From: Thomas Munro <tmunro@postgresql.org>
Date: Sat, 6 Aug 2022 00:02:43 +0000 (+1200)
Subject: Replace pgwin32_is_junction() with lstat().
X-Git-Tag: REL_14_14~16
X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=ca9921936ea352df30db2955fb2662695d8377be;p=postgresql.git
Replace pgwin32_is_junction() with lstat().
Now that lstat() reports junction points with S_IFLNK/S_ISLINK(), and
unlink() can unlink them, there is no need for conditional code for
Windows in a few places. That was expressed by testing for WIN32 or
S_ISLNK, which we can now constant-fold.
The coding around pgwin32_is_junction() was a bit suspect anyway, as we
never checked for errors, and we also know that errors can be spuriously
reported because of transient sharing violations on this OS. The
lstat()-based code has handling for that.
This also reverts 4fc6b6ee on master only. That was done because
lstat() didn't previously work for symlinks (junction points), but now
it does.
Tested-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/CA%2BhUKGLfOOeyZpm5ByVcAt7x5Pn-%3DxGRNCvgiUPVVzjFLtnY0w%40mail.gmail.com
(cherry picked from commit 5fc88c5d53e43fa7dcea93499d230a0bf70f4f77)
Author: Thomas Munro <tmunro@postgresql.org>
Author: Alexandra Wang <alexandra.wang.oss@gmail.com>
---
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index edd1ac03306..9d895960aaf 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -787,8 +787,7 @@ destroy_tablespace_directories(Oid tablespaceoid, bool redo)
/*
* Try to remove the symlink. We must however deal with the possibility
* that it's a directory instead of a symlink --- this could happen during
- * WAL replay (see TablespaceCreateDbspace), and it is also the case on
- * Windows where junction points lstat() as directories.
+ * WAL replay (see TablespaceCreateDbspace).
*
* Note: in the redo case, we'll return true if this final step fails;
* there's no point in retrying it. Also, ENOENT should provoke no more
@@ -818,7 +817,6 @@ remove_symlink:
linkloc)));
}
}
-#ifdef S_ISLNK
else if (S_ISLNK(st.st_mode))
{
if (unlink(linkloc) < 0)
@@ -831,7 +829,6 @@ remove_symlink:
linkloc)));
}
}
-#endif
else
{
/* Refuse to remove anything that's not a directory or symlink */
@@ -909,7 +906,6 @@ remove_tablespace_symlink(const char *linkloc)
errmsg("could not remove directory \"%s\": %m",
linkloc)));
}
-#ifdef S_ISLNK
else if (S_ISLNK(st.st_mode))
{
if (unlink(linkloc) < 0 && errno != ENOENT)
@@ -918,7 +914,6 @@ remove_tablespace_symlink(const char *linkloc)
errmsg("could not remove symbolic link \"%s\": %m",
linkloc)));
}
-#endif
else
{
/* Refuse to remove anything that's not a directory or symlink */
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index d142cc21319..a535180ba41 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1415,13 +1415,7 @@ sendDir(const char *path, int basepathlen, bool sizeonly, List *tablespaces,
}
/* Allow symbolic links in pg_tblspc only */
- if (strcmp(path, "./pg_tblspc") == 0 &&
-#ifndef WIN32
- S_ISLNK(statbuf.st_mode)
-#else
- pgwin32_is_junction(pathbuf)
-#endif
- )
+ if (strcmp(path, "./pg_tblspc") == 0 && S_ISLNK(statbuf.st_mode))
{
#if defined(HAVE_READLINK) || defined(WIN32)
char linkpath[MAXPGPATH];
@@ -1884,11 +1878,7 @@ _tarWriteDir(const char *pathbuf, int basepathlen, struct stat *statbuf,
bool sizeonly)
{
/* If symlink, write it as a directory anyway */
-#ifndef WIN32
if (S_ISLNK(statbuf->st_mode))
-#else
- if (pgwin32_is_junction(pathbuf))
-#endif
statbuf->st_mode = S_IFDIR | pg_dir_create_mode;
return _tarWriteHeader(pathbuf + basepathlen + 1, NULL, statbuf, sizeonly);
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 3933c06ecc8..09c4a93e40b 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -3351,7 +3351,6 @@ SyncDataDirectory(void)
*/
xlog_is_symlink = false;
-#ifndef WIN32
{
struct stat st;
@@ -3363,10 +3362,6 @@ SyncDataDirectory(void)
else if (S_ISLNK(st.st_mode))
xlog_is_symlink = true;
}
-#else
- if (pgwin32_is_junction("pg_wal"))
- xlog_is_symlink = true;
-#endif
#ifdef HAVE_SYNCFS
if (recovery_init_sync_method == RECOVERY_INIT_SYNC_METHOD_SYNCFS)
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 10b8384ef70..6617cb8adc2 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -310,9 +310,7 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
char sourcepath[MAXPGPATH];
char targetpath[MAXPGPATH];
int rllen;
-#ifndef WIN32
struct stat st;
-#endif
/*
* It's useful to apply this function to pg_class.reltablespace, wherein
@@ -343,10 +341,6 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
* created with allow_in_place_tablespaces enabled. If a directory is
* found, a relative path to the data directory is returned.
