HardenedBSD/libexec/rtld-elf/rtld_printf.c

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1986, 1988, 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 * Copyright (c) 2011 Konstantin Belousov <kib@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <inttypes.h>
#include <stdarg.h>
#include <stddef.h>
#include <string.h>
#include <unistd.h>
#include "rtld_printf.h"
#include "rtld_libc.h"

#define MAXNBUF	(sizeof(intmax_t) * NBBY + 1)

#define	PRINT_METHOD_SNPRINTF	1
#define	PRINT_METHOD_WRITE	2

struct snprintf_arg {
	int	method;
	char	*str;
	char	*buf;
	size_t	remain;
	size_t	buf_total;
	int	fd;
};

static void
printf_out(struct snprintf_arg *info)
{

	if (info->remain == info->buf_total)
		return;
	write(info->fd, info->buf, info->buf_total - info->remain);
	info->str = info->buf;
	info->remain = info->buf_total;
}

static void
snprintf_func(int ch, struct snprintf_arg *const info)
{

	switch (info->method) {
	case PRINT_METHOD_SNPRINTF:
		if (info->remain >= 2) {
			*info->str++ = ch;
			info->remain--;
		}
		break;
	case PRINT_METHOD_WRITE:
		if (info->remain > 0) {
			*info->str++ = ch;
			info->remain--;
		} else
			printf_out(info);
		break;
	}
}

static char const hex2ascii_lower[] = "0123456789abcdefghijklmnopqrstuvwxyz";
static char const hex2ascii_upper[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
#define	hex2ascii(hex)	(hex2ascii_lower[hex])
#define	hex2ascii_upper(hex)	(hex2ascii_upper[hex])

static __inline int
imax(int a, int b)
{

	return (a > b ? a : b);
}

static char *
ksprintn(char *nbuf, uintmax_t num, int base, int *lenp, int upper)
{
	char *p, c;

	p = nbuf;
	*p = '\0';
	do {
		c = upper ? hex2ascii_upper(num % base) :
		    hex2ascii(num % base);
		*++p = c;
	} while (num /= base);
	if (lenp)
		*lenp = p - nbuf;
	return (p);
}

static int
kvprintf(char const *fmt, struct snprintf_arg *arg, int radix, va_list ap)
{
#define PCHAR(c) snprintf_func((c), arg)
	char nbuf[MAXNBUF];
	const char *p, *percent, *q;
	u_char *up;
	int ch, n;
	uintmax_t num;
	int base, lflag, qflag, tmp, width, ladjust, sharpflag, neg, sign, dot;
	int cflag, hflag, jflag, tflag, zflag;
	int dwidth, upper;
	char padc;
	int stop = 0, retval = 0;

	num = 0;

	if (fmt == NULL)
		fmt = "(fmt null)\n";

	if (radix < 2 || radix > 36)
		radix = 10;

	for (;;) {
		padc = ' ';
		width = 0;
		while ((ch = (u_char)*fmt++) != '%' || stop) {
			if (ch == '\0')
				return (retval);
			PCHAR(ch);
		}
		percent = fmt - 1;
		qflag = 0; lflag = 0; ladjust = 0; sharpflag = 0; neg = 0;
		sign = 0; dot = 0; dwidth = 0; upper = 0;
		cflag = 0; hflag = 0; jflag = 0; tflag = 0; zflag = 0;
reswitch:	switch (ch = (u_char)*fmt++) {
		case '.':
			dot = 1;
			goto reswitch;
		case '#':
			sharpflag = 1;
			goto reswitch;
		case '+':
			sign = 1;
			goto reswitch;
		case '-':
			ladjust = 1;
			goto reswitch;
		case '%':
			PCHAR(ch);
			break;
		case '*':
			if (!dot) {
				width = va_arg(ap, int);
				if (width < 0) {
					ladjust = !ladjust;
					width = -width;
				}
			} else {
				dwidth = va_arg(ap, int);
			}
			goto reswitch;
		case '0':
			if (!dot) {
				padc = '0';
				goto reswitch;
			}
			/* FALLTHROUGH */
		case '1': case '2': case '3': case '4':
		case '5': case '6': case '7': case '8': case '9':
				for (n = 0;; ++fmt) {
					n = n * 10 + ch - '0';
					ch = *fmt;
					if (ch < '0' || ch > '9')
						break;
				}
			if (dot)
				dwidth = n;
			else
				width = n;
			goto reswitch;
		case 'b':
			num = (u_int)va_arg(ap, int);
			p = va_arg(ap, char *);
			for (q = ksprintn(nbuf, num, *p++, NULL, 0); *q;)
				PCHAR(*q--);

