Adding upstream version 2.2.40.upstream/2.2.40

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 909 insertions, 0 deletions

diff --git a/common/exechelp-posix.c b/common/exechelp-posix.c
new file mode 100644
index 0000000..e9cb7ed
--- /dev/null
+++ b/common/exechelp-posix.c
@@ -0,0 +1,909 @@
+/* exechelp.c - Fork and exec helpers for POSIX
+ * Copyright (C) 2004, 2007, 2008, 2009,
+ *               2010 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - 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.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#if defined(HAVE_W32_SYSTEM) || defined (HAVE_W32CE_SYSTEM)
+#error This code is only used on POSIX
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#ifdef HAVE_SIGNAL_H
+# include <signal.h>
+#endif
+#include <unistd.h>
+#include <fcntl.h>
+
+#ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth.  */
+#undef HAVE_NPTH
+#undef USE_NPTH
+#endif
+
+#ifdef HAVE_NPTH
+#include <npth.h>
+#endif
+#include <sys/wait.h>
+
+#ifdef HAVE_GETRLIMIT
+#include <sys/time.h>
+#include <sys/resource.h>
+#endif /*HAVE_GETRLIMIT*/
+
+#ifdef HAVE_STAT
+# include <sys/stat.h>
+#endif
+
+#if __linux__
+# include <sys/types.h>
+# include <dirent.h>
+#endif /*__linux__ */
+
+#include "util.h"
+#include "i18n.h"
+#include "sysutils.h"
+#include "exechelp.h"
+
+
+/* Helper */
+static inline gpg_error_t
+my_error_from_syserror (void)
+{
+  return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
+}
+
+static inline gpg_error_t
+my_error (int errcode)
+{
+  return gpg_err_make (default_errsource, errcode);
+}
+
+
+/* Return the maximum number of currently allowed open file
+   descriptors.  Only useful on POSIX systems but returns a value on
+   other systems too.  */
+int
+get_max_fds (void)
+{
+  int max_fds = -1;
+#ifdef HAVE_GETRLIMIT
+  struct rlimit rl;
+
+  /* Under Linux we can figure out the highest used file descriptor by
+   * reading /proc/PID/fd.  This is in the common cases much fast than
+   * for example doing 4096 close calls where almost all of them will
+   * fail.  On a system with a limit of 4096 files and only 8 files
+   * open with the highest number being 10, we speedup close_all_fds
+   * from 125ms to 0.4ms including readdir.
+   *
+   * Another option would be to close the file descriptors as returned
+   * from reading that directory - however then we need to snapshot
+   * that list before starting to close them.  */
+#ifdef __linux__
+  {
+    DIR *dir = NULL;
+    struct dirent *dir_entry;
+    const char *s;
+    int x;
+
+    dir = opendir ("/proc/self/fd");
+    if (dir)
+      {
+        while ((dir_entry = readdir (dir)))
+          {
+            s = dir_entry->d_name;
+            if ( *s < '0' || *s > '9')
+              continue;
+            x = atoi (s);
+            if (x > max_fds)
+              max_fds = x;
+          }
+        closedir (dir);
+      }
+    if (max_fds != -1)
+      return max_fds + 1;
+    }
+#endif /* __linux__ */
+
+
+# ifdef RLIMIT_NOFILE
+  if (!getrlimit (RLIMIT_NOFILE, &rl))
+    max_fds = rl.rlim_max;
+# endif
+
+# ifdef RLIMIT_OFILE
+  if (max_fds == -1 && !getrlimit (RLIMIT_OFILE, &rl))
+    max_fds = rl.rlim_max;
+
+# endif
+#endif /*HAVE_GETRLIMIT*/
+
+#ifdef _SC_OPEN_MAX
+  if (max_fds == -1)
+    {
+      long int scres = sysconf (_SC_OPEN_MAX);
+      if (scres >= 0)
+        max_fds = scres;
+    }
+#endif
+
+#ifdef _POSIX_OPEN_MAX
+  if (max_fds == -1)
+    max_fds = _POSIX_OPEN_MAX;
+#endif
+
+#ifdef OPEN_MAX
+  if (max_fds == -1)
+    max_fds = OPEN_MAX;
+#endif
+
+  if (max_fds == -1)
+    max_fds = 256;  /* Arbitrary limit.  */
+
