/*
 *	tardy - a tar post-processor
 *	Copyright (C) 1991-1995, 1998, 1999, 2001-2004 Peter Miller;
 *	All rights reserved.
 *
 *	This program 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 of the License, or
 *	(at your option) any later version.
 *
 *	This program 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 this program; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to report errors
 */

#include <ac/assert.h>
#include <ac/ctype.h>
#include <ac/errno.h>
#include <ac/grp.h>
#include <ac/pwd.h>
#include <ac/stdarg.h>
#include <ac/stddef.h>
#include <ac/stdio.h>
#include <ac/stdlib.h>
#include <ac/string.h>
#include <ac/unistd.h>

#include <arglex.h>
#include <error.h>
#include <mprintf.h>
#include <progname.h>


static void
error_get_id(int *uid, int *gid)
{
	*uid = geteuid();
	*gid = getegid();
}


static	error_id_ty errid = error_get_id;


void
error_set_id_func(error_id_ty f)
{
	if (f)
		errid = f;
	else
		errid = error_get_id;
}


/*
 * NAME
 *	wrap - wrap s string over lines
 *
 * SYNOPSIS
 *	void wrap(char *);
 *
 * DESCRIPTION
 *	The wrap function is used to print error messages onto stderr
 *	wrapping ling lines.
 *
 * CAVEATS
 *	Line length is assumed to be 80 characters.
 */

static void
wrap(char *s)
{
	static char escapes[] = "\rr\nn\ff\bb\tt";
	int	page_width;
	char	tmp[200];
	int	first_line;
	char	*tp;

	if (fflush(stdout) || ferror(stdout))
		nfatal("(stdout)");
	/* don't use last column, many terminals are dumb */
	page_width = 79;
	const char *progname = progname_get();
	first_line = 1;
	while (*s)
	{
		char	*ep;
		int	ocol;

		/*
		 * Work out how many characters fit on the line.
		 */
		if (first_line)
			ocol = strlen(progname) + 2;
		else
			ocol = 8;
		for (ep = s; *ep; ++ep)
		{
			int	cw;
			int	c;

			c = (unsigned char)*ep;
			if (isprint(c))
				cw = 1 + (c == '\\');
			else
				cw = (strchr(escapes, c) ? 2 : 4);
			if (ocol + cw > page_width)
				break;
			ocol += cw;
		}

		/*
		 * see if there is a better place to break the line
		 */
		if (*ep && *ep != ' ')
		{
			char	*mp;

			for (mp = ep; mp > s; --mp)
			{
				if (strchr(" /", mp[-1]))
				{
					ep = mp;
					break;
				}
			}
		}

		/*
		 * ignore trailing blanks
		 */
		while (ep > s && ep[-1] == ' ')
			ep--;

		/*
		 * print the line
		 */
		if (first_line)
			snprintf(tmp, sizeof(tmp), "%s: ", progname);
		else
			strcpy(tmp, "\t");
		tp = tmp + strlen(tmp);
		while (s < ep)
		{
		    int c = (unsigned char)*s++;
		    if (isprint(c))
		    {
			if (c == '\\')
			    *tp++ = '\\';
			*tp++ = c;
		    }
		    else
		    {
			char *esc = strchr(escapes, c);
			if (esc)
			{
			    *tp++ = '\\';
			    *tp++ = esc[1];
			}
			else
			{
			    snprintf(tp, tmp + sizeof(tmp) - tp, "\\%3.3o", c);
			    tp += strlen(tp);
			}
		    }
		}
		*tp++ = '\n';
		*tp = 0;
		fputs(tmp, stderr);
		if (ferror(stderr))
			break;

		/*
		 * skip leading spaces for subsequent lines
		 */
		while (*s == ' ')
			s++;
		first_line = 0;
	}
	if (fflush(stderr) || ferror(stderr))
		nfatal("(stderr)");
}


static void
double_jeopardy(void)
{
	char buffer[200];
	snprintf
	(
		buffer,
		sizeof(buffer),
		"while attempting to construct an error message: %s (fatal)",
		strerror(errno)
	);
	wrap(buffer);
	quit(1);
}


static char *
copy_string(const char *s)
{
	char		*cp;

	errno = 0;
	cp = (char *)malloc(strlen(s) + 1);
	if (!cp)
	{
		if (!errno)
			errno = ENOMEM;
		double_jeopardy();
	}
	strcpy(cp, s);
	return cp;
}


