networking/udhcp/script.c - busybox - Git at Google

 /* 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 len_of_option_as_string[] = {
 	[OPTION_IP] =		sizeof("255.255.255.255 "),
 	[OPTION_IP_PAIR] =	sizeof("255.255.255.255 ") * 2,
  	[OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
 	[OPTION_STRING] =	1,
 #if ENABLE_FEATURE_UDHCP_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 "),
 };


 /* note: ip is a pointer to an IP in network order, possibly misaliged */
 static int sprint_nip(char *dest, const char *pre, const uint8_t *ip)
 {
 	return sprintf(dest, "%s%u.%u.%u.%u", 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;
 }


 /* Create "opt_name=opt_value" string */
 static NOINLINE char *xmalloc_optname_optval(uint8_t *option, const struct dhcp_option *type_p, const char *opt_name)
 {
 	unsigned upper_length;
 	int len, type, optlen;
 	uint16_t val_u16;
 	int16_t val_s16;
 	uint32_t val_u32;
 	int32_t val_s32;
 	char *dest, *ret;

 	/* option points to OPT_DATA, need to go back and get OPT_LEN */
 	len = option[OPT_LEN - OPT_DATA];
 	type = type_p->flags & TYPE_MASK;
 	optlen = dhcp_option_lengths[type];
 	upper_length = len_of_option_as_string[type] * (len / optlen);

 	dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
 	dest += sprintf(ret, "%s=", opt_name);

 	while (len >= optlen) {
 		switch (type) {
 		case OPTION_IP_PAIR:
 			dest += sprint_nip(dest, "", option);
 			*dest++ = '/';
 			option += 4;
 			optlen = 4;
 		case OPTION_IP:	/* Works regardless of host byte order. */
 			dest += sprint_nip(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:
 			move_from_unaligned16(val_u16, option);
 			dest += sprintf(dest, "%u", ntohs(val_u16));
 			break;
 		case OPTION_S16:
 			move_from_unaligned16(val_s16, option);
 			dest += sprintf(dest, "%d", ntohs(val_s16));
 			break;
 		case OPTION_U32:
 			move_from_unaligned32(val_u32, option);
 			dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
 			break;
 		case OPTION_S32:
 			move_from_unaligned32(val_s32, option);
 			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 */
 		case OPTION_STATIC_ROUTES: {
 			/* Option binary format:
 			 * mask [one byte, 0..32]
 			 * ip [big endian, 0..4 bytes depending on mask]
 			 * router [big endian, 4 bytes]
 			 * may be repeated
 			 *
 			 * We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
 			 */
 			const char *pfx = "";

 			while (len >= 1 + 4) { /* mask + 0-byte ip + router */
 				uint32_t nip;
 				uint8_t *p;
 				unsigned mask;
 				int bytes;

 				mask = *option++;
 				if (mask > 32)
 					break;
 				len--;

 				nip = 0;
 				p = (void*) &nip;
 				bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
 				while (--bytes >= 0) {
 					*p++ = *option++;
 					len--;
 				}
 				if (len < 4)
 					break;

 				/* print ip/mask */
 				dest += sprint_nip(dest, pfx, (void*) &nip);
 				pfx = " ";
 				dest += sprintf(dest, "/%u ", mask);
 				/* print router */
 				dest += sprint_nip(dest, "", option);
 				option += 4;
 				len -= 4;
 			}

 			return ret;
 		}
 #if ENABLE_FEATURE_UDHCP_RFC3397
 		case OPTION_STR1035:
 			/* unpack option into dest; use ret for prefix (i.e., "optname=") */
 			dest = dname_dec(option, len, ret);
 			if (dest) {
 				free(ret);
 				return dest;
 			}
 			/* error. return "optname=" string */
 			return ret;
 #endif
 		}
 		option += optlen;
 		len -= optlen;
 		if (len <= 0)
 			break;
 		*dest++ = ' ';
 		*dest = '\0';
 	}
 	return ret;
 }


 /* put all the parameters into an environment */
 static char **fill_envp(struct dhcp_packet *packet)
 {
 	int num_options = 0;
 	int i;
 	char **envp, **curr;
 	const char *opt_name;
 	uint8_t *temp;
 	uint8_t 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_nip)
 			num_options++;
 		temp = get_option(packet, DHCP_OPTION_OVERLOAD);
 		if (temp)
 			over = *temp;
 		if (!(over & FILE_FIELD) && packet->file[0])
 			num_options++;
 		if (!(over & SNAME_FIELD) && packet->sname[0])
 			num_options++;
 	}

 	curr = envp = xzalloc(sizeof(char *) * (num_options + 3));
 	*curr = xasprintf("interface=%s", client_config.interface);
 	putenv(*curr++);

 	if (packet == NULL)
 		return envp;

