[1765] | 1 | /* vi: set sw=4 ts=4: */
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[821] | 2 | /* script.c
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| 3 | *
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| 4 | * Functions to call the DHCP client notification scripts
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| 5 | *
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| 6 | * Russ Dill <Russ.Dill@asu.edu> July 2001
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| 7 | *
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| 8 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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| 9 | */
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| 10 |
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| 11 | #include "common.h"
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[1765] | 12 | #include "dhcpc.h"
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[821] | 13 | #include "options.h"
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| 14 |
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[1765] | 15 |
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[821] | 16 | /* get a rough idea of how long an option will be (rounding up...) */
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[1765] | 17 | static const uint8_t max_option_length[] = {
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[821] | 18 | [OPTION_IP] = sizeof("255.255.255.255 "),
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| 19 | [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
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| 20 | [OPTION_STRING] = 1,
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[1765] | 21 | #if ENABLE_FEATURE_RFC3397
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| 22 | [OPTION_STR1035] = 1,
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| 23 | #endif
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[821] | 24 | [OPTION_BOOLEAN] = sizeof("yes "),
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| 25 | [OPTION_U8] = sizeof("255 "),
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| 26 | [OPTION_U16] = sizeof("65535 "),
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| 27 | [OPTION_S16] = sizeof("-32768 "),
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| 28 | [OPTION_U32] = sizeof("4294967295 "),
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| 29 | [OPTION_S32] = sizeof("-2147483684 "),
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| 30 | };
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| 31 |
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| 32 |
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| 33 | static inline int upper_length(int length, int opt_index)
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| 34 | {
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| 35 | return max_option_length[opt_index] *
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| 36 | (length / option_lengths[opt_index]);
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| 37 | }
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| 38 |
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| 39 |
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[1765] | 40 | static int sprintip(char *dest, const char *pre, const uint8_t *ip)
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[821] | 41 | {
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| 42 | return sprintf(dest, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]);
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| 43 | }
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| 44 |
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| 45 |
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| 46 | /* really simple implementation, just count the bits */
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| 47 | static int mton(struct in_addr *mask)
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| 48 | {
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| 49 | int i;
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| 50 | unsigned long bits = ntohl(mask->s_addr);
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| 51 | /* too bad one can't check the carry bit, etc in c bit
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| 52 | * shifting */
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| 53 | for (i = 0; i < 32 && !((bits >> i) & 1); i++);
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| 54 | return 32 - i;
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| 55 | }
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| 56 |
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| 57 |
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[1765] | 58 | /* Allocate and fill with the text of option 'option'. */
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| 59 | static char *alloc_fill_opts(uint8_t *option, const struct dhcp_option *type_p)
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[821] | 60 | {
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[1765] | 61 | int len, type, optlen;
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[821] | 62 | uint16_t val_u16;
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| 63 | int16_t val_s16;
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| 64 | uint32_t val_u32;
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| 65 | int32_t val_s32;
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[1765] | 66 | char *dest, *ret;
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[821] | 67 |
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[1765] | 68 | len = option[OPT_LEN - 2];
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[821] | 69 | type = type_p->flags & TYPE_MASK;
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| 70 | optlen = option_lengths[type];
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[1765] | 71 |
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| 72 | dest = ret = xmalloc(upper_length(len, type) + strlen(type_p->name) + 2);
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| 73 | dest += sprintf(ret, "%s=", type_p->name);
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| 74 |
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| 75 | for (;;) {
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[821] | 76 | switch (type) {
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| 77 | case OPTION_IP_PAIR:
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| 78 | dest += sprintip(dest, "", option);
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[1765] | 79 | *dest++ = '/';
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[821] | 80 | option += 4;
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| 81 | optlen = 4;
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| 82 | case OPTION_IP: /* Works regardless of host byte order. */
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| 83 | dest += sprintip(dest, "", option);
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| 84 | break;
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| 85 | case OPTION_BOOLEAN:
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| 86 | dest += sprintf(dest, *option ? "yes" : "no");
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| 87 | break;
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| 88 | case OPTION_U8:
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| 89 | dest += sprintf(dest, "%u", *option);
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| 90 | break;
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| 91 | case OPTION_U16:
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| 92 | memcpy(&val_u16, option, 2);
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| 93 | dest += sprintf(dest, "%u", ntohs(val_u16));
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| 94 | break;
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| 95 | case OPTION_S16:
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| 96 | memcpy(&val_s16, option, 2);
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| 97 | dest += sprintf(dest, "%d", ntohs(val_s16));
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| 98 | break;
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| 99 | case OPTION_U32:
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| 100 | memcpy(&val_u32, option, 4);
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| 101 | dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
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| 102 | break;
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| 103 | case OPTION_S32:
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| 104 | memcpy(&val_s32, option, 4);
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| 105 | dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
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| 106 | break;
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| 107 | case OPTION_STRING:
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| 108 | memcpy(dest, option, len);
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| 109 | dest[len] = '\0';
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[1765] | 110 | return ret; /* Short circuit this case */
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| 111 | #if ENABLE_FEATURE_RFC3397
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| 112 | case OPTION_STR1035:
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| 113 | /* unpack option into dest; use ret for prefix (i.e., "optname=") */
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| 114 | dest = dname_dec(option, len, ret);
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| 115 | free(ret);
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| 116 | return dest;
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| 117 | #endif
