1 files changed, 829 insertions, 0 deletions

diff --git a/src/lib/util/os_installation.c b/src/lib/util/os_installation.c
new file mode 100644
index 000000000..ff04a8a7f
--- /dev/null
+++ b/src/lib/util/os_installation.c
@@ -0,0 +1,829 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2006-2018, 2022 GNUnet e.V.
+
+     GNUnet 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.
+
+     GNUnet 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @file src/util/os_installation.c
+ * @brief get paths used by the program
+ * @author Milan
+ * @author Christian Fuchs
+ * @author Christian Grothoff
+ * @author Matthias Wachs
+ * @author Heikki Lindholm
+ * @author LRN
+ */
+#include "platform.h"
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <unistr.h> /* for u16_to_u8 */
+
+
+#include "gnunet_util_lib.h"
+#if DARWIN
+#include <mach-o/ldsyms.h>
+#include <mach-o/dyld.h>
+#endif
+
+
+#define LOG(kind, ...) \
+  GNUNET_log_from (kind, "util-os-installation", __VA_ARGS__)
+
+#define LOG_STRERROR_FILE(kind, syscall, filename)       \
+  GNUNET_log_from_strerror_file (kind,                   \
+                                 "util-os-installation", \
+                                 syscall,                \
+                                 filename)
+
+
+/**
+ * Default project data used for installation path detection
+ * for GNUnet (core).
+ */
+static const struct GNUNET_OS_ProjectData default_pd = {
+  .libname = "libgnunetutil",
+  .project_dirname = "gnunet",
+  .binary_name = "gnunet-arm",
+  .version = PACKAGE_VERSION " " VCS_VERSION,
+  .env_varname = "GNUNET_PREFIX",
+  .base_config_varname = "GNUNET_BASE_CONFIG",
+  .bug_email = "gnunet-developers@gnu.org",
+  .homepage = "http://www.gnu.org/s/gnunet/",
+  .config_file = "gnunet.conf",
+  .user_config_file = "~/.config/gnunet.conf",
+  .is_gnu = 1,
+  .gettext_domain = "gnunet",
+  .gettext_path = NULL,
+  .agpl_url = GNUNET_AGPL_URL,
+};
+
+/**
+ * Which project data do we currently use for installation
+ * path detection? Never NULL.
+ */
+static const struct GNUNET_OS_ProjectData *current_pd = &default_pd;
+
+/**
+ * PD for which gettext has been initialized last.
+ * Note that the gettext initialization done within
+ * GNUNET_PROGRAM_run2 is for the specific application.
+ */
+static const struct GNUNET_OS_ProjectData *gettextinit;
+
+
+/**
+ * Return default project data used by 'libgnunetutil' for GNUnet.
+ */
+const struct GNUNET_OS_ProjectData *
+GNUNET_OS_project_data_default (void)
+{
+  return &default_pd;
+}
+
+
+/**
+ * @return current project data.
