[libguestfs.git] / fish / fish.c

/* guestfish - the filesystem interactive shell
 * Copyright (C) 2009-2010 Red Hat Inc.
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <getopt.h>
#include <signal.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <locale.h>
#include <langinfo.h>
#include <termios.h>

#ifdef HAVE_LIBREADLINE
#include <readline/readline.h>
#include <readline/history.h>
#endif

#include <guestfs.h>

#include "fish.h"
#include "c-ctype.h"
#include "closeout.h"
#include "progname.h"

/* List of drives added via -a, -d or -N options. */
struct drv {
  struct drv *next;
  enum { drv_a, drv_d, drv_N } type;
  union {
    struct {
      char *filename;       /* disk filename */
    } a;
    struct {
      char *guest;          /* guest name */
    } d;
    struct {
      char *filename;       /* disk filename (testX.img) */
      prep_data *data;      /* prepared type */
      char *device;         /* device inside the appliance */
    } N;
  };
};

struct mp {
  struct mp *next;
  char *device;
  char *mountpoint;
};

static void set_up_terminal (void);
static char add_drives (struct drv *drv, char next_drive);
static void prepare_drives (struct drv *drv);
static void mount_mps (struct mp *mp);
static int launch (void);
static void interactive (void);
static void shell_script (void);
static void script (int prompt);
static void cmdline (char *argv[], int optind, int argc);
static void initialize_readline (void);
static void cleanup_readline (void);
#ifdef HAVE_LIBREADLINE
static void add_history_line (const char *);
#endif

static int override_progress_bars = -1;

/* Currently open libguestfs handle. */
guestfs_h *g;

int read_only = 0;
int quit = 0;
int verbose = 0;
int remote_control_listen = 0;
int remote_control = 0;
int exit_on_error = 1;
int command_num = 0;
int keys_from_stdin = 0;
const char *libvirt_uri = NULL;
int inspector = 0;
int utf8_mode = 0;
int have_terminfo = 0;
int progress_bars = 0;

static void __attribute__((noreturn))
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
             program_name);
  else {
    fprintf (stdout,
           _("%s: guest filesystem shell\n"
             "%s lets you edit virtual machine filesystems\n"
             "Copyright (C) 2009 Red Hat Inc.\n"
             "Usage:\n"
             "  %s [--options] cmd [: cmd : cmd ...]\n"
             "  %s -i libvirt-domain\n"
             "  %s -i disk-image(s)\n"
             "or for interactive use:\n"
             "  %s\n"
             "or from a shell script:\n"
             "  %s <<EOF\n"
             "  cmd\n"
             "  ...\n"
             "  EOF\n"
             "Options:\n"
             "  -h|--cmd-help        List available commands\n"
             "  -h|--cmd-help cmd    Display detailed help on 'cmd'\n"
             "  -a|--add image       Add image\n"
             "  -c|--connect uri     Specify libvirt URI for -d option\n"
             "  -d|--domain guest    Add disks from libvirt guest\n"
             "  -D|--no-dest-paths   Don't tab-complete paths from guest fs\n"
             "  -f|--file file       Read commands from file\n"
             "  -i|--inspector       Automatically mount filesystems\n"
             "  --keys-from-stdin    Read passphrases from stdin\n"
             "  --listen             Listen for remote commands\n"
             "  -m|--mount dev[:mnt] Mount dev on mnt (if omitted, /)\n"
             "  -n|--no-sync         Don't autosync\n"
             "  -N|--new type        Create prepared disk (test1.img, ...)\n"
             "  --progress-bars      Enable progress bars even when not interactive\n"
             "  --no-progress-bars   Disable progress bars\n"
             "  --remote[=pid]       Send commands to remote %s\n"
             "  -r|--ro              Mount read-only\n"
             "  --selinux            Enable SELinux support\n"
             "  -v|--verbose         Verbose messages\n"
             "  -x                   Echo each command before executing it\n"
             "  -V|--version         Display version and exit\n"
             "For more information,  see the manpage %s(1).\n"),
             program_name, program_name, program_name,
             program_name, program_name, program_name,
             program_name, program_name, program_name);
  }
  exit (status);
}

int
main (int argc, char *argv[])
{
  /* Set global program name that is not polluted with libtool artifacts.  */
  set_program_name (argv[0]);

  atexit (close_stdout);

  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEBASEDIR);
  textdomain (PACKAGE);

  set_up_terminal ();

  enum { HELP_OPTION = CHAR_MAX + 1 };

  static const char *options = "a:c:d:Df:h::im:nN:rv?Vx";
  static const struct option long_options[] = {
    { "add", 1, 0, 'a' },
    { "cmd-help", 2, 0, 'h' },
    { "connect", 1, 0, 'c' },
    { "domain", 1, 0, 'd' },
    { "file", 1, 0, 'f' },
    { "help", 0, 0, HELP_OPTION },
    { "inspector", 0, 0, 'i' },
    { "keys-from-stdin", 0, 0, 0 },
    { "listen", 0, 0, 0 },
    { "mount", 1, 0, 'm' },
    { "new", 1, 0, 'N' },
    { "no-dest-paths", 0, 0, 'D' },
    { "no-sync", 0, 0, 'n' },
    { "progress-bars", 0, 0, 0 },
    { "no-progress-bars", 0, 0, 0 },
    { "remote", 2, 0, 0 },
    { "ro", 0, 0, 'r' },
    { "selinux", 0, 0, 0 },
    { "verbose", 0, 0, 'v' },
    { "version", 0, 0, 'V' },
    { 0, 0, 0, 0 }
  };
  struct drv *drvs = NULL;
  struct drv *drv;
  struct mp *mps = NULL;
  struct mp *mp;
  char *p, *file = NULL;
  int c;
  int option_index;
  struct sigaction sa;
  int next_prepared_drive = 1;

  initialize_readline ();

  memset (&sa, 0, sizeof sa);
  sa.sa_handler = SIG_IGN;
  sa.sa_flags = SA_RESTART;
  sigaction (SIGPIPE, &sa, NULL);

  /* guestfs_create is meant to be a lightweight operation, so
   * it's OK to do it early here.
   */
  g = guestfs_create ();
  if (g == NULL) {
    fprintf (stderr, _("guestfs_create: failed to create handle\n"));
    exit (EXIT_FAILURE);
  }

  guestfs_set_autosync (g, 1);

