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

diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 526e82e388b2aacbbcc4b0b07923751de270b2eb..f260b484fc4929950930a5e244e5143b810c7ba8 100644 (file)
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -792,8 +792,7 @@ 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
@@ -823,7 +822,6 @@ remove_symlink:
                            linkloc)));
        }
    }
-#ifdef S_ISLNK
    else if (S_ISLNK(st.st_mode))
    {
        if (unlink(linkloc) < 0)
@@ -836,7 +834,6 @@ remove_symlink:
                            linkloc)));
        }
    }
-#endif
    else
    {
        /* Refuse to remove anything that's not a directory or symlink */
@@ -914,7 +911,6 @@ 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)
@@ -923,7 +919,6 @@ 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 5e457f9be990f657c9532e8deee9f14a85141925..deeddd09a9c5f4dc743a2a8d76e0a9b2a1d2313a 100644 (file)
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1322,13 +1322,7 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
        }
 
        /* 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))
        {
            char        linkpath[MAXPGPATH];
            int         rllen;
@@ -1798,11 +1792,7 @@ static void
 convert_link_to_directory(const char *pathbuf, struct stat *statbuf)
 {
    /* 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;
 }
 

diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index ccb540d6178b798da563ddc16552dbada1e8bfaa..efb34d4dcbcfa6be91e85288734f35ac5abc30d5 100644 (file)
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -3365,7 +3365,6 @@ SyncDataDirectory(void)
     */
    xlog_is_symlink = false;
 
-#ifndef WIN32
    {
        struct stat st;
 
@@ -3377,10 +3376,6 @@ 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 af0d924459e4d48e79f2a0976e0efc0a5af4e9e4..d35b5d1f4fac70efac67d3c38c71c4c19f97fb4e 100644 (file)
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -283,9 +283,7 @@ 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
@@ -314,10 +312,6 @@ 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,
@@ -328,7 +322,6 @@ 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 dc20122c8940c2ba960205ac56bf52781b2a4960..324ccf77834e12da1c8676130df78f3cc7df7efd 100644 (file)
--- a/src/bin/pg_checksums/pg_checksums.c
+++ b/src/bin/pg_checksums/pg_checksums.c
@@ -384,11 +384,7 @@ 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 5e6d8b89c49c512694cca95a46c7165ac4d583e5..db190bcba715c2d95a2998e565efd8d406ceb405 100644 (file)
--- 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
        {
            char        link_target[MAXPGPATH];
            int         len;

diff --git a/src/common/file_utils.c b/src/common/file_utils.c
index 966b987d6487b4ec9e557e059c0754957ee3ace7..df4d6d240c06f99a650659eb2b18f1126c27802f 100644 (file)
--- 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 14b640fe33e3425d24cb8fb1ac8a194cb6d4caae..feb2ae840dd75e24bf866f441d1b025cf786d55a 100644 (file)
--- 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 c27b34de5bf54361fb0fb1fb52b1683ac83374ea..a65996cce51e025a4905463d1a12758cef0fe16b 100644 (file)
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -230,7 +230,6 @@ int         setitimer(int which, const struct itimerval *value, struct itimerval *oval
  */
 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 ea191e99c65e2ff0d214f09877c069d24091c10b..2818bfd2e95fa0b050a57095a76c055dcc983995 100644 (file)
--- 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__) */