+ */
+const struct GNUNET_OS_ProjectData *
+GNUNET_OS_project_data_get ()
+{
+  if (current_pd != gettextinit)
+  {
+    char *path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LOCALEDIR);
+
+    if (NULL != path)
+      bindtextdomain (PACKAGE,
+                      path);
+    GNUNET_free (path);
+    gettextinit = current_pd;
+  }
+  return current_pd;
+}
+
+
+void
+GNUNET_OS_init (const struct GNUNET_OS_ProjectData *pd)
+{
+  GNUNET_assert (NULL != pd);
+  current_pd = pd;
+  if (pd != gettextinit)
+  {
+    char *path = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LOCALEDIR);
+
+    if (NULL != path)
+      bindtextdomain (PACKAGE,
+                      path);
+    GNUNET_free (path);
+    gettextinit = pd;
+  }
+}
+
+
+#ifdef __linux__
+/**
+ * Try to determine path by reading /proc/PID/exe
+ *
+ * @return NULL on error
+ */
+static char *
+get_path_from_proc_maps (void)
+{
+  char fn[64];
+  char line[1024];
+  char dir[1024];
+  FILE *f;
+  char *lgu;
+
+  if (NULL == current_pd->libname)
+    return NULL;
+  GNUNET_snprintf (fn,
+                   sizeof(fn),
+                   "/proc/%u/maps",
+                   getpid ());
+  if (NULL == (f = fopen (fn, "r")))
+    return NULL;
+  while (NULL != fgets (line, sizeof(line), f))
+  {
+    if ((1 == sscanf (line,
+                      "%*p-%*p %*c%*c%*c%*c %*x %*x:%*x %*u%*[ ]%1023s",
+                      dir)) &&
+        (NULL != (lgu = strstr (dir,
+                                current_pd->libname))))
+    {
+      lgu[0] = '\0';
+      fclose (f);
+      return GNUNET_strdup (dir);
+    }
+  }
+  fclose (f);
+  return NULL;
+}
+
+
+/**
+ * Try to determine path by reading /proc/PID/exe
+ *
+ * @return NULL on error
+ */
+static char *
+get_path_from_proc_exe (void)
+{
+  char fn[64];
+  char lnk[1024];
+  ssize_t size;
+  char *lep;
+
+  GNUNET_snprintf (fn, sizeof(fn), "/proc/%u/exe", getpid ());
+  size = readlink (fn, lnk, sizeof(lnk) - 1);
+  if (size <= 0)
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_ERROR, "readlink", fn);
+    return NULL;
+  }
+  GNUNET_assert (((size_t) size) < sizeof(lnk));
+  lnk[size] = '\0';
+  while ((lnk[size] != '/') && (size > 0))
+    size--;
+  GNUNET_asprintf (&lep, "/%s/libexec/", current_pd->project_dirname);
+  /* test for being in lib/gnunet/libexec/ or lib/MULTIARCH/gnunet/libexec */
+  if ((((size_t) size) > strlen (lep)) &&
+      (0 == strcmp (lep, &lnk[size - strlen (lep)])))
+    size -= strlen (lep) - 1;
+  GNUNET_free (lep);
+  if ((size < 4) || (lnk[size - 4] != '/'))
+  {
+    /* not installed in "/bin/" -- binary path probably useless */
+    return NULL;
+  }
+  lnk[size] = '\0';
+  return GNUNET_strdup (lnk);
+}
+
+
+#endif
+
+
+#if DARWIN
+/**
+ * Signature of the '_NSGetExecutablePath" function.
+ *
+ * @param buf where to write the path
+ * @param number of bytes available in @a buf
+ * @return 0 on success, otherwise desired number of bytes is stored in 'bufsize'
+ */
+typedef int (*MyNSGetExecutablePathProto) (char *buf, size_t *bufsize);
+
+
+/**
+ * Try to obtain the path of our executable using '_NSGetExecutablePath'.
+ *
+ * @return NULL on error
+ */
+static char *
+get_path_from_NSGetExecutablePath (void)
+{
+  static char zero = '\0';
+  char *path;
+  size_t len;
+  MyNSGetExecutablePathProto func;
+
+  path = NULL;
+  if (NULL ==
+      (func = (MyNSGetExecutablePathProto) dlsym (RTLD_DEFAULT,
+                                                  "_NSGetExecutablePath")))
+    return NULL;
+  path = &zero;
+  len = 0;
+  /* get the path len, including the trailing \0 */
+  (void) func (path, &len);
+  if (0 == len)
+    return NULL;
+  path = GNUNET_malloc (len);
+  if (0 != func (path, &len))
+  {
+    GNUNET_free (path);
+    return NULL;
+  }
+  len = strlen (path);
+  while ((path[len] != '/') && (len > 0))
+    len--;
+  path[len] = '\0';
+  return path;
+}
+
+
+/**
+ * Try to obtain the path of our executable using '_dyld_image' API.
