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Member "dhcpcd-9.4.1/src/common.c" (22 Oct 2021, 4693 Bytes) of package /linux/misc/dhcpcd-9.4.1.tar.xz:


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    1 /* SPDX-License-Identifier: BSD-2-Clause */
    2 /*
    3  * dhcpcd - DHCP client daemon
    4  * Copyright (c) 2006-2021 Roy Marples <roy@marples.name>
    5  * All rights reserved
    6 
    7  * Redistribution and use in source and binary forms, with or without
    8  * modification, are permitted provided that the following conditions
    9  * are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   26  * SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/stat.h>
   30 #include <sys/statvfs.h>
   31 
   32 #include <ctype.h>
   33 #include <errno.h>
   34 #include <fcntl.h>
   35 #include <stdio.h>
   36 #include <stdlib.h>
   37 #include <string.h>
   38 
   39 #include "common.h"
   40 #include "dhcpcd.h"
   41 #include "if-options.h"
   42 
   43 const char *
   44 hwaddr_ntoa(const void *hwaddr, size_t hwlen, char *buf, size_t buflen)
   45 {
   46     const unsigned char *hp, *ep;
   47     char *p;
   48 
   49     if (buf == NULL || hwlen == 0)
   50         return NULL;
   51 
   52     if (hwlen * 3 > buflen) {
   53         errno = ENOBUFS;
   54         return NULL;
   55     }
   56 
   57     hp = hwaddr;
   58     ep = hp + hwlen;
   59     p = buf;
   60 
   61     while (hp < ep) {
   62         if (hp != hwaddr)
   63             *p ++= ':';
   64         p += snprintf(p, 3, "%.2x", *hp++);
   65     }
   66     *p ++= '\0';
   67     return buf;
   68 }
   69 
   70 size_t
   71 hwaddr_aton(uint8_t *buffer, const char *addr)
   72 {
   73     char c[3];
   74     const char *p = addr;
   75     uint8_t *bp = buffer;
   76     size_t len = 0;
   77 
   78     c[2] = '\0';
   79     while (*p != '\0') {
   80         /* Skip separators */
   81         c[0] = *p++;
   82         switch (c[0]) {
   83         case '\n':  /* long duid split on lines */
   84         case ':':   /* typical mac address */
   85         case '-':   /* uuid */
   86             continue;
   87         }
   88         c[1] = *p++;
   89         /* Ensure that digits are hex */
   90         if (isxdigit((unsigned char)c[0]) == 0 ||
   91             isxdigit((unsigned char)c[1]) == 0)
   92         {
   93             errno = EINVAL;
   94             return 0;
   95         }
   96         /* We should have at least two entries 00:01 */
   97         if (len == 0 && *p == '\0') {
   98             errno = EINVAL;
   99             return 0;
  100         }
  101         if (bp)
  102             *bp++ = (uint8_t)strtol(c, NULL, 16);
  103         len++;
  104     }
  105     return len;
  106 }
  107 
  108 ssize_t
  109 readfile(const char *file, void *data, size_t len)
  110 {
  111     int fd;
  112     ssize_t bytes;
  113 
  114     fd = open(file, O_RDONLY);
  115     if (fd == -1)
  116         return -1;
  117     bytes = read(fd, data, len);
  118     close(fd);
  119     if ((size_t)bytes == len) {
  120         errno = ENOBUFS;
  121         return -1;
  122     }
  123     return bytes;
  124 }
  125 
  126 ssize_t
  127 writefile(const char *file, mode_t mode, const void *data, size_t len)
  128 {
  129     int fd;
  130     ssize_t bytes;
  131 
  132     fd = open(file, O_WRONLY | O_CREAT | O_TRUNC, mode);
  133     if (fd == -1)
  134         return -1;
  135     bytes = write(fd, data, len);
  136     close(fd);
  137     return bytes;
  138 }
  139 
  140 int
  141 filemtime(const char *file, time_t *time)
  142 {
  143     struct stat st;
  144 
  145     if (stat(file, &st) == -1)
  146         return -1;
  147     *time = st.st_mtime;
  148     return 0;
  149 }
  150 
  151 /* Handy routine to read very long lines in text files.
  152  * This means we read the whole line and avoid any nasty buffer overflows.
  153  * We strip leading space and avoid comment lines, making the code that calls
  154  * us smaller. */
  155 char *
  156 get_line(char ** __restrict buf, ssize_t * __restrict buflen)
  157 {
  158     char *p, *c;
  159     bool quoted;
  160 
  161     do {
  162         p = *buf;
  163         if (*buf == NULL)
  164             return NULL;
  165         c = memchr(*buf, '\n', (size_t)*buflen);
  166         if (c == NULL) {
  167             c = memchr(*buf, '\0', (size_t)*buflen);
  168             if (c == NULL)
  169                 return NULL;
  170             *buflen = c - *buf;
  171             *buf = NULL;
  172         } else {
  173             *c++ = '\0';
  174             *buflen -= c - *buf;
  175             *buf = c;
  176         }
  177         for (; *p == ' ' || *p == '\t'; p++)
  178             ;
  179     } while (*p == '\0' || *p == '\n' || *p == '#' || *p == ';');
  180 
  181     /* Strip embedded comments unless in a quoted string or escaped */
  182     quoted = false;
  183     for (c = p; *c != '\0'; c++) {
  184         if (*c == '\\') {
  185             c++; /* escaped */
  186             continue;
  187         }
  188         if (*c == '"')
  189             quoted = !quoted;
  190         else if (*c == '#' && !quoted) {
  191             *c = '\0';
  192             break;
  193         }
  194     }
  195     return p;
  196 }
  197 
  198 
  199 int
  200 is_root_local(void)
  201 {
  202 #ifdef ST_LOCAL
  203     struct statvfs vfs;
  204 
  205     if (statvfs("/", &vfs) == -1)
  206         return -1;
  207     return vfs.f_flag & ST_LOCAL ? 1 : 0;
  208 #else
  209     errno = ENOTSUP;
  210     return -1;
  211 #endif
  212 }