 	*curr = xmalloc(sizeof("ip=255.255.255.255"));
 	sprint_nip(*curr, "ip=", (uint8_t *) &packet->yiaddr);
 	putenv(*curr++);

 	opt_name = dhcp_option_strings;
 	i = 0;
 	while (*opt_name) {
 		temp = get_option(packet, dhcp_options[i].code);
 		if (!temp)
 			goto next;
 		*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
 		putenv(*curr++);

 		/* Fill in a subnet bits option for things like /24 */
 		if (dhcp_options[i].code == DHCP_SUBNET) {
 			uint32_t subnet;
 			move_from_unaligned32(subnet, temp);
 			*curr = xasprintf("mask=%d", mton(subnet));
 			putenv(*curr++);
 		}
  next:
 		opt_name += strlen(opt_name) + 1;
 		i++;
 	}
 	if (packet->siaddr_nip) {
 		*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
 		sprint_nip(*curr, "siaddr=", (uint8_t *) &packet->siaddr_nip);
 		putenv(*curr++);
 	}
 	if (!(over & FILE_FIELD) && packet->file[0]) {
 		/* watch out for invalid packets */
 		packet->file[sizeof(packet->file) - 1] = '\0';
 		*curr = xasprintf("boot_file=%s", packet->file);
 		putenv(*curr++);
 	}
 	if (!(over & SNAME_FIELD) && packet->sname[0]) {
 		/* watch out for invalid packets */
 		packet->sname[sizeof(packet->sname) - 1] = '\0';
 		*curr = xasprintf("sname=%s", packet->sname);
 		putenv(*curr++);
 	}
 	return envp;
 }


 /* Call a script with a par file and env vars */
 void FAST_FUNC udhcp_run_script(struct dhcp_packet *packet, const char *name)
 {
 	char **envp, **curr;
 	char *argv[3];

 	if (client_config.script == NULL)
 		return;

 	envp = fill_envp(packet);

 	/* call script */
 	log1("Executing %s", client_config.script);
 	argv[0] = (char*) client_config.script;
 	argv[1] = (char*) name;
 	argv[2] = NULL;
 	wait4pid(spawn(argv));

 	for (curr = envp; *curr; curr++) {
 		log2(" %s", *curr);
 		bb_unsetenv(*curr);
 		free(*curr);
 	}
 	free(envp);
 }
	/* 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 len_of_option_as_string[] = {
	[OPTION_IP] = sizeof("255.255.255.255 "),
	[OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
	[OPTION_STATIC_ROUTES]= sizeof("255.255.255.255/32 255.255.255.255 "),
	[OPTION_STRING] = 1,
	#if ENABLE_FEATURE_UDHCP_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 "),
	};


	/* note: ip is a pointer to an IP in network order, possibly misaliged */
	static int sprint_nip(char dest, const char pre, const uint8_t *ip)
	{
	return sprintf(dest, "%s%u.%u.%u.%u", 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;
	}


	/* Create "opt_name=opt_value" string */
	static NOINLINE char xmalloc_optname_optval(uint8_t option, const struct dhcp_option type_p, const char opt_name)
	{
	unsigned upper_length;
	int len, type, optlen;
	uint16_t val_u16;
	int16_t val_s16;
	uint32_t val_u32;
	int32_t val_s32;
	char dest, ret;

	/* option points to OPT_DATA, need to go back and get OPT_LEN */
	len = option[OPT_LEN - OPT_DATA];
	type = type_p->flags & TYPE_MASK;
	optlen = dhcp_option_lengths[type];
	upper_length = len_of_option_as_string[type] * (len / optlen);

	dest = ret = xmalloc(upper_length + strlen(opt_name) + 2);
	dest += sprintf(ret, "%s=", opt_name);

	while (len >= optlen) {
	switch (type) {
	case OPTION_IP_PAIR:
	dest += sprint_nip(dest, "", option);
	*dest++ = '/';
	option += 4;
	optlen = 4;
	case OPTION_IP: /* Works regardless of host byte order. */
	dest += sprint_nip(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:
	move_from_unaligned16(val_u16, option);
	dest += sprintf(dest, "%u", ntohs(val_u16));
	break;
	case OPTION_S16:
	move_from_unaligned16(val_s16, option);
	dest += sprintf(dest, "%d", ntohs(val_s16));
	break;
	case OPTION_U32:
	move_from_unaligned32(val_u32, option);
	dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
	break;
	case OPTION_S32:
	move_from_unaligned32(val_s32, option);
	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 */
	case OPTION_STATIC_ROUTES: {
	/* Option binary format:
	* mask [one byte, 0..32]
	* ip [big endian, 0..4 bytes depending on mask]
	* router [big endian, 4 bytes]
	* may be repeated
	*
	* We convert it to a string "IP/MASK ROUTER IP2/MASK2 ROUTER2"
	*/
	const char *pfx = "";

