1/* vi: set sw=4 ts=4: */ 2/* script.c 3 * 4 * Functions to call the DHCP client notification scripts 5 * 6 * Russ Dill <Russ.Dill@asu.edu> July 2001 7 * 8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. 9 */ 10 11#include "common.h" 12#include "dhcpc.h" 13#include "options.h" 14 15 16/* get a rough idea of how long an option will be (rounding up...) */ 17static const uint8_t max_option_length[] = { 18 [OPTION_IP] = sizeof("255.255.255.255 "), 19 [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2, 20 [OPTION_STRING] = 1, 21#if ENABLE_FEATURE_RFC3397 22 [OPTION_STR1035] = 1, 23#endif 24 [OPTION_BOOLEAN] = sizeof("yes "), 25 [OPTION_U8] = sizeof("255 "), 26 [OPTION_U16] = sizeof("65535 "), 27 [OPTION_S16] = sizeof("-32768 "), 28 [OPTION_U32] = sizeof("4294967295 "), 29 [OPTION_S32] = sizeof("-2147483684 "), 30}; 31 32 33static inline int upper_length(int length, int opt_index) 34{ 35 return max_option_length[opt_index] * 36 (length / option_lengths[opt_index]); 37} 38 39 40static int sprintip(char *dest, const char *pre, const uint8_t *ip) 41{ 42 return sprintf(dest, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]); 43} 44 45 46/* really simple implementation, just count the bits */ 47static int mton(struct in_addr *mask) 48{ 49 int i; 50 unsigned long bits = ntohl(mask->s_addr); 51 /* too bad one can't check the carry bit, etc in c bit 52 * shifting */ 53 for (i = 0; i < 32 && !((bits >> i) & 1); i++); 54 return 32 - i; 55} 56 57 58/* Allocate and fill with the text of option 'option'. */ 59static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p) 60{ 61 int len, type, optlen; 62 uint16_t val_u16; 63 int16_t val_s16; 64 uint32_t val_u32; 65 int32_t val_s32; 66 char *dest, *ret; 67 68 len = option[OPT_LEN - 2]; 69 type = type_p->flags & TYPE_MASK; 70 optlen = option_lengths[type]; 71 72 dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->name) + 2); 73 dest += sprintf(ret, "%s=", type_p->name); 74 75 for (;;) { 76 switch (type) { 77 case OPTION_IP_PAIR: 78 dest += sprintip(dest, "", option); 79 *dest++ = '/'; 80 option += 4; 81 optlen = 4; 82 case OPTION_IP: /* Works regardless of host byte order. */ 83 dest += sprintip(dest, "", option); 84 break; 85 case OPTION_BOOLEAN: 86 dest += sprintf(dest, *option ? "yes" : "no"); 87 break; 88 case OPTION_U8: 89 dest += sprintf(dest, "%u", *option); 90 break; 91 case OPTION_U16: 92 memcpy(&val_u16, option, 2); 93 dest += sprintf(dest, "%u", ntohs(val_u16)); 94 break; 95 case OPTION_S16: 96 memcpy(&val_s16, option, 2); 97 dest += sprintf(dest, "%d", ntohs(val_s16)); 98 break; 99 case OPTION_U32: 100 memcpy(&val_u32, option, 4); 101 dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32)); 102 break; 103 case OPTION_S32: 104 memcpy(&val_s32, option, 4); 105 dest += sprintf(dest, "%ld", (long) ntohl(val_s32)); 106 break; 107 case OPTION_STRING: 108 memcpy(dest, option, len); 109 dest[len] = '\0'; 110 return ret; /* Short circuit this case */ 111#if ENABLE_FEATURE_RFC3397 112 case OPTION_STR1035: 113 /* unpack option into dest; use ret for prefix (i.e., "optname=") */ 114 dest = dname_dec(option, len, ret); 115 