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https://github.com/systemd/systemd.git
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508 lines
10 KiB
C
508 lines
10 KiB
C
/*
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* libudev - interface to udev device information
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*
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* Copyright (C) 2008-2009 Kay Sievers <kay.sievers@vrfy.org>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <unistd.h>
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#include <errno.h>
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#include <string.h>
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#include <dirent.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include "libudev.h"
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#include "libudev-private.h"
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static ssize_t get_sys_link(struct udev *udev, const char *slink, const char *syspath, char *value, size_t size)
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{
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char path[UTIL_PATH_SIZE];
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ssize_t len;
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const char *pos;
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util_strscpyl(path, sizeof(path), syspath, "/", slink, NULL);
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len = readlink(path, path, sizeof(path));
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if (len <= 0 || len == (ssize_t)sizeof(path))
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return -1;
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path[len] = '\0';
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pos = strrchr(path, '/');
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if (pos == NULL)
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return -1;
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pos = &pos[1];
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dbg(udev, "resolved link to: '%s'\n", pos);
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return util_strscpy(value, size, pos);
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}
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ssize_t util_get_sys_subsystem(struct udev *udev, const char *syspath, char *subsystem, size_t size)
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{
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return get_sys_link(udev, "subsystem", syspath, subsystem, size);
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}
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ssize_t util_get_sys_driver(struct udev *udev, const char *syspath, char *driver, size_t size)
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{
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return get_sys_link(udev, "driver", syspath, driver, size);
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}
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int util_resolve_sys_link(struct udev *udev, char *syspath, size_t size)
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{
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char link_target[UTIL_PATH_SIZE];
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ssize_t len;
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int i;
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int back;
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char *base;
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len = readlink(syspath, link_target, sizeof(link_target));
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if (len <= 0 || len == (ssize_t)sizeof(link_target))
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return -1;
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link_target[len] = '\0';
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dbg(udev, "path link '%s' points to '%s'\n", syspath, link_target);
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for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
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;
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dbg(udev, "base '%s', tail '%s', back %i\n", syspath, &link_target[back * 3], back);
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for (i = 0; i <= back; i++) {
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base = strrchr(syspath, '/');
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if (base == NULL)
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return -1;
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base[0] = '\0';
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}
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dbg(udev, "after moving back '%s'\n", syspath);
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util_strscpyl(base, size - (base - syspath), "/", &link_target[back * 3], NULL);
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return 0;
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}
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int util_log_priority(const char *priority)
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{
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char *endptr;
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int prio;
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prio = strtol(priority, &endptr, 10);
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if (endptr[0] == '\0')
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return prio;
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if (strncmp(priority, "err", 3) == 0)
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return LOG_ERR;
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if (strcmp(priority, "info") == 0)
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return LOG_INFO;
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if (strcmp(priority, "debug") == 0)
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return LOG_DEBUG;
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return 0;
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}
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size_t util_path_encode(const char *src, char *dest, size_t size)
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{
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size_t i, j;
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for (i = 0, j = 0; src[i] != '\0'; i++) {
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if (src[i] == '/') {
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if (j+4 >= size) {
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j = 0;
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break;
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}
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memcpy(&dest[j], "\\x2f", 4);
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j += 4;
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} else if (src[i] == '\\') {
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if (j+4 >= size) {
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j = 0;
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break;
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}
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memcpy(&dest[j], "\\x5c", 4);
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j += 4;
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} else {
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if (j+1 >= size) {
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j = 0;
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break;
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}
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dest[j] = src[i];
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j++;
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}
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}
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dest[j] = '\0';
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return j;
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}
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size_t util_path_decode(char *s)
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{
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size_t i, j;
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for (i = 0, j = 0; s[i] != '\0'; j++) {
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if (memcmp(&s[i], "\\x2f", 4) == 0) {
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s[j] = '/';
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i += 4;
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} else if (memcmp(&s[i], "\\x5c", 4) == 0) {
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s[j] = '\\';
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i += 4;
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} else {
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s[j] = s[i];
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i++;
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}
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}
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s[j] = '\0';
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return j;
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}
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void util_remove_trailing_chars(char *path, char c)
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{
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size_t len;
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if (path == NULL)
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return;
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len = strlen(path);
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while (len > 0 && path[len-1] == c)
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path[--len] = '\0';
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}
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/*
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* Concatenates strings. In any case, terminates in _all_ cases with '\0'
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* and moves the @dest pointer forward to the added '\0'. Returns the
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* remaining size, and 0 if the string was truncated.
