[thirdparty/util-linux.git] / lib / mangle.c

/*
 * Functions for \oct encoding used in mtab/fstab/swaps/etc.
 *
 * Based on code from mount(8).
 *
 * Copyright (C) 2010 Karel Zak <kzak@redhat.com>
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "mangle.h"

#define isoctal(a) (((a) & ~7) == '0')

static unsigned char need_escaping[] = { ' ', '\t', '\n', '\\' };

char *mangle(const char *s)
{
	char *ss, *sp;
	int n;

	n = strlen(s);
	ss = sp = malloc(4*n+1);
	if (!sp)
		return NULL;
	while(1) {
		for (n = 0; n < sizeof(need_escaping); n++) {
			if (*s == need_escaping[n]) {
				*sp++ = '\\';
				*sp++ = '0' + ((*s & 0300) >> 6);
				*sp++ = '0' + ((*s & 070) >> 3);
				*sp++ = '0' + (*s & 07);
				goto next;
			}
		}
		*sp++ = *s;
		if (*s == 0)
			break;
	next:
		s++;
	}
	return ss;
}

void unmangle_to_buffer(const char *s, char *buf, size_t len)
{
	size_t sz = 0;

	while(*s && sz < len - 1) {
		if (*s == '\\' && sz + 4 < len - 1 && isoctal(s[1]) &&
		    isoctal(s[2]) && isoctal(s[3])) {

			*buf++ = 64*(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7);
			s += 4;
			sz += 4;
		} else {
			*buf++ = *s++;
			sz++;
		}
	}
	*buf = '\0';
}

static inline const char *skip_nonspaces(const char *s)
{
	while (*s && !(*s == ' ' || *s == '\t'))
		s++;
	return s;
}

/*
 * Returns mallocated buffer or NULL in case of error.
 */
char *unmangle(const char *s)
{
	char *buf;
	const char *end;
	size_t sz;

	end = skip_nonspaces(s);
	sz = end - s + 1;

	buf = malloc(sz);
	if (!buf)
		return NULL;

	unmangle_to_buffer(s, buf, sz);
	return buf;
}

#ifdef TEST_PROGRAM
#include <err.h>
#include <errno.h>
int main(int argc, char *argv[])
{
	if (argc < 3) {
		fprintf(stderr, "usage: %s --mangle | --unmangle <string>\n",
						program_invocation_short_name);
		return EXIT_FAILURE;
	}

	if (!strcmp(argv[1], "--mangle"))
		printf("mangled: '%s'\n", mangle(argv[2]));

	else if (!strcmp(argv[1], "--unmangle")) {
		char *x = unmangle(argv[2]);
		if (x)
			printf("unmangled: '%s'\n", x);
		else
			err(EXIT_FAILURE, "unmangle failed");
	}

	return EXIT_SUCCESS;
}
#endif /* TEST_PROGRAM */
Commit	Line	Data
21169393 KZ	1	/*
	2	* Functions for \oct encoding used in mtab/fstab/swaps/etc.
	3	*
	4	* Based on code from mount(8).
	5	*
	6	* Copyright (C) 2010 Karel Zak <kzak@redhat.com>
	7	*/
	8	#include <stdio.h>
	9	#include <stdlib.h>
	10	#include <string.h>
	11	#include <ctype.h>
	12
	13	#include "mangle.h"
	14
	15	#define isoctal(a) (((a) & ~7) == '0')
	16
	17	static unsigned char need_escaping[] = { ' ', '\t', '\n', '\\' };
	18
	19	char mangle(const char s)
	20	{
	21	char ss, sp;
	22	int n;
	23
	24	n = strlen(s);
	25	ss = sp = malloc(4*n+1);
	26	if (!sp)
	27	return NULL;
	28	while(1) {
	29	for (n = 0; n < sizeof(need_escaping); n++) {
	30	if (*s == need_escaping[n]) {
	31	*sp++ = '\\';
	32	sp++ = '0' + ((s & 0300) >> 6);
	33	sp++ = '0' + ((s & 070) >> 3);
	34	sp++ = '0' + (s & 07);
	35	goto next;
	36	}
	37	}
	38	sp++ = s;
	39	if (*s == 0)
	40	break;
	41	next:
	42	s++;
	43	}
	44	return ss;
	45	}
	46
3c5e4ef8	47	void unmangle_to_buffer(const char s, char buf, size_t len)
21169393 KZ	48	{
	49	size_t sz = 0;
	50
	51	while(*s && sz < len - 1) {
	52	if (*s == '\\' && sz + 4 < len - 1 && isoctal(s[1]) &&
	53	isoctal(s[2]) && isoctal(s[3])) {
	54
	55	buf++ = 64(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7);
	56	s += 4;
	57	sz += 4;
	58	} else {
	59	buf++ = s++;
	60	sz++;
	61	}
	62	}
	63	*buf = '\0';
	64	}
	65
3c5e4ef8	66	static inline const char skip_nonspaces(const char s)
21169393 KZ	67	{
	68	while (s && !(s == ' ' \|\| *s == '\t'))
	69	s++;
	70	return s;
	71	}
	72
	73	/*
	74	* Returns mallocated buffer or NULL in case of error.
	75	*/
3c5e4ef8	76	char unmangle(const char s)
21169393	77	{
3c5e4ef8 KZ	78	char *buf;
3c5e4ef8 KZ	79	const char *end;
21169393 KZ	80	size_t sz;
	81
	82	end = skip_nonspaces(s);
	83	sz = end - s + 1;
	84
	85	buf = malloc(sz);
	86	if (!buf)
	87	return NULL;
	88
	89	unmangle_to_buffer(s, buf, sz);
	90	return buf;
	91	}
	92
	93	#ifdef TEST_PROGRAM
	94	#include <err.h>
	95	#include <errno.h>
	96	int main(int argc, char *argv[])
	97	{
	98	if (argc < 3) {
	99	fprintf(stderr, "usage: %s --mangle \| --unmangle <string>\n",
	100	program_invocation_short_name);
	101	return EXIT_FAILURE;
	102	}
	103
	104	if (!strcmp(argv[1], "--mangle"))
	105	printf("mangled: '%s'\n", mangle(argv[2]));
	106
	107	else if (!strcmp(argv[1], "--unmangle")) {
	108	char *x = unmangle(argv[2]);
	109	if (x)
	110	printf("unmangled: '%s'\n", x);
	111	else
	112	err(EXIT_FAILURE, "unmangle failed");
	113	}
	114
	115	return EXIT_SUCCESS;
	116	}
	117	#endif /* TEST_PROGRAM */