0005-Remove-configure-probes-for-readlink-and-dead-code-a.patch

From 20df3fb6b0f2ab7f0391738a99958da91a22a114 Mon Sep 17 00:00:00 2001
From: Thomas Munro <thomas.munro@gmail.com>
Date: Sun, 24 Jul 2022 01:03:11 +1200
Subject: [PATCH 05/13] Remove configure probes for readlink, and dead code and
 docs.

readlink() is in SUSv2 and all targeted Unix systems have it.
---
 configure                               |  2 +-
 configure.ac                            |  1 -
 doc/src/sgml/ref/create_tablespace.sgml |  4 ----
 src/backend/access/transam/xlog.c       | 12 ------------
 src/backend/replication/basebackup.c    | 13 -------------
 src/backend/utils/adt/misc.c            |  8 --------
 src/bin/initdb/findtimezone.c           |  2 +-
 src/bin/pg_rewind/file_ops.c            |  5 -----
 src/common/exec.c                       |  4 ++--
 src/include/pg_config.h.in              |  3 ---
 src/tools/msvc/Solution.pm              |  1 -
 11 files changed, 4 insertions(+), 51 deletions(-)

diff --git a/configure b/configure
index 62ff8250d4..6e10773263 100755
--- a/configure
+++ b/configure
@@ -16039,7 +16039,7 @@ fi
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pthread_is_threaded_np readlink readv setproctitle setproctitle_fast strchrnul strsignal symlink syncfs sync_file_range uselocale wcstombs_l writev
+for ac_func in backtrace_symbols clock_gettime copyfile fdatasync getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s poll posix_fallocate ppoll pthread_is_threaded_np readv setproctitle setproctitle_fast strchrnul strsignal symlink syncfs sync_file_range uselocale wcstombs_l writev
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
diff --git a/configure.ac b/configure.ac
index eb29046398..b4015aebb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1805,7 +1805,6 @@ AC_CHECK_FUNCS(m4_normalize([
 	posix_fallocate
 	ppoll
 	pthread_is_threaded_np
-	readlink
 	readv
 	setproctitle
 	setproctitle_fast
diff --git a/doc/src/sgml/ref/create_tablespace.sgml b/doc/src/sgml/ref/create_tablespace.sgml
index 84fa7ee5e2..9d5ab02526 100644
--- a/doc/src/sgml/ref/create_tablespace.sgml
+++ b/doc/src/sgml/ref/create_tablespace.sgml
@@ -127,10 +127,6 @@ CREATE TABLESPACE <replaceable class="parameter">tablespace_name</replaceable>
  <refsect1>
   <title>Notes</title>
 
-  <para>
-   Tablespaces are only supported on systems that support symbolic links.
-  </para>
-
    <para>
     <command>CREATE TABLESPACE</command> cannot be executed inside a transaction
     block.
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 15ab8d90d4..26fbed00a4 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8305,7 +8305,6 @@ do_pg_backup_start(const char *backupidstr, bool fast, TimeLineID *starttli_p,
 			if (get_dirent_type(fullpath, de, false, ERROR) != PGFILETYPE_LNK)
 				continue;
 
-#if defined(HAVE_READLINK) || defined(WIN32)
 			rllen = readlink(fullpath, linkpath, sizeof(linkpath));
 			if (rllen < 0)
 			{
@@ -8358,17 +8357,6 @@ do_pg_backup_start(const char *backupidstr, bool fast, TimeLineID *starttli_p,
 							 ti->oid, escapedpath.data);
 
 			pfree(escapedpath.data);
-#else
-
-			/*
-			 * If the platform does not have symbolic links, it should not be
-			 * possible to have tablespaces - clearly somebody else created
-			 * them. Warn about it and ignore.
-			 */
-			ereport(WARNING,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("tablespaces are not supported on this platform")));
-#endif
 		}
 		FreeDir(tblspcdir);
 
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index 637c0ce459..1a569e2582 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1328,7 +1328,6 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
 #endif
 			)
 		{
-#if defined(HAVE_READLINK) || defined(WIN32)
 			char		linkpath[MAXPGPATH];
 			int			rllen;
 