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*/
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size_t util_strpcpy(char **dest, size_t size, const char *src)
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{
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size_t len;
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len = strlen(src);
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if (len >= size) {
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if (size > 1)
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*dest = mempcpy(*dest, src, size-1);
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size = 0;
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*dest[0] = '\0';
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} else {
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if (len > 0) {
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*dest = mempcpy(*dest, src, len);
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size -= len;
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}
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*dest[0] = '\0';
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}
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return size;
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}
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/* concatenates list of strings, moves dest forward */
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size_t util_strpcpyl(char **dest, size_t size, const char *src, ...)
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{
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va_list va;
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va_start(va, src);
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do {
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size = util_strpcpy(dest, size, src);
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src = va_arg(va, char *);
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} while (src != NULL);
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va_end(va);
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return size;
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}
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/* copies string */
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size_t util_strscpy(char *dest, size_t size, const char *src)
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{
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char *s;
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s = dest;
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return util_strpcpy(&s, size, src);
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}
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/* concatenates list of strings */
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size_t util_strscpyl(char *dest, size_t size, const char *src, ...)
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{
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va_list va;
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char *s;
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va_start(va, src);
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s = dest;
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do {
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size = util_strpcpy(&s, size, src);
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src = va_arg(va, char *);
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} while (src != NULL);
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va_end(va);
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return size;
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}
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/* count of characters used to encode one unicode char */
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static int utf8_encoded_expected_len(const char *str)
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{
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unsigned char c = (unsigned char)str[0];
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if (c < 0x80)
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return 1;
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if ((c & 0xe0) == 0xc0)
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return 2;
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if ((c & 0xf0) == 0xe0)
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return 3;
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if ((c & 0xf8) == 0xf0)
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return 4;
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if ((c & 0xfc) == 0xf8)
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return 5;
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if ((c & 0xfe) == 0xfc)
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return 6;
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return 0;
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}
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/* decode one unicode char */
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static int utf8_encoded_to_unichar(const char *str)
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{
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int unichar;
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int len;
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int i;
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len = utf8_encoded_expected_len(str);
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switch (len) {
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case 1:
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return (int)str[0];
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case 2:
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unichar = str[0] & 0x1f;
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break;
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case 3:
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unichar = (int)str[0] & 0x0f;
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break;
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case 4:
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unichar = (int)str[0] & 0x07;
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break;
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case 5:
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unichar = (int)str[0] & 0x03;
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break;
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case 6:
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unichar = (int)str[0] & 0x01;
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break;
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default:
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return -1;
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}
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for (i = 1; i < len; i++) {
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if (((int)str[i] & 0xc0) != 0x80)
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return -1;
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unichar <<= 6;
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unichar |= (int)str[i] & 0x3f;
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}
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return unichar;
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}
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/* expected size used to encode one unicode char */
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static int utf8_unichar_to_encoded_len(int unichar)
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{
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if (unichar < 0x80)
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return 1;
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if (unichar < 0x800)
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return 2;
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if (unichar < 0x10000)
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return 3;
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if (unichar < 0x200000)
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return 4;
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if (unichar < 0x4000000)
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return 5;
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return 6;
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}
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/* check if unicode char has a valid numeric range */
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static int utf8_unichar_valid_range(int unichar)
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{
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if (unichar > 0x10ffff)
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return 0;
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if ((unichar & 0xfffff800) == 0xd800)
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return 0;
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if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
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return 0;
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if ((unichar & 0xffff) == 0xffff)
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return 0;
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return 1;
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}
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/* validate one encoded unicode char and return its length */
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static int utf8_encoded_valid_unichar(const char *str)
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{
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int len;
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int unichar;
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int i;
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len = utf8_encoded_expected_len(str);
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if (len == 0)
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return -1;
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/* ascii is valid */
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if (len == 1)
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return 1;
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/* check if expected encoded chars are available */
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for (i = 0; i < len; i++)
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if ((str[i] & 0x80) != 0x80)
