482 lines
13 KiB
C
482 lines
13 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include "alloc-util.h"
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#include "escape.h"
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#include "hexdecoct.h"
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#include "utf8.h"
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#include "util.h"
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size_t cescape_char(char c, char *buf) {
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char * buf_old = buf;
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switch (c) {
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case '\a':
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*(buf++) = '\\';
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*(buf++) = 'a';
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break;
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case '\b':
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*(buf++) = '\\';
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*(buf++) = 'b';
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break;
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case '\f':
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*(buf++) = '\\';
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*(buf++) = 'f';
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break;
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case '\n':
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*(buf++) = '\\';
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*(buf++) = 'n';
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break;
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case '\r':
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*(buf++) = '\\';
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*(buf++) = 'r';
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break;
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case '\t':
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*(buf++) = '\\';
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*(buf++) = 't';
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break;
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case '\v':
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*(buf++) = '\\';
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*(buf++) = 'v';
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break;
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case '\\':
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*(buf++) = '\\';
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*(buf++) = '\\';
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break;
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case '"':
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*(buf++) = '\\';
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*(buf++) = '"';
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break;
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case '\'':
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*(buf++) = '\\';
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*(buf++) = '\'';
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break;
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default:
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/* For special chars we prefer octal over
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* hexadecimal encoding, simply because glib's
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* g_strescape() does the same */
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if ((c < ' ') || (c >= 127)) {
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*(buf++) = '\\';
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*(buf++) = octchar((unsigned char) c >> 6);
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*(buf++) = octchar((unsigned char) c >> 3);
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*(buf++) = octchar((unsigned char) c);
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} else
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*(buf++) = c;
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break;
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}
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return buf - buf_old;
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}
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char *cescape(const char *s) {
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char *r, *t;
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const char *f;
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assert(s);
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/* Does C style string escaping. May be reversed with
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* cunescape(). */
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r = new(char, strlen(s)*4 + 1);
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if (!r)
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return NULL;
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for (f = s, t = r; *f; f++)
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t += cescape_char(*f, t);
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*t = 0;
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return r;
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}
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int cunescape_one(const char *p, size_t length, char *ret, uint32_t *ret_unicode) {
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int r = 1;
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assert(p);
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assert(*p);
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assert(ret);
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/* Unescapes C style. Returns the unescaped character in ret,
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* unless we encountered a \u sequence in which case the full
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* unicode character is returned in ret_unicode, instead. */
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if (length != (size_t) -1 && length < 1)
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return -EINVAL;
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switch (p[0]) {
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case 'a':
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*ret = '\a';
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break;
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case 'b':
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*ret = '\b';
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break;
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case 'f':
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*ret = '\f';
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break;
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case 'n':
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*ret = '\n';
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break;
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case 'r':
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*ret = '\r';
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break;
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case 't':
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*ret = '\t';
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break;
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case 'v':
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*ret = '\v';
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break;
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case '\\':
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*ret = '\\';
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break;
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case '"':
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*ret = '"';
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break;
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case '\'':
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*ret = '\'';
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break;
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case 's':
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/* This is an extension of the XDG syntax files */
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*ret = ' ';
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break;
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case 'x': {
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/* hexadecimal encoding */
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int a, b;
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if (length != (size_t) -1 && length < 3)
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return -EINVAL;
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a = unhexchar(p[1]);
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if (a < 0)
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return -EINVAL;
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b = unhexchar(p[2]);
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if (b < 0)
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return -EINVAL;
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/* Don't allow NUL bytes */
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if (a == 0 && b == 0)
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return -EINVAL;
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*ret = (char) ((a << 4U) | b);
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r = 3;
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break;
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}
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case 'u': {
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/* C++11 style 16bit unicode */
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int a[4];
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unsigned i;
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uint32_t c;
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if (length != (size_t) -1 && length < 5)
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return -EINVAL;
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for (i = 0; i < 4; i++) {
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a[i] = unhexchar(p[1 + i]);
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if (a[i] < 0)
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return a[i];
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}
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c = ((uint32_t) a[0] << 12U) | ((uint32_t) a[1] << 8U) | ((uint32_t) a[2] << 4U) | (uint32_t) a[3];
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/* Don't allow 0 chars */
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if (c == 0)
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return -EINVAL;
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if (c < 128)
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*ret = c;
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else {
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if (!ret_unicode)
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return -EINVAL;
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*ret = 0;
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*ret_unicode = c;
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}
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r = 5;
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break;
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}
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case 'U': {
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/* C++11 style 32bit unicode */
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int a[8];
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unsigned i;
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char32_t c;
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if (length != (size_t) -1 && length < 9)
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return -EINVAL;
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for (i = 0; i < 8; i++) {
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a[i] = unhexchar(p[1 + i]);
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if (a[i] < 0)
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return a[i];
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}
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c = (a[0] << 28U) | (a[1] << 24U) | (a[2] << 20U) | (a[3] << 16U) |
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(a[4] << 12U) | (a[5] << 8U) | (a[6] << 4U) | (a[7] << 0U);
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/* Don't allow 0 chars */
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if (c == 0)
