diff options
Diffstat (limited to 'networking/udhcp/script.c')
| -rw-r--r-- | networking/udhcp/script.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/networking/udhcp/script.c b/networking/udhcp/script.c new file mode 100644 index 000000000..b6b0e0d59 --- /dev/null +++ b/networking/udhcp/script.c @@ -0,0 +1,234 @@ +/* script.c + * + * Functions to call the DHCP client notification scripts + * + * Russ Dill <Russ.Dill@asu.edu> July 2001 + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <string.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <arpa/inet.h> +#include <sys/types.h> +#include <sys/wait.h> + +#include "common.h" +#include "options.h" +#include "dhcpd.h" +#include "dhcpc.h" +#include "script.h" + +/* get a rough idea of how long an option will be (rounding up...) */ +static const int max_option_length[] = { + [OPTION_IP] = sizeof("255.255.255.255 "), + [OPTION_IP_PAIR] = sizeof("255.255.255.255 ") * 2, + [OPTION_STRING] = 1, + [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 / option_lengths[opt_index]); +} + + +static int sprintip(char *dest, char *pre, 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(struct in_addr *mask) +{ + int i; + unsigned long bits = ntohl(mask->s_addr); + /* too bad one can't check the carry bit, etc in c bit + * shifting */ + for (i = 0; i < 32 && !((bits >> i) & 1); i++); + return 32 - i; +} + + +/* Fill dest with the text of option 'option'. */ +static void fill_options(char *dest, uint8_t *option, struct dhcp_option *type_p) +{ + int type, optlen; + uint16_t val_u16; + int16_t val_s16; + uint32_t val_u32; + int32_t val_s32; + int len = option[OPT_LEN - 2]; + + dest += sprintf(dest, "%s=", type_p->name); + + type = type_p->flags & TYPE_MASK; + optlen = option_lengths[type]; + 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; /* Short circuit this case */ + } + option += optlen; + len -= optlen; + if (len <= 0) break; + dest += sprintf(dest, " "); + } +} + + +/* put all the parameters into an environment */ +static char **fill_envp(struct dhcpMessage *packet) +{ + int num_options = 0; + int i, j; + char **envp; + uint8_t *temp; + struct in_addr subnet; + char over = 0; + + if (packet == NULL) + num_options = 0; + else { + 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++; + if ((temp = get_option(packet, DHCP_OPTION_OVER))) + over = *temp; + if (!(over & FILE_FIELD) && packet->file[0]) num_options++; + if (!(over & SNAME_FIELD) && packet->sname[0]) num_options++; + } + + envp = xcalloc(sizeof(char *), num_options + 5); + j = 0; + asprintf(&envp[j++], "interface=%s", client_config.interface); + asprintf(&envp[j++], "%s=%s", "PATH", + getenv("PATH") ? : "/bin:/usr/bin:/sbin:/usr/sbin"); + asprintf(&envp[j++], "%s=%s", "HOME", getenv("HOME") ? : "/"); + + if (packet == NULL) return envp; + + envp[j] = xmalloc(sizeof("ip=255.255.255.255")); + sprintip(envp[j++], "ip=", (uint8_t *) &packet->yiaddr); + + + for (i = 0; dhcp_options[i].code; i++) { + if (!(temp = get_option(packet, dhcp_options[i].code))) + continue; + envp[j] = xmalloc(upper_length(temp[OPT_LEN - 2], + dhcp_options[i].flags & TYPE_MASK) + strlen(dhcp_options[i].name) + 2); + fill_options(envp[j++], temp, &dhcp_options[i]); + + /* Fill in a subnet bits option for things like /24 */ + if (dhcp_options[i].code == DHCP_SUBNET) { + memcpy(&subnet, temp, 4); + asprintf(&envp[j++], "mask=%d", mton(&subnet)); + } + } + 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'; + asprintf(&envp[j++], "boot_file=%s", packet->file); + } + if (!(over & SNAME_FIELD) && packet->sname[0]) { + /* watch out for invalid packets */ + packet->sname[sizeof(packet->sname) - 1] = '\0'; + asprintf(&envp[j++], "sname=%s", packet->sname); + } + return envp; +} + + +/* Call a script with a par file and env vars */ +void run_script(struct dhcpMessage *packet, const char *name) +{ + int pid; + char **envp, **curr; + + if (client_config.script == NULL) + return; + + DEBUG(LOG_INFO, "vforking and execle'ing %s", client_config.script); + + envp = fill_envp(packet); + /* call script */ + pid = vfork(); + if (pid) { + waitpid(pid, NULL, 0); + for (curr = envp; *curr; curr++) free(*curr); + free(envp); + return; + } else if (pid == 0) { + /* close fd's? */ + + /* exec script */ + execle(client_config.script, client_config.script, + name, NULL, envp); + LOG(LOG_ERR, "script %s failed: %m", client_config.script); + exit(1); + } +} |