+ *
+ * @return NULL on error
+ */
+static char *
+get_path_from_dyld_image (void)
+{
+  const char *path;
+  char *p;
+  char *s;
+  unsigned int i;
+  int c;
+
+  c = _dyld_image_count ();
+  for (i = 0; i < c; i++)
+  {
+    if (((const void *) _dyld_get_image_header (i)) !=
+        ((const void *) &_mh_dylib_header))
+      continue;
+    path = _dyld_get_image_name (i);
+    if ((NULL == path) || (0 == strlen (path)))
+      continue;
+    p = GNUNET_strdup (path);
+    s = p + strlen (p);
+    while ((s > p) && ('/' != *s))
+      s--;
+    s++;
+    *s = '\0';
+    return p;
+  }
+  return NULL;
+}
+
+
+#endif
+
+
+/**
+ * Return the actual path to a file found in the current
+ * PATH environment variable.
+ *
+ * @param binary the name of the file to find
+ * @return path to binary, NULL if not found
+ */
+static char *
+get_path_from_PATH (const char *binary)
+{
+  char *path;
+  char *pos;
+  char *end;
+  char *buf;
+  const char *p;
+
+  if (NULL == (p = getenv ("PATH")))
+    return NULL;
+
+  path = GNUNET_strdup (p);  /* because we write on it */
+
+  buf = GNUNET_malloc (strlen (path) + strlen (binary) + 1 + 1);
+  pos = path;
+  while (NULL != (end = strchr (pos, PATH_SEPARATOR)))
+  {
+    *end = '\0';
+    sprintf (buf, "%s/%s", pos, binary);
+    if (GNUNET_DISK_file_test (buf) == GNUNET_YES)
+    {
+      pos = GNUNET_strdup (pos);
+      GNUNET_free (buf);
+      GNUNET_free (path);
+      return pos;
+    }
+    pos = end + 1;
+  }
+  sprintf (buf, "%s/%s", pos, binary);
+  if (GNUNET_YES == GNUNET_DISK_file_test (buf))
+  {
+    pos = GNUNET_strdup (pos);
+    GNUNET_free (buf);
+    GNUNET_free (path);
+    return pos;
+  }
+  GNUNET_free (buf);
+  GNUNET_free (path);
+  return NULL;
+}
+
+
+/**
+ * Try to obtain the installation path using the "GNUNET_PREFIX" environment
+ * variable.
+ *
+ * @return NULL on error (environment variable not set)
+ */
+static char *
+get_path_from_GNUNET_PREFIX (void)
+{
+  const char *p;
+
+  if ((NULL != current_pd->env_varname) &&
+      (NULL != (p = getenv (current_pd->env_varname))))
+    return GNUNET_strdup (p);
+  if ((NULL != current_pd->env_varname_alt) &&
+      (NULL != (p = getenv (current_pd->env_varname_alt))))
+    return GNUNET_strdup (p);
+  return NULL;
+}
+
+
+/**
+ * @brief get the path to GNUnet bin/ or lib/, preferring the lib/ path
+ * @author Milan
+ *
+ * @return a pointer to the executable path, or NULL on error
+ */
+static char *
+os_get_gnunet_path (void)
+{
+  char *ret;
+
+  if (NULL != (ret = get_path_from_GNUNET_PREFIX ()))
+    return ret;
+#ifdef __linux__
+  if (NULL != (ret = get_path_from_proc_maps ()))
+    return ret;
+  /* try path *first*, before /proc/exe, as /proc/exe can be wrong */
+  if ((NULL != current_pd->binary_name) &&
+      (NULL != (ret = get_path_from_PATH (current_pd->binary_name))))
+    return ret;
+  if (NULL != (ret = get_path_from_proc_exe ()))
+    return ret;
+#endif
+#if DARWIN
+  if (NULL != (ret = get_path_from_dyld_image ()))
+    return ret;
+  if (NULL != (ret = get_path_from_NSGetExecutablePath ()))
+    return ret;
+#endif
+  if ((NULL != current_pd->binary_name) &&