  /* If developing, add ./appliance to the path.  Note that libtools
   * interferes with this because uninstalled guestfish is a shell
   * script that runs the real program with an absolute path.  Detect
   * that too.
   *
   * BUT if LIBGUESTFS_PATH environment variable is already set by
   * the user, then don't override it.
   */
  if (getenv ("LIBGUESTFS_PATH") == NULL &&
      argv[0] &&
      (argv[0][0] != '/' || strstr (argv[0], "/.libs/lt-") != NULL))
    guestfs_set_path (g, "appliance:" GUESTFS_DEFAULT_PATH);

  /* CAUTION: we are careful to modify argv[0] here, only after
   * using it just above.
   *
   * getopt_long uses argv[0], so give it the sanitized name.  Save a copy
   * of the original, in case it's needed below.
   */
  char *real_argv0 = argv[0];
  argv[0] = bad_cast (program_name);

  for (;;) {
    c = getopt_long (argc, argv, options, long_options, &option_index);
    if (c == -1) break;

    switch (c) {
    case 0:                     /* options which are long only */
      if (STREQ (long_options[option_index].name, "listen"))
        remote_control_listen = 1;
      else if (STREQ (long_options[option_index].name, "remote")) {
        if (optarg) {
          if (sscanf (optarg, "%d", &remote_control) != 1) {
            fprintf (stderr, _("%s: --listen=PID: PID was not a number: %s\n"),
                     program_name, optarg);
            exit (EXIT_FAILURE);
          }
        } else {
          p = getenv ("GUESTFISH_PID");
          if (!p || sscanf (p, "%d", &remote_control) != 1) {
            fprintf (stderr, _("%s: remote: $GUESTFISH_PID must be set"
                               " to the PID of the remote process\n"),
                     program_name);
            exit (EXIT_FAILURE);
          }
        }
      } else if (STREQ (long_options[option_index].name, "selinux")) {
        guestfs_set_selinux (g, 1);
      } else if (STREQ (long_options[option_index].name, "keys-from-stdin")) {
        keys_from_stdin = 1;
      } else if (STREQ (long_options[option_index].name, "progress-bars")) {
        override_progress_bars = 1;
      } else if (STREQ (long_options[option_index].name, "no-progress-bars")) {
        override_progress_bars = 0;
      } else {
        fprintf (stderr, _("%s: unknown long option: %s (%d)\n"),
                 program_name, long_options[option_index].name, option_index);
        exit (EXIT_FAILURE);
      }
      break;

    case 'a':
      if (access (optarg, R_OK) != 0) {
        perror (optarg);
        exit (EXIT_FAILURE);
      }
      drv = malloc (sizeof (struct drv));
      if (!drv) {
        perror ("malloc");
        exit (EXIT_FAILURE);
      }
      drv->type = drv_a;
      drv->a.filename = optarg;
      drv->next = drvs;
      drvs = drv;
      break;

    case 'c':
      libvirt_uri = optarg;
      break;

    case 'd':
      drv = malloc (sizeof (struct drv));
      if (!drv) {
        perror ("malloc");
        exit (EXIT_FAILURE);
      }
      drv->type = drv_d;
      drv->d.guest = optarg;
      drv->next = drvs;
      drvs = drv;
      break;

    case 'N':
      if (STRCASEEQ (optarg, "list") ||
          STRCASEEQ (optarg, "help") ||
          STRCASEEQ (optarg, "h") ||
          STRCASEEQ (optarg, "?")) {
        list_prepared_drives ();
        exit (EXIT_SUCCESS);
      }
      drv = malloc (sizeof (struct drv));
      if (!drv) {
        perror ("malloc");
        exit (EXIT_FAILURE);
      }
      drv->type = drv_N;
      if (asprintf (&drv->N.filename, "test%d.img",
                    next_prepared_drive++) == -1) {
        perror ("asprintf");
        exit (EXIT_FAILURE);
      }
      drv->N.data = create_prepared_file (optarg, drv->N.filename);
      drv->N.device = NULL;     /* filled in by add_drives */
      drv->next = drvs;
      drvs = drv;
      break;

    case 'D':
      complete_dest_paths = 0;
      break;

    case 'f':
      if (file) {
        fprintf (stderr, _("%s: only one -f parameter can be given\n"),
                 program_name);
        exit (EXIT_FAILURE);
      }
      file = optarg;
      break;

    case 'h': {
      int r = 0;

      if (optarg)
        r = display_command (optarg);
      else if (argv[optind] && argv[optind][0] != '-')
        r = display_command (argv[optind++]);
      else
        list_commands ();

      exit (r == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
    }

    case 'i':
      inspector = 1;
      break;

    case 'm':
      mp = malloc (sizeof (struct mp));
      if (!mp) {
        perror ("malloc");
        exit (EXIT_FAILURE);
      }
      p = strchr (optarg, ':');
      if (p) {
        *p = '\0';
        mp->mountpoint = p+1;
      } else
        mp->mountpoint = bad_cast ("/");
      mp->device = optarg;
      mp->next = mps;
      mps = mp;
      break;

    case 'n':
      guestfs_set_autosync (g, 0);
      break;

    case 'r':
      read_only = 1;
      break;

    case 'v':
      verbose++;
      guestfs_set_verbose (g, verbose);
      break;

    case 'V': {
      struct guestfs_version *v = guestfs_version (g);
      printf ("%s %"PRIi64".%"PRIi64".%"PRIi64"%s\n", program_name,
              v->major, v->minor, v->release, v->extra);
      exit (EXIT_SUCCESS);
    }

    case 'x':
      guestfs_set_trace (g, 1);
      break;

    case HELP_OPTION:
      usage (EXIT_SUCCESS);

    default:
      usage (EXIT_FAILURE);
    }
  }

  /* Old-style -i syntax?  Since -a/-d/-N and -i was disallowed
   * previously, if we have -i without any drives but with something
   * on the command line, it must be old-style syntax.
   */
  if (inspector && drvs == NULL && optind < argc) {
    while (optind < argc) {
      if (strchr (argv[optind], '/') ||
          access (argv[optind], F_OK) == 0) { /* simulate -a option */
        drv = malloc (sizeof (struct drv));
        if (!drv) {
          perror ("malloc");
          exit (EXIT_FAILURE);
        }
        drv->type = drv_a;
        drv->a.filename = argv[optind];
        drv->next = drvs;
        drvs = drv;
      } else {                  /* simulate -d option */
        drv = malloc (sizeof (struct drv));
        if (!drv) {
          perror ("malloc");
          exit (EXIT_FAILURE);
        }
        drv->type = drv_d;
        drv->d.guest = argv[optind];
        drv->next = drvs;
        drvs = drv;
      }

      optind++;
    }
  }

  /* If we've got drives to add, add them now. */
  add_drives (drvs, 'a');

