/*

  Copyright 2008 Nathan Phillip Brink, Ethan Zonca

  This file is a part of DistRen.

  DistRen is free software: you can redistribute it and/or modify

  it under the terms of the GNU Affero General Public License as published by

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  DistRen 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License

  along with DistRen.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "execio.h"

#include <unistd.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <signal.h>

#include <malloc.h>

#include <fcntl.h>

#include <stdio.h>

#include <errno.h>

int execio_open(struct execio **rem, const char *progname, char *const argv[])

{

  /* pipe used to write to child */

  int pipe_write[2];

  /* pipe used to read from child */

  int pipe_read[2];

  pid_t child;

  /* for wait(2) if needed */

  int childstatus;

  int counter;

  int counter2;

  int maxfds;

  /* create two pipes to facilitate communication with child */

  if(pipe(pipe_write))

    return 1;

  if(pipe(pipe_read))

    {

      close(pipe_write[0]);

      close(pipe_write[1]);

      return 1;

    }

  /* parent */

  child = fork();

  if(child == -1)

    {

      close(pipe_write[0]);

      close(pipe_write[1]);

      close(pipe_read[0]);

      close(pipe_read[1]);

      return 1;

    }

  if(child)

    /* the parent proc: */

    {

      /* close sides of pipe we won't use */

      close(pipe_write[0]);

      close(pipe_read[1]);

      dup2(pipe_read[1], STDOUT_FILENO);

      dup2(pipe_write[0], STDIN_FILENO);

      /*

	close the fds that were dup'd

       */

      close(pipe_read[1]);

      close(pipe_write[0]);

      /* 

	 close all other file descriptors. We want to keep 0, 1, and 2 open. We don't know that the last open() or pipe() always gives the highest fd number. However, I will assume that it does. Maybe this is a bad idea:

       */

      counter = pipe_write[0];

      if(counter < pipe_write[1])

	counter = pipe_write[1];

      if(counter < pipe_read[0])

	counter = pipe_read[0];

      if(counter < pipe_read[1])

	counter = pipe_read[1];

      counter2 = 0;

      maxfds = counter;

      while(counter > 2)

	{

	  if(!close(counter))

	    counter2 ++; /* record how many descriptors we still had open :-) */

	  counter --;

	}

      /* stderr is the only stream we haven't confiscated atm - just for fun - I will confiscate it later, though, to support parsing error messages */

      fprintf(stderr, "closed %d/%d fds before execing \"%s\"\n", counter2, maxfds, progname);

      /*

	now exec: execvp uses interpreter to find the file to exec

       */

      execvp(progname, argv);

      return 1; /* this line should never be reached because we exec -- unless if the exec returns something bad. Then we'd have to tell execio over the pipe about that somehow... */

      /* in fact, maybe we should abort() here because if we returned, a monster of a distren client would exist! */

    }

}

/*

  returns 1 if child has exited, 

  returns 0 if child is still alive

 */

int _execio_checkpid(struct execio *eio)

{

  int childstatus;

  waitpid(eio->child, &childstatus, WNOHANG);

  /* perror()? */

  return WIFEXITED(childstatus);

}

int execio_read(struct execio *eio, void *buf, size_t len, size_t *bytesread)

{

  /*

    TODO: detect NULL eio? 

    TODO: errno?

    update status of eio for execio_status/to be able to cleanup subproc??

    whenever read() returns 0, it means EOF

   */

  (*bytesread) = read(eio->pipe_read, buf, len);

  if(!*bytesread)

    {

      /* should also be able to figure out if is bad fd and should set EXECIO_STATE_ERROR instead of _EOF */

      eio->state = EXECIO_STATE_EOF;

      return 1;

    }

  return 0;

}

int execio_write(struct execio *eio, void *buf, size_t len, size_t *bytesread)

{

  errno = 0;

  (*bytesread) = write(eio->pipe_write, buf, len);

  if(!*bytesread)

    {

      switch(errno)

	{

	case EPIPE:

	  /* 

	     the program closed the pipe (died)

	  */

	fprintf(stderr, "execio_write: the child program closed its stdin pipe\n");

	eio->state = EXECIO_STATE_EOF;

	break;

	default:

	  fprintf(stderr, "execio_write: unhandled error writing to an fd: \n");

	  perror("write");

	  eio->state = EXECIO_STATE_ERROR;

	  break;

/*

  Copyright 2010 Nathan Phillip Brink <ohnobinki@ohnopublishing.net>

  This file is a part of DistRen.

  DistRen is free software: you can redistribute it and/or modify

  it under the terms of the GNU Affero General Public License as published by

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  DistRen 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License

  along with DistRen.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "common/misc.h"

#include <errno.h>

#include <unistd.h>

char *distren_getcwd()

{

  char *mycwd;

  size_t counter;

  /**

     This is completely wrong, feel free to rewrite with

     pathconf() in mind.