+      (NULL != (ret = get_path_from_PATH (current_pd->binary_name))))
+    return ret;
+  /* other attempts here */
+  LOG (GNUNET_ERROR_TYPE_ERROR,
+       _ (
+         "Could not determine installation path for %s.  Set `%s' environment variable.\n"),
+       current_pd->project_dirname,
+       current_pd->env_varname);
+  return NULL;
+}
+
+
+/**
+ * @brief get the path to current app's bin/
+ * @return a pointer to the executable path, or NULL on error
+ */
+static char *
+os_get_exec_path ()
+{
+  char *ret = NULL;
+
+#ifdef __linux__
+  if (NULL != (ret = get_path_from_proc_exe ()))
+    return ret;
+#endif
+#if DARWIN
+  if (NULL != (ret = get_path_from_NSGetExecutablePath ()))
+    return ret;
+#endif
+  /* other attempts here */
+  return ret;
+}
+
+
+/**
+ * @brief get the path to a specific GNUnet installation directory or,
+ * with #GNUNET_OS_IPK_SELF_PREFIX, the current running apps installation directory
+ * @return a pointer to the dir path (to be freed by the caller)
+ */
+char *
+GNUNET_OS_installation_get_path (enum GNUNET_OS_InstallationPathKind dirkind)
+{
+  size_t n;
+  char *dirname;
+  char *execpath = NULL;
+  char *tmp;
+  char *multiarch;
+  char *libdir;
+  int isbasedir;
+
+  /* if wanted, try to get the current app's bin/ */
+  if (dirkind == GNUNET_OS_IPK_SELF_PREFIX)
+    execpath = os_get_exec_path ();
+
+  /* try to get GNUnet's bin/ or lib/, or if previous was unsuccessful some
+   * guess for the current app */
+  if (NULL == execpath)
+    execpath = os_get_gnunet_path ();
+  if (NULL == execpath)
+    return NULL;
+
+  n = strlen (execpath);
+  if (0 == n)
+  {
+    /* should never happen, but better safe than sorry */
+    GNUNET_free (execpath);
+    return NULL;
+  }
+  /* remove filename itself */
+  while ((n > 1) && (DIR_SEPARATOR == execpath[n - 1]))
+    execpath[--n] = '\0';
+
+  isbasedir = 1;
+  if ((n > 6) && ((0 == strcasecmp (&execpath[n - 6], "/lib32")) ||
+                  (0 == strcasecmp (&execpath[n - 6], "/lib64"))))
+  {
+    if ((GNUNET_OS_IPK_LIBDIR != dirkind) &&
+        (GNUNET_OS_IPK_LIBEXECDIR != dirkind))
+    {
+      /* strip '/lib32' or '/lib64' */
+      execpath[n - 6] = '\0';
+      n -= 6;
+    }
+    else
+      isbasedir = 0;
+  }
+  else if ((n > 4) && ((0 == strcasecmp (&execpath[n - 4], "/bin")) ||
+                       (0 == strcasecmp (&execpath[n - 4], "/lib"))))
+  {
+    /* strip '/bin' or '/lib' */
+    execpath[n - 4] = '\0';
+    n -= 4;
+  }
+  multiarch = NULL;
+  if (NULL != (libdir = strstr (execpath, "/lib/")))
+  {
+    /* test for multi-arch path of the form "PREFIX/lib/MULTIARCH/";
+       here we need to re-add 'multiarch' to lib and libexec paths later! */
+    multiarch = &libdir[5];
+    if (NULL == strchr (multiarch, '/'))
+      libdir[0] =
+        '\0';   /* Debian multiarch format, cut of from 'execpath' but preserve in multicarch */
+    else
+      multiarch =
+        NULL;   /* maybe not, multiarch still has a '/', which is not OK */
+  }
+  /* in case this was a directory named foo-bin, remove "foo-" */
+  while ((n > 1) && (execpath[n - 1] == DIR_SEPARATOR))
+    execpath[--n] = '\0';
+  switch (dirkind)
+  {