  /* If we've got mountpoints or prepared drives or -i option, we must
   * launch the guest and mount them.
   */
  if (next_prepared_drive > 1 || mps != NULL || inspector) {
    /* RHBZ#612178: If --listen flag is given, then we will fork into
     * the background in rc_listen().  However you can't do this while
     * holding a libguestfs handle open because the recovery process
     * will think the main program has died and kill qemu.  Therefore
     * don't use the recovery process for this case.  (A better
     * solution would be to call launch () etc after the fork, but
     * that greatly complicates the code here).
     */
    if (remote_control_listen)
      guestfs_set_recovery_proc (g, 0);

    if (launch () == -1) exit (EXIT_FAILURE);

    if (inspector)
      inspect_mount ();

    prepare_drives (drvs);
    mount_mps (mps);
  }

  /* Remote control? */
  if (remote_control_listen && remote_control) {
    fprintf (stderr,
             _("%s: cannot use --listen and --remote options at the same time\n"),
             program_name);
    exit (EXIT_FAILURE);
  }

  if (remote_control_listen) {
    if (optind < argc) {
      fprintf (stderr,
               _("%s: extra parameters on the command line with --listen flag\n"),
               program_name);
      exit (EXIT_FAILURE);
    }
    if (file) {
      fprintf (stderr,
               _("%s: cannot use --listen and --file options at the same time\n"),
               program_name);
      exit (EXIT_FAILURE);
    }
    rc_listen ();
  }

  /* -f (file) parameter? */
  if (file) {
    close (0);
    if (open (file, O_RDONLY) == -1) {
      perror (file);
      exit (EXIT_FAILURE);
    }
  }

  /* Decide if we display progress bars. */
  progress_bars =
    override_progress_bars >= 0
    ? override_progress_bars
    : (optind >= argc && isatty (0));

  if (progress_bars)
    guestfs_set_progress_callback (g, progress_callback, NULL);

  /* Interactive, shell script, or command(s) on the command line? */
  if (optind >= argc) {
    if (isatty (0))
      interactive ();
    else
      shell_script ();
  }
  else
    cmdline (argv, optind, argc);

  cleanup_readline ();

  exit (EXIT_SUCCESS);
}

/* The <term.h> header file which defines this has "issues". */
extern int tgetent (char *, const char *);

static void
set_up_terminal (void)
{
  /* http://www.cl.cam.ac.uk/~mgk25/unicode.html#activate */
  utf8_mode = STREQ (nl_langinfo (CODESET), "UTF-8");

  char *term = getenv ("TERM");
  if (term == NULL) {
    //fprintf (stderr, _("guestfish: TERM (terminal type) not defined.\n"));
    return;
  }

  int r = tgetent (NULL, term);
  if (r == -1) {
    fprintf (stderr, _("guestfish: could not access termcap or terminfo database.\n"));
    return;
  }
  if (r == 0) {
    fprintf (stderr, _("guestfish: terminal type \"%s\" not defined.\n"),
             term);
    return;
  }

  have_terminfo = 1;
}

void
pod2text (const char *name, const char *shortdesc, const char *str)
{
  FILE *fp;

  fp = popen ("pod2text", "w");
  if (fp == NULL) {
    /* pod2text failed, maybe not found, so let's just print the
     * source instead, since that's better than doing nothing.
     */
    printf ("%s - %s\n\n%s\n", name, shortdesc, str);
    return;
  }
  fprintf (fp, "=head1 NAME\n\n%s - %s\n\n", name, shortdesc);
  fputs (str, fp);
  pclose (fp);
}

/* List is built in reverse order, so mount them in reverse order. */
static void
mount_mps (struct mp *mp)
{
  int r;

  if (mp) {
    mount_mps (mp->next);

    /* Don't use guestfs_mount here because that will default to mount
     * options -o sync,noatime.  For more information, see guestfs(3)
     * section "LIBGUESTFS GOTCHAS".
     */
    const char *options = read_only ? "ro" : "";
    r = guestfs_mount_options (g, options, mp->device, mp->mountpoint);
    if (r == -1)
      exit (EXIT_FAILURE);
  }
}

static char
add_drives (struct drv *drv, char next_drive)
{
  int r;

  if (next_drive > 'z') {
    fprintf (stderr,
             _("guestfish: too many drives added on the command line\n"));
    exit (EXIT_FAILURE);
  }

  if (drv) {
    next_drive = add_drives (drv->next, next_drive);

    switch (drv->type) {
    case drv_a:
      if (!read_only)
        r = guestfs_add_drive (g, drv->a.filename);
      else
        r = guestfs_add_drive_ro (g, drv->a.filename);
      if (r == -1)
        exit (EXIT_FAILURE);

      next_drive++;
      break;

    case drv_d:
      r = add_libvirt_drives (drv->d.guest);
      if (r == -1)
        exit (EXIT_FAILURE);

      next_drive += r;
      break;

    case drv_N:
      /* -N option is not affected by --ro */
      r = guestfs_add_drive (g, drv->N.filename);
      if (r == -1)
        exit (EXIT_FAILURE);

      if (asprintf (&drv->N.device, "/dev/sd%c", next_drive) == -1) {
        perror ("asprintf");
        exit (EXIT_FAILURE);
      }

      next_drive++;
      break;

    default: /* keep GCC happy */
      abort ();
    }
  }

  return next_drive;
}

static void
prepare_drives (struct drv *drv)
{
  if (drv) {
    prepare_drives (drv->next);
    if (drv->type == drv_N)
      prepare_drive (drv->N.filename, drv->N.data, drv->N.device);
  }
}

