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283 lines
6.8 KiB
C
283 lines
6.8 KiB
C
/* vi: set sw=4 ts=4: */
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/* 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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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include "common.h"
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#include "dhcpc.h"
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#include "options.h"
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/* get a rough idea of how long an option will be (rounding up...) */
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static const uint8_t len_of_option_as_string[] = {
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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_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
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[OPTION_STRING] = 1,
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#if ENABLE_FEATURE_UDHCP_RFC3397
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[OPTION_STR1035] = 1,
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#endif
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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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/* note: ip is a pointer to an IP in network order, possibly misaliged */
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static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
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{
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return sprintf(dest, "%s%u.%u.%u.%u", 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(uint32_t mask)
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{
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int i = 0;
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mask = ntohl(mask); /* 111110000-like bit pattern */
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while (mask) {
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i++;
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mask <<= 1;
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}
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return i;
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}
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/* Create "opt_name=opt_value" string */
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static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
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{
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unsigned upper_length;
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int len, type, optlen;
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uint16_t val_u16;
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int16_t val_s16;
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uint32_t val_u32;
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int32_t val_s32;
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char *dest, *ret;
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/* option points to OPT_DATA, need to go back and get OPT_LEN */
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len = option[OPT_LEN - OPT_DATA];
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type = type_p->flags & TYPE_MASK;
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optlen = dhcp_option_lengths[type];
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upper_length = len_of_option_as_string[type] * (len / optlen);
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dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
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dest += sprintf(ret, "%s=", opt_name);
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while (len >= optlen) {
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switch (type) {
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case OPTION_IP_PAIR:
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dest += sprint_nip(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 += sprint_nip(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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move_from_unaligned16(val_u16, option);
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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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move_from_unaligned16(val_s16, option);
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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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move_from_unaligned32(val_u32, option);
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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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move_from_unaligned32(val_s32, option);
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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 ret; /* Short circuit this case */
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case OPTION_STATIC_ROUTES: {
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/* Option binary format:
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* mask [one byte, 0..32]
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* ip [big endian, 0..4 bytes depending on mask]
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* router [big endian, 4 bytes]
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* may be repeated
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*
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* We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
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*/
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const char *pfx = "";
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while (len >= 1 + 4) { /* mask + 0-byte ip + router */
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uint32_t nip;
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uint8_t *p;
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unsigned mask;
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int bytes;
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mask = *option++;
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if (mask > 32)
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break;
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len--;
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nip = 0;
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p = (void*) &nip;
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bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
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while (--bytes >= 0) {
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*p++ = *option++;
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len--;
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}
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if (len < 4)
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break;
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/* print ip/mask */
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dest += sprint_nip(dest, pfx, (void*) &nip);
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pfx = " ";
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dest += sprintf(dest, "/%u ", mask);
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/* print router */
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dest += sprint_nip(dest, "", option);
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option += 4;
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len -= 4;
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}
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return ret;
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}
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#if ENABLE_FEATURE_UDHCP_RFC3397
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case OPTION_STR1035:
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/* unpack option into dest; use ret for prefix (i.e., "optname=") */
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dest = dname_dec(option, len, ret);
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if (dest) {
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free(ret);
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return dest;
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}
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/* error. return "optname=" string */
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return ret;
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#endif
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}
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option += optlen;
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len -= optlen;
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if (len <= 0)
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break;
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*dest++ = ' ';
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*dest = '\0';
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}
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return ret;
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}
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/* put all the parameters into an environment */
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static char **fill_envp(struct dhcp_packet *packet)
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{
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int num_options = 0;
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int i;
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char **envp, **curr;
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const char *opt_name;
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uint8_t *temp;
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uint8_t over = 0;
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if (packet) {
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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 (dhcp_options[i].code == DHCP_SUBNET)
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num_options++; /* for mton */
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}
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}
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if (packet->siaddr_nip)
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num_options++;
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temp = get_option(packet, DHCP_OPTION_OVERLOAD);
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if (temp)
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over = *temp;
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if (!(over & FILE_FIELD) && packet->file[0])
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num_options++;
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if (!(over & SNAME_FIELD) && packet->sname[0])
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num_options++;
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}
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curr = envp = xzalloc(sizeof(char *) * (num_options + 3));
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*curr = xasprintf("interface=%s", client_config.interface);
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putenv(*curr++);
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if (packet == NULL)
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return envp;
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*curr = xmalloc(sizeof("ip=255.255.255.255"));
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sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
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putenv(*curr++);
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opt_name = dhcp_option_strings;
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i = 0;
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while (*opt_name) {
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temp = get_option(packet, dhcp_options[i].code);
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if (!temp)
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goto next;
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*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
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putenv(*curr++);
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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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uint32_t subnet;
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move_from_unaligned32(subnet, temp);
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*curr = xasprintf("mask=%d", mton(subnet));
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putenv(*curr++);
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}
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next:
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opt_name += strlen(opt_name) + 1;
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i++;
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}
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if (packet->siaddr_nip) {
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*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
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sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
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putenv(*curr++);
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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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*curr = xasprintf("boot_file=%s", packet->file);
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putenv(*curr++);
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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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*curr = xasprintf("sname=%s", packet->sname);
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putenv(*curr++);
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}
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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 FAST_FUNC udhcp_run_script(struct dhcp_packet *packet, const char *name)
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{
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char **envp, **curr;
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char *argv[3];
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if (client_config.script == NULL)
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return;
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envp = fill_envp(packet);
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/* call script */
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log1("Executing %s %s", client_config.script, name);
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argv[0] = (char*) client_config.script;
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argv[1] = (char*) name;
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argv[2] = NULL;
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wait4pid(spawn(argv));
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for (curr = envp; *curr; curr++) {
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log2(" %s", *curr);
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bb_unsetenv(*curr);
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free(*curr);
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}
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free(envp);
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}
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