Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  *
       3              :  * pgcheckdir.c
       4              :  *
       5              :  * A simple subroutine to check whether a directory exists and is empty or not.
       6              :  * Useful in both initdb and the backend.
       7              :  *
       8              :  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
       9              :  * Portions Copyright (c) 1994, Regents of the University of California
      10              :  *
      11              :  * IDENTIFICATION
      12              :  *      src/port/pgcheckdir.c
      13              :  *-------------------------------------------------------------------------
      14              :  */
      15              : 
      16              : #include "c.h"
      17              : 
      18              : #include <dirent.h>
      19              : 
      20              : 
      21              : /*
      22              :  * Test to see if a directory exists and is empty or not.
      23              :  *
      24              :  * Returns:
      25              :  *      0 if nonexistent
      26              :  *      1 if exists and empty
      27              :  *      2 if exists and contains _only_ dot files
      28              :  *      3 if exists and contains a mount point
      29              :  *      4 if exists and not empty
      30              :  *      -1 if trouble accessing directory (errno reflects the error)
      31              :  */
      32              : int
      33          367 : pg_check_dir(const char *dir)
      34              : {
      35          367 :     int         result = 1;
      36              :     DIR        *chkdir;
      37              :     struct dirent *file;
      38          367 :     bool        dot_found = false;
      39          367 :     bool        mount_found = false;
      40              :     int         readdir_errno;
      41              : 
      42          367 :     chkdir = opendir(dir);
      43          367 :     if (chkdir == NULL)
      44          335 :         return (errno == ENOENT) ? 0 : -1;
      45              : 
      46           87 :     while (errno = 0, (file = readdir(chkdir)) != NULL)
      47              :     {
      48           62 :         if (strcmp(".", file->d_name) == 0 ||
      49           35 :             strcmp("..", file->d_name) == 0)
      50              :         {
      51              :             /* skip this and parent directory */
      52           54 :             continue;
      53              :         }
      54              : #ifndef WIN32
      55              :         /* file starts with "." */
      56            8 :         else if (file->d_name[0] == '.')
      57              :         {
      58            0 :             dot_found = true;
      59              :         }
      60              :         /* lost+found directory */
      61            8 :         else if (strcmp("lost+found", file->d_name) == 0)
      62              :         {
      63            1 :             mount_found = true;
      64              :         }
      65              : #endif
      66              :         else
      67              :         {
      68            7 :             result = 4;         /* not empty */
      69            7 :             break;
      70              :         }
      71              :     }
      72              : 
      73           32 :     if (errno)
      74            0 :         result = -1;            /* some kind of I/O error? */
      75              : 
      76              :     /* Close chkdir and avoid overwriting the readdir errno on success */
      77           32 :     readdir_errno = errno;
      78           32 :     if (closedir(chkdir))
      79            0 :         result = -1;            /* error executing closedir */
      80              :     else
      81           32 :         errno = readdir_errno;
      82              : 
      83              :     /* We report on mount point if we find a lost+found directory */
      84           32 :     if (result == 1 && mount_found)
      85            1 :         result = 3;
      86              : 
      87              :     /* We report on dot-files if we _only_ find dot files */
      88           32 :     if (result == 1 && dot_found)
      89            0 :         result = 2;
      90              : 
      91           32 :     return result;
      92              : }