+  case GNUNET_OS_IPK_PREFIX:
+  case GNUNET_OS_IPK_SELF_PREFIX:
+    dirname = GNUNET_strdup (DIR_SEPARATOR_STR);
+    break;
+
+  case GNUNET_OS_IPK_BINDIR:
+    dirname = GNUNET_strdup (DIR_SEPARATOR_STR "bin" DIR_SEPARATOR_STR);
+    break;
+
+  case GNUNET_OS_IPK_LIBDIR:
+    if (isbasedir)
+    {
+      GNUNET_asprintf (&tmp,
+                       "%s%s%s%s%s%s%s",
+                       execpath,
+                       DIR_SEPARATOR_STR "lib",
+                       (NULL != multiarch) ? DIR_SEPARATOR_STR : "",
+                       (NULL != multiarch) ? multiarch : "",
+                       DIR_SEPARATOR_STR,
+                       current_pd->project_dirname,
+                       DIR_SEPARATOR_STR);
+      if (GNUNET_YES == GNUNET_DISK_directory_test (tmp, GNUNET_YES))
+      {
+        GNUNET_free (execpath);
+        return tmp;
+      }
+      GNUNET_free (tmp);
+      tmp = NULL;
+      dirname = NULL;
+      if (4 == sizeof(void *))
+      {
+        GNUNET_asprintf (&dirname,
+                         DIR_SEPARATOR_STR "lib32" DIR_SEPARATOR_STR
+                         "%s" DIR_SEPARATOR_STR,
+                         current_pd->project_dirname);
+        GNUNET_asprintf (&tmp, "%s%s", execpath, dirname);
+      }
+      if (8 == sizeof(void *))
+      {
+        GNUNET_asprintf (&dirname,
+                         DIR_SEPARATOR_STR "lib64" DIR_SEPARATOR_STR
+                         "%s" DIR_SEPARATOR_STR,
+                         current_pd->project_dirname);
+        GNUNET_asprintf (&tmp, "%s%s", execpath, dirname);
+      }
+
+      if ((NULL != tmp) &&
+          (GNUNET_YES == GNUNET_DISK_directory_test (tmp, GNUNET_YES)))
+      {
+        GNUNET_free (execpath);
+        GNUNET_free (dirname);
+        return tmp;
+      }
+      GNUNET_free (tmp);
+      GNUNET_free (dirname);
+    }
+    GNUNET_asprintf (&dirname,
+                     DIR_SEPARATOR_STR "%s" DIR_SEPARATOR_STR,
+                     current_pd->project_dirname);
+    break;
+
+  case GNUNET_OS_IPK_DATADIR:
+    GNUNET_asprintf (&dirname,
+                     DIR_SEPARATOR_STR "share" DIR_SEPARATOR_STR
+                     "%s" DIR_SEPARATOR_STR,
+                     current_pd->project_dirname);
+    break;
+
+  case GNUNET_OS_IPK_LOCALEDIR:
+    dirname = GNUNET_strdup (DIR_SEPARATOR_STR "share" DIR_SEPARATOR_STR
+                             "locale" DIR_SEPARATOR_STR);
+    break;
+
+  case GNUNET_OS_IPK_ICONDIR:
+    dirname = GNUNET_strdup (DIR_SEPARATOR_STR "share" DIR_SEPARATOR_STR
+                             "icons" DIR_SEPARATOR_STR);
+    break;
+
+  case GNUNET_OS_IPK_DOCDIR:
+    GNUNET_asprintf (&dirname,
+                     DIR_SEPARATOR_STR "share" DIR_SEPARATOR_STR
+                     "doc" DIR_SEPARATOR_STR
+                     "%s" DIR_SEPARATOR_STR,
+                     current_pd->project_dirname);
+    break;
+
+  case GNUNET_OS_IPK_LIBEXECDIR:
+    if (isbasedir)
+    {
+      GNUNET_asprintf (&dirname,
+                       DIR_SEPARATOR_STR "%s" DIR_SEPARATOR_STR
+                       "libexec" DIR_SEPARATOR_STR,
+                       current_pd->project_dirname);
