/mandos/trunk

To get this branch, use:
bzr branch http://bzr.recompile.se/loggerhead/mandos/trunk
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
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/*  -*- coding: utf-8 -*- */
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/*
261 by Teddy Hogeborn
* plugins.d/askpass-fifo.c: Fix name in header.
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 * Splashy - Read a password from splashy and output it
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
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 * 
246 by Teddy Hogeborn
* README: Update copyright year; add "2009".
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 * Copyright © 2008,2009 Teddy Hogeborn
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 * Copyright © 2008,2009 Björn Påhlsson
237.1.2 by Teddy Hogeborn
Further steps towards a D-Bus server interface, plus minor syntax
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 * 
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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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 * 
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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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 * 
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 * You should have received a copy of the GNU General Public License
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 * along with this program.  If not, see
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 * <http://www.gnu.org/licenses/>.
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 * 
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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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 */
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205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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#define _GNU_SOURCE		/* asprintf() */
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#include <signal.h>		/* sig_atomic_t, struct sigaction,
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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				   sigemptyset(), sigaddset(), SIGINT,
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				   SIGHUP, SIGTERM, sigaction,
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				   SIG_IGN, kill(), SIGKILL */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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#include <stddef.h>		/* NULL */
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#include <stdlib.h>		/* getenv() */
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#include <stdio.h>		/* asprintf(), perror() */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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#include <stdlib.h>		/* EXIT_FAILURE, free(), strtoul(),
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				   EXIT_SUCCESS */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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#include <sys/types.h>		/* pid_t, DIR, struct dirent,
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				   ssize_t */
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#include <dirent.h>		/* opendir(), readdir(), closedir() */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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#include <sys/stat.h>		/* struct stat, lstat(), S_ISLNK */
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#include <iso646.h>		/* not, or, and */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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#include <unistd.h>		/* readlink(), fork(), execl(),
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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				   sleep(), dup2() STDERR_FILENO,
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				   STDOUT_FILENO, _exit() */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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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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				   WEXITSTATUS() */
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sig_atomic_t interrupted_by_signal = 0;
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static void termination_handler(__attribute__((unused))int signum){
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  interrupted_by_signal = 1;
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}
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208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
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int main(__attribute__((unused))int argc,
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	 __attribute__((unused))char **argv){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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  int ret = 0;
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  /* Create prompt string */
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  char *prompt = NULL;
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  {
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    const char *const cryptsource = getenv("cryptsource");
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    const char *const crypttarget = getenv("crypttarget");
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    const char *const prompt_start = "getpass "
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      "Enter passphrase to unlock the disk";
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    if(cryptsource == NULL){
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      if(crypttarget == NULL){
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	ret = asprintf(&prompt, "%s: ", prompt_start);
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      } else {
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	ret = asprintf(&prompt, "%s (%s): ", prompt_start,
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		       crypttarget);
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      }
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    } else {
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      if(crypttarget == NULL){
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	ret = asprintf(&prompt, "%s %s: ", prompt_start, cryptsource);
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      } else {
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	ret = asprintf(&prompt, "%s %s (%s): ", prompt_start,
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		       cryptsource, crypttarget);
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      }
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    }
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    if(ret == -1){
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      return EXIT_FAILURE;
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    }
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  }
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  /* Find splashy process */
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  pid_t splashy_pid = 0;
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  {
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    const char splashy_name[] = "/sbin/splashy";
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    DIR *proc_dir = opendir("/proc");
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    if(proc_dir == NULL){
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      free(prompt);
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      perror("opendir");
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      return EXIT_FAILURE;
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    }
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    for(struct dirent *proc_ent = readdir(proc_dir);
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	proc_ent != NULL;
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	proc_ent = readdir(proc_dir)){
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      pid_t pid = (pid_t) strtoul(proc_ent->d_name, NULL, 10);
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      if(pid == 0){
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	/* Not a process */
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	continue;
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      }
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      /* Find the executable name by doing readlink() on the
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	 /proc/<pid>/exe link */
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      char exe_target[sizeof(splashy_name)];
208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
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      ssize_t sret;
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      {
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	char *exe_link;
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	ret = asprintf(&exe_link, "/proc/%s/exe", proc_ent->d_name);
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	if(ret == -1){
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	  perror("asprintf");
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	  free(prompt);
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	  closedir(proc_dir);
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	  return EXIT_FAILURE;
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	}
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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	/* Check that it refers to a symlink owned by root:root */
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	struct stat exe_stat;
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	ret = lstat(exe_link, &exe_stat);
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	if(ret == -1){
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	  perror("lstat");
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	  free(exe_link);
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	  free(prompt);
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	  closedir(proc_dir);
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	  return EXIT_FAILURE;
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	}
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	if(not S_ISLNK(exe_stat.st_mode)
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	   or exe_stat.st_uid != 0
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	   or exe_stat.st_gid != 0){