			if (num == 0)
				break;

			for (tmp = 0; *p;) {
				n = *p++;
				if (num & (1 << (n - 1))) {
					PCHAR(tmp ? ',' : '<');
					for (; (n = *p) > ' '; ++p)
						PCHAR(n);
					tmp = 1;
				} else
					for (; *p > ' '; ++p)
						continue;
			}
			if (tmp)
				PCHAR('>');
			break;
		case 'c':
			PCHAR(va_arg(ap, int));
			break;
		case 'D':
			up = va_arg(ap, u_char *);
			p = va_arg(ap, char *);
			if (!width)
				width = 16;
			while(width--) {
				PCHAR(hex2ascii(*up >> 4));
				PCHAR(hex2ascii(*up & 0x0f));
				up++;
				if (width)
					for (q=p;*q;q++)
						PCHAR(*q);
			}
			break;
		case 'd':
		case 'i':
			base = 10;
			sign = 1;
			goto handle_sign;
		case 'h':
			if (hflag) {
				hflag = 0;
				cflag = 1;
			} else
				hflag = 1;
			goto reswitch;
		case 'j':
			jflag = 1;
			goto reswitch;
		case 'l':
			if (lflag) {
				lflag = 0;
				qflag = 1;
			} else
				lflag = 1;
			goto reswitch;
		case 'n':
			if (jflag)
				*(va_arg(ap, intmax_t *)) = retval;
			else if (qflag)
				*(va_arg(ap, quad_t *)) = retval;
			else if (lflag)
				*(va_arg(ap, long *)) = retval;
			else if (zflag)
				*(va_arg(ap, size_t *)) = retval;
			else if (hflag)
				*(va_arg(ap, short *)) = retval;
			else if (cflag)
				*(va_arg(ap, char *)) = retval;
			else
				*(va_arg(ap, int *)) = retval;
			break;
		case 'o':
			base = 8;
			goto handle_nosign;
		case 'p':
			base = 16;
			sharpflag = (width == 0);
			sign = 0;
			num = (uintptr_t)va_arg(ap, void *);
			goto number;
		case 'q':
			qflag = 1;
			goto reswitch;
		case 'r':
			base = radix;
			if (sign)
				goto handle_sign;
			goto handle_nosign;
		case 's':
			p = va_arg(ap, char *);
			if (p == NULL)
				p = "(null)";
			if (!dot)
				n = strlen (p);
			else
				for (n = 0; n < dwidth && p[n]; n++)
					continue;

			width -= n;

