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/* vi: set sw=4 ts=4: */
/* script.c
*
* Functions to call the DHCP client notification scripts
*
* Russ Dill <Russ.Dill@asu.edu> July 2001
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "common.h"
#include "dhcpc.h"
#include "options.h"
/* get a rough idea of how long an option will be (rounding up...) */
static const uint8_t max_option_length[] = {
[OPTION_IP] = sizeof("255.255.255.255 "),
[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
[OPTION_STRING] = 1,
#if ENABLE_FEATURE_RFC3397
[OPTION_STR1035] = 1,
#endif
[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 inline int upper_length(int length, int opt_index)
{
return max_option_length[opt_index] *
(length / dhcp_option_lengths[opt_index]);
}
static int sprintip(char *dest, const char *pre, const uint8_t *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(uint32_t mask)
{
int i = 0;
mask = ntohl(mask); /* 111110000-like bit pattern */
while (mask) {
i++;
mask <<= 1;
}
return i;
}
/* Allocate and fill with the text of option 'option'. */
static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
{
int len, type, optlen;
uint16_t val_u16;
int16_t val_s16;
uint32_t val_u32;
int32_t val_s32;
char *dest, *ret;
len = option[OPT_LEN - 2];
type = type_p->flags & TYPE_MASK;
optlen = dhcp_option_lengths[type];
dest = ret = xmalloc(upper_length(len, type) + strlen(opt_name) + 2);
dest += sprintf(ret, "%s=", opt_name);
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 ret; /* Short circuit this case */
#if ENABLE_FEATURE_RFC3397
case OPTION_STR1035:
/* unpack option into dest; use ret for prefix (i.e., "optname=") */
dest = dname_dec(option, len, ret);
free(ret);
return dest;
#endif
}
option += optlen;
len -= optlen;
if (len <= 0) break;
dest += sprintf(dest, " ");
}
return ret;
}
/* put all the parameters into an environment */
static char **fill_envp(struct dhcpMessage *packet)
{
int num_options = 0;
int i, j;
char **envp;
char *var;
const char *opt_name;
uint8_t *temp;
char over = 0;
if (packet) {
for (i = 0; dhcp_options[i].code; i++) {
if (get_option(packet, dhcp_options[i].code)) {
num_options++;
if (dhcp_options[i].code == DHCP_SUBNET)
num_options++; /* for mton */
}
}
if (packet->siaddr)
num_options++;
temp = get_option(packet, DHCP_OPTION_OVER);
if (temp)
over = *temp;
if (!(over & FILE_FIELD) && packet->file[0])
num_options++;
if (!(over & SNAME_FIELD) && packet->sname[0])
num_options++;
}
envp = xzalloc(sizeof(char *) * (num_options + 5));
j = 0;
envp[j++] = xasprintf("interface=%s", client_config.interface);
var = getenv("PATH");
if (var)
envp[j++] = xasprintf("PATH=%s", var);
var = getenv("HOME");
if (var)
envp[j++] = xasprintf("HOME=%s", var);
if (packet == NULL)
return envp;
envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
opt_name = dhcp_option_strings;
i = 0;
while (*opt_name) {
temp = get_option(packet, dhcp_options[i].code);
if (!temp)
goto next;
envp[j++] = alloc_fill_opts(temp, &dhcp_options[i], opt_name);
/* Fill in a subnet bits option for things like /24 */
if (dhcp_options[i].code == DHCP_SUBNET) {
uint32_t subnet;
memcpy(&subnet, temp, 4);
envp[j++] = xasprintf("mask=%d", mton(subnet));
}
next:
opt_name += strlen(opt_name) + 1;
i++;
}
if (packet->siaddr) {
envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
sprintip(envp[j++], "siaddr=", (uint8_t *) &packet->siaddr);
}
if (!(over & FILE_FIELD) && packet->file[0]) {
/* watch out for invalid packets */
packet->file[sizeof(packet->file) - 1] = '\0';
envp[j++] = xasprintf("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++] = xasprintf("sname=%s", packet->sname);
}
return envp;
}
/* Call a script with a par file and env vars */
void FAST_FUNC udhcp_run_script(struct dhcpMessage *packet, const char *name)
{
int pid;
char **envp, **curr;
if (client_config.script == NULL)
return;
DEBUG("vfork'ing and execle'ing %s", client_config.script);
envp = fill_envp(packet);
/* call script */
// can we use wait4pid(spawn(...)) here?
pid = vfork();
if (pid < 0) return;
if (pid == 0) {
/* close fd's? */
/* exec script */
execle(client_config.script, client_config.script,
name, NULL, envp);
bb_perror_msg_and_die("exec %s", client_config.script);
}
safe_waitpid(pid, NULL, 0);
for (curr = envp; *curr; curr++)
free(*curr);
free(envp);
}
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