static int
launch (void)
{
  if (guestfs_is_config (g)) {
    if (guestfs_launch (g) == -1)
      return -1;
  }
  return 0;
}

static void
interactive (void)
{
  script (1);
}

static void
shell_script (void)
{
  script (0);
}

#define FISH "><fs> "

static char *line_read = NULL;

static char *
rl_gets (int prompt)
{
#ifdef HAVE_LIBREADLINE

  if (prompt) {
    if (line_read) {
      free (line_read);
      line_read = NULL;
    }

    line_read = readline (prompt ? FISH : "");

    if (line_read && *line_read)
      add_history_line (line_read);

    return line_read;
  }

#endif /* HAVE_LIBREADLINE */

  static char buf[8192];
  int len;

  if (prompt) printf (FISH);
  line_read = fgets (buf, sizeof buf, stdin);

  if (line_read) {
    len = strlen (line_read);
    if (len > 0 && buf[len-1] == '\n') buf[len-1] = '\0';
  }

  return line_read;
}

static void
script (int prompt)
{
  char *buf;
  char *cmd;
  char *p, *pend;
  char *argv[64];
  int len;
  int global_exit_on_error = !prompt;
  int tilde_candidate;

  if (prompt) {
    printf (_("\n"
              "Welcome to guestfish, the libguestfs filesystem interactive shell for\n"
              "editing virtual machine filesystems.\n"
              "\n"
              "Type: 'help' for a list of commands\n"
              "      'man' to read the manual\n"
              "      'quit' to quit the shell\n"
              "\n"));

    if (inspector) {
      print_inspect_prompt ();
      printf ("\n");
    }
  }

  while (!quit) {
    char *pipe = NULL;

    exit_on_error = global_exit_on_error;

    buf = rl_gets (prompt);
    if (!buf) {
      quit = 1;
      break;
    }

    /* Skip any initial whitespace before the command. */
  again:
    while (*buf && c_isspace (*buf))
      buf++;

    if (!*buf) continue;

    /* If the next character is '#' then this is a comment. */
    if (*buf == '#') continue;

    /* If the next character is '!' then pass the whole lot to system(3). */
    if (*buf == '!') {
      int r;

      r = system (buf+1);
      if (exit_on_error) {
        if (r == -1 ||
            (WIFSIGNALED (r) &&
             (WTERMSIG (r) == SIGINT || WTERMSIG (r) == SIGQUIT)) ||
            WEXITSTATUS (r) != 0)
          exit (EXIT_FAILURE);
      }
      continue;
    }

    /* If the next character is '-' allow the command to fail without
     * exiting on error (just for this one command though).
     */
    if (*buf == '-') {
      exit_on_error = 0;
      buf++;
      goto again;
    }

    /* Get the command (cannot be quoted). */
    len = strcspn (buf, " \t");

    if (len == 0) continue;

    cmd = buf;
    unsigned int i = 0;
    if (buf[len] == '\0') {
      argv[0] = NULL;
      goto got_command;
    }

    buf[len] = '\0';
    p = &buf[len+1];
    p += strspn (p, " \t");

    /* Get the parameters. */
    while (*p && i < sizeof argv / sizeof argv[0]) {
      tilde_candidate = 0;

      /* Parameters which start with quotes or pipes are treated
       * specially.  Bare parameters are delimited by whitespace.
       */
      if (*p == '"') {
        p++;
        len = strcspn (p, "\"");
        if (p[len] == '\0') {
          fprintf (stderr, _("%s: unterminated double quote\n"), program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        if (p[len+1] && (p[len+1] != ' ' && p[len+1] != '\t')) {
          fprintf (stderr,
                   _("%s: command arguments not separated by whitespace\n"),
                   program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        p[len] = '\0';
        pend = p[len+1] ? &p[len+2] : &p[len+1];
      } else if (*p == '\'') {
        p++;
        len = strcspn (p, "'");
        if (p[len] == '\0') {
          fprintf (stderr, _("%s: unterminated single quote\n"), program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        if (p[len+1] && (p[len+1] != ' ' && p[len+1] != '\t')) {
          fprintf (stderr,
                   _("%s: command arguments not separated by whitespace\n"),
                   program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        p[len] = '\0';
        pend = p[len+1] ? &p[len+2] : &p[len+1];
      } else if (*p == '|') {
        *p = '\0';
        pipe = p+1;
        continue;
        /*
      } else if (*p == '[') {
        int c = 1;
        p++;
        pend = p;
        while (*pend && c != 0) {
          if (*pend == '[') c++;
          else if (*pend == ']') c--;
          pend++;
        }
        if (c != 0) {
          fprintf (stderr,
                   _("%s: unterminated \"[...]\" sequence\n"), program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        if (*pend && (*pend != ' ' && *pend != '\t')) {
          fprintf (stderr,
                   _("%s: command arguments not separated by whitespace\n"),
                   program_name);
          if (exit_on_error) exit (EXIT_FAILURE);
          goto next_command;
        }
        *(pend-1) = '\0';
        */
      } else if (*p != ' ' && *p != '\t') {
        /* If the first character is a ~ then note that this parameter
         * is a candidate for ~username expansion.  NB this does not
         * apply to quoted parameters.
         */
        tilde_candidate = *p == '~';
        len = strcspn (p, " \t");
        if (p[len]) {
          p[len] = '\0';
          pend = &p[len+1];
        } else
          pend = &p[len];
      } else {
        fprintf (stderr, _("%s: internal error parsing string at '%s'\n"),
                 program_name, p);
        abort ();
      }

      if (!tilde_candidate)
        argv[i] = p;
      else
        argv[i] = try_tilde_expansion (p);
      i++;
      p = pend;

      if (*p)
        p += strspn (p, " \t");
    }

    if (i == sizeof argv / sizeof argv[0]) {
      fprintf (stderr, _("%s: too many arguments\n"), program_name);
      if (exit_on_error) exit (EXIT_FAILURE);
      goto next_command;
    }

    argv[i] = NULL;

  got_command:
    if (issue_command (cmd, argv, pipe) == -1) {
      if (exit_on_error) exit (EXIT_FAILURE);
    }

  next_command:;
  }
  if (prompt) printf ("\n");
}

static void
cmdline (char *argv[], int optind, int argc)
{
  const char *cmd;
  char **params;

  exit_on_error = 1;

  if (optind >= argc) return;

  cmd = argv[optind++];
  if (STREQ (cmd, ":")) {
    fprintf (stderr, _("%s: empty command on command line\n"), program_name);
    exit (EXIT_FAILURE);
  }