   */

  for(counter = 128; ; counter +=32)

    {

      mycwd = malloc(counter);

      errno = 0;

      if(getcwd(mycwd, counter))

	return mycwd;

      /** ERANGE means that counter is too small */

      if(errno != ERANGE)

	return (char *)NULL;

      free(mycwd);

    }

  return (char *)NULL;

}

/*

  Copyright 2009 Nathan Phillip Brink

  This file is a part of DistRen.

  DistRen is free software: you can redistribute it and/or modify

  it under the terms of the GNU Affero General Public License as published by

  the Free Software Foundation, either version 3 of the License, or

  (at your option) any later version.

  DistRen 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 Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License

  along with DistRen.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "libremoteio.h"

#include "execio.h"

#include "asprintf.h"

#include <errno.h>

#include <netdb.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <unistd.h>

#include <sys/un.h>

#endif

/* local */

#define REMOTEIO_DEFAULT_PORT "4050"

int _remoteio_ssh_open(struct remoteio *rem, struct remoteio_server *server);

int _remoteio_ssh_read(struct remoteio *rem, void *buf, size_t len, size_t *bytesread);

int _remoteio_ssh_write(struct remoteio *rem, void *buf, size_t len, size_t *byteswritten);

int _remoteio_ssh_close(struct remoteio *rem);

int _remoteio_sock_open(struct remoteio *rem, struct remoteio_server *server);

int _remoteio_sock_close(struct remoteio *rem);

#endif

int _remoteio_sock_read(struct remoteio *rem, void *buf, size_t len, size_t *bytesread);

int _remoteio_sock_write(struct remoteio *rem, void *buf, size_t len, size_t *byteswritten);

int _remoteio_tcp_open(struct remoteio *rem, struct remoteio_server *server);

int _remoteio_tcp_close(struct remoteio *rem);

/**

  lookup table for different methods of remoteio:

  the enum remoteio_method is the index of the entry to use for that method. 

  Regardless, a NULL terminator is required because the configuration function

  searches through this table for the method specified in the config file.

*/

struct remoteio_method_funcmap funcmap[] = 

  {

    /* [REMOTEIO_METHOD_SSH] */

    {REMOTEIO_METHOD_SSH, &_remoteio_ssh_open, &_remoteio_ssh_read, &_remoteio_ssh_write, &_remoteio_ssh_close, "ssh"},

    {REMOTEIO_METHOD_UNIX, &_remoteio_sock_open, &_remoteio_sock_read, &_remoteio_sock_write, &_remoteio_sock_close, "unix"},

#endif

    {REMOTEIO_METHOD_TCP, &_remoteio_tcp_open, &_remoteio_sock_read, &_remoteio_sock_write, &_remoteio_tcp_close, "tcp"},

    {REMOTEIO_METHOD_MAX, NULL, NULL, NULL, NULL, NULL}

  };

struct remoteio_server *remoteio_getserver(const struct remoteio_opts *opts, const char *servername);

int remoteio_config(cfg_t *cfg, struct remoteio_opts *opts)

{

  size_t numservers;

  size_t counter;

  static int haslisted_methods = 0;

  struct remoteio_server *aserver;

  opts->servers = malloc(sizeof(struct remoteio_server));

  if(!opts->servers)

    {

      fprintf(stderr, "@todo cleanup!\n");

      abort();

    }

  aserver = opts->servers;

  numservers = cfg_size(cfg, "server"); 

  for(counter = 0; counter < numservers; counter ++)

    {

      cfg_t *cfg_aserver;

      char *method;

      cfg_aserver = cfg_getnsec(cfg, "server", counter);

      if(!aserver) /*< if the malloc in the previous loop failed */

	abort();

      aserver->name = strdup(cfg_title(cfg_aserver));

      aserver->hostname = strdup(cfg_getstr(cfg_aserver, "hostname"));

      aserver->username = strdup(cfg_getstr(cfg_aserver, "username"));

      aserver->method = REMOTEIO_METHOD_MAX;

      method = cfg_getstr(cfg_aserver, "method");

      for(counter = 0; funcmap[counter].name; counter ++)

	if(strcmp(method, funcmap[counter].name) == 0)

	  aserver->method = REMOTEIO_METHOD_SSH;

      if(aserver->method == REMOTEIO_METHOD_MAX)

	{

	  fprintf(stderr, "No such method as %s\n", method);

*/

int _remoteio_ssh_open(struct remoteio *rem, struct remoteio_server *server)

{

  char *userhost;

  char *sshargs[] = {rem->opts->ssh_command, NULL /* userhost */, "distrend", "-d", (char *)NULL};

  int rtn;

  if(server->username)

    _distren_asprintf(&userhost, "%s@%s", server->username, server->hostname);

  else

    userhost = strdup(server->hostname);

  sshargs[1] = userhost;

  rtn = execio_open( &rem->execio, "ssh", sshargs);

  if(rtn)

