src/bltin/printf.c

/*
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * 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.
 */

#include <sys/types.h>

#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static int	 conv_escape_str(char *, char **);
static char	*conv_escape(char *, int *);
static int	 getchr(void);
static double	 getdouble(void);
static uintmax_t getuintmax(int);
static char	*getstr(void);
static char	*mklong(const char *, const char *);
static void      check_conversion(const char *, const char *);

static int	rval;
static char  **gargv;

#define isodigit(c)	((c) >= '0' && (c) <= '7')
#define octtobin(c)	((c) - '0')

#include "bltin.h"
#include "system.h"

#define PF(f, func) { \
	switch ((char *)param - (char *)array) { \
	default: \
		(void)printf(f, array[0], array[1], func); \
		break; \
	case sizeof(*param): \
		(void)printf(f, array[0], func); \
		break; \
	case 0: \
		(void)printf(f, func); \
		break; \
	} \
}

#define ASPF(sp, f, func) ({ \
	int ret; \
	switch ((char *)param - (char *)array) { \
	default: \
		ret = xasprintf(sp, f, array[0], array[1], func); \
		break; \
	case sizeof(*param): \
		ret = xasprintf(sp, f, array[0], func); \
		break; \
	case 0: \
		ret = xasprintf(sp, f, func); \
		break; \
	} \
	ret; \
})


static int print_escape_str(const char *f, int *param, int *array, char *s)
{
	struct stackmark smark;
	char *p, *q;
	int done;
	int len;
	int total;

	setstackmark(&smark);
	done = conv_escape_str(s, &p);
	q = stackblock();
	len = p - q;

	p = makestrspace(len, p);
	memset(p, 'X', len - 1);
	p[len - 1] = 0;

	q = stackblock();
	total = ASPF(&p, f, p);

	len = strchrnul(p, 'X') - p;
	memcpy(p + len, q, strchrnul(p + len, ' ') - (p + len));

	out1mem(p, total);

	popstackmark(&smark);
	return done;
}


int printfcmd(int argc, char *argv[])
{
	char *fmt;
	char *format;
	int ch;

	rval = 0;

	nextopt(nullstr);

	argv = argptr;
	format = *argv;

	if (!format)
		error("usage: printf format [arg ...]");

	gargv = ++argv;

#define SKIP1	"#-+ 0"
#define SKIP2	"*0123456789"
	do {
		/*
		 * Basic algorithm is to scan the format string for conversion
		 * specifications -- once one is found, find out if the field
		 * width or precision is a '*'; if it is, gather up value. 
		 * Note, format strings are reused as necessary to use up the
		 * provided arguments, arguments of zero/null string are 
		 * provided to use up the format string.
		 */

		/* find next format specification */
		for (fmt = format; (ch = *fmt++) ;) {
			char *start;
			char nextch;
			int array[2];
			int *param;

			if (ch == '\\') {
				int c_ch;
				fmt = conv_escape(fmt, &c_ch);
				ch = c_ch;
				goto pc;
			}
			if (ch != '%' || (*fmt == '%' && (++fmt || 1))) {
pc:
				putchar(ch);
				continue;
			}

			/* Ok - we've found a format specification,
			   Save its address for a later printf(). */
			start = fmt - 1;
			param = array;

			/* skip to field width */
			fmt += strspn(fmt, SKIP1);
			if (*fmt == '*') {
				++fmt;
				*param++ = getuintmax(1);
			} else {
				/* skip to possible '.',
				 * get following precision
				 */
				fmt += strspn(fmt, SKIP2);
			}

			if (*fmt == '.') {
				++fmt;
				if (*fmt == '*') {
					++fmt;
					*param++ = getuintmax(1);
				} else
					fmt += strspn(fmt, SKIP2);
			}

			ch = *fmt;
			if (!ch)
				error("missing format character");
			/* null terminate format string to we can use it
			   as an argument to printf. */
			nextch = fmt[1];
			fmt[1] = 0;
			switch (ch) {

			case 'b':
				*fmt = 's';
				/* escape if a \c was encountered */
				if (print_escape_str(start, param, array,
						     getstr()))
					goto out;
				break;
			case 'c': {
				int p = getchr();
				PF(start, p);
				break;
			}
			case 's': {
				char *p = getstr();
				PF(start, p);
				break;
			}
			case 'd':
			case 'i': {
				uintmax_t p = getuintmax(1);
				start = mklong(start, fmt);
				PF(start, p);
				break;
			}
			case 'o':
			case 'u':
			case 'x':
			case 'X': {
				uintmax_t p = getuintmax(0);
				start = mklong(start, fmt);
				PF(start, p);
				break;
			}
			case 'a':
			case 'A':
			case 'e':
			case 'E':
			case 'f':
			case 'F':
			case 'g':
			case 'G': {
				double p = getdouble();
				PF(start, p);
				break;
			}
			default:
				error("%s: invalid directive", start);
			}
			*++fmt = nextch;
		}
	} while (gargv != argv && *gargv);

out:
	return rval;
}


/*
 * Print SysV echo(1) style escape string 
 *	Halts processing string if a \c escape is encountered.
 */
static int
conv_escape_str(char *str, char **sp)
{
	int c;
	int ch;
	char *cp;

