diff options
Diffstat (limited to 'networking/udhcp/script.c')
-rw-r--r-- | networking/udhcp/script.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c new file mode 100644 index 0000000..8dff9b7 --- /dev/null +++ b/networking/udhcp/script.c @@ -0,0 +1,239 @@ +/* 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); +} |