client/tripectl.c: Unblock SIGCHLD in child.

[tripe] / client / tripectl.c

/* -*-c-*-
 *
 * Client for TrIPE
 *
 * (c) 2001 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Trivial IP Encryption (TrIPE).
 *
 * TrIPE 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 2 of the License, or
 * (at your option) any later version.
 *
 * TrIPE 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 TrIPE; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/*----- Header files ------------------------------------------------------*/

#include "config.h"

#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <syslog.h>

#include <sys/socket.h>
#include <sys/un.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <mLib/alloc.h>
#include <mLib/daemonize.h>
#include <mLib/darray.h>
#include <mLib/dstr.h>
#include <mLib/mdup.h>
#include <mLib/mdwopt.h>
#include <mLib/quis.h>
#include <mLib/report.h>
#include <mLib/sel.h>
#include <mLib/selbuf.h>
#include <mLib/sig.h>
#include <mLib/str.h>
#include <mLib/versioncmp.h>

#include "util.h"

#undef sun
#define IGNORE(x) do if (x); while (0)

/*----- Data structures ---------------------------------------------------*/

#ifndef STRING_V
#  define STRING_V
   DA_DECL(string_v, char *);
#endif

/*----- Static variables --------------------------------------------------*/

static sel_state sel;
static const char *pidfile = 0;
static const char *logname = 0;
static FILE *logfp = 0;
static unsigned f = 0;
static int fd;
static const char *bgtag = 0;

#define f_bogus 1u
#define f_spawn 2u
#define f_daemon 4u
#define f_spawnopts 8u
#define f_syslog 16u
#define f_command 32u
#define f_noinput 64u
#define f_warn 128u
#define f_uclose 256u
#define f_losing 512u

/*----- Main code ---------------------------------------------------------*/

static void reap(int sig)
{
  int e = errno;
  while (waitpid(-1, 0, WNOHANG) > 0)
    ;
  errno = e;
}

static void writelog(const char *cat, const char *msg)
{
  char buf[256];
  time_t t = time(0);
  struct tm *tm = localtime(&t);
  strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tm);
  fprintf(logfp, "%s %s: %s\n", buf, cat, msg);
}

static void checkbg(char **p)
{
  char *q = str_getword(p);
  if (!q)
    die(EXIT_FAILURE, "missing background tag");
  if (!bgtag || strcmp(bgtag, q) != 0)
    die(EXIT_FAILURE, "unexpected background tag `%s'", q);
}

static void dolog(int prio, const char *msg, ...)
{
  va_list ap;
  dstr d = DSTR_INIT;
  const char *cat;

  va_start(ap, msg);
  dstr_vputf(&d, msg, &ap);
  va_end(ap);
  if (f & f_syslog) syslog(prio, "%s", d.buf);
  if (logfp) {
    switch (prio) {
      case LOG_WARNING: cat = "warning"; break;
      case LOG_DEBUG: cat = "debug"; break;
      case LOG_ERR: cat = "error"; break;
      default: cat = "message"; break;
    }
    writelog(cat, d.buf);
  }
  if (prio == LOG_WARNING && (f & f_warn))
    fprintf(stderr, "Warning: %s\n", d.buf);
  dstr_destroy(&d);
}

static void checkfg(void)
  { if (bgtag) die(EXIT_FAILURE, "unexpected foreground response"); }

static void cline(char *p, size_t len, void *b)
{
  char *q;
  if (!p) {
    if (f & f_command)
      die(EXIT_FAILURE, "server dropped the connection");
    f &= ~f_losing;
    exit(0);
  }
  q = str_getword(&p);
  if (!q)
    return;
  if (strcmp(q, "WARN") == 0)
    dolog(LOG_WARNING, p);
  else if (strcmp(q, "TRACE") == 0)
    dolog(LOG_DEBUG, p);
  else if (!(f & f_command))
    dolog(LOG_ERR, "unexpected output `%s %s'", q, p);
  else if (strcmp(q, "FAIL") == 0) {
    checkfg();
    die(EXIT_FAILURE, "%s", p);
  } else if (strcmp(q, "INFO") == 0) {
    checkfg();
    puts(p);
    fflush(stdout);
  } else if (strcmp(q, "OK") == 0) {
    checkfg();
    exit(0);
  } else if (strcmp(q, "BGDETACH") == 0) {
    if (bgtag)
      die(EXIT_FAILURE, "repeat detach");
    bgtag = xstrdup(p);
  } else if (strcmp(q, "BGOK") == 0) {
    checkbg(&p);
    exit(0);
  } else if (strcmp(q, "BGINFO") == 0) {
    checkbg(&p);
    puts(p);
    fflush(stdout);
  } else if (strcmp(q, "BGFAIL") == 0) {
    checkbg(&p);
    die(EXIT_FAILURE, "%s", p);
  } else
    die(EXIT_FAILURE, "unexpected output `%s %s'", q, p);
}