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return -EINVAL;
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/* Don't allow invalid code points */
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if (!unichar_is_valid(c))
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return -EINVAL;
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if (c < 128)
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*ret = c;
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else {
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if (!ret_unicode)
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return -EINVAL;
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*ret = 0;
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*ret_unicode = c;
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}
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r = 9;
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break;
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}
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case '0':
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case '1':
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case '2':
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case '3':
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case '4':
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case '5':
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case '6':
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case '7': {
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/* octal encoding */
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int a, b, c;
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char32_t m;
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if (length != (size_t) -1 && length < 3)
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return -EINVAL;
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a = unoctchar(p[0]);
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if (a < 0)
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return -EINVAL;
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b = unoctchar(p[1]);
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if (b < 0)
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return -EINVAL;
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c = unoctchar(p[2]);
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if (c < 0)
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return -EINVAL;
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/* don't allow NUL bytes */
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if (a == 0 && b == 0 && c == 0)
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return -EINVAL;
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/* Don't allow bytes above 255 */
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m = (a << 6U) | (b << 3U) | (char32_t) c;
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if (m > 255)
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return -EINVAL;
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*ret = m;
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r = 3;
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break;
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}
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default:
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return -EINVAL;
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}
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return r;
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}
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int cunescape_length_with_prefix(const char *s, size_t length, const char *prefix, UnescapeFlags flags, char **ret) {
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char *r, *t;
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const char *f;
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size_t pl;
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assert(s);
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assert(ret);
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/* Undoes C style string escaping, and optionally prefixes it. */
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pl = prefix ? strlen(prefix) : 0;
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r = new(char, pl+length+1);
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if (!r)
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return -ENOMEM;
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if (prefix)
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memcpy(r, prefix, pl);
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for (f = s, t = r + pl; f < s + length; f++) {
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size_t remaining;
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char32_t u;
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char c;
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int k;
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remaining = s + length - f;
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assert(remaining > 0);
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if (*f != '\\') {
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/* A literal literal, copy verbatim */
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*(t++) = *f;
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continue;
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}
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if (remaining == 1) {
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if (flags & UNESCAPE_RELAX) {
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/* A trailing backslash, copy verbatim */
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*(t++) = *f;
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continue;
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}
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free(r);
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return -EINVAL;
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}
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k = cunescape_one(f + 1, remaining - 1, &c, &u);
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if (k < 0) {
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if (flags & UNESCAPE_RELAX) {
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/* Invalid escape code, let's take it literal then */
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*(t++) = '\\';
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continue;
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}
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free(r);
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return k;
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}
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if (c != 0)
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/* Non-Unicode? Let's encode this directly */
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*(t++) = c;
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else
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/* Unicode? Then let's encode this in UTF-8 */
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t += utf8_encode_unichar(t, u);
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f += k;
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}
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*t = 0;
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*ret = r;
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return t - r;
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}
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int cunescape_length(const char *s, size_t length, UnescapeFlags flags, char **ret) {
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return cunescape_length_with_prefix(s, length, NULL, flags, ret);
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}
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int cunescape(const char *s, UnescapeFlags flags, char **ret) {
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return cunescape_length(s, strlen(s), flags, ret);
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}
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char *xescape(const char *s, const char *bad) {
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char *r, *t;
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const char *f;
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/* Escapes all chars in bad, in addition to \ and all special
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* chars, in \xFF style escaping. May be reversed with
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* cunescape(). */
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r = new(char, strlen(s) * 4 + 1);
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if (!r)
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return NULL;
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for (f = s, t = r; *f; f++) {
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if ((*f < ' ') || (*f >= 127) ||
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(*f == '\\') || strchr(bad, *f)) {
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*(t++) = '\\';
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*(t++) = 'x';
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*(t++) = hexchar(*f >> 4);
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*(t++) = hexchar(*f);
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} else
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*(t++) = *f;
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}
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*t = 0;
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return r;
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}
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static char *strcpy_backslash_escaped(char *t, const char *s, const char *bad) {
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assert(bad);
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for (; *s; s++) {
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if (*s == '\\' || strchr(bad, *s))
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*(t++) = '\\';
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*(t++) = *s;
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}
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return t;
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}
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char *shell_escape(const char *s, const char *bad) {
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char *r, *t;
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r = new(char, strlen(s)*2+1);
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if (!r)
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return NULL;
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t = strcpy_backslash_escaped(r, s, bad);
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*t = 0;
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return r;
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}
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char *shell_maybe_quote(const char *s) {
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const char *p;
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char *r, *t;
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assert(s);
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/* Encloses a string in double quotes if necessary to make it
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* OK as shell string. */
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for (p = s; *p; p++)
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if (*p <= ' ' ||
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*p >= 127 ||
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strchr(SHELL_NEED_QUOTES, *p))
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break;
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if (!*p)
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return strdup(s);
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r = new(char, 1+strlen(s)*2+1+1);
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if (!r)
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return NULL;
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t = r;
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*(t++) = '"';
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t = mempcpy(t, s, p - s);
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t = strcpy_backslash_escaped(t, p, SHELL_NEED_ESCAPE);
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*(t++)= '"';
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*t = 0;
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return r;
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}
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