162 lines
2.6 KiB
C
162 lines
2.6 KiB
C
/*
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* Functions for \oct encoding used in mtab/fstab/swaps/etc.
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*
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* Based on code from mount(8).
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*
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* Copyright (C) 2010 Karel Zak <kzak@redhat.com>
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include "mangle.h"
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#include "c.h"
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#define isoctal(a) (((a) & ~7) == '0')
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#define from_hex(c) (isdigit(c) ? c - '0' : tolower(c) - 'a' + 10)
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#define is_unwanted_char(x) (strchr(" \t\n\\", (unsigned int) x) != NULL)
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char *mangle(const char *s)
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{
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char *ss, *sp;
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if (!s)
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return NULL;
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ss = sp = malloc(4 * strlen(s) + 1);
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if (!sp)
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return NULL;
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while(1) {
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if (is_unwanted_char(*s)) {
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*sp++ = '\\';
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*sp++ = '0' + ((*s & 0300) >> 6);
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*sp++ = '0' + ((*s & 070) >> 3);
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*sp++ = '0' + (*s & 07);
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} else {
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*sp++ = *s;
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if (!*s)
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break;
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}
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s++;
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}
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return ss;
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}
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void unmangle_to_buffer(const char *s, char *buf, size_t len)
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{
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size_t sz = 0;
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if (!s)
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return;
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while(*s && sz < len - 1) {
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if (*s == '\\' && sz + 4 < len - 1 && isoctal(s[1]) &&
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isoctal(s[2]) && isoctal(s[3])) {
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*buf++ = 64*(s[1] & 7) + 8*(s[2] & 7) + (s[3] & 7);
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s += 4;
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sz += 4;
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} else {
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*buf++ = *s++;
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sz++;
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}
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}
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*buf = '\0';
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}
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void unhexmangle_to_buffer(const char *s, char *buf, size_t len)
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{
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size_t sz = 0;
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if (!s)
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return;
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while(*s && sz < len - 1) {
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if (*s == '\\' && sz + 4 < len - 1 && s[1] == 'x' &&
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isxdigit(s[2]) && isxdigit(s[3])) {
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*buf++ = from_hex(s[2]) << 4 | from_hex(s[3]);
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s += 4;
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sz += 4;
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} else {
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*buf++ = *s++;
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sz++;
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}
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}
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*buf = '\0';
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}
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static inline char *skip_nonspaces(const char *s)
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{
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while (*s && !(*s == ' ' || *s == '\t'))
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s++;
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return (char *) s;
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}
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/*
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* Returns mallocated buffer or NULL in case of error.
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*/
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char *unmangle(const char *s, char **end)
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{
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char *buf;
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char *e;
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size_t sz;
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if (!s)
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return NULL;
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e = skip_nonspaces(s);
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sz = e - s + 1;
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if (end)
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*end = e;
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if (e == s)
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return NULL; /* empty string */
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buf = malloc(sz);
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if (!buf)
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return NULL;
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unmangle_to_buffer(s, buf, sz);
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return buf;
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}
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#ifdef TEST_PROGRAM
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#include <errno.h>
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int main(int argc, char *argv[])
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{
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if (argc < 3) {
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fprintf(stderr, "usage: %s --mangle|unmangle <string>\n",
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program_invocation_short_name);
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return EXIT_FAILURE;
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}
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if (!strcmp(argv[1], "--mangle"))
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printf("mangled: '%s'\n", mangle(argv[2]));
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else if (!strcmp(argv[1], "--unmangle")) {
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char *x = unmangle(argv[2], NULL);
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if (x) {
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printf("unmangled: '%s'\n", x);
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free(x);
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}
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x = strdup(argv[2]);
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unmangle_to_buffer(x, x, strlen(x) + 1);
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if (x) {
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printf("self-unmangled: '%s'\n", x);
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free(x);
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}
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}
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return EXIT_SUCCESS;
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}
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#endif /* TEST_PROGRAM */
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