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