			if (!ladjust && width > 0)
				while (width--)
					PCHAR(padc);
			while (n--)
				PCHAR(*p++);
			if (ladjust && width > 0)
				while (width--)
					PCHAR(padc);
			break;
		case 't':
			tflag = 1;
			goto reswitch;
		case 'u':
			base = 10;
			goto handle_nosign;
		case 'X':
			upper = 1;
			/* FALLTHROUGH */
		case 'x':
			base = 16;
			goto handle_nosign;
		case 'y':
			base = 16;
			sign = 1;
			goto handle_sign;
		case 'z':
			zflag = 1;
			goto reswitch;
handle_nosign:
			sign = 0;
			if (jflag)
				num = va_arg(ap, uintmax_t);
			else if (qflag)
				num = va_arg(ap, u_quad_t);
			else if (tflag)
				num = va_arg(ap, ptrdiff_t);
			else if (lflag)
				num = va_arg(ap, u_long);
			else if (zflag)
				num = va_arg(ap, size_t);
			else if (hflag)
				num = (u_short)va_arg(ap, int);
			else if (cflag)
				num = (u_char)va_arg(ap, int);
			else
				num = va_arg(ap, u_int);
			goto number;
handle_sign:
			if (jflag)
				num = va_arg(ap, intmax_t);
			else if (qflag)
				num = va_arg(ap, quad_t);
			else if (tflag)
				num = va_arg(ap, ptrdiff_t);
			else if (lflag)
				num = va_arg(ap, long);
			else if (zflag)
				num = va_arg(ap, ssize_t);
			else if (hflag)
				num = (short)va_arg(ap, int);
			else if (cflag)
				num = (char)va_arg(ap, int);
			else
				num = va_arg(ap, int);
number:
			if (sign && (intmax_t)num < 0) {
				neg = 1;
				num = -(intmax_t)num;
			}
			p = ksprintn(nbuf, num, base, &n, upper);
			tmp = 0;
			if (sharpflag && num != 0) {
				if (base == 8)
					tmp++;
				else if (base == 16)
					tmp += 2;
			}
			if (neg)
				tmp++;

			if (!ladjust && padc == '0')
				dwidth = width - tmp;
			width -= tmp + imax(dwidth, n);
			dwidth -= n;
			if (!ladjust)
				while (width-- > 0)
					PCHAR(' ');
			if (neg)
				PCHAR('-');
			if (sharpflag && num != 0) {
				if (base == 8) {
					PCHAR('0');
				} else if (base == 16) {
					PCHAR('0');
					PCHAR('x');
				}
			}
			while (dwidth-- > 0)
				PCHAR('0');

			while (*p)
				PCHAR(*p--);

			if (ladjust)
				while (width-- > 0)
					PCHAR(' ');

			break;
		default:
			while (percent < fmt)
				PCHAR(*percent++);
			/*
			 * Since we ignore an formatting argument it is no
			 * longer safe to obey the remaining formatting
			 * arguments as the arguments will no longer match
			 * the format specs.
			 */
			stop = 1;
			break;
		}
	}
#undef PCHAR
}

int
rtld_snprintf(char *buf, size_t bufsize, const char *fmt, ...)
{
	va_list ap;
	int retval;

	va_start(ap, fmt);
	retval = rtld_vsnprintf(buf, bufsize, fmt, ap);
	va_end(ap);
	return (retval);
}

int
rtld_vsnprintf(char *buf, size_t bufsize, const char *fmt, va_list ap)
{
	struct snprintf_arg info;
	int retval;

	info.method = PRINT_METHOD_SNPRINTF;
	info.buf = info.str = buf;
	info.buf_total = info.remain = bufsize;
	info.fd = -1;
	retval = kvprintf(fmt, &info, 10, ap);
	if (info.remain >= 1)
		*info.str++ = '\0';
	return (retval);
}

int
rtld_vfdprintf(int fd, const char *fmt, va_list ap)
{
	char buf[512];
	struct snprintf_arg info;
	int retval;

	info.method = PRINT_METHOD_WRITE;
	info.buf = info.str = buf;
	info.buf_total = info.remain = sizeof(buf);
	info.fd = fd;
	retval = kvprintf(fmt, &info, 10, ap);
	printf_out(&info);
	return (retval);
}

int
rtld_fdprintf(int fd, const char *fmt, ...)
{
	va_list ap;
	int retval;

	va_start(ap, fmt);
	retval = rtld_vfdprintf(fd, fmt, ap);
	va_end(ap);
	return (retval);
}

void
rtld_fdputstr(int fd, const char *str)
{

	write(fd, str, strlen(str));
}

void
rtld_fdputchar(int fd, int c)
{
	char c1;

	c1 = c;
	write(fd, &c1, 1);
}