static void sline(char *p, size_t len, void *b)
{
  if (!p) {
    if (!(f & f_uclose))
      moan("server closed the connection");
    exit(0);
  }
  puts(p);
  fflush(stdout);
}

static void uline(char *p, size_t len, void *b)
{
  if (!p) {
    selbuf_destroy(b);
    shutdown(fd, 1);
    f |= f_uclose;
  } else {
    p[len] = '\n';
    errno = EIO;
    if (write(fd, p, len + 1) != len + 1)
      moan("write failed: %s", strerror(errno));
  }
}

static void eline(char *p, size_t len, void *b)
{
  if (p)
    dolog(LOG_WARNING, "(stderr): %s", p);
  else {
    selbuf_destroy(b);
    close(fd);
  }
}

static void setup(const char *cmd)
{
  dstr d = DSTR_INIT;
  char ch;
  char *p, *q;
  int n;

  dstr_puts(&d, cmd);
  dstr_putc(&d, '\n');
  errno = EIO; /* Relax: be vague */
  if (write(fd, d.buf, d.len) != d.len) {
    die(EXIT_FAILURE, "error sending setup command `%s': %s",
	cmd, strerror(errno));
  }
  dstr_reset(&d);
  for (;;) {
    n = read(fd, &ch, 1);
    if (!n)
      die(EXIT_FAILURE, "unexpected EOF during setup");
    if (n < 0) {
      die(EXIT_FAILURE, "error receiving reply to `%s': %s",
	  cmd, strerror(errno));
    }
    if (d.len < 256)
      dstr_putc(&d, ch);
    if (ch == '\n') {
      p = d.buf;
      q = str_getword(&p);
      if (!q)
	;
      else if (strcmp(q, "OK") == 0)
	return;
      else if (strcmp(q, "FAIL") == 0)
	die(EXIT_FAILURE, "setup command `%s' failed: %s", cmd, p);
      dstr_reset(&d);
    }
  }
}

static void logfile(const char *name)
{
  FILE *fp;

  if ((fp = fopen(name, "a")) != 0) {
    if (logfp)
      fclose(logfp);
    logfp =  fp;
    setvbuf(logfp, 0, _IOLBF, BUFSIZ);
  } else {
    dstr d = DSTR_INIT;
    dstr_putf(&d, "error opening logfile `%s': %s", name, strerror(errno));
    if (logfp)
      writelog("error", d.buf);
    else if (logname)
      die(EXIT_FAILURE, d.buf);
    if (f & f_syslog)
      syslog(LOG_ERR, "%s", d.buf);
    dstr_destroy(&d);
  }
}

static void sighup(int sig, void *v) { logfile(logname); }

static void cleanup(void) { if (pidfile) unlink(pidfile); }

static void sigdie(int sig)
  { cleanup(); signal(sig, SIG_DFL); raise(sig); }

static void putarg(string_v *av, const char *fmt, ...)
{
  va_list ap;
  dstr d = DSTR_INIT;

  va_start(ap, fmt);
  dstr_vputf(&d, fmt, &ap);
  dstr_putz(&d);
  va_end(ap);
  DA_UNSHIFT(av, xstrdup(d.buf));
  dstr_destroy(&d);
}

static void version(FILE *fp)
  { pquis(fp, "$, TrIPE version " VERSION "\n"); }

static void usage(FILE *fp)
{
  pquis(fp, "\
Usage:\n\
	$ [-w] [-OPTIONS] [COMMAND [ARGS]...]\n\
	$ [-Dl] [-f FILE] [-OPTIONS]\n\
Options:\n\
	[-s] [-d DIRECTORY] [-a SOCKET] [-P PIDFILE]\n\
	[-p PROGRAM] [-S ARG,ARG,...]\n\
");
}

static void help(FILE *fp)
{
  version(fp);
  fputc('\n', fp);
  usage(fp);
  fputs("\
\n\
Options in full:\n\
\n\
-h, --help		Show this help text.\n\
-v, --version		Show version number.\n\
-u, --usage		Show brief usage message.\n\
\n\
-D, --daemon		Become a background task after connecting.\n\
-d, --directory=DIR	Select current directory [default " CONFIGDIR "].\n\
-U, --setuid=USER	Set uid to USER after initialization.\n\
-G, --setgid=GROUP	Set gid to GROUP after initialization.\n\
-a, --admin-socket=FILE	Select socket to connect to\n\
			  [default " SOCKETDIR "/tripesock].\n\
-P, --pidfile=FILE	Write process-id to FILE.\n\
\n\
-s, --spawn		Start server rather than connecting.\n\
-p, --spawn-path=PATH	Specify path to executable.\n\
-S, --spawn-args=ARGS	Specify comma-separated arguments.\n\
\n\
-l, --syslog		Log messages to system log.\n\
-f, --logfile=FILE	Log messages to FILE.\n\
-w, --warnings		Show warnings when running commands.\n\
", fp);
}