+      GNUNET_asprintf (&tmp,
+                       "%s%s%s%s",
+                       execpath,
+                       DIR_SEPARATOR_STR "lib" DIR_SEPARATOR_STR,
+                       (NULL != multiarch) ? multiarch : "",
+                       dirname);
+      GNUNET_free (dirname);
+      if (GNUNET_YES == GNUNET_DISK_directory_test (tmp, GNUNET_YES))
+      {
+        GNUNET_free (execpath);
+        return tmp;
+      }
+      GNUNET_free (tmp);
+      tmp = NULL;
+      dirname = NULL;
+      if (4 == sizeof(void *))
+      {
+        GNUNET_asprintf (&dirname,
+                         DIR_SEPARATOR_STR "lib32" DIR_SEPARATOR_STR
+                         "%s" DIR_SEPARATOR_STR
+                         "libexec" DIR_SEPARATOR_STR,
+                         current_pd->project_dirname);
+        GNUNET_asprintf (&tmp, "%s%s", execpath, dirname);
+      }
+      if (8 == sizeof(void *))
+      {
+        GNUNET_asprintf (&dirname,
+                         DIR_SEPARATOR_STR "lib64" DIR_SEPARATOR_STR
+                         "%s" DIR_SEPARATOR_STR
+                         "libexec" DIR_SEPARATOR_STR,
+                         current_pd->project_dirname);
+        GNUNET_asprintf (&tmp, "%s%s", execpath, dirname);
+      }
+      if ((NULL != tmp) &&
+          (GNUNET_YES == GNUNET_DISK_directory_test (tmp, GNUNET_YES)))
+      {
+        GNUNET_free (execpath);
+        GNUNET_free (dirname);
+        return tmp;
+      }
+      GNUNET_free (tmp);
+      GNUNET_free (dirname);
+    }
+    GNUNET_asprintf (&dirname,
+                     DIR_SEPARATOR_STR "%s" DIR_SEPARATOR_STR
+                     "libexec" DIR_SEPARATOR_STR,
+                     current_pd->project_dirname);
+    break;
+
+  default:
+    GNUNET_free (execpath);
+    return NULL;
+  }
+  GNUNET_asprintf (&tmp, "%s%s", execpath, dirname);
+  GNUNET_free (dirname);
+  GNUNET_free (execpath);
+  return tmp;
+}
+
+
+/**
+ * Given the name of a gnunet-helper, gnunet-service or gnunet-daemon
+ * binary, try to prefix it with the libexec/-directory to get the
+ * full path.
+ *
+ * @param progname name of the binary
+ * @return full path to the binary, if possible, otherwise copy of 'progname'
+ */
+char *
+GNUNET_OS_get_libexec_binary_path (const char *progname)
+{
+  static char *cache;
+  char *libexecdir;
+  char *binary;
+
+  if ((DIR_SEPARATOR == progname[0]) ||
+      (GNUNET_YES ==
+       GNUNET_STRINGS_path_is_absolute (progname, GNUNET_NO, NULL, NULL)))
+    return GNUNET_strdup (progname);
+  if (NULL != cache)
+    libexecdir = cache;
+  else
+    libexecdir = GNUNET_OS_installation_get_path (GNUNET_OS_IPK_LIBEXECDIR);
+  if (NULL == libexecdir)
+    return GNUNET_strdup (progname);
+  GNUNET_asprintf (&binary, "%s%s", libexecdir, progname);
+  cache = libexecdir;
+  return binary;
+}
+
+
+/**
+ * Given the name of a helper, service or daemon binary construct the full
+ * path to the binary using the SUID_BINARY_PATH in the PATHS section of the
+ * configuration. If that option is not present, fall back to
+ * GNUNET_OS_get_libexec_binary_path. If @a progname is an absolute path, a
+ * copy of this path is returned.