  /* Allow -cmd on the command line to mean (temporarily) override
   * the normal exit on error (RHBZ#578407).
   */
  if (cmd[0] == '-') {
    exit_on_error = 0;
    cmd++;
  }

  params = &argv[optind];

  /* Search for end of command list or ":" ... */
  while (optind < argc && STRNEQ (argv[optind], ":"))
    optind++;

  if (optind == argc) {
    if (issue_command (cmd, params, NULL) == -1 && exit_on_error)
        exit (EXIT_FAILURE);
  } else {
    argv[optind] = NULL;
    if (issue_command (cmd, params, NULL) == -1 && exit_on_error)
      exit (EXIT_FAILURE);
    cmdline (argv, optind+1, argc);
  }
}

int
issue_command (const char *cmd, char *argv[], const char *pipecmd)
{
  int argc;
  int stdout_saved_fd = -1;
  int pid = 0;
  int i, r;

  reset_progress_bar ();

  /* This counts the commands issued, starting at 1. */
  command_num++;

  /* For | ... commands.  Annoyingly we can't use popen(3) here. */
  if (pipecmd) {
    int fd[2];

    if (fflush (stdout) == EOF) {
      perror ("failed to flush standard output");
      return -1;
    }
    if (pipe (fd) < 0) {
      perror ("pipe failed");
      return -1;
    }
    pid = fork ();
    if (pid == -1) {
      perror ("fork");
      return -1;
    }

    if (pid == 0) {             /* Child process. */
      close (fd[1]);
      if (dup2 (fd[0], 0) < 0) {
        perror ("dup2 of stdin failed");
        _exit (1);
      }

      r = system (pipecmd);
      if (r == -1) {
        perror (pipecmd);
        _exit (1);
      }
      _exit (WEXITSTATUS (r));
    }

    if ((stdout_saved_fd = dup (1)) < 0) {
      perror ("failed to dup stdout");
      return -1;
    }
    close (fd[0]);
    if (dup2 (fd[1], 1) < 0) {
      perror ("failed to dup stdout");
      close (stdout_saved_fd);
      return -1;
    }
    close (fd[1]);
  }

  for (argc = 0; argv[argc] != NULL; ++argc)
    ;

  /* If --remote was set, then send this command to a remote process. */
  if (remote_control)
    r = rc_remote (remote_control, cmd, argc, argv, exit_on_error);

  /* Otherwise execute it locally. */
  else if (STRCASEEQ (cmd, "help")) {
    if (argc == 0) {
      list_commands ();
      r = 0;
    } else
      r = display_command (argv[0]);
  }
  else if (STRCASEEQ (cmd, "quit") ||
           STRCASEEQ (cmd, "exit") ||
           STRCASEEQ (cmd, "q")) {
    quit = 1;
    r = 0;
  }
  else if (STRCASEEQ (cmd, "alloc") ||
           STRCASEEQ (cmd, "allocate"))
    r = do_alloc (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "copy-in") ||
           STRCASEEQ (cmd, "copy_in"))
    r = do_copy_in (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "copy-out") ||
           STRCASEEQ (cmd, "copy_out"))
    r = do_copy_out (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "echo"))
    r = do_echo (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "edit") ||
           STRCASEEQ (cmd, "vi") ||
           STRCASEEQ (cmd, "emacs"))
    r = do_edit (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "lcd"))
    r = do_lcd (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "glob"))
    r = do_glob (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "man") ||
           STRCASEEQ (cmd, "manual"))
    r = do_man (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "more") ||
           STRCASEEQ (cmd, "less"))
    r = do_more (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "reopen"))
    r = do_reopen (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "sparse"))
    r = do_sparse (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "supported"))
    r = do_supported (cmd, argc, argv);
  else if (STRCASEEQ (cmd, "time"))
    r = do_time (cmd, argc, argv);
  else
    r = run_action (cmd, argc, argv);

  /* Always flush stdout after every command, so that messages, results
   * etc appear immediately.
   */
  if (fflush (stdout) == EOF) {
    perror ("failed to flush standard output");
    return -1;
  }

  if (pipecmd) {
    close (1);
    if (dup2 (stdout_saved_fd, 1) < 0) {
      perror ("failed to dup2 standard output");
      r = -1;
    }
    close (stdout_saved_fd);
    if (waitpid (pid, NULL, 0) < 0) {
      perror ("waiting for command to complete");
      r = -1;
    }
  }

  return r;
}

void
list_builtin_commands (void)
{
  /* help, man and quit should appear at the top */
  printf ("%-20s %s\n",
          "help", _("display a list of commands or help on a command"));
  printf ("%-20s %s\n",
          "man", _("read the manual"));
  printf ("%-20s %s\n",
          "quit", _("quit guestfish"));

  printf ("%-20s %s\n",
          "alloc", _("allocate an image"));
  printf ("%-20s %s\n",
          "copy-in", _("copy files into an image"));
  printf ("%-20s %s\n",
          "copy-out", _("copy files out of an image"));
  printf ("%-20s %s\n",
          "echo", _("display a line of text"));
  printf ("%-20s %s\n",
          "edit", _("edit a file in the image"));
  printf ("%-20s %s\n",
          "lcd", _("local change directory"));
  printf ("%-20s %s\n",
          "glob", _("expand wildcards in command"));
  printf ("%-20s %s\n",
          "more", _("view a file in the pager"));
  printf ("%-20s %s\n",
          "reopen", _("close and reopen libguestfs handle"));
  printf ("%-20s %s\n",
          "sparse", _("allocate a sparse image file"));
  printf ("%-20s %s\n",
          "supported", _("list supported groups of commands"));
  printf ("%-20s %s\n",
          "time", _("measure time taken to run command"));