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	  free(exe_link);
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	  continue;
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	}
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208 by Teddy Hogeborn
* Makefile (PLUGINS): Added "plugins.d/usplash".
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	sret = readlink(exe_link, exe_target, sizeof(exe_target));
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	free(exe_link);
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      }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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      if((sret == ((ssize_t)sizeof(exe_target)-1))
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	 and (memcmp(splashy_name, exe_target,
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		     sizeof(exe_target)-1) == 0)){
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	splashy_pid = pid;
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	break;
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      }
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    }
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    closedir(proc_dir);
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  }
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  if(splashy_pid == 0){
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    free(prompt);
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    return EXIT_FAILURE;
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  }
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  /* Set up the signal handler */
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  {
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    struct sigaction old_action,
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      new_action = { .sa_handler = termination_handler,
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		     .sa_flags = 0 };
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    sigemptyset(&new_action.sa_mask);
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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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    if(ret == -1){
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      perror("sigaction");
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      free(prompt);
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      return EXIT_FAILURE;
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    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
168
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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      ret = sigaction(SIGINT, &new_action, NULL);
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      if(ret == -1){
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	perror("sigaction");
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	free(prompt);
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	return EXIT_FAILURE;
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      }
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    }
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    ret = sigaction(SIGHUP, NULL, &old_action);
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    if(ret == -1){
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      perror("sigaction");
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      free(prompt);
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      return EXIT_FAILURE;
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    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
182
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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      ret = sigaction(SIGHUP, &new_action, NULL);
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      if(ret == -1){
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	perror("sigaction");
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	free(prompt);
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	return EXIT_FAILURE;
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      }
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    }
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    ret = sigaction(SIGTERM, NULL, &old_action);
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    if(ret == -1){
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      perror("sigaction");
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      free(prompt);
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      return EXIT_FAILURE;
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    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
196
    if(old_action.sa_handler != SIG_IGN){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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      ret = sigaction(SIGTERM, &new_action, NULL);
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      if(ret == -1){
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	perror("sigaction");
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	free(prompt);
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	return EXIT_FAILURE;
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      }
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    }
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  }
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  /* Fork off the splashy command to prompt for password */
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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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	perror("fork");
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      }
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      return EXIT_FAILURE;
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    }
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    /* Child */
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    if(splashy_command_pid == 0){
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      const char splashy_command[] = "/sbin/splashy_update";
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      ret = execl(splashy_command, splashy_command, prompt,
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		  (char *)NULL);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
221
      if(not interrupted_by_signal){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
222
	perror("execl");
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      }
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      free(prompt);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
225
      _exit(EXIT_FAILURE);
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
226
    }
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  }
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  /* Parent */
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  free(prompt);
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232
  /* Wait for command to complete */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
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  if(not interrupted_by_signal and splashy_command_pid != 0){
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    int status;
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    ret = waitpid(splashy_command_pid, &status, 0);
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    if(ret == -1){
237
      if(errno != EINTR){
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	perror("waitpid");
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      }
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      if(errno == ECHILD){
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	splashy_command_pid = 0;
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      }
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    } else {
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      /* The child process has exited */
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      splashy_command_pid = 0;
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      if(not interrupted_by_signal and WIFEXITED(status)
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	 and WEXITSTATUS(status)==0){
248
	return EXIT_SUCCESS;
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      }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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    }
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  }
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  kill(splashy_pid, SIGTERM);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
253
  if(interrupted_by_signal and splashy_command_pid != 0){
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
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    kill(splashy_command_pid, SIGTERM);
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  }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
256
  sleep(2);
257
  while(kill(splashy_pid, 0) == 0){
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    kill(splashy_pid, SIGKILL);
259
    sleep(1);
260
  }
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
261
  pid_t new_splashy_pid = fork();
262
  if(new_splashy_pid == 0){
207 by Teddy Hogeborn
* plugins.d/splashy.c (main): Bug fix: free "exe_link".
263
    /* Child; will become new splashy process */
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
264
    
265
    /* Make the effective user ID (root) the only user ID instead of
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       the real user ID (mandos) */
267
    ret = setuid(geteuid());
268
    if(ret == -1){
269
      perror("setuid");
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
270
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
271
    
272
    setsid();
273
    ret = chdir("/");
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/*     if(fork() != 0){ */
275
/*       _exit(EXIT_SUCCESS); */
276
/*     } */
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
277
    ret = dup2(STDERR_FILENO, STDOUT_FILENO); /* replace our stdout */
278
    if(ret == -1){
279
      perror("dup2");
280
      _exit(EXIT_FAILURE);
281
    }
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
282
    
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
283
    execl("/sbin/splashy", "/sbin/splashy", "boot", (char *)NULL);
223 by Teddy Hogeborn
* .bzrignore (plugins.d/askpass-fifo): Added.
284
    if(not interrupted_by_signal){
285
      perror("execl");
286
    }
287
    _exit(EXIT_FAILURE);
205 by Teddy Hogeborn
* Makefile (PLUGINS, uninstall-client,
288
  }
289
  
290
  return EXIT_FAILURE;
291
}