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* Splashy - Read a password from splashy and output it
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* Copyright © 2008-2017 Teddy Hogeborn
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* Copyright © 2008-2017 Björn Påhlsson
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* This file is part of Mandos.
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* Mandos is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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* Mandos is distributed in the hope that it will be useful, but
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* Copyright © 2008,2009 Teddy Hogeborn
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* Copyright © 2008,2009 Björn Påhlsson
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* This program is free software: you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
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* along with this program. If not, see
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* <http://www.gnu.org/licenses/>.
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* Contact the authors at <mandos@recompile.se>.
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* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
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* <https://www.fukt.bsnet.se/~teddy/>.
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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), asprintf() */
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#define _GNU_SOURCE /* asprintf() */
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#include <signal.h> /* sig_atomic_t, struct sigaction,
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sigemptyset(), sigaddset(), SIGINT,
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SIGHUP, SIGTERM, sigaction,
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SIG_IGN, kill(), SIGKILL */
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#include <stddef.h> /* NULL */
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#include <stdlib.h> /* getenv() */
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#include <stdio.h> /* asprintf(), vasprintf(), vprintf(),
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#include <stdio.h> /* asprintf(), perror(), sscanf() */
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#include <stdlib.h> /* EXIT_FAILURE, free(),
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#include <sys/types.h> /* pid_t, DIR, struct dirent,
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#include <dirent.h> /* opendir(), readdir(), closedir() */
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#include <inttypes.h> /* intmax_t, strtoimax() */
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#include <sys/stat.h> /* struct stat, lstat(), S_ISLNK */
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#include <iso646.h> /* not, or, and */
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#include <unistd.h> /* readlink(), fork(), execl(),
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sleep(), dup2() STDERR_FILENO,
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STDOUT_FILENO, _exit(),
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#include <string.h> /* memcmp(), strerror() */
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#include <errno.h> /* errno, EACCES, ENOTDIR, ELOOP,
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ENOENT, ENAMETOOLONG, EMFILE,
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ENFILE, ENOMEM, ENOEXEC, EINVAL,
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E2BIG, EFAULT, EIO, ETXTBSY,
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EISDIR, ELIBBAD, EPERM, EINTR,
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#include <error.h> /* error() */
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STDOUT_FILENO, _exit() */
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#include <string.h> /* memcmp() */
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#include <errno.h> /* errno */
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#include <sys/wait.h> /* waitpid(), WIFEXITED(),
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#include <sysexits.h> /* EX_OSERR, EX_OSFILE,
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#include <stdarg.h> /* va_list, va_start(), ... */
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sig_atomic_t interrupted_by_signal = 0;
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/* Function to use when printing errors */
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__attribute__((format (gnu_printf, 3, 4)))
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void error_plus(int status, int errnum, const char *formatstring,
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va_start(ap, formatstring);
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ret = vasprintf(&text, formatstring, ap);
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fprintf(stderr, "Mandos plugin %s: ",
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program_invocation_short_name);
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vfprintf(stderr, formatstring, ap);
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fprintf(stderr, ": ");
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fprintf(stderr, "%s\n", strerror(errnum));
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error(status, errno, "vasprintf while printing error");
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fprintf(stderr, "Mandos plugin ");
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error(status, errnum, "%s", text);
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static void termination_handler(int signum){
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if(interrupted_by_signal){
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static void termination_handler(__attribute__((unused))int signum){
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interrupted_by_signal = 1;
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signal_received = signum;
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int main(__attribute__((unused))int argc,
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__attribute__((unused))char **argv){
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/* Create prompt string */
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char *prompt = NULL;
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DIR *proc_dir = NULL;
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pid_t splashy_pid = 0;
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pid_t splashy_command_pid = 0;
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int exitstatus = EXIT_FAILURE;
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/* Create prompt string */
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const char *const cryptsource = getenv("cryptsource");
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const char *const crypttarget = getenv("crypttarget");
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new_action = { .sa_handler = termination_handler,
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sigemptyset(&new_action.sa_mask);
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ret = sigaddset(&new_action.sa_mask, SIGINT);
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error_plus(0, errno, "sigaddset");
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exitstatus = EX_OSERR;
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ret = sigaddset(&new_action.sa_mask, SIGHUP);
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error_plus(0, errno, "sigaddset");
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exitstatus = EX_OSERR;
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ret = sigaddset(&new_action.sa_mask, SIGTERM);
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error_plus(0, errno, "sigaddset");
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exitstatus = EX_OSERR;
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sigaddset(&new_action.sa_mask, SIGINT);
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sigaddset(&new_action.sa_mask, SIGHUP);
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sigaddset(&new_action.sa_mask, SIGTERM);