int main(int argc, char *argv[])
{
  const char *dir = CONFIGDIR;
  const char *sock = SOCKETDIR "/tripesock";
  const char *spawnpath = "tripe";
  string_v spawnopts = DA_INIT;
  char *p;
  FILE *pidfp = 0;
  int i;
  size_t sz;
  uid_t u = -1;
  gid_t g = -1;
  int pfd[2], efd[2];
  mdup_fd md[3];
  pid_t kid;
  struct sigaction sa;
  sigset_t newmask, oldmask;
  struct sockaddr_un sun;
  selbuf bu, bs, be;
  dstr d = DSTR_INIT;
  sig hup;

  ego(argv[0]);

  if ((p = getenv("TRIPEDIR")) != 0)
    dir = p;
  if ((p = getenv("TRIPESOCK")) != 0)
    sock = p;

  /* --- Parse the arguments --- */

  for (;;) {
    static const struct option opts[] = {
      { "help",		0,		0,	'h' },
      { "version",	0,		0,	'v' },
      { "usage",	0,		0,	'u' },
      { "daemon",	0,		0,	'D' },
      { "uid",		OPTF_ARGREQ,	0,	'U' },
      { "setuid",	OPTF_ARGREQ,	0,	'U' },
      { "gid",		OPTF_ARGREQ,	0,	'G' },
      { "setgid",	OPTF_ARGREQ,	0,	'G' },
      { "directory",	OPTF_ARGREQ,	0,	'd' },
      { "admin-socket",	OPTF_ARGREQ,	0,	'a' },
      { "spawn",	0,		0,	's' },
      { "spawn-path",	OPTF_ARGREQ,	0,	'p' },
      { "spawn-args",	OPTF_ARGREQ,	0,	'S' },
      { "syslog",	0,		0,	'l' },
      { "logfile",	OPTF_ARGREQ,	0,	'f' },
      { "warnings",	0,		0,	'w' },
      { "pidfile",	OPTF_ARGREQ,	0,	'P' },
      { 0,		0,		0,	0 }
    };

    i = mdwopt(argc, argv, "+hvuDU:G:d:a:sp:S:lwf:nP:", opts, 0, 0, 0);
    if (i < 0)
      break;
    switch (i) {
      case 'h':
	help(stdout);
	exit(0);
      case 'v':
	version(stdout);
	exit(0);
      case 'u':
	usage(stdout);
	exit(0);
      case 'D':
	f |= f_daemon | f_noinput;
	break;
      case 'U':
	u = u_getuser(optarg, &g);
	break;
      case 'G':
	g = u_getgroup(optarg);
	break;
      case 'd':
	dir = optarg;
	break;
      case 'a':
	sock = optarg;
	break;
      case 's':
	f |= f_spawn;
	break;
      case 'p':
	f |= f_spawn;
	spawnpath = optarg;
	break;
      case 'S':
	f |= f_spawn | f_spawnopts;
	for (p = strtok(optarg, ","); p; p = strtok(0, ","))
	  DA_PUSH(&spawnopts, p);
	break;
      case 'l':
	f |= f_syslog | f_noinput;
	break;
      case 'w':
	f |= f_warn;
	break;
      case 'f':
	logname = optarg;
	f |= f_noinput;
	break;
      case 'P':
	pidfile = optarg;
	break;
      default:
	f |= f_bogus;
	break;
    }
  }
  if ((f & f_bogus) || ((f & f_noinput) && optind < argc)) {
    usage(stderr);
    exit(EXIT_FAILURE);
  }

  /* --- Set various things up --- */

  if (chdir(dir)) {
    die(EXIT_FAILURE, "couldn't set `%s' as current directory: %s",
	dir, strerror(errno));
  }
  if (!pidfile && (f & f_daemon) && ((f & f_syslog) || logname))
    pidfile = "tripectl.pid";
  if (pidfile && (pidfp = fopen(pidfile, "w")) == 0) {
    die(EXIT_FAILURE, "couldn't open `%s' for writing: %s",
	pidfile, strerror(errno));
  }
  sel_init(&sel);
  sig_init(&sel);
  signal(SIGINT, sigdie);
  signal(SIGQUIT, sigdie);
  signal(SIGTERM, sigdie);
  atexit(cleanup);