+  /* AIX returns INT32_MAX instead of a proper value.  We assume that
+     this is always an error and use an arbitrary limit.  */
+#ifdef INT32_MAX
+  if (max_fds == INT32_MAX)
+    max_fds = 256;
+#endif
+
+  return max_fds;
+}
+
+
+/* Close all file descriptors starting with descriptor FIRST.  If
+   EXCEPT is not NULL, it is expected to be a list of file descriptors
+   which shall not be closed.  This list shall be sorted in ascending
+   order with the end marked by -1.  */
+void
+close_all_fds (int first, int *except)
+{
+  int max_fd = get_max_fds ();
+  int fd, i, except_start;
+
+  if (except)
+    {
+      except_start = 0;
+      for (fd=first; fd < max_fd; fd++)
+        {
+          for (i=except_start; except[i] != -1; i++)
+            {
+              if (except[i] == fd)
+                {
+                  /* If we found the descriptor in the exception list
+                     we can start the next compare run at the next
+                     index because the exception list is ordered.  */
+                except_start = i + 1;
+                break;
+                }
+            }
+          if (except[i] == -1)
+            close (fd);
+        }
+    }
+  else
+    {
+      for (fd=first; fd < max_fd; fd++)
+        close (fd);
+    }
+
+  gpg_err_set_errno (0);
+}
+
+
+/* Returns an array with all currently open file descriptors.  The end
+   of the array is marked by -1.  The caller needs to release this
+   array using the *standard free* and not with xfree.  This allow the
+   use of this function right at startup even before libgcrypt has
+   been initialized.  Returns NULL on error and sets ERRNO
+   accordingly.  */
+int *
+get_all_open_fds (void)
+{
+  int *array;
+  size_t narray;
+  int fd, max_fd, idx;
+#ifndef HAVE_STAT
+  array = calloc (1, sizeof *array);
+  if (array)
+    array[0] = -1;
+#else /*HAVE_STAT*/
+  struct stat statbuf;
+
+  max_fd = get_max_fds ();
+  narray = 32;  /* If you change this change also t-exechelp.c.  */
+  array = calloc (narray, sizeof *array);
+  if (!array)
+    return NULL;
+
+  /* Note:  The list we return is ordered.  */
+  for (idx=0, fd=0; fd < max_fd; fd++)
+    if (!(fstat (fd, &statbuf) == -1 && errno == EBADF))
+      {
+        if (idx+1 >= narray)
+          {
+            int *tmp;
+
+            narray += (narray < 256)? 32:256;
+            tmp = realloc (array, narray * sizeof *array);
+            if (!tmp)
+              {
+                free (array);
+                return NULL;
+              }
+            array = tmp;
+          }
+        array[idx++] = fd;
+      }
+  array[idx] = -1;
+#endif /*HAVE_STAT*/
+  return array;
+}
+
+
+/* The exec core used right after the fork. This will never return. */
+static void
+do_exec (const char *pgmname, const char *argv[],
+         int fd_in, int fd_out, int fd_err,
+         int *except, void (*preexec)(void), unsigned int flags)
+{
+  char **arg_list;
+  int i, j;
+  int fds[3];
+  int nodevnull[3];
+
+  fds[0] = fd_in;
+  fds[1] = fd_out;
+  fds[2] = fd_err;
+
+  nodevnull[0] = !!(flags & GNUPG_SPAWN_KEEP_STDIN);
+  nodevnull[1] = !!(flags & GNUPG_SPAWN_KEEP_STDOUT);
+  nodevnull[2] = !!(flags & GNUPG_SPAWN_KEEP_STDERR);
+
+  /* Create the command line argument array.  */
+  i = 0;
+  if (argv)
+    while (argv[i])
+      i++;
+  arg_list = xcalloc (i+2, sizeof *arg_list);
+  arg_list[0] = strrchr (pgmname, '/');
+  if (arg_list[0])
+    arg_list[0]++;
+  else
+    arg_list[0] = xstrdup (pgmname);
+  if (argv)
+    for (i=0,j=1; argv[i]; i++, j++)
+      arg_list[j] = (char*)argv[i];
+
+  /* Assign /dev/null to unused FDs. */
+  for (i=0; i <= 2; i++)
+    {
