/mandos/trunk

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

/*

 * Mandos plugin runner - Run Mandos plugins

 *

 * Copyright © 2007-2008 Teddy Hogeborn & 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 <mandos@fukt.bsnet.se>.

 */

#define _GNU_SOURCE		/* TEMP_FAILURE_RETRY() */

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

				   stderr, STDOUT_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, struct dirent, opendir(),

				   readdir(), closedir() */

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

#include <unistd.h>		/* struct stat, stat(), S_ISREG(),

				   fcntl() */

#include <fcntl.h>		/* fcntl() */

#include <stddef.h>		/* NULL */

#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 */

#include <argp.h>		/* struct argp_option,

				   struct argp_state, struct argp,

				   argp_parse() */

struct process;

typedef struct process{

  pid_t pid;

  int fd;

  char *buffer;

  size_t buffer_size;

  size_t buffer_length;

  struct process *next;

} process;

typedef struct plugin{

  char *name;			/* can be NULL or any plugin name */

  char **argv;

  int argc;

  bool disabled;

  struct plugin *next;

} plugin;

plugin *getplugin(char *name, plugin **plugin_list){

  for (plugin *p = *plugin_list; p != NULL; p = p->next){

    if ((p->name == name)

	or (p->name and name and (strcmp(p->name, name) == 0))){

      return p;

    }

  }

  /* Create a new plugin */

  plugin *new_plugin = malloc(sizeof(plugin));

  if (new_plugin == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  new_plugin->name = name;

  new_plugin->argv = malloc(sizeof(char *) * 2);

  if (new_plugin->argv == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  new_plugin->argv[0] = name;

  new_plugin->argv[1] = NULL;

  new_plugin->argc = 1;

  new_plugin->disabled = false;

  new_plugin->next = *plugin_list;

  /* Append the new plugin to the list */

  *plugin_list = new_plugin;

  return new_plugin;

}

void addargument(plugin *p, char *arg){

  p->argv[p->argc] = arg;

  p->argv = realloc(p->argv, sizeof(char *) * (size_t)(p->argc + 2));

  if (p->argv == NULL){

    perror("malloc");

    exit(EXIT_FAILURE);

  }

  p->argc++;

  p->argv[p->argc] = NULL;

}

/*

 * Based on the example in the GNU LibC manual chapter 13.13 "File

 * Descriptor Flags".

 * *Note File Descriptor Flags:(libc)Descriptor Flags.

 */

int set_cloexec_flag(int fd)

{

  int ret = fcntl(fd, F_GETFD, 0);

  /* If reading the flags failed, return error indication now. */

  if(ret < 0){

    return ret;

  }

  /* Store modified flag word in the descriptor. */

  return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);

}

#define BUFFER_SIZE 256

const char *argp_program_version =

  "plugbasedclient 0.9";

const char *argp_program_bug_address =

  "<mandos@fukt.bsnet.se>";

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

  const char *plugindir = "/conf/conf.d/mandos/plugins.d";

  size_t d_name_len;

  DIR *dir;

  struct dirent *dirst;

  struct stat st;

  fd_set rfds_all;

  int ret, maxfd = 0;

  process *process_list = NULL;

  bool debug = false;

  int exitstatus = EXIT_SUCCESS;

  /* The options we understand. */

  struct argp_option options[] = {

    { .name = "global-options", .key = 'g',

      .arg = "OPTION[,OPTION[,...]]",

      .doc = "Options passed to all plugins" },

    { .name = "options-for", .key = 'o',

      .arg = "PLUGIN:OPTION[,OPTION[,...]]",

      .doc = "Options passed only to specified plugin" },

    { .name = "disable", .key = 'd',

      .arg = "PLUGIN",

      .doc = "Disable a specific plugin", .group = 1 },

    { .name = "plugin-dir", .key = 128,

      .arg = "DIRECTORY",

      .doc = "Specify a different plugin directory", .group = 2 },

    { .name = "debug", .key = 129,

      .doc = "Debug mode", .group = 3 },

    { .name = NULL }

  };

  error_t parse_opt (int key, char *arg, struct argp_state *state) {

       /* Get the INPUT argument from `argp_parse', which we

          know is a pointer to our plugin list pointer. */

    plugin **plugins = state->input;

    switch (key) {

    case 'g':

      if (arg != NULL){

	char *p = strtok(arg, ",");

	do{

	  addargument(getplugin(NULL, plugins), p);

	  p = strtok(NULL, ",");

