symbolic name string
SYNOPSIS
char *strsigno (int signo)
DESCRIPTION
Given an signal number, returns a pointer to a string containing
the symbolic name of that signal number, as found in <signal.h>.
If the supplied signal number is within the valid range of indices
for symbolic names, but no name is available for the particular
signal number, then returns the string "Signal NUM", where NUM is
the signal number.
If the supplied signal number is not within the range of valid
indices, then returns NULL.
BUGS
The contents of the location pointed to are only guaranteed to be
valid until the next call to strsigno.
*/
char *
strsigno (signo)
int signo;
{
char *name;
static char buf[32];
if (signal_names == NULL)
{
init_signal_tables ();
}
if ((signo < 0) || (signo >= num_signal_names))
{
/* Out of range, just return NULL */
name = NULL;
}
else if ((signal_names == NULL) || (signal_names[signo] == NULL))
{
/* In range, but no signal_names or no entry at this index. */
sprintf (buf, "Signal %d", signo);
name = buf;
}
else
{
/* In range, and a valid name. Just return the name. */
name = signal_names[signo];
}
return (name);
}
/*
NAME
strtosigno -- map a symbolic signal name to a numeric value
SYNOPSIS
int strtosigno (char *name)
DESCRIPTION
Given the symbolic name of a signal, map it to a signal number.
If no translation is found, returns 0.
*/
int
strtosigno (name)
char *name;
{
int signo = 0;
if (name != NULL)
{
if (signal_names == NULL)
{
init_signal_tables ();
}
for (signo = 0; signo < num_signal_names; signo++)
{
if ((signal_names[signo] != NULL) &&
(strcmp (name, signal_names[signo]) == 0))
{
break;
}
}
if (signo == num_signal_names)
{
signo = 0;
}
}
return (signo);
}
/*
NAME
psignal -- print message about signal to stderr
SYNOPSIS
void psignal (unsigned signo, char *message);
DESCRIPTION
Print to the standard error the message, followed by a colon,
followed by the description of the signal specified by signo,
followed by a newline.
*/
#ifdef NEED_psignal
void
psignal (signo, message)
unsigned signo;
char *message;
{
if (signal_names == NULL)
{
init_signal_tables ();
}
if ((signo <= 0) || (signo >= sys_nsig))
{
fprintf (stderr, "%s: unknown signal\n", message);
}
else
{
fprintf (stderr, "%s: %s\n", message, sys_siglist[signo]);
}
}
#endif /* NEED_psignal */
/* A simple little main that does nothing but print all the signal translations
if MAIN is defined and this file is compiled and linked. */
#ifdef MAIN
main ()
{
int signo;
int maxsigno;
char *name;
char *msg;
char *strsigno ();
char *strsignal ();
maxsigno = signo_max ();
printf ("%d entries in names table.\n", num_signal_names);
printf ("%d entries in messages table.\n", sys_nsig);
printf ("%d is max useful index.\n", maxsigno);
/* Keep printing values until we get to the end of *both* tables, not
*either* table. Note that knowing the maximum useful index does *not*
relieve us of the responsibility of testing the return pointer for
NULL. */
for (signo = 0; signo <= maxsigno; signo++)
{
name = strsigno (signo);
name = (name == NULL) ? "<NULL>" : name;
msg = strsignal (signo);
msg = (msg == NULL) ? "<NULL>" : msg;
printf ("%-4d%-18s%s\n", signo, name, msg);
}
}
#endif