  /* actions are printed after this (see list_commands) */
}

int
display_builtin_command (const char *cmd)
{
  /* help for actions is auto-generated, see display_command */

  if (STRCASEEQ (cmd, "alloc") ||
      STRCASEEQ (cmd, "allocate")) {
    printf (_("alloc - allocate an image\n"
              "     alloc <filename> <size>\n"
              "\n"
              "    This creates an empty (zeroed) file of the given size,\n"
              "    and then adds so it can be further examined.\n"
              "\n"
              "    For more advanced image creation, see qemu-img utility.\n"
              "\n"
              "    Size can be specified using standard suffixes, eg. '1M'.\n"
              ));
    return 0;
  }
  else if (STRCASEEQ (cmd, "copy-in") ||
           STRCASEEQ (cmd, "copy_in")) {
    printf (_("copy-in - copy files into an image\n"
              "     copy-in <local> [<local> ...] <remotedir>\n"
              "\n"
              "    Copy local files or directories recursively into the\n"
              "    image, placing them on a remote directory.\n"
              ));
    return 0;
  }
  else if (STRCASEEQ (cmd, "copy-out") ||
           STRCASEEQ (cmd, "copy_out")) {
    printf (_("copy-out - copy files out of an image\n"
              "     copy-out <remote> [<remote> ...] <localdir>\n"
              "\n"
              "    Copy remote files or directories recursively out of the\n"
              "    image, placing them in a local directory.\n"
              ));
    return 0;
  }
  else if (STRCASEEQ (cmd, "echo")) {
    printf (_("echo - display a line of text\n"
              "     echo [<params> ...]\n"
              "\n"
              "    This echos the parameters to the terminal.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "edit") ||
           STRCASEEQ (cmd, "vi") ||
           STRCASEEQ (cmd, "emacs")) {
    printf (_("edit - edit a file in the image\n"
              "     edit <filename>\n"
              "\n"
              "    This is used to edit a file.\n"
              "\n"
              "    It is the equivalent of (and is implemented by)\n"
              "    running \"cat\", editing locally, and then \"write\".\n"
              "\n"
              "    Normally it uses $EDITOR, but if you use the aliases\n"
              "    \"vi\" or \"emacs\" you will get those editors.\n"
              "\n"
              "    NOTE: This will not work reliably for large files\n"
              "    (> 2 MB) or binary files containing \\0 bytes.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "lcd")) {
    printf (_("lcd - local change directory\n"
              "    lcd <directory>\n"
              "\n"
              "    Change guestfish's current directory. This command is\n"
              "    useful if you want to download files to a particular\n"
              "    place.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "glob")) {
    printf (_("glob - expand wildcards in command\n"
              "    glob <command> [<args> ...]\n"
              "\n"
              "    Glob runs <command> with wildcards expanded in any\n"
              "    command args.  Note that the command is run repeatedly\n"
              "    once for each expanded argument.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "man") ||
           STRCASEEQ (cmd, "manual")) {
    printf (_("man - read the manual\n"
              "    man\n"
              "\n"
              "    Opens the manual page for guestfish.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "help")) {
    printf (_("help - display a list of commands or help on a command\n"
              "     help cmd\n"
              "     help\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "more") ||
           STRCASEEQ (cmd, "less")) {
    printf (_("more - view a file in the pager\n"
              "     more <filename>\n"
              "\n"
              "    This is used to view a file in the pager.\n"
              "\n"
              "    It is the equivalent of (and is implemented by)\n"
              "    running \"cat\" and using the pager.\n"
              "\n"
              "    Normally it uses $PAGER, but if you use the alias\n"
              "    \"less\" then it always uses \"less\".\n"
              "\n"
              "    NOTE: This will not work reliably for large files\n"
              "    (> 2 MB) or binary files containing \\0 bytes.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "quit") ||
           STRCASEEQ (cmd, "exit") ||
           STRCASEEQ (cmd, "q")) {
    printf (_("quit - quit guestfish\n"
              "     quit\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "reopen")) {
    printf (_("reopen - close and reopen the libguestfs handle\n"
              "     reopen\n"
              "\n"
              "Close and reopen the libguestfs handle.  It is not necessary to use\n"
              "this normally, because the handle is closed properly when guestfish\n"
              "exits.  However this is occasionally useful for testing.\n"));
    return 0;
  }
  else if (STRCASEEQ (cmd, "sparse")) {
    printf (_("sparse - allocate a sparse image file\n"
              "     sparse <filename> <size>\n"
              "\n"
              "    This creates an empty sparse file of the given size,\n"
              "    and then adds so it can be further examined.\n"
              "\n"
              "    In all respects it works the same as the 'alloc'\n"
              "    command, except that the image file is allocated\n"
              "    sparsely, which means that disk blocks are not assigned\n"
              "    to the file until they are needed.  Sparse disk files\n"
              "    only use space when written to, but they are slower\n"
              "    and there is a danger you could run out of real disk\n"
              "    space during a write operation.\n"
              "\n"
              "    For more advanced image creation, see qemu-img utility.\n"
              "\n"
              "    Size can be specified using standard suffixes, eg. '1M'.\n"
              ));
    return 0;
  }
  else if (STRCASEEQ (cmd, "supported")) {
    printf (_("supported - list supported groups of commands\n"
              "     supported\n"
              "\n"
              "    This command returns a list of the optional groups\n"
              "    known to the daemon, and indicates which ones are\n"
              "    supported by this build of the libguestfs appliance.\n"
              "\n"
              "    See also guestfs(3) section AVAILABILITY.\n"
              ));
    return 0;
  }
  else if (STRCASEEQ (cmd, "time")) {
    printf (_("time - measure time taken to run command\n"
              "    time <command> [<args> ...]\n"
              "\n"
              "    This runs <command> as usual, and prints the elapsed\n"
              "    time afterwards.\n"));
    return 0;
  }
  else {
    fprintf (stderr, _("%s: command not known, use -h to list all commands\n"),
             cmd);
    return -1;
  }
}

