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#include <inttypes.h> /* PRIu16, PRIdMAX, intmax_t,
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#include <assert.h> /* assert() */
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#include <errno.h> /* perror(), errno */
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#include <time.h> /* nanosleep(), time() */
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#include <errno.h> /* perror(), errno,
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program_invocation_short_name */
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#include <time.h> /* nanosleep(), time(), sleep() */
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#include <net/if.h> /* ioctl, ifreq, SIOCGIFFLAGS, IFF_UP,
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SIOCSIFFLAGS, if_indextoname(),
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if_nametoindex(), IF_NAMESIZE */
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gnutls_dh_params_t dh_params;
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const char *priority;
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server *current_server;
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} mandos_context;
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/* global context so signal handler can reach it*/
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mandos_context mc = { .simple_poll = NULL, .server = NULL,
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.dh_bits = 1024, .priority = "SECURE256"
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":!CTYPE-X.509:+CTYPE-OPENPGP" };
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":!CTYPE-X.509:+CTYPE-OPENPGP",
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.current_server = NULL };
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sig_atomic_t quit_now = 0;
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int signal_received = 0;
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/* Function to use when printing errors */
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void perror_plus(const char *print_text){
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fprintf(stderr, "Mandos plugin %s: ",
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program_invocation_short_name);
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* Make additional room in "buffer" for at least BUFFER_SIZE more
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* bytes. "buffer_capacity" is how much is currently allocated,
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return buffer_capacity;
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int add_server(const char *ip, uint16_t port,
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AvahiIfIndex if_index,
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server *new_server = malloc(sizeof(server));
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if(new_server == NULL){
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perror_plus("malloc");
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*new_server = (server){ .ip = strdup(ip),
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.if_index = if_index,
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if(new_server->ip == NULL){
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perror_plus("strdup");
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/* unique case of first server */
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if (mc.current_server == NULL){
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new_server->next = new_server;
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new_server->prev = new_server;
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mc.current_server = new_server;
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/* Placing the new server last in the list */
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new_server->next = mc.current_server;
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new_server->prev = mc.current_server->prev;
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new_server->prev->next = new_server;
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mc.current_server->prev = new_server;
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ret = clock_gettime(CLOCK_MONOTONIC, &mc.current_server->last_seen);
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perror_plus("clock_gettime");
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* Initialize GPGME.
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signal_received = sig;
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int old_errno = errno;
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/* set main loop to exit */
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if(mc.simple_poll != NULL){
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avahi_simple_poll_quit(mc.simple_poll);
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errno = old_errno;
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* This function determines if a directory entry in /sys/class/net
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* corresponds to an acceptable network device.
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* (This function is passed to scandir(3) as a filter function.)
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int good_interface(const struct dirent *if_entry){
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char *flagname = NULL;
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if(if_entry->d_name[0] == '.'){
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int ret = asprintf(&flagname, "%s/%s/flags", sys_class_net,
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perror_plus("asprintf");
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int flags_fd = (int)TEMP_FAILURE_RETRY(open(flagname, O_RDONLY));
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perror_plus("open");
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typedef short ifreq_flags; /* ifreq.ifr_flags in netdevice(7) */
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/* read line from flags_fd */
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ssize_t to_read = 2+(sizeof(ifreq_flags)*2)+1; /* "0x1003\n" */
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char *flagstring = malloc((size_t)to_read+1); /* +1 for final \0 */
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flagstring[(size_t)to_read] = '\0';
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if(flagstring == NULL){
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perror_plus("malloc");
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ssret = (ssize_t)TEMP_FAILURE_RETRY(read(flags_fd, flagstring,
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perror_plus("read");
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tmpmax = strtoimax(flagstring, &tmp, 0);
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if(errno != 0 or tmp == flagstring or (*tmp != '\0'
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and not (isspace(*tmp)))
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or tmpmax != (ifreq_flags)tmpmax){
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fprintf(stderr, "Invalid flags \"%s\" for interface \"%s\"\n",
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flagstring, if_entry->d_name);
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ifreq_flags flags = (ifreq_flags)tmpmax;
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/* Reject the loopback device */
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if(flags & IFF_LOOPBACK){
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fprintf(stderr, "Rejecting loopback interface \"%s\"\n",
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/* Accept point-to-point devices only if connect_to is specified */
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if(connect_to != NULL and (flags & IFF_POINTOPOINT)){
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fprintf(stderr, "Accepting point-to-point interface \"%s\"\n",
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/* Otherwise, reject non-broadcast-capable devices */
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if(not (flags & IFF_BROADCAST)){
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fprintf(stderr, "Rejecting non-broadcast interface \"%s\"\n",
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/* Reject non-ARP interfaces (including dummy interfaces) */
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if(flags & IFF_NOARP){
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fprintf(stderr, "Rejecting non-ARP interface \"%s\"\n",
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/* Accept this device */
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fprintf(stderr, "Interface \"%s\" is acceptable\n",
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int notdotentries(const struct dirent *direntry){
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/* Skip "." and ".." */
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if(direntry->d_name[0] == '.'
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and (direntry->d_name[1] == '\0'
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or (direntry->d_name[1] == '.'