*/
-#ifdef WIN32
- if (!pgwin32_is_junction(sourcepath))
- PG_RETURN_TEXT_P(cstring_to_text(sourcepath));
-#else
if (lstat(sourcepath, &st) < 0)
{
ereport(ERROR,
@@ -357,7 +351,6 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
if (!S_ISLNK(st.st_mode))
PG_RETURN_TEXT_P(cstring_to_text(sourcepath));
-#endif
/*
* In presence of a link or a junction point, return the path pointing to.
diff --git a/src/bin/pg_checksums/pg_checksums.c b/src/bin/pg_checksums/pg_checksums.c
index 831cf42d3ad..8f80d8b8916 100644
--- a/src/bin/pg_checksums/pg_checksums.c
+++ b/src/bin/pg_checksums/pg_checksums.c
@@ -391,11 +391,7 @@ scan_directory(const char *basedir, const char *subdir, bool sizeonly)
if (!sizeonly)
scan_file(fn, segmentno);
}
-#ifndef WIN32
else if (S_ISDIR(st.st_mode) || S_ISLNK(st.st_mode))
-#else
- else if (S_ISDIR(st.st_mode) || pgwin32_is_junction(fn))
-#endif
{
/*
* If going through the entries of pg_tblspc, we assume to operate
diff --git a/src/bin/pg_rewind/file_ops.c b/src/bin/pg_rewind/file_ops.c
index c50f283ede4..1671feea68f 100644
--- a/src/bin/pg_rewind/file_ops.c
+++ b/src/bin/pg_rewind/file_ops.c
@@ -431,11 +431,7 @@ recurse_dir(const char *datadir, const char *parentpath,
/* recurse to handle subdirectories */
recurse_dir(datadir, path, callback);
}
-#ifndef WIN32
else if (S_ISLNK(fst.st_mode))
-#else
- else if (pgwin32_is_junction(fullpath))
-#endif
{
#if defined(HAVE_READLINK) || defined(WIN32)
char link_target[MAXPGPATH];
diff --git a/src/common/file_utils.c b/src/common/file_utils.c
index fd2d11375c9..f37c89317f7 100644
--- a/src/common/file_utils.c
+++ b/src/common/file_utils.c
@@ -79,7 +79,6 @@ fsync_pgdata(const char *pg_data,
*/
xlog_is_symlink = false;
-#ifndef WIN32
{
struct stat st;
@@ -88,10 +87,6 @@ fsync_pgdata(const char *pg_data,
else if (S_ISLNK(st.st_mode))
xlog_is_symlink = true;
}
-#else
- if (pgwin32_is_junction(pg_wal))
- xlog_is_symlink = true;
-#endif
/*
* If possible, hint to the kernel that we're soon going to fsync the data
@@ -459,27 +454,9 @@ get_dirent_type(const char *path,
result = PGFILETYPE_REG;
else if (S_ISDIR(fst.st_mode))
result = PGFILETYPE_DIR;
-#ifdef S_ISLNK
else if (S_ISLNK(fst.st_mode))
result = PGFILETYPE_LNK;
-#endif
}
-#if defined(WIN32) && !defined(_MSC_VER)
-
- /*
- * If we're on native Windows (not Cygwin, which has its own POSIX
- * symlinks), but not using the MSVC compiler, then we're using a
- * readdir() emulation provided by the MinGW runtime that has no d_type.
- * Since the lstat() fallback code reports junction points as directories,
- * we need an extra system call to check if we should report them as
- * symlinks instead, following our convention.
- */
- if (result == PGFILETYPE_DIR &&
- !look_through_symlinks &&
- pgwin32_is_junction(path))
- result = PGFILETYPE_LNK;
-#endif
-
return result;
}
diff --git a/src/include/port.h b/src/include/port.h
index 2368e9c654d..da18268d17d 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -284,7 +284,6 @@ extern int pgunlink(const char *path);
#if defined(WIN32) && !defined(__CYGWIN__)
extern int pgsymlink(const char *oldpath, const char *newpath);
extern int pgreadlink(const char *path, char *buf, size_t size);
-extern bool pgwin32_is_junction(const char *path);
#define symlink(oldpath, newpath) pgsymlink(oldpath, newpath)
#define readlink(path, buf, size) pgreadlink(path, buf, size)
diff --git a/src/include/port/win32_port.h b/src/include/port/win32_port.h
index 2537e583abe..9ca80e574e9 100644
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -228,7 +228,6 @@ extern pgoff_t _pgftello64(FILE *stream);
*/
extern int pgsymlink(const char *oldpath, const char *newpath);
extern int pgreadlink(const char *path, char *buf, size_t size);
-extern bool pgwin32_is_junction(const char *path);
#define symlink(oldpath, newpath) pgsymlink(oldpath, newpath)
#define readlink(path, buf, size) pgreadlink(path, buf, size)
diff --git a/src/port/dirmod.c b/src/port/dirmod.c
index 9403c8adb8a..bc2ad75966e 100644
--- a/src/port/dirmod.c
+++ b/src/port/dirmod.c
@@ -362,20 +362,4 @@ pgreadlink(const char *path, char *buf, size_t size)
return r;
}
-/*
- * Assumes the file exists, so will return false if it doesn't
- * (since a nonexistent file is not a junction)
- */
-bool
-pgwin32_is_junction(const char *path)
-{
- DWORD attr = GetFileAttributes(path);
-
- if (attr == INVALID_FILE_ATTRIBUTES)
- {
- _dosmaperr(GetLastError());
- return false;
- }
- return ((attr & FILE_ATTRIBUTE_REPARSE_POINT) == FILE_ATTRIBUTE_REPARSE_POINT);
-}
#endif /* defined(WIN32) && !defined(__CYGWIN__) */