/mandos/release

/*  -*- coding: utf-8 -*- */

/*

 * Mandos plugin runner - Run Mandos plugins

 *

 * Copyright © 2007-2008 Teddy Hogeborn and Björn Påhlsson.

 * 

 * 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 3 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, see

 * <http://www.gnu.org/licenses/>.

 * 

 * Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and

 * <https://www.fukt.bsnet.se/~teddy/>.

 */

#define _FORTIFY_SOURCE 2

#include <stdio.h>	/* popen, fileno */

#include <iso646.h>	/* and, or, not */

#include <sys/types.h>	/* DIR, opendir, stat, struct stat, waitpid,

			   WIFEXITED, WEXITSTATUS, wait */

#include <sys/wait.h>	/* wait */

#include <dirent.h>	/* DIR, opendir */

#include <sys/stat.h>	/* stat, struct stat */

#include <unistd.h>	/* stat, struct stat, chdir */

#include <stdlib.h>	/* EXIT_FAILURE */

#include <sys/select.h>	/* fd_set, select, FD_ZERO, FD_SET,

			   FD_ISSET */

#include <string.h>	/* strlen, strcpy, strcat */

#include <stdbool.h>	/* true */

#include <sys/wait.h>	/* waitpid, WIFEXITED, WEXITSTATUS */

#include <errno.h>	/* errno */

struct process;

typedef struct process{

  pid_t pid;

  int fd;

  char *buffer;

  size_t buffer_size;

  size_t buffer_length;

  struct process *next;

} process;

#define BUFFER_SIZE 256

int main(int argc, char *argv[]){

  char plugindir[] = "plugins.d";

  size_t d_name_len, plugindir_len = sizeof(plugindir)-1;

  DIR *dir;

  struct dirent *dirst;

  struct stat st;

  fd_set rfds_orig;

  int ret, maxfd = 0;

  process *process_list = NULL;

  dir = opendir(plugindir);

  if(dir == NULL){

    fprintf(stderr, "Can not open directory\n");

    return EXIT_FAILURE;

  }

  FD_ZERO(&rfds_orig);

  while(true){

    dirst = readdir(dir);

    // All directory entries have been processed

    if(dirst == NULL){

      break;

    }

    d_name_len = strlen(dirst->d_name);

    // Ignore dotfiles and backup files

    if (dirst->d_name[0] == '.'

	or dirst->d_name[d_name_len - 1] == '~'){

      continue;

    }

    char *filename = malloc(d_name_len + plugindir_len + 2);

    strcpy(filename, plugindir);

    strcat(filename, "/");

    strcat(filename, dirst->d_name);    

    stat(filename, &st);

    if (S_ISREG(st.st_mode) and (access(filename, X_OK) == 0)){

      // Starting a new process to be watched

      process *new_process = malloc(sizeof(process));

      int pipefd[2];

      pipe(pipefd);

      new_process->pid = fork();

      if(new_process->pid == 0){

	/* this is the child process */

	closedir(dir);

	close(pipefd[0]);	/* close unused read end of pipe */

	dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */

	/* create a new modified argument list */

	char **new_argv = malloc(sizeof(char *)

				 * ((unsigned int) argc + 1));

	new_argv[0] = filename;

	for(int i = 1; i < argc; i++){

	  new_argv[i] = argv[i];

	}

	new_argv[argc] = NULL;

	if(execv(filename, new_argv) < 0){

	  perror(argv[0]);

	  close(pipefd[1]);

	  exit(EXIT_FAILURE);

	}

	/* no return */

      }

      close(pipefd[1]);		/* close unused write end of pipe */

      new_process->fd = pipefd[0];

      new_process->buffer = malloc(BUFFER_SIZE);

      if (new_process->buffer == NULL){

	perror(argv[0]);

	goto end;

      }

      new_process->buffer_size = BUFFER_SIZE;

      new_process->buffer_length = 0;

      FD_SET(new_process->fd, &rfds_orig);

      if (maxfd < new_process->fd){

	maxfd = new_process->fd;

      }

      //List handling

      new_process->next = process_list;

      process_list = new_process;

    }

  }

  closedir(dir);

  if (process_list != NULL){

    while(true){

      fd_set rfds = rfds_orig;

      int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);

      if (select_ret == -1){

	perror(argv[0]);

	goto end;

      }else{	

	for(process *process_itr = process_list; process_itr != NULL;

	    process_itr = process_itr->next){

	  if(FD_ISSET(process_itr->fd, &rfds)){

	    if(process_itr->buffer_length + BUFFER_SIZE

	       > process_itr->buffer_size){

		process_itr->buffer = realloc(process_itr->buffer,

					      process_itr->buffer_size

					      + (size_t) BUFFER_SIZE);

		if (process_itr->buffer == NULL){

		  perror(argv[0]);

		  goto end;

		}

		process_itr->buffer_size += BUFFER_SIZE;

	    }

	    ret = read(process_itr->fd, process_itr->buffer

		       + process_itr->buffer_length, BUFFER_SIZE);

	    if(ret < 0){

	      /* Read error from this process; ignore it */

	      continue;

	    }

	    process_itr->buffer_length += (size_t) ret;

	    if(ret == 0){

	      /* got EOF */

	      /* wait for process exit */

	      int status;

	      waitpid(process_itr->pid, &status, 0);

	      if(WIFEXITED(status) and WEXITSTATUS(status) == 0){

		write(STDOUT_FILENO, process_itr->buffer,

		      process_itr->buffer_length);

		goto end;

	      } else {

		FD_CLR(process_itr->fd, &rfds_orig);

	      }

	    }

	  }

	}

      }

    }

  }

 end:

  for(process *process_itr = process_list; process_itr != NULL;

      process_itr = process_itr->next){

    close(process_itr->fd);

    kill(process_itr->pid, SIGTERM);

    free(process_itr->buffer);

  }

  while(true){

    int status;

    ret = wait(&status);

    if (ret == -1){

      if(errno != ECHILD){

	perror("wait");

      }

      break;

    }

  }  

  return EXIT_SUCCESS;

}