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/*
* 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;
if (!s)
return NULL;
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;
if (!s)
return;
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;
if (!s)
return NULL;
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 */
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