	} while (p);

      }

      break;

    case 'o':

      if (arg != NULL){

	char *name = strtok(arg, ":");

	char *p = strtok(NULL, ":");

	if(p){

	  p = strtok(p, ",");

	  do{

	    addargument(getplugin(name, plugins), p);

	    p = strtok(NULL, ",");

	  } while (p);

	}

      }

      break;

    case 'd':

      if (arg != NULL){

	getplugin(arg, plugins)->disabled = true;

      }

      break;

    case 128:

      plugindir = arg;

      break;

    case 129:

      debug = true;

      break;

    case ARGP_KEY_ARG:

      argp_usage (state);

      break;

    case ARGP_KEY_END:

      break;

    default:

      return ARGP_ERR_UNKNOWN;

    }

    return 0;

  }

  plugin *plugin_list = NULL;

  struct argp argp = { .options = options, .parser = parse_opt,

		       .args_doc = "",

		       .doc = "Mandos plugin runner -- Run plugins" };

  argp_parse (&argp, argc, argv, 0, 0, &plugin_list);

  if(debug){

    for(plugin *p = plugin_list; p != NULL; p=p->next){

      fprintf(stderr, "Plugin: %s has %d arguments\n",

	      p->name ? p->name : "Global", p->argc - 1);

      for(char **a = p->argv; *a != NULL; a++){

	fprintf(stderr, "\tArg: %s\n", *a);

      }

    }

  }

  dir = opendir(plugindir);

  if(dir == NULL){

    perror("Could not open plugin dir");

    exitstatus = EXIT_FAILURE;

    goto end;

  }

  /* Set the FD_CLOEXEC flag on the directory, if possible */

  {

    int dir_fd = dirfd(dir);

    if(dir_fd >= 0){

      ret = set_cloexec_flag(dir_fd);

      if(ret < 0){

	perror("set_cloexec_flag");

	exitstatus = EXIT_FAILURE;

	goto end;

      }

    }

  }

  if(dir == NULL){

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

    return EXIT_FAILURE;

  }

  FD_ZERO(&rfds_all);

  while(true){

    dirst = readdir(dir);

    // All directory entries have been processed

    if(dirst == NULL){

      break;

    }

    d_name_len = strlen(dirst->d_name);

    // Ignore dotfiles, backup files and other junk

    {

      bool bad_name = false;

      const char const *bad_prefixes[] = { ".", "#", NULL };

      const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",

					   ".dpkg-old",

					   ".dpkg-divert", NULL };

      for(const char **pre = bad_prefixes; *pre != NULL; pre++){

	size_t pre_len = strlen(*pre);

	if((d_name_len >= pre_len)

	   and strncmp((dirst->d_name), *pre, pre_len) == 0){

	  if(debug){

	    fprintf(stderr, "Ignoring plugin dir entry \"%s\""

		    " with bad prefix %s\n", dirst->d_name, *pre);

	  }

	  bad_name = true;

	  break;

	}

      }

      if(bad_name){

	continue;

      }

      for(const char **suf = bad_suffixes; *suf != NULL; suf++){

	size_t suf_len = strlen(*suf);

	if((d_name_len >= suf_len)

	   and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)

		== 0)){

	  if(debug){

	    fprintf(stderr, "Ignoring plugin dir entry \"%s\""

		    " with bad suffix %s\n", dirst->d_name, *suf);

	  }

	  bad_name = true;

	  break;

	}

      }

      if(bad_name){

	continue;

      }

    }

    char *filename = malloc(d_name_len + strlen(plugindir) + 2);

    if (filename == NULL){

      perror("malloc");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    strcpy(filename, plugindir);

    strcat(filename, "/");

    strcat(filename, dirst->d_name);    

    stat(filename, &st);

    if (not S_ISREG(st.st_mode)	or (access(filename, X_OK) != 0)){

      if(debug){

	fprintf(stderr, "Ignoring plugin dir entry \"%s\""