+      if (nodevnull[i])
+        continue;
+      if (fds[i] == -1)
+        {
+          fds[i] = open ("/dev/null", i? O_WRONLY : O_RDONLY);
+          if (fds[i] == -1)
+            log_fatal ("failed to open '%s': %s\n",
+                       "/dev/null", strerror (errno));
+        }
+    }
+
+  /* Connect the standard files.  */
+  for (i=0; i <= 2; i++)
+    {
+      if (nodevnull[i])
+        continue;
+      if (fds[i] != i && dup2 (fds[i], i) == -1)
+        log_fatal ("dup2 std%s failed: %s\n",
+                   i==0?"in":i==1?"out":"err", strerror (errno));
+    }
+
+  /* Close all other files. */
+  close_all_fds (3, except);
+
+  if (preexec)
+    preexec ();
+  execv (pgmname, arg_list);
+  /* No way to print anything, as we have closed all streams. */
+  _exit (127);
+}
+
+
+static gpg_error_t
+do_create_pipe (int filedes[2])
+{
+  gpg_error_t err = 0;
+
+  if (pipe (filedes) == -1)
+    {
+      err = my_error_from_syserror ();
+      filedes[0] = filedes[1] = -1;
+    }
+
+  return err;
+}
+
+
+static gpg_error_t
+create_pipe_and_estream (int filedes[2], estream_t *r_fp,
+                         int outbound, int nonblock)
+{
+  gpg_error_t err;
+
+  if (pipe (filedes) == -1)
+    {
+      err = my_error_from_syserror ();
+      log_error (_("error creating a pipe: %s\n"), gpg_strerror (err));
+      filedes[0] = filedes[1] = -1;
+      *r_fp = NULL;
+      return err;
+    }
+
+  if (!outbound)
+    *r_fp = es_fdopen (filedes[0], nonblock? "r,nonblock" : "r");
+  else
+    *r_fp = es_fdopen (filedes[1], nonblock? "w,nonblock" : "w");
+  if (!*r_fp)
+    {
+      err = my_error_from_syserror ();
+      log_error (_("error creating a stream for a pipe: %s\n"),
+                 gpg_strerror (err));
+      close (filedes[0]);
+      close (filedes[1]);
+      filedes[0] = filedes[1] = -1;
+      return err;
+    }
+  return 0;
+}
+
+
+/* Portable function to create a pipe.  Under Windows the write end is
+   inheritable.  If R_FP is not NULL, an estream is created for the
+   read end and stored at R_FP.  */
+gpg_error_t
+gnupg_create_inbound_pipe (int filedes[2], estream_t *r_fp, int nonblock)
+{
+  if (r_fp)
+    return create_pipe_and_estream (filedes, r_fp, 0, nonblock);
+  else
+    return do_create_pipe (filedes);
+}
+
+
+/* Portable function to create a pipe.  Under Windows the read end is
+   inheritable.  If R_FP is not NULL, an estream is created for the
+   write end and stored at R_FP.  */
+gpg_error_t
+gnupg_create_outbound_pipe (int filedes[2], estream_t *r_fp, int nonblock)
+{
+  if (r_fp)
+    return create_pipe_and_estream (filedes, r_fp, 1, nonblock);
+  else
+    return do_create_pipe (filedes);
+}
+
+
+/* Portable function to create a pipe.  Under Windows both ends are
+   inheritable.  */
+gpg_error_t
+gnupg_create_pipe (int filedes[2])
+{
+  return do_create_pipe (filedes);
+}
+
+
+/* Fork and exec the PGMNAME, see exechelp.h for details.  */
+gpg_error_t
+gnupg_spawn_process (const char *pgmname, const char *argv[],
+                     int *except, void (*preexec)(void), unsigned int flags,
+                     estream_t *r_infp,
+                     estream_t *r_outfp,
+                     estream_t *r_errfp,
+                     pid_t *pid)
+{
+  gpg_error_t err;
+  int inpipe[2] = {-1, -1};
+  int outpipe[2] = {-1, -1};
+  int errpipe[2] = {-1, -1};
+  estream_t infp = NULL;
+  estream_t outfp = NULL;
+  estream_t errfp = NULL;
+  int nonblock = !!(flags & GNUPG_SPAWN_NONBLOCK);
+
+  if (r_infp)
+    *r_infp = NULL;
+  if (r_outfp)
+    *r_outfp = NULL;
+  if (r_errfp)
+    *r_errfp = NULL;
+  *pid = (pid_t)(-1); /* Always required.  */
+