static char *
id(void)
{
	int uid;
	int gid;
	errid(&uid, &gid);
	struct passwd *pw = getpwuid(uid);
	char uidn[20];
	if (pw)
		snprintf(uidn, sizeof(uidn), "user \"%.8s\"", pw->pw_name);
	else
		snprintf(uidn, sizeof(uidn), "uid %d", uid);

	struct group *gr = getgrgid(gid);
	char gidn[20];
	if (gr)
		snprintf(gidn, sizeof(gidn), "group \"%.8s\"", gr->gr_name);
	else
		snprintf(gidn, sizeof(gidn), "gid %d", gid);

	char buffer[100];
	snprintf(buffer, sizeof(buffer), " [%s, %s]", uidn, gidn);
	return copy_string(buffer);
}


/*
 *  NAME
 *	error - place a message on the error stream
 *
 *  SYNOPSIS
 *	void error(char *fmt, ...);
 *
 *  DESCRIPTION
 *	Error places a message on the error output stream.
 *	The first argument is a printf-like format string,
 *	optionally followed by other arguments.
 *	The message will be prefixed by the program name and a colon,
 *	and will be terminated with a newline, automatically.
 *
 *  CAVEAT
 *	Things like "error(filename)" blow up if the filename
 *	contains a '%' character.
 */

/*VARARGS1*/
void
error(const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	char *buffer = vmprintf_errok(fmt, ap);
	va_end(ap);
	if (!buffer)
		double_jeopardy();
	wrap(buffer);
}


/*
 *  NAME
 *	nerror - place a system fault message on the error stream
 *
 *  SYNOPSIS
 *	void nerror(char *fmt, ...);
 *
 *  DESCRIPTION
 *	Nerror places a message on the error output stream.
 *	The first argument is a printf-like format string,
 *	optionally followed by other arguments.
 *	The message will be prefixed by the program name and a colon,
 *	and will be terminated with a text description of the error
 *	indicated by the 'errno' global variable, automatically.
 *
 *  CAVEAT
 *	Things like "nerror(filename)" blow up if the filename
 *	contains a '%' character.
 */

/*VARARGS1*/
void
nerror(const char *fmt, ...)
{
	int n = errno;
	va_list ap;
	va_start(ap, fmt);
	char *s1 = vmprintf_errok(fmt, ap);
	va_end(ap);
	if (!s1)
		double_jeopardy();
	s1 = copy_string(s1);
	char *s2;
	if (n == EPERM || n == EACCES)
		s2 = id();
	else
		s2 = copy_string("");
	error("%s: %s%s", s1, strerror(n), s2);
	free(s1);
	free(s2);
}


/*
 *  NAME
 *	nfatal - place a system fault message on the error stream and exit
 *
 *  SYNOPSIS
 *	void nfatal(char *fmt, ...);
 *
 *  DESCRIPTION
 *	Nfatal places a message on the error output stream and exits.
 *	The first argument is a printf-like format string,
 *	optionally followed by other arguments.
 *	The message will be prefixed by the program name and a colon,
 *	and will be terminated with a text description of the error
 *	indicated by the 'errno' global variable, automatically.
 *
 *  CAVEAT
 *	Things like "nfatal(filename)" blow up if the filename
 *	contains a '%' character.
 *
 *	This function does NOT return.
 */

/*VARARGS1*/
void
nfatal(const char *fmt, ...)
{
	int n = errno;
	va_list ap;
	va_start(ap, fmt);
	char *s1 = vmprintf_errok(fmt, ap);
	va_end(ap);
	if (!s1)
		double_jeopardy();
	s1 = copy_string(s1);

	char *s2;
	if (n == EPERM || n == EACCES)
		s2 = id();
	else
		s2 = "";

	fatal("%s: %s%s", s1, strerror(n), s2);
}


/*
 *  NAME
 *	fatal - place a message on the error stream and exit
 *
 *  SYNOPSIS
 *	void fatal(char *fmt, ...);
 *
 *  DESCRIPTION
 *	Fatal places a message on the error output stream and exits.
 *	The first argument is a printf-like format string,
 *	optionally followed by other arguments.
 *	The message will be prefixed by the program name and a colon,
 *	and will be terminated with a newline, automatically.
 *
 *  CAVEAT
 *	Things like "error(filename)" blow up if the filename
 *	contains a '%' character.
 *
 *	This function does NOT return.
 */