		" with bad type or mode\n", filename);

      }

      continue;

    }

    if(getplugin(dirst->d_name, &plugin_list)->disabled){

      if(debug){

	fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",

		dirst->d_name);

      }

      continue;

    }

    plugin *p = getplugin(dirst->d_name, &plugin_list);

    {

      /* Add global arguments to argument list for this plugin */

      plugin *g = getplugin(NULL, &plugin_list);

      for(char **a = g->argv + 1; *a != NULL; a++){

	addargument(p, *a);

      }

    }

    int pipefd[2]; 

    ret = pipe(pipefd);

    if (ret == -1){

      perror("pipe");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    ret = set_cloexec_flag(pipefd[0]);

    if(ret < 0){

      perror("set_cloexec_flag");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    ret = set_cloexec_flag(pipefd[1]);

    if(ret < 0){

      perror("set_cloexec_flag");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    // Starting a new process to be watched

    pid_t pid = fork();

    if(pid == 0){

      /* this is the child process */

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

      if(dirfd(dir) < 0){

	/* If dir has no file descriptor, we could not set FD_CLOEXEC

	   and must close it manually  */

	closedir(dir);

      }

      if(execv(filename, p->argv) < 0){

	perror("execv");

	_exit(EXIT_FAILURE);

      }

      /* no return */

    }

    /* parent process */

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

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

    if (new_process == NULL){

      perror("malloc");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    *new_process = (struct process){ .pid = pid,

				     .fd = pipefd[0],

				     .next = process_list };

    FD_SET(new_process->fd, &rfds_all);

    if (maxfd < new_process->fd){

      maxfd = new_process->fd;

    }

    //List handling

    process_list = new_process;

  }

  /* Free the plugin list */

  for(plugin *next; plugin_list != NULL; plugin_list = next){

    next = plugin_list->next;

    free(plugin_list->argv);

    free(plugin_list);

  }

  closedir(dir);

  if (process_list == NULL){

    fprintf(stderr, "No plugin processes started, exiting\n");

    return EXIT_FAILURE;

  }

  while(true){

    fd_set rfds = rfds_all;

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

    if (select_ret == -1){

      perror("select");

      exitstatus = EXIT_FAILURE;

      goto end;

    }

    for(process *proc = process_list; proc ; proc = proc->next){

      if(not FD_ISSET(proc->fd, &rfds)){

	continue;

      }

      if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){

	proc->buffer = realloc(proc->buffer, proc->buffer_size

			       + (size_t) BUFFER_SIZE);

	if (proc->buffer == NULL){

	  perror("malloc");

	  exitstatus = EXIT_FAILURE;

	  goto end;

	}

	proc->buffer_size += BUFFER_SIZE;

      }

      ret = read(proc->fd, proc->buffer + proc->buffer_length,

		 BUFFER_SIZE);

      if(ret < 0){

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

	continue;

      }

      proc->buffer_length += (size_t) ret;

      if(ret == 0){

	/* got EOF */

	/* wait for process exit */

	int status;

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

	if(not WIFEXITED(status) or WEXITSTATUS(status) != 0){

	  FD_CLR(proc->fd, &rfds_all);

	  continue;

	}

	for(size_t written = 0;

	    written < proc->buffer_length; written += (size_t)ret){

	  ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,

					 proc->buffer + written,

					 proc->buffer_length

					 - written));

	  if(ret < 0){

	    perror("write");

	    exitstatus = EXIT_FAILURE;

	    goto end;

	  }

	}

	goto end;

      }

    }

  }

 end:

  for(process *next; process_list != NULL; process_list = next){

    close(process_list->fd);

    kill(process_list->pid, SIGTERM);

    free(process_list->buffer);

    free(process_list);

  }

  while(true){

    int status;

    ret = wait(&status);

    if (ret == -1){

      if(errno != ECHILD){

	perror("wait");

      }

      break;

    }

  }  

  return exitstatus;

}