+ *
+ * @param cfg configuration to inspect
+ * @param progname name of the binary
+ * @return full path to the binary, if possible, a copy of @a progname
+ *         otherwise
+ */
+char *
+GNUNET_OS_get_suid_binary_path (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                                const char *progname)
+{
+  static char *cache;
+  char *binary = NULL;
+  char *path = NULL;
+  size_t path_len;
+
+  if (GNUNET_YES ==
+      GNUNET_STRINGS_path_is_absolute (progname, GNUNET_NO, NULL, NULL))
+  {
+    return GNUNET_strdup (progname);
+  }
+  if (NULL != cache)
+    path = cache;
+  else
+    GNUNET_CONFIGURATION_get_value_string (cfg,
+                                           "PATHS",
+                                           "SUID_BINARY_PATH",
+                                           &path);
+  if ((NULL == path) || (0 == strlen (path)))
+  {
+    if (NULL != path)
+      GNUNET_free (path);
+    cache = NULL;
+    return GNUNET_OS_get_libexec_binary_path (progname);
+  }
+  path_len = strlen (path);
+  GNUNET_asprintf (&binary,
+                   "%s%s%s",
+                   path,
+                   (path[path_len - 1] == DIR_SEPARATOR) ? ""
+                   : DIR_SEPARATOR_STR,
+                   progname);
+  cache = path;
+  return binary;
+}
+
+
+enum GNUNET_GenericReturnValue
+GNUNET_OS_check_helper_binary (const char *binary,
+                               bool check_suid,
+                               const char *params)
+{
+  struct stat statbuf;
+  char *p;
+  char *pf;
+
+  if ((GNUNET_YES ==
+       GNUNET_STRINGS_path_is_absolute (binary, GNUNET_NO, NULL, NULL)) ||
+      (0 == strncmp (binary, "./", 2)))
+  {
+    p = GNUNET_strdup (binary);
+  }
+  else
+  {
+    p = get_path_from_PATH (binary);
+    if (NULL != p)
+    {
+      GNUNET_asprintf (&pf, "%s/%s", p, binary);
+      GNUNET_free (p);
+      p = pf;
+    }
+  }
+
+  if (NULL == p)
+  {
+    LOG (GNUNET_ERROR_TYPE_INFO,
+         _ ("Could not find binary `%s' in PATH!\n"),
+         binary);
+    return GNUNET_SYSERR;
+  }
+  if (0 != access (p, X_OK))
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "access", p);
+    GNUNET_free (p);
+    return GNUNET_SYSERR;
+  }
+
+  if (0 == getuid ())
+  {
+    /* as we run as root, we don't insist on SUID */
+    GNUNET_free (p);
+    return GNUNET_YES;
+  }
+
+  if (0 != stat (p, &statbuf))
+  {
+    LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "stat", p);
+    GNUNET_free (p);
+    return GNUNET_SYSERR;
+  }
+  if (check_suid)
+  {
+    (void) params;
+    if ((0 != (statbuf.st_mode & S_ISUID)) && (0 == statbuf.st_uid))
+    {
+      GNUNET_free (p);
+      return GNUNET_YES;
+    }
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                _ ("Binary `%s' exists, but is not SUID\n"),
+                p);
+    /* binary exists, but not SUID */
+  }
+  GNUNET_free (p);
+  return GNUNET_NO;
+}
+
+
+/* end of os_installation.c */