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-rw-r--r--networking/udhcp/script.c213
1 files changed, 213 insertions, 0 deletions
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c
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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 "dhcpd.h"
13#include "dhcpc.h"
14#include "options.h"
15
16
17/* get a rough idea of how long an option will be (rounding up...) */
18static const int max_option_length[] = {
19 [OPTION_IP] = sizeof("255.255.255.255 "),
20 [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2,
21 [OPTION_STRING] = 1,
22 [OPTION_BOOLEAN] = sizeof("yes "),
23 [OPTION_U8] = sizeof("255 "),
24 [OPTION_U16] = sizeof("65535 "),
25 [OPTION_S16] = sizeof("-32768 "),
26 [OPTION_U32] = sizeof("4294967295 "),
27 [OPTION_S32] = sizeof("-2147483684 "),
28};
29
30
31static inline int upper_length(int length, int opt_index)
32{
33 return max_option_length[opt_index] *
34 (length / option_lengths[opt_index]);
35}
36
37
38static int sprintip(char *dest, char *pre, uint8_t *ip)
39{
40 return sprintf(dest, "%s%d.%d.%d.%d", pre, ip[0], ip[1], ip[2], ip[3]);
41}
42
43
44/* really simple implementation, just count the bits */
45static int mton(struct in_addr *mask)
46{
47 int i;
48 unsigned long bits = ntohl(mask->s_addr);
49 /* too bad one can't check the carry bit, etc in c bit
50 * shifting */
51 for (i = 0; i < 32 && !((bits >> i) & 1); i++);
52 return 32 - i;
53}
54
55
56/* Fill dest with the text of option 'option'. */
57static void fill_options(char *dest, uint8_t *option,
58 const struct dhcp_option *type_p)
59{
60 int type, optlen;
61 uint16_t val_u16;
62 int16_t val_s16;
63 uint32_t val_u32;
64 int32_t val_s32;
65 int len = option[OPT_LEN - 2];
66
67 dest += sprintf(dest, "%s=", type_p->name);
68
69 type = type_p->flags & TYPE_MASK;
70 optlen = option_lengths[type];
71 for (;;) {
72 switch (type) {
73 case OPTION_IP_PAIR:
74 dest += sprintip(dest, "", option);
75 *(dest++) = '/';
76 option += 4;
77 optlen = 4;
78 case OPTION_IP: /* Works regardless of host byte order. */
79 dest += sprintip(dest, "", option);
80 break;
81 case OPTION_BOOLEAN:
82 dest += sprintf(dest, *option ? "yes" : "no");
83 break;
84 case OPTION_U8:
85 dest += sprintf(dest, "%u", *option);
86 break;
87 case OPTION_U16:
88 memcpy(&val_u16, option, 2);
89 dest += sprintf(dest, "%u", ntohs(val_u16));
90 break;
91 case OPTION_S16:
92 memcpy(&val_s16, option, 2);
93 dest += sprintf(dest, "%d", ntohs(val_s16));
94 break;
95 case OPTION_U32:
96 memcpy(&val_u32, option, 4);
97 dest += sprintf(dest, "%lu", (unsigned long) ntohl(val_u32));
98 break;
99 case OPTION_S32:
100 memcpy(&val_s32, option, 4);
101 dest += sprintf(dest, "%ld", (long) ntohl(val_s32));
102 break;
103 case OPTION_STRING:
104 memcpy(dest, option, len);
105 dest[len] = '\0';
106 return; /* Short circuit this case */
107 }
108 option += optlen;
109 len -= optlen;
110 if (len <= 0) break;
111 dest += sprintf(dest, " ");
112 }
113}
114
115
116/* put all the parameters into an environment */
117static char **fill_envp(struct dhcpMessage *packet)
118{
119 int num_options = 0;
120 int i, j;
121 char **envp;
122 uint8_t *temp;
123 struct in_addr subnet;
124 char over = 0;
125
126 if (packet == NULL)
127 num_options = 0;
128 else {
129 for (i = 0; dhcp_options[i].code; i++)
130 if (get_option(packet, dhcp_options[i].code)) {
131 num_options++;
132 if (dhcp_options[i].code == DHCP_SUBNET)
133 num_options++; /* for mton */
134 }
135 if (packet->siaddr) num_options++;
136 if ((temp = get_option(packet, DHCP_OPTION_OVER)))
137 over = *temp;
138 if (!(over & FILE_FIELD) && packet->file[0]) num_options++;
139 if (!(over & SNAME_FIELD) && packet->sname[0]) num_options++;
140 }
141
142 envp = xzalloc(sizeof(char *) * (num_options + 5));
143 j = 0;
144 envp[j++] = xasprintf("interface=%s", client_config.interface);
145 envp[j++] = xasprintf("PATH=%s",
146 getenv("PATH") ? : "/bin:/usr/bin:/sbin:/usr/sbin");
147 envp[j++] = xasprintf("HOME=%s", getenv("HOME") ? : "/");
148
149 if (packet == NULL) return envp;
150
151 envp[j] = xmalloc(sizeof("ip=255.255.255.255"));
152 sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr);
153
154 for (i = 0; dhcp_options[i].code; i++) {
155 temp = get_option(packet, dhcp_options[i].code);
156 if (!temp)
157 continue;
158 envp[j] = xmalloc(upper_length(temp[OPT_LEN - 2],
159 dhcp_options[i].flags & TYPE_MASK) + strlen(dhcp_options[i].name) + 2);
160 fill_options(envp[j++], temp, &dhcp_options[i]);
161
162 /* Fill in a subnet bits option for things like /24 */
163 if (dhcp_options[i].code == DHCP_SUBNET) {
164 memcpy(&subnet, temp, 4);
165 envp[j++] = xasprintf("mask=%d", mton(&subnet));
166 }
167 }
168 if (packet->siaddr) {
169 envp[j] = xmalloc(sizeof("siaddr=255.255.255.255"));
170 sprintip(envp[j++], "siaddr=", (uint8_t *) &packet->siaddr);
171 }
172 if (!(over & FILE_FIELD) && packet->file[0]) {
173 /* watch out for invalid packets */
174 packet->file[sizeof(packet->file) - 1] = '\0';
175 envp[j++] = xasprintf("boot_file=%s", packet->file);
176 }
177 if (!(over & SNAME_FIELD) && packet->sname[0]) {
178 /* watch out for invalid packets */
179 packet->sname[sizeof(packet->sname) - 1] = '\0';
180 envp[j++] = xasprintf("sname=%s", packet->sname);
181 }
182 return envp;
183}
184
185
186/* Call a script with a par file and env vars */
187void udhcp_run_script(struct dhcpMessage *packet, const char *name)
188{
189 int pid;
190 char **envp, **curr;
191
192 if (client_config.script == NULL)
193 return;
194
195 DEBUG("vfork'ing and execle'ing %s", client_config.script);
196
197 envp = fill_envp(packet);
198 /* call script */
199 pid = vfork();
200 if (pid) {
201 waitpid(pid, NULL, 0);
202 for (curr = envp; *curr; curr++) free(*curr);
203 free(envp);
204 return;
205 } else if (pid == 0) {
206 /* close fd's? */
207 /* exec script */
208 execle(client_config.script, client_config.script,
209 name, NULL, envp);
210 bb_perror_msg("script %s failed", client_config.script);
211 exit(1);
212 }
213}
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