1/*-------------------------------------------------------------------------
2 *
3 * src/port/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) 1996-2019, PostgreSQL Global Development Group
9 * Portions Copyright (c) 1994, Regents of the University of California
10 *
11 *-------------------------------------------------------------------------
12 */
13
14#include "c.h"
15
16#include <dirent.h>
17
18
19/*
20 * Test to see if a directory exists and is empty or not.
21 *
22 * Returns:
23 * 0 if nonexistent
24 * 1 if exists and empty
25 * 2 if exists and contains _only_ dot files
26 * 3 if exists and contains a mount point
27 * 4 if exists and not empty
28 * -1 if trouble accessing directory (errno reflects the error)
29 */
30int
31pg_check_dir(const char *dir)
32{
33 int result = 1;
34 DIR *chkdir;
35 struct dirent *file;
36 bool dot_found = false;
37 bool mount_found = false;
38 int readdir_errno;
39
40 chkdir = opendir(dir);
41 if (chkdir == NULL)
42 return (errno == ENOENT) ? 0 : -1;
43
44 while (errno = 0, (file = readdir(chkdir)) != NULL)
45 {
46 if (strcmp(".", file->d_name) == 0 ||
47 strcmp("..", file->d_name) == 0)
48 {
49 /* skip this and parent directory */
50 continue;
51 }
52#ifndef WIN32
53 /* file starts with "." */
54 else if (file->d_name[0] == '.')
55 {
56 dot_found = true;
57 }
58 /* lost+found directory */
59 else if (strcmp("lost+found", file->d_name) == 0)
60 {
61 mount_found = true;
62 }
63#endif
64 else
65 {
66 result = 4; /* not empty */
67 break;
68 }
69 }
70
71 if (errno)
72 result = -1; /* some kind of I/O error? */
73
74 /* Close chkdir and avoid overwriting the readdir errno on success */
75 readdir_errno = errno;
76 if (closedir(chkdir))
77 result = -1; /* error executing closedir */
78 else
79 errno = readdir_errno;
80
81 /* We report on mount point if we find a lost+found directory */
82 if (result == 1 && mount_found)
83 result = 3;
84
85 /* We report on dot-files if we _only_ find dot files */
86 if (result == 1 && dot_found)
87 result = 2;
88
89 return result;
90}
91