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and direntry->d_name[2] == '\0'))){
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int avahi_loop_with_timeout(AvahiSimplePoll *s, int retry_interval){
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struct timespec now;
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struct timespec waited_time;
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intmax_t block_time;
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if(mc.current_server == NULL){
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"Wait until first server is found. No timeout!\n");
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ret = avahi_simple_poll_iterate(s, -1);
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fprintf(stderr, "Check current_server if we should run it,"
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/* the current time */
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ret = clock_gettime(CLOCK_MONOTONIC, &now);
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perror_plus("clock_gettime");
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/* Calculating in ms how long time between now and server
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who we visted longest time ago. Now - last seen. */
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waited_time.tv_sec = (now.tv_sec
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- mc.current_server->last_seen.tv_sec);
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waited_time.tv_nsec = (now.tv_nsec
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- mc.current_server->last_seen.tv_nsec);
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/* total time is 10s/10,000ms.
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Converting to s from ms by dividing by 1,000,
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and ns to ms by dividing by 1,000,000. */
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block_time = ((retry_interval
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- ((intmax_t)waited_time.tv_sec * 1000))
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- ((intmax_t)waited_time.tv_nsec / 1000000));
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fprintf(stderr, "Blocking for %ld ms\n", block_time);
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if(block_time <= 0){
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ret = start_mandos_communication(mc.current_server->ip,
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mc.current_server->port,
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mc.current_server->if_index,
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mc.current_server->af);
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avahi_simple_poll_quit(mc.simple_poll);
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ret = clock_gettime(CLOCK_MONOTONIC,
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&mc.current_server->last_seen);
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perror_plus("clock_gettime");
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mc.current_server = mc.current_server->next;
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block_time = 0; /* Call avahi to find new Mandos
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servers, but don't block */
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ret = avahi_simple_poll_iterate(s, (int)block_time);
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if (ret > 0 or errno != EINTR) {
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return (ret != 1) ? ret : 0;
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int main(int argc, char *argv[]){
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AvahiSServiceBrowser *sb = NULL;
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ret = sigaction(SIGINT, NULL, &old_sigterm_action);
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perror("sigaction");
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perror_plus("sigaction");
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return EX_OSERR;
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if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &sigterm_action, NULL);
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perror("sigaction");
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perror_plus("sigaction");
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exitcode = EX_OSERR;
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ret = sigaction(SIGHUP, NULL, &old_sigterm_action);
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perror("sigaction");
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perror_plus("sigaction");
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return EX_OSERR;
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if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &sigterm_action, NULL);
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perror("sigaction");
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perror_plus("sigaction");
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exitcode = EX_OSERR;
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ret = sigaction(SIGTERM, NULL, &old_sigterm_action);
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perror("sigaction");
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perror_plus("sigaction");
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return EX_OSERR;
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if(old_sigterm_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &sigterm_action, NULL);
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perror("sigaction");
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perror_plus("sigaction");
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exitcode = EX_OSERR;
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/* If the interface is down, bring it up */
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if(interface[0] != '\0'){
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if(strcmp(interface, "none") != 0){
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if_index = (AvahiIfIndex) if_nametoindex(interface);
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if(if_index == 0){
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fprintf(stderr, "No such interface: \"%s\"\n", interface);
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ret = seteuid(uid);
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perror_plus("seteuid");
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/* sleep checking until interface is running */
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/* Sleep checking until interface is running.
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Check every 0.25s, up to total time of delay */
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for(int i=0; i < delay * 4; i++){
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ret = ioctl(sd, SIOCGIFFLAGS, &network);
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perror("ioctl SIOCGIFFLAGS");
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perror_plus("ioctl SIOCGIFFLAGS");
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} else if(network.ifr_flags & IFF_RUNNING){
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struct timespec sleeptime = { .tv_nsec = 250000000 };
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ret = nanosleep(&sleeptime, NULL);
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if(ret == -1 and errno != EINTR){
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perror("nanosleep");
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perror_plus("nanosleep");
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if(not take_down_interface){
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/* We won't need the socket anymore */
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ret = (int)TEMP_FAILURE_RETRY(close(sd));
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perror_plus("close");
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#ifdef __linux__
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ret = seteuid(0);
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perror_plus("seteuid");
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if(geteuid() == 0){
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ret = ioctl(sd, SIOCGIFFLAGS, &network);
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perror("ioctl SIOCGIFFLAGS");
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perror_plus("ioctl SIOCGIFFLAGS");
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} else if(network.ifr_flags & IFF_UP) {
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network.ifr_flags &= ~(short)IFF_UP; /* clear flag */
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ret = ioctl(sd, SIOCSIFFLAGS, &network);
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perror("ioctl SIOCSIFFLAGS");
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perror_plus("ioctl SIOCSIFFLAGS -IFF_UP");
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ret = (int)TEMP_FAILURE_RETRY(close(sd));
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perror_plus("close");
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/* Lower privileges permanently */
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ret = setuid(uid);
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perror_plus("setuid");
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/* Removes the temp directory used by GPGME */
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/* Removes the GPGME temp directory and all files inside */
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if(tempdir_created){
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struct dirent *direntry;
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d = opendir(tempdir);
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if(errno != ENOENT){
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direntry = readdir(d);
1655
if(direntry == NULL){
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/* Skip "." and ".." */
1659
if(direntry->d_name[0] == '.'
1660
and (direntry->d_name[1] == '\0'
1661
or (direntry->d_name[1] == '.'
1662
and direntry->d_name[2] == '\0'))){
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struct dirent **direntries = NULL;
1938
struct dirent *direntry = NULL;
1939
ret = scandir(tempdir, &direntries, notdotentries, alphasort);
1941
for(int i = 0; i < ret; i++){
1942
direntry = direntries[i];
1665
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char *fullname = NULL;
1666
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ret = asprintf(&fullname, "%s/%s", tempdir,
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direntry->d_name);
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perror_plus("asprintf");
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ret = remove(fullname);