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return -1;
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unichar = utf8_encoded_to_unichar(str);
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/* check if encoded length matches encoded value */
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if (utf8_unichar_to_encoded_len(unichar) != len)
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return -1;
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/* check if value has valid range */
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if (!utf8_unichar_valid_range(unichar))
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return -1;
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return len;
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}
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int udev_util_replace_whitespace(const char *str, char *to, size_t len)
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{
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size_t i, j;
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/* strip trailing whitespace */
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len = strnlen(str, len);
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while (len && isspace(str[len-1]))
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len--;
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/* strip leading whitespace */
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i = 0;
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while (isspace(str[i]) && (i < len))
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i++;
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j = 0;
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while (i < len) {
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/* substitute multiple whitespace with a single '_' */
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if (isspace(str[i])) {
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while (isspace(str[i]))
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i++;
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to[j++] = '_';
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}
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to[j++] = str[i++];
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}
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to[j] = '\0';
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return 0;
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}
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static int is_whitelisted(char c, const char *white)
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{
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if ((c >= '0' && c <= '9') ||
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(c >= 'A' && c <= 'Z') ||
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(c >= 'a' && c <= 'z') ||
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strchr("#+-.:=@_", c) != NULL ||
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(white != NULL && strchr(white, c) != NULL))
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return 1;
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return 0;
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}
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/* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
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int udev_util_replace_chars(char *str, const char *white)
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{
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size_t i = 0;
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int replaced = 0;
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while (str[i] != '\0') {
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int len;
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if (is_whitelisted(str[i], white)) {
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i++;
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continue;
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}
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/* accept hex encoding */
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if (str[i] == '\\' && str[i+1] == 'x') {
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i += 2;
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continue;
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}
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/* accept valid utf8 */
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len = utf8_encoded_valid_unichar(&str[i]);
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if (len > 1) {
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i += len;
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continue;
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}
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/* if space is allowed, replace whitespace with ordinary space */
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if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
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str[i] = ' ';
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i++;
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replaced++;
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continue;
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}
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/* everything else is replaced with '_' */
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str[i] = '_';
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i++;
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replaced++;
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}
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return replaced;
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}
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/**
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* util_encode_string:
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* @str: input string to be encoded
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* @str_enc: output string to store the encoded input string
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* @len: maximum size of the output string, which may be
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* four times as long as the input string
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*
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* Encode all potentially unsafe characters of a string to the
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* corresponding hex value prefixed by '\x'.
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*
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* Returns: 0 if the entire string was copied, non-zero otherwise.
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**/
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int udev_util_encode_string(const char *str, char *str_enc, size_t len)
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{
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size_t i, j;
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if (str == NULL || str_enc == NULL)
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return -1;
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for (i = 0, j = 0; str[i] != '\0'; i++) {
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int seqlen;
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seqlen = utf8_encoded_valid_unichar(&str[i]);
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if (seqlen > 1) {
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if (len-j < (size_t)seqlen)
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goto err;
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memcpy(&str_enc[j], &str[i], seqlen);
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j += seqlen;
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i += (seqlen-1);
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} else if (str[i] == '\\' || !is_whitelisted(str[i], NULL)) {
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if (len-j < 4)
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goto err;
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sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
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j += 4;
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} else {
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if (len-j < 1)
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goto err;
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str_enc[j] = str[i];
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j++;
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}
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}
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if (len-j < 1)
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goto err;
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str_enc[j] = '\0';
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return 0;
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err:
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return -1;
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}
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void util_set_fd_cloexec(int fd)
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{
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int flags;
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flags = fcntl(fd, F_GETFD);
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if (flags < 0)
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flags = FD_CLOEXEC;
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else
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flags |= FD_CLOEXEC;
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fcntl(fd, F_SETFD, flags);
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}
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unsigned int util_string_hash32(const char *str)
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{
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unsigned int hash = 0;
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while (str[0] != '\0') {
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hash += str[0] << 4;
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hash += str[0] >> 4;
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hash *= 11;
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str++;
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}
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return hash;
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}
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