/* This is printed when the user types in an unknown command for the
 * first command issued.  A common case is the user doing:
 *   guestfish disk.img
 * expecting guestfish to open 'disk.img' (in fact, this tried to
 * run a command 'disk.img').
 */
void
extended_help_message (void)
{
  fprintf (stderr,
           _("Did you mean to open a disk image?  guestfish -a disk.img\n"
             "For a list of commands:             guestfish -h\n"
             "For complete documentation:         man guestfish\n"));
}

void
free_strings (char **argv)
{
  int argc;

  for (argc = 0; argv[argc] != NULL; ++argc)
    free (argv[argc]);
  free (argv);
}

int
count_strings (char *const *argv)
{
  int c;

  for (c = 0; argv[c]; ++c)
    ;
  return c;
}

void
print_strings (char *const *argv)
{
  int argc;

  for (argc = 0; argv[argc] != NULL; ++argc)
    printf ("%s\n", argv[argc]);
}

void
print_table (char *const *argv)
{
  int i;

  for (i = 0; argv[i] != NULL; i += 2)
    printf ("%s: %s\n", argv[i], argv[i+1]);
}

int
is_true (const char *str)
{
  return
    STRCASENEQ (str, "0") &&
    STRCASENEQ (str, "f") &&
    STRCASENEQ (str, "false") &&
    STRCASENEQ (str, "n") &&
    STRCASENEQ (str, "no");
}

/* Free strings from a non-NULL terminated char** */
static void
free_n_strings (char **str, size_t len)
{
  size_t i;

  for (i = 0; i < len; i++) {
    free (str[i]);
  }
  free (str);
}

char **
parse_string_list (const char *str)
{
  char **argv = NULL;
  size_t argv_len = 0;

  /* Current position pointer */
  const char *p = str;

  /* Token might be simple:
   *  Token
   * or be quoted:
   *  'This is a single token'
   * or contain embedded single-quoted sections:
   *  This' is a sing'l'e to'ken
   *
   * The latter may seem over-complicated, but it's what a normal shell does.
   * Not doing it risks surprising somebody.
   *
   * This outer loop is over complete tokens.
   */
  while (*p) {
    char *tok = NULL;
    size_t tok_len = 0;

    /* Skip leading whitespace */
    p += strspn (p, " \t");

    char in_quote = 0;

    /* This loop is over token 'fragments'. A token can be in multiple bits if
     * it contains single quotes. We also treat both sides of an escaped quote
     * as separate fragments because we can't just copy it: we have to remove
     * the \.
     */
    while (*p && (!c_isblank (*p) || in_quote)) {
      const char *end = p;

      /* Check if the fragment starts with a quote */
      if ('\'' == *p) {
        /* Toggle in_quote */
        in_quote = !in_quote;

        /* Skip the quote */
        p++; end++;
      }

      /* If we're in a quote, look for an end quote */
      if (in_quote) {
        end += strcspn (end, "'");
      }

      /* Otherwise, look for whitespace or a quote */
      else {
        end += strcspn (end, " \t'");
      }

      /* Grow the token to accommodate the fragment */
      size_t tok_end = tok_len;
      tok_len += end - p;
      char *tok_new = realloc (tok, tok_len + 1);
      if (NULL == tok_new) {
        perror ("realloc");
        free_n_strings (argv, argv_len);
        free (tok);
        exit (EXIT_FAILURE);
      }
      tok = tok_new;

      /* Check if we stopped on an escaped quote */
      if ('\'' == *end && end != p && *(end-1) == '\\') {
        /* Add everything before \' to the token */
        memcpy (&tok[tok_end], p, end - p - 1);

        /* Add the quote */
        tok[tok_len-1] = '\'';

        /* Already processed the quote */
        p = end + 1;
      }

      else {
        /* Add the whole fragment */
        memcpy (&tok[tok_end], p, end - p);

        p = end;
      }
    }

    /* We've reached the end of a token. We shouldn't still be in quotes. */
    if (in_quote) {
      fprintf (stderr, _("Runaway quote in string \"%s\"\n"), str);

      free_n_strings (argv, argv_len);

      return NULL;
    }

    /* Add this token if there is one. There might not be if there was
     * whitespace at the end of the input string */
    if (tok) {
      /* Add the NULL terminator */
      tok[tok_len] = '\0';

      /* Add the argument to the argument list */
      argv_len++;
      char **argv_new = realloc (argv, sizeof (*argv) * argv_len);
      if (NULL == argv_new) {
        perror ("realloc");
        free_n_strings (argv, argv_len-1);
        free (tok);
        exit (EXIT_FAILURE);
      }
      argv = argv_new;

      argv[argv_len-1] = tok;
    }
  }

  /* NULL terminate the argument list */
  argv_len++;
  char **argv_new = realloc (argv, sizeof (*argv) * argv_len);
  if (NULL == argv_new) {
    perror ("realloc");
    free_n_strings (argv, argv_len-1);
    exit (EXIT_FAILURE);
  }
  argv = argv_new;

  argv[argv_len-1] = NULL;

  return argv;
}

#ifdef HAVE_LIBREADLINE
static char histfile[1024];
static int nr_history_lines = 0;
#endif

static void
initialize_readline (void)
{
#ifdef HAVE_LIBREADLINE
  const char *home;

  home = getenv ("HOME");
  if (home) {
    snprintf (histfile, sizeof histfile, "%s/.guestfish", home);
    using_history ();
    (void) read_history (histfile);
  }

  rl_readline_name = "guestfish";
  rl_attempted_completion_function = do_completion;

  /* Note that .inputrc (or /etc/inputrc) is not read until the first
   * call the readline(), which happens later.  Therefore, these
   * provide default values which can be overridden by the user if
   * they wish.
   */
  (void) rl_variable_bind ("completion-ignore-case", "on");
#endif
}

static void
cleanup_readline (void)
{
#ifdef HAVE_LIBREADLINE
  int fd;

  if (histfile[0] != '\0') {
    fd = open (histfile, O_WRONLY|O_CREAT, 0644);
    if (fd == -1) {
      perror (histfile);
      return;
    }
    close (fd);

#ifdef HAVE_APPEND_HISTORY
    (void) append_history (nr_history_lines, histfile);
#else
    (void) write_history (histfile);
#endif
  }
#endif
}