+  if (r_infp)
+    {
+      err = create_pipe_and_estream (inpipe, &infp, 1, nonblock);
+      if (err)
+        return err;
+    }
+
+  if (r_outfp)
+    {
+      err = create_pipe_and_estream (outpipe, &outfp, 0, nonblock);
+      if (err)
+        {
+          if (infp)
+            es_fclose (infp);
+          else if (inpipe[1] != -1)
+            close (inpipe[1]);
+          if (inpipe[0] != -1)
+            close (inpipe[0]);
+
+          return err;
+        }
+    }
+
+  if (r_errfp)
+    {
+      err = create_pipe_and_estream (errpipe, &errfp, 0, nonblock);
+      if (err)
+        {
+          if (infp)
+            es_fclose (infp);
+          else if (inpipe[1] != -1)
+            close (inpipe[1]);
+          if (inpipe[0] != -1)
+            close (inpipe[0]);
+
+          if (outfp)
+            es_fclose (outfp);
+          else if (outpipe[0] != -1)
+            close (outpipe[0]);
+          if (outpipe[1] != -1)
+            close (outpipe[1]);
+
+          return err;
+        }
+    }
+
+
+  *pid = fork ();
+  if (*pid == (pid_t)(-1))
+    {
+      err = my_error_from_syserror ();
+      log_error (_("error forking process: %s\n"), gpg_strerror (err));
+
+      if (infp)
+        es_fclose (infp);
+      else if (inpipe[1] != -1)
+        close (inpipe[1]);
+      if (inpipe[0] != -1)
+        close (inpipe[0]);
+
+      if (outfp)
+        es_fclose (outfp);
+      else if (outpipe[0] != -1)
+        close (outpipe[0]);
+      if (outpipe[1] != -1)
+        close (outpipe[1]);
+
+      if (errfp)
+        es_fclose (errfp);
+      else if (errpipe[0] != -1)
+        close (errpipe[0]);
+      if (errpipe[1] != -1)
+        close (errpipe[1]);
+      return err;
+    }
+
+  if (!*pid)
+    {
+      /* This is the child. */
+      gcry_control (GCRYCTL_TERM_SECMEM);
+      es_fclose (infp);
+      es_fclose (outfp);
+      es_fclose (errfp);
+      do_exec (pgmname, argv, inpipe[0], outpipe[1], errpipe[1],
+               except, preexec, flags);
+      /*NOTREACHED*/
+    }
+
+  /* This is the parent. */
+  if (inpipe[0] != -1)
+    close (inpipe[0]);
+  if (outpipe[1] != -1)
+    close (outpipe[1]);
+  if (errpipe[1] != -1)
+    close (errpipe[1]);
+
+  if (r_infp)
+    *r_infp = infp;
+  if (r_outfp)
+    *r_outfp = outfp;
+  if (r_errfp)
+    *r_errfp = errfp;
+
+  return 0;
+}
+
+
+
+/* Simplified version of gnupg_spawn_process.  This function forks and
+   then execs PGMNAME, while connecting INFD to stdin, OUTFD to stdout
+   and ERRFD to stderr (any of them may be -1 to connect them to
+   /dev/null).  The arguments for the process are expected in the NULL
+   terminated array ARGV.  The program name itself should not be
+   included there.  Calling gnupg_wait_process is required.
+
+   Returns 0 on success or an error code. */
+gpg_error_t
+gnupg_spawn_process_fd (const char *pgmname, const char *argv[],
+                        int infd, int outfd, int errfd, pid_t *pid)
+{
+  gpg_error_t err;
+
+  *pid = fork ();
+  if (*pid == (pid_t)(-1))
+    {
+      err = my_error_from_syserror ();
+      log_error (_("error forking process: %s\n"), strerror (errno));
+      return err;
+    }
+
+  if (!*pid)
+    {
+      gcry_control (GCRYCTL_TERM_SECMEM);
+      /* Run child. */
+      do_exec (pgmname, argv, infd, outfd, errfd, NULL, NULL, 0);
+      /*NOTREACHED*/
+    }
+
+  return 0;
+}
+
+
+
+
+/* Waiting for child processes.
+
+   waitpid(2) may return information about terminated children that we
+   did not yet request, and there is no portable way to wait for a
+   specific set of children.
+
+   As a workaround, we store the results of children for later use.