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ret = sigaction(SIGINT, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGINT, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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ret = sigaction(SIGHUP, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGHUP, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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ret = sigaction(SIGTERM, NULL, &old_action);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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if(old_action.sa_handler != SIG_IGN){
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ret = sigaction(SIGTERM, &new_action, NULL);
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error_plus(0, errno, "sigaction");
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exitstatus = EX_OSERR;
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if(interrupted_by_signal){
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/* Fork off the splashy command to prompt for password */
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splashy_command_pid = fork();
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if(splashy_command_pid != 0 and interrupted_by_signal){
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if(splashy_command_pid == -1){
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error_plus(0, errno, "fork");
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exitstatus = EX_OSERR;
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if(splashy_command_pid == 0){
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if(not interrupted_by_signal){
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pid_t splashy_command_pid = 0;
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if(not interrupted_by_signal){
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splashy_command_pid = fork();
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if(splashy_command_pid == -1){
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if(not interrupted_by_signal){
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if(splashy_command_pid == 0){
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const char splashy_command[] = "/sbin/splashy_update";
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execl(splashy_command, splashy_command, prompt, (char *)NULL);
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error_plus(0, errno, "execl");
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_exit(EX_UNAVAILABLE);
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case ELIBBAD: /* Linux only */
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ret = execl(splashy_command, splashy_command, prompt,
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if(not interrupted_by_signal){
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if(interrupted_by_signal){
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/* Wait for command to complete */
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if(not interrupted_by_signal and splashy_command_pid != 0){
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ret = waitpid(splashy_command_pid, &status, 0);
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} while(ret == -1 and errno == EINTR
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and not interrupted_by_signal);
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if(interrupted_by_signal){
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ret = waitpid(splashy_command_pid, &status, 0);
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error_plus(0, errno, "waitpid");
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if(errno == ECHILD){
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splashy_command_pid = 0;
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/* The child process has exited */
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splashy_command_pid = 0;
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if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
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if(not interrupted_by_signal and WIFEXITED(status)
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and WEXITSTATUS(status)==0){
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return EXIT_SUCCESS;
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if(proc_dir != NULL){
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TEMP_FAILURE_RETRY(closedir(proc_dir));
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if(splashy_command_pid != 0){
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TEMP_FAILURE_RETRY(kill(splashy_command_pid, SIGTERM));
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TEMP_FAILURE_RETRY(kill(splashy_pid, SIGTERM));
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while(TEMP_FAILURE_RETRY(kill(splashy_pid, 0)) == 0){
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TEMP_FAILURE_RETRY(kill(splashy_pid, SIGKILL));
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pid_t new_splashy_pid = (pid_t)TEMP_FAILURE_RETRY(fork());
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if(new_splashy_pid == 0){
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/* Child; will become new splashy process */
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/* Make the effective user ID (root) the only user ID instead of
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the real user ID (_mandos) */
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ret = setuid(geteuid());
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error_plus(0, errno, "setuid");
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error_plus(0, errno, "chdir");
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/* if(fork() != 0){ */
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/* _exit(EXIT_SUCCESS); */
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace stdout */
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error_plus(0, errno, "dup2");
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execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
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error_plus(0, errno, "execl");
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_exit(EX_UNAVAILABLE);
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if(interrupted_by_signal){
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struct sigaction signal_action;
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sigemptyset(&signal_action.sa_mask);
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signal_action.sa_handler = SIG_DFL;
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ret = (int)TEMP_FAILURE_RETRY(sigaction(signal_received,
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&signal_action, NULL));
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error_plus(0, errno, "sigaction");
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ret = raise(signal_received);
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} while(ret != 0 and errno == EINTR);
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error_plus(0, errno, "raise");
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TEMP_FAILURE_RETRY(pause());
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kill(splashy_pid, SIGTERM);
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if(interrupted_by_signal and splashy_command_pid != 0){
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kill(splashy_command_pid, SIGTERM);
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while(kill(splashy_pid, 0) == 0){
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kill(splashy_pid, SIGKILL);
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pid_t new_splashy_pid = fork();
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if(new_splashy_pid == 0){
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/* Child; will become new splashy process */
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/* Make the effective user ID (root) the only user ID instead of
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the real user ID (_mandos) */
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ret = setuid(geteuid());
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/* if(fork() != 0){ */
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/* _exit(EXIT_SUCCESS); */
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ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
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execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
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if(not interrupted_by_signal){