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[821] | 118 | }
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| 119 | option += optlen;
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| 120 | len -= optlen;
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| 121 | if (len <= 0) break;
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| 122 | dest += sprintf(dest, " ");
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| 123 | }
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[1765] | 124 | return ret;
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[821] | 125 | }
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| 126 |
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| 127 |
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| 128 | /* put all the parameters into an environment */
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| 129 | static char **fill_envp(struct dhcpMessage *packet)
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| 130 | {
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| 131 | int num_options = 0;
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| 132 | int i, j;
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| 133 | char **envp;
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[1765] | 134 | char *var;
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[821] | 135 | uint8_t *temp;
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| 136 | struct in_addr subnet;
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| 137 | char over = 0;
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| 138 |
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[1765] | 139 | if (packet) {
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| 140 | for (i = 0; dhcp_options[i].code; i++) {
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[821] | 141 | if (get_option(packet, dhcp_options[i].code)) {
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| 142 | num_options++;
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| 143 | if (dhcp_options[i].code == DHCP_SUBNET)
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| 144 | num_options++; /* for mton */
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| 145 | }
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[1765] | 146 | }
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| 147 | if (packet->siaddr)
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| 148 | num_options++;
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| 149 | temp = get_option(packet, DHCP_OPTION_OVER);
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| 150 | if (temp)
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[821] | 151 | over = *temp;
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[1765] | 152 | if (!(over & FILE_FIELD) && packet->file[0])
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| 153 | num_options++;
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| 154 | if (!(over & SNAME_FIELD) && packet->sname[0])
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| 155 | num_options++;
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[821] | 156 | }
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| 157 |
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| 158 | envp = xzalloc(sizeof(char *) * (num_options + 5));
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| 159 | j = 0;
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[1765] | 160 | envp[j++] = xasprintf("interface=%s", client_config.interface);
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| 161 | var = getenv("PATH");
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| 162 | if (var)
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| 163 | envp[j++] = xasprintf("PATH=%s", var);
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| 164 | var = getenv("HOME");
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| 165 | if (var)
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| 166 | envp[j++] = xasprintf("HOME=%s", var);
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[821] | 167 |
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[1765] | 168 | if (packet == NULL)
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| 169 | return envp;
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[821] | 170 |
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| 171 | envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
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| 172 | sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
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| 173 |
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| 174 | for (i = 0; dhcp_options[i].code; i++) {
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[1765] | 175 | temp = get_option(packet, dhcp_options[i].code);
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| 176 | if (!temp)
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[821] | 177 | continue;
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[1765] | 178 | envp[j++] = alloc_fill_opts(temp, &dhcp_options[i]);
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[821] | 179 |
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| 180 | /* Fill in a subnet bits option for things like /24 */
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| 181 | if (dhcp_options[i].code == DHCP_SUBNET) {
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| 182 | memcpy(&subnet, temp, 4);
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[1765] | 183 | envp[j++] = xasprintf("mask=%d", mton(&subnet));
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[821] | 184 | }
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| 185 | }
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| 186 | if (packet->siaddr) {
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| 187 | envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
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| 188 | sprintip(envp[j++], "siaddr=", (uint8_t *) &packet->siaddr);
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| 189 | }
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| 190 | if (!(over & FILE_FIELD) && packet->file[0]) {
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| 191 | /* watch out for invalid packets */
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| 192 | packet->file[sizeof(packet->file) - 1] = '\0';
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[1765] | 193 | envp[j++] = xasprintf("boot_file=%s", packet->file);
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[821] | 194 | }
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| 195 | if (!(over & SNAME_FIELD) && packet->sname[0]) {
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| 196 | /* watch out for invalid packets */
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| 197 | packet->sname[sizeof(packet->sname) - 1] = '\0';
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[1765] | 198 | envp[j++] = xasprintf("sname=%s", packet->sname);
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[821] | 199 | }
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| 200 | return envp;
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| 201 | }
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| 202 |
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| 203 |
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| 204 | /* Call a script with a par file and env vars */
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| 205 | void udhcp_run_script(struct dhcpMessage *packet, const char *name)
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| 206 | {
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| 207 | int pid;
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| 208 | char **envp, **curr;
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| 209 |
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| 210 | if (client_config.script == NULL)
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| 211 | return;
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| 212 |
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[1765] | 213 | DEBUG("vfork'ing and execle'ing %s", client_config.script);
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[821] | 214 |
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| 215 | envp = fill_envp(packet);
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[1765] | 216 |
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[821] | 217 | /* call script */
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[1765] | 218 | // can we use wait4pid(spawn(...)) here?
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[821] | 219 | pid = vfork();
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[1765] | 220 | if (pid < 0) return;
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| 221 | if (pid == 0) {
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[821] | 222 | /* close fd's? */
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| 223 | /* exec script */
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| 224 | execle(client_config.script, client_config.script,
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| 225 | name, NULL, envp);
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[1765] | 226 | bb_perror_msg_and_die("script %s failed", client_config.script);
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[821] | 227 | }
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[1765] | 228 | waitpid(pid, NULL, 0);
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| 229 | for (curr = envp; *curr; curr++)
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| 230 | free(*curr);
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| 231 | free(envp);
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[821] | 232 | }
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