TLA  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) 1996-2023, 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 CBC         465 : pg_check_dir(const char *dir)
      34                 : {
      35             465 :     int         result = 1;
      36                 :     DIR        *chkdir;
      37                 :     struct dirent *file;
      38             465 :     bool        dot_found = false;
      39             465 :     bool        mount_found = false;
      40                 :     int         readdir_errno;
      41                 : 
      42             465 :     chkdir = opendir(dir);
      43             465 :     if (chkdir == NULL)
      44             442 :         return (errno == ENOENT) ? 0 : -1;
      45                 : 
      46              66 :     while (errno = 0, (file = readdir(chkdir)) != NULL)
      47                 :     {
      48              46 :         if (strcmp(".", file->d_name) == 0 ||
      49              25 :             strcmp("..", file->d_name) == 0)
      50                 :         {
      51                 :             /* skip this and parent directory */
      52              42 :             continue;
      53                 :         }
      54                 : #ifndef WIN32
      55                 :         /* file starts with "." */
      56               4 :         else if (file->d_name[0] == '.')
      57                 :         {
      58 UBC           0 :             dot_found = true;
      59                 :         }
      60                 :         /* lost+found directory */
      61 CBC           4 :         else if (strcmp("lost+found", file->d_name) == 0)
      62                 :         {
      63               1 :             mount_found = true;
      64                 :         }
      65                 : #endif
      66                 :         else
      67                 :         {
      68               3 :             result = 4;         /* not empty */
      69               3 :             break;
      70                 :         }
      71                 :     }
      72                 : 
      73              23 :     if (errno)
      74 UBC           0 :         result = -1;            /* some kind of I/O error? */
      75                 : 
      76                 :     /* Close chkdir and avoid overwriting the readdir errno on success */
      77 CBC          23 :     readdir_errno = errno;
      78              23 :     if (closedir(chkdir))
      79 UBC           0 :         result = -1;            /* error executing closedir */
      80                 :     else
      81 CBC          23 :         errno = readdir_errno;
      82                 : 
      83                 :     /* We report on mount point if we find a lost+found directory */
      84              23 :     if (result == 1 && mount_found)
      85               1 :         result = 3;
      86                 : 
      87                 :     /* We report on dot-files if we _only_ find dot files */
      88              23 :     if (result == 1 && dot_found)
      89 UBC           0 :         result = 2;
      90                 : 
      91 CBC          23 :     return result;
      92                 : }