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/* script.c
*
* Functions to call the DHCP client notification scripts
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include "options.h"
#include "dhcpd.h"
#include "dhcpc.h"
#include "packet.h"
#include "options.h"
#include "debug.h"
/* get a rough idea of how long an option will be (rounding up...) */
static int max_option_length[] = {
[OPTION_IP] = sizeof("255.255.255.255 "),
[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
[OPTION_STRING] = 1,
[OPTION_BOOLEAN] = sizeof("yes "),
[OPTION_U8] = sizeof("255 "),
[OPTION_U16] = sizeof("65535 "),
[OPTION_S16] = sizeof("-32768 "),
[OPTION_U32] = sizeof("4294967295 "),
[OPTION_S32] = sizeof("-2147483684 "),
};
static int upper_length(int length, struct dhcp_option *option)
{
return max_option_length[option->flags & TYPE_MASK] *
(length / option_lengths[option->flags & TYPE_MASK]);
}
static int sprintip(char *dest, char *pre, unsigned char *ip)
{
return sprintf(dest, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]);
}
/* really simple implementation, just count the bits */
static int mton(struct in_addr *mask)
{
int i;
/* note: mask will always be in network byte order, so
* there are no endian issues */
for (i = 31; i >= 0 && !((mask->s_addr >> i) & 1); i--);
return i + 1;
}
/* Fill dest with the text of option 'option'. */
static void fill_options(char *dest, unsigned char *option, struct dhcp_option *type_p)
{
int type, optlen;
u_int16_t val_u16;
int16_t val_s16;
u_int32_t val_u32;
int32_t val_s32;
int len = option[OPT_LEN - 2];
dest += sprintf(dest, "%s=", type_p->name);
type = type_p->flags & TYPE_MASK;
optlen = option_lengths[type];
for(;;) {
switch (type) {
case OPTION_IP_PAIR:
dest += sprintip(dest, "", option);
*(dest++) = '/';
option += 4;
optlen = 4;
case OPTION_IP: /* Works regardless of host byte order. */
dest += sprintip(dest, "", option);
break;
case OPTION_BOOLEAN:
dest += sprintf(dest, *option ? "yes" : "no");
break;
case OPTION_U8:
dest += sprintf(dest, "%u", *option);
break;
case OPTION_U16:
memcpy(&val_u16, option, 2);
dest += sprintf(dest, "%u", ntohs(val_u16));
break;
case OPTION_S16:
memcpy(&val_s16, option, 2);
dest += sprintf(dest, "%d", ntohs(val_s16));
break;
case OPTION_U32:
memcpy(&val_u32, option, 4);
dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
break;
case OPTION_S32:
memcpy(&val_s32, option, 4);
dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
break;
case OPTION_STRING:
memcpy(dest, option, len);
dest[len] = '\0';
return; /* Short circuit this case */
}
option += optlen;
len -= optlen;
if (len <= 0) break;
dest += sprintf(dest, " ");
}
}
static char *find_env(const char *prefix, char *defaultstr)
{
extern char **environ;
char **ptr;
const int len = strlen(prefix);
for (ptr = environ; *ptr != NULL; ptr++) {
if (strncmp(prefix, *ptr, len) == 0)
return *ptr;
}
return defaultstr;
}
/* put all the paramaters into an environment */
static char **fill_envp(struct dhcpMessage *packet)
{
int num_options = 0;
int i, j;
char **envp;
unsigned char *temp;
struct in_addr subnet;
char over = 0;
if (packet == NULL)
num_options = 0;
else {
for (i = 0; options[i].code; i++)
if (get_option(packet, options[i].code))
num_options++;
if (packet->siaddr) num_options++;
if ((temp = get_option(packet, DHCP_OPTION_OVER)))
over = *temp;
if (!(over & FILE_FIELD) && packet->file[0]) num_options++;
if (!(over & SNAME_FIELD) && packet->sname[0]) num_options++;
}
envp = xmalloc((num_options + 5) * sizeof(char *));
j = 0;
envp[j++] = xmalloc(sizeof("interface=") + strlen(client_config.interface));
sprintf(envp[0], "interface=%s", client_config.interface);
envp[j++] = find_env("PATH", "PATH=/bin:/usr/bin:/sbin:/usr/sbin");
envp[j++] = find_env("HOME", "HOME=/");
if (packet == NULL) {
envp[j++] = NULL;
return envp;
}
envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
sprintip(envp[j++], "ip=", (unsigned char *) &packet->yiaddr);
for (i = 0; options[i].code; i++) {
if (!(temp = get_option(packet, options[i].code)))
continue;
envp[j] = xmalloc(upper_length(temp[OPT_LEN - 2], &options[i]) + strlen(options[i].name) + 2);
fill_options(envp[j++], temp, &options[i]);
/* Fill in a subnet bits option for things like /24 */
if (options[i].code == DHCP_SUBNET) {
envp[j] = xmalloc(sizeof("mask=32"));
memcpy(&subnet, temp, 4);
sprintf(envp[j++], "mask=%d", mton(&subnet));
}
}
if (packet->siaddr) {
envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
sprintip(envp[j++], "siaddr=", (unsigned char *) &packet->siaddr);
}
if (!(over & FILE_FIELD) && packet->file[0]) {
/* watch out for invalid packets */
packet->file[sizeof(packet->file) - 1] = '\0';
envp[j] = xmalloc(sizeof("boot_file=") + strlen(packet->file));
sprintf(envp[j++], "boot_file=%s", packet->file);
}
if (!(over & SNAME_FIELD) && packet->sname[0]) {
/* watch out for invalid packets */
packet->sname[sizeof(packet->sname) - 1] = '\0';
envp[j] = xmalloc(sizeof("sname=") + strlen(packet->sname));
sprintf(envp[j++], "sname=%s", packet->sname);
}
envp[j] = NULL;
return envp;
}
/* Call a script with a par file and env vars */
void run_script(struct dhcpMessage *packet, const char *name)
{
int pid;
char **envp;
if (client_config.script == NULL)
return;
/* call script */
pid = fork();
if (pid) {
waitpid(pid, NULL, 0);
return;
} else if (pid == 0) {
envp = fill_envp(packet);
/* close fd's? */
/* exec script */
DEBUG(LOG_INFO, "execle'ing %s", client_config.script);
execle(client_config.script, client_config.script,
name, NULL, envp);
LOG(LOG_ERR, "script %s failed: %s",
client_config.script, strerror(errno));
exit(1);
}
}
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