/*--------------------------------------------------------------------

 * conffiles.c

 *

 * Utilities related to the handling of configuration files.

 *

 * This file contains some generic tools to work on configuration files

 * used by PostgreSQL, be they related to GUCs or authentication.

 *

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 * IDENTIFICATION

 *    src/backend/utils/misc/conffiles.c

 *

 *--------------------------------------------------------------------

 */

#include "postgres.h"

#include <dirent.h>

#include "common/file_utils.h"

#include "miscadmin.h"

#include "storage/fd.h"

#include "utils/conffiles.h"

/*

 * AbsoluteConfigLocation

 *

 * Given a configuration file or directory location that may be a relative

 * path, return an absolute one.  We consider the location to be relative to

 * the directory holding the calling file, or to DataDir if no calling file.

 */

char *

AbsoluteConfigLocation(const char *location, const char *calling_file)

{

  if (is_absolute_path(location))

    return pstrdup(location);

  else

  {

    char    abs_path[MAXPGPATH];

    if (calling_file != NULL)

    {

      strlcpy(abs_path, calling_file, sizeof(abs_path));

      get_parent_directory(abs_path);

      join_path_components(abs_path, abs_path, location);

      canonicalize_path(abs_path);

    }

    else

    {

      Assert(DataDir);

      join_path_components(abs_path, DataDir, location);

      canonicalize_path(abs_path);

    }

    return pstrdup(abs_path);

  }

}

/*

 * GetConfFilesInDir

 *

 * Returns the list of config files located in a directory, in alphabetical

 * order.  On error, returns NULL with details about the error stored in

 * "err_msg".

 */

char    **

GetConfFilesInDir(const char *includedir, const char *calling_file,

          int elevel, int *num_filenames, char **err_msg)

{

  char     *directory;

  DIR      *d;

  struct dirent *de;

  char    **filenames = NULL;

  int     size_filenames;

  /*

   * Reject directory name that is all-blank (including empty), as that

   * leads to confusion --- we'd read the containing directory, typically

   * resulting in recursive inclusion of the same file(s).

   */

  if (strspn(includedir, " \t\r\n") == strlen(includedir))

  {

    ereport(elevel,

        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

         errmsg("empty configuration directory name: \"%s\"",

            includedir)));

    *err_msg = "empty configuration directory name";

    return NULL;

  }

  directory = AbsoluteConfigLocation(includedir, calling_file);

  d = AllocateDir(directory);

  if (d == NULL)

  {

    ereport(elevel,

        (errcode_for_file_access(),

         errmsg("could not open configuration directory \"%s\": %m",

            directory)));

    *err_msg = psprintf("could not open directory \"%s\"", directory);

    goto cleanup;

  }

  /*

   * Read the directory and put the filenames in an array, so we can sort

   * them prior to caller processing the contents.

   */

  size_filenames = 32;

  filenames = (char **) palloc(size_filenames * sizeof(char *));

  *num_filenames = 0;

  while ((de = ReadDir(d, directory)) != NULL)

  {

    PGFileType  de_type;

    char    filename[MAXPGPATH];

    /*

     * Only parse files with names ending in ".conf".  Explicitly reject

     * files starting with ".".  This excludes things like "." and "..",

     * as well as typical hidden files, backup files, and editor debris.

     */

    if (strlen(de->d_name) < 6)

      continue;

    if (de->d_name[0] == '.')

      continue;

    if (strcmp(de->d_name + strlen(de->d_name) - 5, ".conf") != 0)

      continue;

    join_path_components(filename, directory, de->d_name);

    canonicalize_path(filename);

    de_type = get_dirent_type(filename, de, true, elevel);

    if (de_type == PGFILETYPE_ERROR)

    {

      *err_msg = psprintf("could not stat file \"%s\"", filename);

      pfree(filenames);

      filenames = NULL;

      goto cleanup;

    }

    else if (de_type != PGFILETYPE_DIR)

    {

      /* Add file to array, increasing its size in blocks of 32 */

      if (*num_filenames >= size_filenames)

      {

        size_filenames += 32;

        filenames = (char **) repalloc(filenames,

                         size_filenames * sizeof(char *));

      }

      filenames[*num_filenames] = pstrdup(filename);

      (*num_filenames)++;

    }

  }

  /* Sort the files by name before leaving */

  if (*num_filenames > 0)

    qsort(filenames, *num_filenames, sizeof(char *), pg_qsort_strcmp);

cleanup:

  if (d)

    FreeDir(d);

  pfree(directory);

  return filenames;

}