    {

      fprintf(stderr, "error opening remoteio channel to ssh userhost ``%s''\n" , userhost);

      free(userhost);

      return 1;

    }

  free(userhost);

  return 0;

}

int _remoteio_ssh_read(struct remoteio *rem, void *buf, size_t len, size_t *bytesread)

{

  return execio_read(rem->execio, buf, len, bytesread);

}

int _remoteio_ssh_write(struct remoteio *rem, void *buf, size_t len, size_t *byteswritten)

{

  return execio_write(rem->execio, buf, len, byteswritten);

}

int _remoteio_ssh_close(struct remoteio *rem)

{

  int rtn;

  rtn = execio_close(rem->execio);

  if(rtn)

    fprintf(stderr, "%s:%d: error closing execio\n", __FILE__, __LINE__);

  return rtn;

}

/*

  local sockets implementation (``named pipes''), unix-only

 */

int _remoteio_sock_open(struct remoteio *rem, struct remoteio_server *server)

{

  int sock;

  struct sockaddr_un sockaddr;

  /*

    The POSIX docs pretty much say that I can't depend on sockpath being able to be longer than 

    some proprietary length. So, if the compiler specifies a long path for RUNSTATEDIR, it could

    cause a buffer overflow.

   */

  char *sockpath = RUNSTATEDIR "/distrend.sock";

  unsigned int sockaddr_len;

  sock = socket(AF_UNIX, SOCK_STREAM, 0);

  if(sock == -1)

    {

      perror("socket");

      return 1;

    }

  sockaddr.sun_family = AF_UNIX;

  /*

    The terminating NULL should not be included in what's copied to sun_path,

    although it won't hurt as long as strlen(sockpath) < max socket length

   */

  for(sockaddr_len = 0; sockpath[sockaddr_len]; sockaddr_len ++)

    sockaddr.sun_path[sockaddr_len] = sockpath[sockaddr_len];

  if(connect(sock, (struct sockaddr *)&sockaddr, sockaddr_len) == -1)

    {

      perror("connect");

      close(sock);

      return 1;

    }

  rem->sock = sock;

  return 0;

}

int _remoteio_sock_close(struct remoteio *rem)

{

  close(rem->sock);

  return 0;

}

#endif

int _remoteio_sock_read(struct remoteio *rem, void *buf, size_t len, size_t *bytesread)

{

  ssize_t readrtn;

    {

      /*

	should we consider this an error? I'm pretty

	sure we should :-/

       */

      fprintf(stderr, "write() returned 0 in remoteio_sock_write()\n");

      return 1;

    }

  return 0;

}

/**

   TCP, taking advantage of the two generic socks read/write functions:

 */

int _remoteio_tcp_open(struct remoteio *rem, struct remoteio_server *server)

{

  int tmp;

  int tmp2;

  int sock;

  char *hostname;

  char *port;

  struct addrinfo addrinfo_hints;

  struct addrinfo *addrinfo_res;

  /**

     only hostname should be free()-ed, not port,

     because both are from the same block of malloc()-ed

     memory

   */

  hostname = strdup(server->hostname);

  for(port = hostname;

      *port && *port != ':';

      port ++)

    ;

  if(*port)

    {

      *port = '\0';

      port ++;

    }

  else

    port = REMOTEIO_DEFAULT_PORT;

  memset(&addrinfo_hints, '\0', sizeof(struct addrinfo));

  addrinfo_hints.ai_family = AF_UNSPEC;

  addrinfo_hints.ai_flags = AI_V4MAPPED | AI_ADDRCONFIG;

  addrinfo_hints.ai_socktype = SOCK_STREAM;

  tmp = getaddrinfo(server->hostname, port, &addrinfo_hints, &addrinfo_res);

  if(tmp)

    fprintf(stderr, "error resolving %s:%s: %s\n", server->hostname, port, gai_strerror(tmp));

  fprintf(stderr, "connecting to %s[%s]:%s\n", server->hostname, addrinfo_res->ai_canonname, port);

  free(hostname);

  sock = socket(addrinfo_res->ai_family, SOCK_STREAM, addrinfo_res->ai_protocol);

  if(sock == -1)

    {

      perror("socket");

      freeaddrinfo(addrinfo_res);

      return 1;

    }

  tmp = connect(sock, addrinfo_res->ai_addr, addrinfo_res->ai_addrlen);

  tmp2 = errno;

  freeaddrinfo(addrinfo_res);

  errno = tmp2;

  if(tmp == -1)

    {

      perror("connect");

      close(sock);

      return 1;

    }

  rem->sock = sock;

  return 0;

}

int _remoteio_tcp_close(struct remoteio *rem)

{

  close(rem->sock);

  return 0;

}