#ifdef HAVE_LIBREADLINE
static void
add_history_line (const char *line)
{
  add_history (line);
  nr_history_lines++;
}
#endif

int
xwrite (int fd, const void *v_buf, size_t len)
{
  int r;
  const char *buf = v_buf;

  while (len > 0) {
    r = write (fd, buf, len);
    if (r == -1) {
      perror ("write");
      return -1;
    }
    buf += r;
    len -= r;
  }

  return 0;
}

/* Resolve the special "win:..." form for Windows-specific paths.
 * This always returns a newly allocated string which is freed by the
 * caller function in "cmds.c".
 */
char *
resolve_win_path (const char *path)
{
  char *ret;
  size_t i;

  if (STRCASENEQLEN (path, "win:", 4)) {
    ret = strdup (path);
    if (ret == NULL)
      perror ("strdup");
    return ret;
  }

  path += 4;

  /* Drop drive letter, if it's "C:". */
  if (STRCASEEQLEN (path, "c:", 2))
    path += 2;

  if (!*path) {
    ret = strdup ("/");
    if (ret == NULL)
      perror ("strdup");
    return ret;
  }

  ret = strdup (path);
  if (ret == NULL) {
    perror ("strdup");
    return NULL;
  }

  /* Blindly convert any backslashes into forward slashes.  Is this good? */
  for (i = 0; i < strlen (ret); ++i)
    if (ret[i] == '\\')
      ret[i] = '/';

  char *t = guestfs_case_sensitive_path (g, ret);
  free (ret);
  ret = t;

  return ret;
}

/* Resolve the special FileIn paths ("-" or "-<<END" or filename).
 * The caller (cmds.c) will call free_file_in after the command has
 * run which should clean up resources.
 */
static char *file_in_heredoc (const char *endmarker);
static char *file_in_tmpfile = NULL;

char *
file_in (const char *arg)
{
  char *ret;

  if (STREQ (arg, "-")) {
    ret = strdup ("/dev/stdin");
    if (!ret) {
      perror ("strdup");
      return NULL;
    }
  }
  else if (STRPREFIX (arg, "-<<")) {
    const char *endmarker = &arg[3];
    if (*endmarker == '\0') {
      fprintf (stderr, "%s: missing end marker in -<< expression\n",
               program_name);
      return NULL;
    }
    ret = file_in_heredoc (endmarker);
    if (ret == NULL)
      return NULL;
  }
  else {
    ret = strdup (arg);
    if (!ret) {
      perror ("strdup");
      return NULL;
    }
  }

  return ret;
}

static char *
file_in_heredoc (const char *endmarker)
{
  static const char template[] = "/tmp/heredocXXXXXX";
  file_in_tmpfile = strdup (template);
  if (file_in_tmpfile == NULL) {
    perror ("strdup");
    return NULL;
  }

  int fd = mkstemp (file_in_tmpfile);
  if (fd == -1) {
    perror ("mkstemp");
    goto error1;
  }

  size_t markerlen = strlen (endmarker);

  char buffer[BUFSIZ];
  int write_error = 0;
  while (fgets (buffer, sizeof buffer, stdin) != NULL) {
    /* Look for "END"<EOF> or "END\n" in input. */
    size_t blen = strlen (buffer);
    if (STREQLEN (buffer, endmarker, markerlen) &&
        (blen == markerlen ||
         (blen == markerlen+1 && buffer[markerlen] == '\n')))
      goto found_end;

    if (xwrite (fd, buffer, blen) == -1) {
      if (!write_error) perror ("write");
      write_error = 1;
      /* continue reading up to the end marker */
    }
  }

  /* Reached EOF of stdin without finding the end marker, which
   * is likely to be an error.
   */
  fprintf (stderr, "%s: end of input reached without finding '%s'\n",
           program_name, endmarker);
  goto error2;

 found_end:
  if (write_error) {
    close (fd);
    goto error2;
  }

  if (close (fd) == -1) {
    perror ("close");
    goto error2;
  }

  return file_in_tmpfile;

 error2:
  unlink (file_in_tmpfile);

 error1:
  free (file_in_tmpfile);
  file_in_tmpfile = NULL;
  return NULL;
}

void
free_file_in (char *s)
{
  if (file_in_tmpfile) {
    if (unlink (file_in_tmpfile) == -1)
      perror (file_in_tmpfile);
    file_in_tmpfile = NULL;
  }

  /* Free the device or file name which was strdup'd in file_in().
   * Note it's not immediately clear, but for -<< heredocs,
   * s == file_in_tmpfile, so this frees up that buffer.
   */
  free (s);
}

/* Resolve the special FileOut paths ("-" or filename).
 * The caller (cmds.c) will call free (str) after the command has run.
 */
char *
file_out (const char *arg)
{
  char *ret;

  if (STREQ (arg, "-"))
    ret = strdup ("/dev/stdout");
  else
    ret = strdup (arg);

  if (!ret) {
    perror ("strdup");
    return NULL;
  }
  return ret;
}

/* Read a passphrase ('Key') from /dev/tty with echo off.
 * The caller (cmds.c) will call free on the string afterwards.
 * Based on the code in cryptsetup file lib/utils.c.
 */
char *
read_key (const char *param)
{
  FILE *infp, *outfp;
  struct termios orig, temp;
  char *ret = NULL;

  /* Read and write to /dev/tty if available. */
  if (keys_from_stdin ||
      (infp = outfp = fopen ("/dev/tty", "w+")) == NULL) {
    infp = stdin;
    outfp = stdout;
  }

  /* Print the prompt and set no echo. */
  int tty = isatty (fileno (infp));
  int tcset = 0;
  if (tty) {
    fprintf (outfp, _("Enter key or passphrase (\"%s\"): "), param);

    if (tcgetattr (fileno (infp), &orig) == -1) {
      perror ("tcgetattr");
      goto error;
    }
    memcpy (&temp, &orig, sizeof temp);
    temp.c_lflag &= ~ECHO;

    tcsetattr (fileno (infp), TCSAFLUSH, &temp);
    tcset = 1;
  }

  size_t n = 0;
  ssize_t len;
  len = getline (&ret, &n, infp);
  if (len == -1) {
    perror ("getline");
    ret = NULL;
    goto error;
  }

  /* Remove the terminating \n if there is one. */
  if (len > 0 && ret[len-1] == '\n')
    ret[len-1] = '\0';

 error:
  /* Restore echo, close file descriptor. */
  if (tty && tcset) {
    printf ("\n");
    tcsetattr (fileno (infp), TCSAFLUSH, &orig);
  }

  if (infp != stdin)
    fclose (infp); /* outfp == infp, so this is closed also */

  return ret;
}