free(ret); 116 return dest; 117#endif 118 } 119 option += optlen; 120 len -= optlen; 121 if (len <= 0) break; 122 dest += sprintf(dest, " "); 123 } 124 return ret; 125} 126 127 128/* put all the parameters into an environment */ 129static char **fill_envp(struct dhcpMessage *packet) 130{ 131 int num_options = 0; 132 int i, j; 133 char **envp; 134 char *var; 135 uint8_t *temp; 136 struct in_addr subnet; 137 char over = 0; 138 139 if (packet) { 140 for (i = 0; dhcp_options[i].code; i++) { 141 if (get_option(packet, dhcp_options[i].code)) { 142 num_options++; 143 if (dhcp_options[i].code == DHCP_SUBNET) 144 num_options++; /* for mton */ 145 } 146 } 147 if (packet->siaddr) 148 num_options++; 149 temp = get_option(packet, DHCP_OPTION_OVER); 150 if (temp) 151 over = *temp; 152 if (!(over & FILE_FIELD) && packet->file[0]) 153 num_options++; 154 if (!(over & SNAME_FIELD) && packet->sname[0]) 155 num_options++; 156 } 157 158 envp = xzalloc(sizeof(char *) * (num_options + 5)); 159 j = 0; 160 envp[j++] = xasprintf("interface=%s", client_config.interface); 161 var = getenv("PATH"); 162 if (var) 163 envp[j++] = xasprintf("PATH=%s", var); 164 var = getenv("HOME"); 165 if (var) 166 envp[j++] = xasprintf("HOME=%s", var); 167 168 if (packet == NULL) 169 return envp; 170 171 envp[j] = xmalloc(sizeof("ip=255.255.255.255")); 172 sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr); 173 174 for (i = 0; dhcp_options[i].code; i++) { 175 temp = get_option(packet, dhcp_options[i].code); 176 if (!temp) 177 continue; 178 envp[j++] = alloc_fill_opts(temp, &dhcp_options[i]); 179 180 /* Fill in a subnet bits option for things like /24 */ 181 if (dhcp_options[i].code == DHCP_SUBNET) { 182 memcpy(&subnet, temp, 4); 183 envp[j++] = xasprintf("mask=%d", mton(&subnet)); 184 } 185 } 186 if (packet->siaddr) { 187 envp[j] = xmalloc(sizeof("siaddr=255.255.255.255")); 188 sprintip(envp[j++], "siaddr=", (uint8_t *) &packet->siaddr); 189 } 190 if (!(over & FILE_FIELD) && packet->file[0]) { 191 /* watch out for invalid packets */ 192 packet->file[sizeof(packet->file) - 1] = '\0'; 193 envp[j++] = xasprintf("boot_file=%s", packet->file); 194 } 195 if (!(over & SNAME_FIELD) && packet->sname[0]) { 196 /* watch out for invalid packets */ 197 packet->sname[sizeof(packet->sname) - 1] = '\0'; 198 envp[j++] = xasprintf("sname=%s", packet->sname); 199 } 200 return envp; 201} 202 203 204/* Call a script with a par file and env vars */ 205void udhcp_run_script(struct dhcpMessage *packet, const char *name) 206{ 207 int pid; 208 char **envp, **curr; 209 210 if (client_config.script == NULL) 211 return; 212 213 DEBUG("vfork'ing and execle'ing %s", client_config.script); 214 215 envp = fill_envp(packet); 216 217 /* call script */ 218// can we use wait4pid(spawn(...)) here? 219 pid = vfork(); 220 if (pid < 0) return; 221 if (pid == 0) { 222 /* close fd's? */ 223 /* exec script */ 224 execle(client_config.script, client_config.script, 225 name, NULL, envp); 226 bb_perror_msg_and_die("script %s failed", client_config.script); 227 } 228 waitpid(pid, NULL, 0); 229 for (curr = envp; *curr; curr++) 230 free(*curr); 231 free(envp); 232} 233