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/*-------------------------------------------------------------------------
*
* src/port/pgcheckdir.c
*
* A simple subroutine to check whether a directory exists and is empty or not.
* Useful in both initdb and the backend.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*-------------------------------------------------------------------------
*/
#include "c.h"
#include <dirent.h>
/*
* Test to see if a directory exists and is empty or not.
*
* Returns:
* 0 if nonexistent
* 1 if exists and empty
* 2 if exists and contains _only_ dot files
* 3 if exists and contains a mount point
* 4 if exists and not empty
* -1 if trouble accessing directory (errno reflects the error)
*/
int
pg_check_dir(const char *dir)
{
int result = 1;
DIR *chkdir;
struct dirent *file;
bool dot_found = false;
bool mount_found = false;
int readdir_errno;
chkdir = opendir(dir);
if (chkdir == NULL)
return (errno == ENOENT) ? 0 : -1;
while (errno = 0, (file = readdir(chkdir)) != NULL)
{
if (strcmp(".", file->d_name) == 0 ||
strcmp("..", file->d_name) == 0)
{
/* skip this and parent directory */
continue;
}
#ifndef WIN32
/* file starts with "." */
else if (file->d_name[0] == '.')
{
dot_found = true;
}
/* lost+found directory */
else if (strcmp("lost+found", file->d_name) == 0)
{
mount_found = true;
}
#endif
else
{
result = 4; /* not empty */
break;
}
}
if (errno)
result = -1; /* some kind of I/O error? */
/* Close chkdir and avoid overwriting the readdir errno on success */
readdir_errno = errno;
if (closedir(chkdir))
result = -1; /* error executing closedir */
else
errno = readdir_errno;
/* We report on mount point if we find a lost+found directory */
if (result == 1 && mount_found)
result = 3;
/* We report on dot-files if we _only_ find dot files */
if (result == 1 && dot_found)
result = 2;
return result;
}
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