	/* convert string into a temporary buffer... */
	STARTSTACKSTR(cp);

	do {
		c = ch = *str++;
		if (ch != '\\')
			continue;

		c = *str++;
		if (c == 'c') {
			/* \c as in SYSV echo - abort all processing.... */
			c = ch = 0x100;
			continue;
		}

		/* 
		 * %b string octal constants are not like those in C.
		 * They start with a \0, and are followed by 0, 1, 2, 
		 * or 3 octal digits. 
		 */
		if (c == '0' && isodigit(*str))
			str++;

		/* Finally test for sequences valid in the format string */
		str = conv_escape(str - 1, &c);
	} while (STPUTC(c, cp), (char)ch);

	*sp = cp;

	return ch;
}

/*
 * Print "standard" escape characters 
 */
static char *
conv_escape(char *str, int *conv_ch)
{
	int value;
	int ch;

	ch = *str;

	switch (ch) {
	default:
		if (!isodigit(*str)) {
			value = '\\';
			goto out;
		}

		ch = 3;
		value = 0;
		do {
			value <<= 3;
			value += octtobin(*str++);
		} while (isodigit(*str) && --ch);
		goto out;

	case '\\':	value = '\\';	break;	/* backslash */
	case 'a':	value = '\a';	break;	/* alert */
	case 'b':	value = '\b';	break;	/* backspace */
	case 'f':	value = '\f';	break;	/* form-feed */
	case 'n':	value = '\n';	break;	/* newline */
	case 'r':	value = '\r';	break;	/* carriage-return */
	case 't':	value = '\t';	break;	/* tab */
	case 'v':	value = '\v';	break;	/* vertical-tab */
	}

	str++;
out:
	*conv_ch = value;
	return str;
}

static char *
mklong(const char *str, const char *ch)
{
	/*
	 * Replace a string like "%92.3u" with "%92.3"PRIuMAX.
	 *
	 * Although C99 does not guarantee it, we assume PRIiMAX,
	 * PRIoMAX, PRIuMAX, PRIxMAX, and PRIXMAX are all the same
	 * as PRIdMAX with the final 'd' replaced by the corresponding
	 * character.
	 */

	char *copy;
	size_t len;	

	len = ch - str + sizeof(PRIdMAX);
	STARTSTACKSTR(copy);
	copy = makestrspace(len, copy);
	memcpy(copy, str, len - sizeof(PRIdMAX));
	memcpy(copy + len - sizeof(PRIdMAX), PRIdMAX, sizeof(PRIdMAX));
	copy[len - 2] = *ch;
	return (copy);	
}

static int
getchr(void)
{
	int val = 0;

	if (*gargv)
		val = **gargv++;
	return val;
}

static char *
getstr(void)
{
	char *val = nullstr;

	if (*gargv)
		val = *gargv++;
	return val;
}

static uintmax_t
getuintmax(int sign)
{
	uintmax_t val = 0;
	char *cp, *ep;

	cp = *gargv;
	if (cp == NULL)
		goto out;
	gargv++;

	val = (unsigned char) cp[1];
	if (*cp == '\"' || *cp == '\'')
		goto out;

	errno = 0;
	val = sign ? strtoimax(cp, &ep, 0) : strtoumax(cp, &ep, 0);
	check_conversion(cp, ep);
out:
	return val;
}

static double
getdouble(void)
{
	double val;
	char *cp, *ep;

	cp = *gargv;
	if (cp == NULL)
		return 0;
	gargv++;

	if (*cp == '\"' || *cp == '\'')
		return (unsigned char) cp[1];

	errno = 0;
	val = strtod(cp, &ep);
	check_conversion(cp, ep);
	return val;
}

static void
check_conversion(const char *s, const char *ep)
{
	if (*ep) {
		if (ep == s)
			warnx("%s: expected numeric value", s);
		else
			warnx("%s: not completely converted", s);
		rval = 1;
	} else if (errno == ERANGE) {
		warnx("%s: %s", s, strerror(ERANGE));
		rval = 1;
	}
}

int
echocmd(int argc, char **argv)
{
	int nonl;

	nonl = *++argv ? equal(*argv, "-n") : 0;
	argv += nonl;

	do {
		int c;

		if (likely(*argv))
			nonl += print_escape_str("%s", NULL, NULL, *argv++);
		if (likely((nonl + !*argv) > 1))
			break;

		c = *argv ? ' ' : '\n';
		out1c(c);
	} while (*argv);
	return 0;
}