+
+   XXX: This assumes that PIDs are not reused too quickly.  */
+
+struct terminated_child
+{
+  pid_t pid;
+  int exitcode;
+  struct terminated_child *next;
+};
+
+struct terminated_child *terminated_children;
+
+
+static gpg_error_t
+store_result (pid_t pid, int exitcode)
+{
+  struct terminated_child *c;
+
+  c = xtrymalloc (sizeof *c);
+  if (c == NULL)
+    return gpg_err_code_from_syserror ();
+
+  c->pid = pid;
+  c->exitcode = exitcode;
+  c->next = terminated_children;
+  terminated_children = c;
+
+  return 0;
+}
+
+
+static int
+get_result (pid_t pid, int *r_exitcode)
+{
+  struct terminated_child *c, **prevp;
+
+  for (prevp = &terminated_children, c = terminated_children;
+       c;
+       prevp = &c->next, c = c->next)
+    if (c->pid == pid)
+      {
+        *prevp = c->next;
+        *r_exitcode = c->exitcode;
+        xfree (c);
+        return 1;
+      }
+
+  return 0;
+}
+
+
+/* See exechelp.h for a description.  */
+gpg_error_t
+gnupg_wait_process (const char *pgmname, pid_t pid, int hang, int *r_exitcode)
+{
+  gpg_err_code_t ec;
+  int i, status;
+
+  if (r_exitcode)
+    *r_exitcode = -1;
+
+  if (pid == (pid_t)(-1))
+    return gpg_error (GPG_ERR_INV_VALUE);
+
+#ifdef USE_NPTH
+  i = npth_waitpid (pid, &status, hang? 0:WNOHANG);
+#else
+  while ((i=waitpid (pid, &status, hang? 0:WNOHANG)) == (pid_t)(-1)
+	 && errno == EINTR);
+#endif
+
+  if (i == (pid_t)(-1))
+    {
+      ec = gpg_err_code_from_errno (errno);
+      log_error (_("waiting for process %d to terminate failed: %s\n"),
+                 (int)pid, strerror (errno));
+    }
+  else if (!i)
+    {
+      ec = GPG_ERR_TIMEOUT; /* Still running.  */
+    }
+  else if (WIFEXITED (status) && WEXITSTATUS (status) == 127)
+    {
+      log_error (_("error running '%s': probably not installed\n"), pgmname);
+      ec = GPG_ERR_CONFIGURATION;
+    }
+  else if (WIFEXITED (status) && WEXITSTATUS (status))
+    {
+      if (!r_exitcode)
+        log_error (_("error running '%s': exit status %d\n"), pgmname,
+                   WEXITSTATUS (status));
+      else
+        *r_exitcode = WEXITSTATUS (status);
+      ec = GPG_ERR_GENERAL;
+    }
+  else if (!WIFEXITED (status))
+    {
+      log_error (_("error running '%s': terminated\n"), pgmname);
+      ec = GPG_ERR_GENERAL;
+    }
+  else
+    {
+      if (r_exitcode)
+        *r_exitcode = 0;
+      ec = 0;
+    }
+
+  return gpg_err_make (GPG_ERR_SOURCE_DEFAULT, ec);
+}
+
+/* See exechelp.h for a description.  */
+gpg_error_t
+gnupg_wait_processes (const char **pgmnames, pid_t *pids, size_t count,
+                      int hang, int *r_exitcodes)
+{
+  gpg_err_code_t ec = 0;
+  size_t i, left;
+  int *dummy = NULL;
+
+  if (r_exitcodes == NULL)
+    {
+      dummy = r_exitcodes = xtrymalloc (sizeof *r_exitcodes * count);
+      if (dummy == NULL)
+        return gpg_err_code_from_syserror ();
+    }
+
+  for (i = 0, left = count; i < count; i++)
+    {
+      int status = -1;
+
+      /* Skip invalid PID.  */
+      if (pids[i] == (pid_t)(-1))
+        {
+          r_exitcodes[i] = -1;
+          left -= 1;
+          continue;
+        }
+
+      /* See if there was a previously stored result for this pid.  */
+      if (get_result (pids[i], &status))
+        left -= 1;
+
+      r_exitcodes[i] = status;
+    }
+
+  while (left > 0)
+    {
+      pid_t pid;
+      int status;
+
+#ifdef USE_NPTH
+      pid = npth_waitpid (-1, &status, hang ? 0 : WNOHANG);
+#else
+      while ((pid = waitpid (-1, &status, hang ? 0 : WNOHANG)) == (pid_t)(-1)
+             && errno == EINTR);
+#endif
+
+      if (pid == (pid_t)(-1))
+        {
+          ec = gpg_err_code_from_errno (errno);
+          log_error (_("waiting for processes to terminate failed: %s\n"),
+                     strerror (errno));