  /* --- Connect to the server --- */

  if (f & f_spawn) {
    sa.sa_handler = reap;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_NOCLDSTOP;
#ifdef SA_RESTART
    sa.sa_flags |= SA_RESTART;
#endif
    sigaction(SIGCHLD, &sa, 0);

    DA_PUSH(&spawnopts, 0);
    if (g != (gid_t)-1) putarg(&spawnopts, "-G%lu", (unsigned long)g);
    if (u != (uid_t)-1) putarg(&spawnopts, "-U%lu", (unsigned long)u);
    putarg(&spawnopts, "-a%s", sock);
    putarg(&spawnopts, "-d.");
    putarg(&spawnopts, "-F");
    putarg(&spawnopts, "%s", spawnpath);
    if (socketpair(PF_UNIX, SOCK_STREAM, 0, pfd) || pipe(efd))
      die(EXIT_FAILURE, "error from socketpair: %s", strerror(errno));
    sigemptyset(&newmask);
    sigaddset(&newmask, SIGCHLD);
    sigprocmask(SIG_BLOCK, &newmask, &oldmask);
    if ((kid = fork()) < 0)
      die(EXIT_FAILURE, "fork failed: %s", strerror(errno));
    if (!kid) {
      close(pfd[0]); close(efd[0]);
      sigprocmask(SIG_SETMASK, &oldmask, 0);
      md[0].cur = pfd[1]; md[0].want = STDIN_FILENO;
      md[1].cur = pfd[1]; md[1].want = STDOUT_FILENO;
      md[2].cur = efd[1]; md[2].want = STDERR_FILENO;
      mdup(md, 3);
      if (pidfp) fclose(pidfp);
      closelog();
      if (f & f_daemon) detachtty();
      execvp(DA(&spawnopts)[0], DA(&spawnopts));
      die(127, "couldn't exec `%s': %s", spawnpath, strerror(errno));
    }
    sigprocmask(SIG_SETMASK, &oldmask, 0);
    fd = pfd[0];
    close(pfd[1]); close(efd[1]);
    selbuf_init(&be, &sel, efd[0], eline, &be);
  } else {
    sz = strlen(sock) + 1;
    if (sz > sizeof(sun.sun_path))
      die(EXIT_FAILURE, "socket name `%s' too long", sock);
    memset(&sun, 0, sizeof(sun));
    sun.sun_family = AF_UNIX;
    memcpy(sun.sun_path, sock, sz);
    sz = sz + offsetof(struct sockaddr_un, sun_path);
    if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
      die(EXIT_FAILURE, "error making socket: %s", strerror(errno));
    if (connect(fd, (struct sockaddr *)&sun, sz)) {
      die(EXIT_FAILURE, "error connecting to `%s': %s",
	  sun.sun_path, strerror(errno));
    }
  }

  f |= f_losing; /* pessimism */
  u_setugid(u, g);
  if (logname)
    logfile(logname);
  if (f & f_daemon) {
    if (daemonize())
      die(EXIT_FAILURE, "error becoming daemon: %s", strerror(errno));
  }
  if (pidfp) {
    fprintf(pidfp, "%li\n", (long)getpid());
    fclose(pidfp);
  }
  signal(SIGPIPE, SIG_IGN);

  /* --- If we're meant to be interactive, do that --- */

  if (optind == argc)
    setup("WATCH -A+tw");
  if (!(f & f_noinput) && optind == argc) {
    selbuf_init(&bu, &sel, STDIN_FILENO, uline, &bu);
    selbuf_init(&bs, &sel, fd, sline, &bs);
    for (;;) {
      if (sel_select(&sel) && errno != EINTR && errno != EAGAIN)
	die(EXIT_FAILURE, "select failed: %s", strerror(errno));
    }
  }

  /* --- If there's a command, submit it --- */

  if (optind < argc) {
    setup((f & f_warn) ? "WATCH -A+w" : "WATCH -A");
    while (optind < argc)
      u_quotify(&d, argv[optind++]);
    dstr_putc(&d, '\n');
    errno = EIO;
    if (write(fd, d.buf, d.len) != d.len || shutdown(fd, 1))
      die(EXIT_FAILURE, "write failed: %s", strerror(errno));
    dstr_destroy(&d);
    f |= f_command;
  }

  /* --- Pull everything else out of the box --- */

  selbuf_init(&bs, &sel, fd, cline, 0);

  if (f & f_syslog)
    openlog(QUIS, 0, LOG_DAEMON);
  if (logfp)
    sig_add(&hup, SIGHUP, sighup, 0);
  for (;;) {
    if (sel_select(&sel) && errno != EINTR && errno != EAGAIN)
      die(EXIT_FAILURE, "select failed: %s", strerror(errno));
  }

  return (0);
}

/*----- That's all, folks -------------------------------------------------*/