	while (len >= 1 + 4) { /* mask + 0-byte ip + router */
	uint32_t nip;
	uint8_t *p;
	unsigned mask;
	int bytes;

	mask = *option++;
	if (mask > 32)
	break;
	len--;

	nip = 0;
	p = (void*) &nip;
	bytes = (mask + 7) / 8; /* 0 -> 0, 1..8 -> 1, 9..16 -> 2 etc */
	while (--bytes >= 0) {
	p++ = option++;
	len--;
	}
	if (len < 4)
	break;

	/* print ip/mask */
	dest += sprint_nip(dest, pfx, (void*) &nip);
	pfx = " ";
	dest += sprintf(dest, "/%u ", mask);
	/* print router */
	dest += sprint_nip(dest, "", option);
	option += 4;
	len -= 4;
	}

	return ret;
	}
	#if ENABLE_FEATURE_UDHCP_RFC3397
	case OPTION_STR1035:
	/* unpack option into dest; use ret for prefix (i.e., "optname=") */
	dest = dname_dec(option, len, ret);
	if (dest) {
	free(ret);
	return dest;
	}
	/* error. return "optname=" string */
	return ret;
	#endif
	}
	option += optlen;
	len -= optlen;
	if (len <= 0)
	break;
	*dest++ = ' ';
	*dest = '\0';
	}
	return ret;
	}


	/* put all the parameters into an environment */
	static char *fill_envp(struct dhcp_packet packet)
	{
	int num_options = 0;
	int i;
	char envp, curr;
	const char *opt_name;
	uint8_t *temp;
	uint8_t 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_nip)
	num_options++;
	temp = get_option(packet, DHCP_OPTION_OVERLOAD);
	if (temp)
	over = *temp;
	if (!(over & FILE_FIELD) && packet->file[0])
	num_options++;
	if (!(over & SNAME_FIELD) && packet->sname[0])
	num_options++;
	}

	curr = envp = xzalloc(sizeof(char ) (num_options + 3));
	*curr = xasprintf("interface=%s", client_config.interface);
	putenv(*curr++);

	if (packet == NULL)
	return envp;

	*curr = xmalloc(sizeof("ip=255.255.255.255"));
	sprint_nip(curr, "ip=", (uint8_t ) &packet->yiaddr);
	putenv(*curr++);

	opt_name = dhcp_option_strings;
	i = 0;
	while (*opt_name) {
	temp = get_option(packet, dhcp_options[i].code);
	if (!temp)
	goto next;
	*curr = xmalloc_optname_optval(temp, &dhcp_options[i], opt_name);
	putenv(*curr++);

	/* Fill in a subnet bits option for things like /24 */
	if (dhcp_options[i].code == DHCP_SUBNET) {
	uint32_t subnet;
	move_from_unaligned32(subnet, temp);
	*curr = xasprintf("mask=%d", mton(subnet));
	putenv(*curr++);
	}
	next:
	opt_name += strlen(opt_name) + 1;
	i++;
	}
	if (packet->siaddr_nip) {
	*curr = xmalloc(sizeof("siaddr=255.255.255.255"));
	sprint_nip(curr, "siaddr=", (uint8_t ) &packet->siaddr_nip);
	putenv(*curr++);
	}
	if (!(over & FILE_FIELD) && packet->file[0]) {
	/* watch out for invalid packets */
	packet->file[sizeof(packet->file) - 1] = '\0';
	*curr = xasprintf("boot_file=%s", packet->file);
	putenv(*curr++);
	}
	if (!(over & SNAME_FIELD) && packet->sname[0]) {
	/* watch out for invalid packets */
	packet->sname[sizeof(packet->sname) - 1] = '\0';
	*curr = xasprintf("sname=%s", packet->sname);
	putenv(*curr++);
	}
	return envp;
	}


	/* Call a script with a par file and env vars */
	void FAST_FUNC udhcp_run_script(struct dhcp_packet packet, const char name)
	{
	char envp, curr;
	char *argv[3];

	if (client_config.script == NULL)
	return;

	envp = fill_envp(packet);

	/* call script */
	log1("Executing %s", client_config.script);
	argv[0] = (char*) client_config.script;
	argv[1] = (char*) name;
	argv[2] = NULL;
	wait4pid(spawn(argv));

	for (curr = envp; *curr; curr++) {
	log2(" %s", *curr);
	bb_unsetenv(*curr);
	free(*curr);
	}
	free(envp);
	}