+          break;
+        }
+      else if (!pid)
+        {
+          ec = GPG_ERR_TIMEOUT; /* Still running.  */
+          break;
+        }
+      else
+        {
+          for (i = 0; i < count; i++)
+            if (pid == pids[i])
+              break;
+
+          if (i == count)
+            {
+              /* No match, store this result.  */
+              ec = store_result (pid, status);
+              if (ec)
+                break;
+              continue;
+            }
+
+          /* Process PIDS[i] died.  */
+          if (r_exitcodes[i] != (pid_t) -1)
+            {
+              log_error ("PID %d was reused", pid);
+              ec = GPG_ERR_GENERAL;
+              break;
+            }
+
+          left -= 1;
+          r_exitcodes[i] = status;
+        }
+    }
+
+  for (i = 0; i < count; i++)
+    {
+      if (r_exitcodes[i] == -1)
+        continue;
+
+      if (WIFEXITED (r_exitcodes[i]) && WEXITSTATUS (r_exitcodes[i]) == 127)
+        {
+          log_error (_("error running '%s': probably not installed\n"),
+                     pgmnames[i]);
+          ec = GPG_ERR_CONFIGURATION;
+        }
+      else if (WIFEXITED (r_exitcodes[i]) && WEXITSTATUS (r_exitcodes[i]))
+        {
+          if (dummy)
+            log_error (_("error running '%s': exit status %d\n"),
+                       pgmnames[i], WEXITSTATUS (r_exitcodes[i]));
+          else
+            r_exitcodes[i] = WEXITSTATUS (r_exitcodes[i]);
+          ec = GPG_ERR_GENERAL;
+        }
+      else if (!WIFEXITED (r_exitcodes[i]))
+        {
+          log_error (_("error running '%s': terminated\n"), pgmnames[i]);
+          ec = GPG_ERR_GENERAL;
+        }
+    }
+
+  xfree (dummy);
+  return gpg_err_make (GPG_ERR_SOURCE_DEFAULT, ec);
+}
+
+
+
+void
+gnupg_release_process (pid_t pid)
+{
+  (void)pid;
+}
+
+
+/* Spawn a new process and immediately detach from it.  The name of
+   the program to exec is PGMNAME and its arguments are in ARGV (the
+   programname is automatically passed as first argument).
+   Environment strings in ENVP are set.  An error is returned if
+   pgmname is not executable; to make this work it is necessary to
+   provide an absolute file name.  All standard file descriptors are
+   connected to /dev/null. */
+gpg_error_t
+gnupg_spawn_process_detached (const char *pgmname, const char *argv[],
+                              const char *envp[] )
+{
+  gpg_err_code_t ec;
+  pid_t pid;
+  int i;
+
+  if (getuid() != geteuid())
+    return my_error (GPG_ERR_BUG);
+
+  if ((ec = gnupg_access (pgmname, X_OK)))
+    return gpg_err_make (default_errsource, ec);
+
+  pid = fork ();
+  if (pid == (pid_t)(-1))
+    {
+      log_error (_("error forking process: %s\n"), strerror (errno));
+      return my_error_from_syserror ();
+    }
+  if (!pid)
+    {
+      pid_t pid2;
+
+      gcry_control (GCRYCTL_TERM_SECMEM);
+      if (setsid() == -1 || chdir ("/"))
+        _exit (1);
+
+      pid2 = fork (); /* Double fork to let init take over the new child. */
+      if (pid2 == (pid_t)(-1))
+        _exit (1);
+      if (pid2)
+        _exit (0);  /* Let the parent exit immediately. */
+
+      if (envp)
+        for (i=0; envp[i]; i++)
+          putenv (xstrdup (envp[i]));
+
+      do_exec (pgmname, argv, -1, -1, -1, NULL, NULL, 0);
+
+      /*NOTREACHED*/
+    }
+
+  if (waitpid (pid, NULL, 0) == -1)
+    log_error ("waitpid failed in gnupg_spawn_process_detached: %s",
+               strerror (errno));
+
+  return 0;
+}
+
+
+/* Kill a process; that is send an appropriate signal to the process.
+   gnupg_wait_process must be called to actually remove the process
+   from the system.  An invalid PID is ignored.  */
+void
+gnupg_kill_process (pid_t pid)
+{
+  if (pid != (pid_t)(-1))
+    {
+      kill (pid, SIGTERM);
+    }
+}