/*VARARGS1*/
void
fatal(const char *fmt, ...)
{
	va_list ap;
	va_start(ap, fmt);
	char *buffer = vmprintf_errok(fmt, ap);
	va_end(ap);
	if (!buffer)
		double_jeopardy();
	wrap(buffer);
	quit(1);
}


/*
 *  NAME
 *      signal_name - find it
 *
 *  SYNOPSIS
 *      char *signal_name(int n);
 *
 *  DESCRIPTION
 *      The signal_name function is used to find the name of a signal from its
 *      number.
 *
 *  RETURNS
 *      char *: pointer to the signal name.
 *
 *  CAVEAT
 *      The signal name may not be written on.  Subsequent calls may alter the
 *      area pointed to.
 */

const char *
signal_name(int n)
{
	static char buffer[16];

	switch (n)
	{
#ifdef SIGHUP
	case SIGHUP:
		return "hang up [SIGHUP]";
#endif /* SIGHUP */

#ifdef SIGINT
	case SIGINT:
		return "user interrupt [SIGINT]";
#endif /* SIGINT */

#ifdef SIGQUIT
	case SIGQUIT:
		return "user quit [SIGQUIT]";
#endif /* SIGQUIT */

#ifdef SIGILL
	case SIGILL:
		return "illegal instruction [SIGILL]";
#endif /* SIGILL */

#ifdef SIGTRAP
	case SIGTRAP:
		return "trace trap [SIGTRAP]";
#endif /* SIGTRAP */

#ifdef SIGIOT
	case SIGIOT:
		return "abort [SIGIOT]";
#endif /* SIGIOT */

#ifdef SIGEMT
	case SIGEMT:
		return "EMT instruction [SIGEMT]";
#endif /* SIGEMT */

#ifdef SIGFPE
	case SIGFPE:
		return "floating point exception [SIGFPE]";
#endif /* SIGFPE */

#ifdef SIGKILL
	case SIGKILL:
		return "kill [SIGKILL]";
#endif /* SIGKILL */

#ifdef SIGBUS
	case SIGBUS:
		return "bus error [SIGBUS]";
#endif /* SIGBUS */

#ifdef SIGSEGV
	case SIGSEGV:
		return "segmentation violation [SIGSEGV]";
#endif /* SIGSEGV */

#ifdef SIGSYS
	case SIGSYS:
		return "bad argument to system call [SIGSYS]";
#endif /* SIGSYS */

#ifdef SIGPIPE
	case SIGPIPE:
		return "write on a pipe with no one to read it [SIGPIPE]";
#endif /* SIGPIPE */

#ifdef SIGALRM
	case SIGALRM:
		return "alarm clock [SIGALRM]";
#endif /* SIGALRM */

#ifdef SIGTERM
	case SIGTERM:
		return "software termination [SIGTERM]";
#endif /* SIGTERM */

#ifdef SIGUSR1
	case SIGUSR1:
		return "user defined signal one [SIGUSR1]";
#endif /* SIGUSR1 */

#ifdef SIGUSR2
	case SIGUSR2:
		return "user defined signal two [SIGUSR2]";
#endif /* SIGUSR2 */

#ifdef SIGCLD
	case SIGCLD:
		return "death of child [SIGCLD]";
#endif /* SIGCLD */

#ifdef SIGPWR
	case SIGPWR:
		return "power failure [SIGPWR]";
#endif /* SIGPWR */

	default:
		snprintf(buffer, sizeof(buffer), "signal %d", n);
		return buffer;
	}
}


static	quit_ty	quit_list[10];
static	int	quit_list_len;


void
quit_register(quit_ty func)
{
	assert(quit_list_len < SIZEOF(quit_list));
	assert(func);
	quit_list[quit_list_len++] = func;
}


void
quit(int n)
{
	int		j;
	static int	quitting;

	if (quitting > 4)
	{
		fprintf
		(
			stderr,
			"%s: incorrectly handled error while quitting (bug)\n",
			progname_get()
		);
		exit(1);
	}
	++quitting;
	for (j = quit_list_len - 1; j >= 0; --j)
		quit_list[j](n);
	exit(n);
}