1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/* 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_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 "),
};
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_UDHCP_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);
}
|