@@ -1347,18 +1346,6 @@ sendDir(bbsink *sink, const char *path, int basepathlen, bool sizeonly,
 
 			size += _tarWriteHeader(sink, pathbuf + basepathlen + 1, linkpath,
 									&statbuf, sizeonly);
-#else
-
-			/*
-			 * If the platform does not have symbolic links, it should not be
-			 * possible to have tablespaces - clearly somebody else created
-			 * them. Warn about it and ignore.
-			 */
-			ereport(WARNING,
-					(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-					 errmsg("tablespaces are not supported on this platform")));
-			continue;
-#endif							/* HAVE_READLINK */
 		}
 		else if (S_ISDIR(statbuf.st_mode))
 		{
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 89690be2ed..af0d924459 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -302,8 +302,6 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 		tablespaceOid == GLOBALTABLESPACE_OID)
 		PG_RETURN_TEXT_P(cstring_to_text(""));
 
-#if defined(HAVE_READLINK) || defined(WIN32)
-
 	/*
 	 * Find the location of the tablespace by reading the symbolic link that
 	 * is in pg_tblspc/<oid>.
@@ -349,12 +347,6 @@ pg_tablespace_location(PG_FUNCTION_ARGS)
 	targetpath[rllen] = '\0';
 
 	PG_RETURN_TEXT_P(cstring_to_text(targetpath));
-#else
-	ereport(ERROR,
-			(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-			 errmsg("tablespaces are not supported on this platform")));
-	PG_RETURN_NULL();
-#endif
 }
 
 /*
diff --git a/src/bin/initdb/findtimezone.c b/src/bin/initdb/findtimezone.c
index ddb65e6489..dc1d4e9a49 100644
--- a/src/bin/initdb/findtimezone.c
+++ b/src/bin/initdb/findtimezone.c
@@ -544,7 +544,7 @@ static bool
 check_system_link_file(const char *linkname, struct tztry *tt,
 					   char *bestzonename)
 {
-#ifdef HAVE_READLINK
+#ifndef WIN32
 	char		link_target[MAXPGPATH];
 	int			len;
 	const char *cur_name;
diff --git a/src/bin/pg_rewind/file_ops.c b/src/bin/pg_rewind/file_ops.c
index 6cb288f099..5e6d8b89c4 100644
--- a/src/bin/pg_rewind/file_ops.c
+++ b/src/bin/pg_rewind/file_ops.c
@@ -437,7 +437,6 @@ recurse_dir(const char *datadir, const char *parentpath,
 		else if (pgwin32_is_junction(fullpath))
 #endif
 		{
-#if defined(HAVE_READLINK) || defined(WIN32)
 			char		link_target[MAXPGPATH];
 			int			len;
 
@@ -460,10 +459,6 @@ recurse_dir(const char *datadir, const char *parentpath,
 			if ((parentpath && strcmp(parentpath, "pg_tblspc") == 0) ||
 				strcmp(path, "pg_wal") == 0)
 				recurse_dir(datadir, path, callback);
-#else
-			pg_fatal("\"%s\" is a symbolic link, but symbolic links are not supported on this platform",
-					 fullpath);
-#endif							/* HAVE_READLINK */
 		}
 	}
 
diff --git a/src/common/exec.c b/src/common/exec.c
index f7d44b0956..2a398f1eb1 100644
--- a/src/common/exec.c
+++ b/src/common/exec.c
@@ -254,7 +254,7 @@ find_my_exec(const char *argv0, char *retpath)
 static int
 resolve_symlinks(char *path)
 {
-#ifdef HAVE_READLINK
+#ifndef WIN32
 	struct stat buf;
 	char		orig_wd[MAXPGPATH],
 				link_buf[MAXPGPATH];
@@ -333,7 +333,7 @@ resolve_symlinks(char *path)
 				  _("could not change directory to \"%s\": %m"), orig_wd);
 		return -1;
 	}
-#endif							/* HAVE_READLINK */
+#endif							/* !WIN32 */
 
 	return 0;
 }
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 9a3372f7de..9fc0298f7d 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -435,9 +435,6 @@
 /* Define to 1 if you have the <readline/readline.h> header file. */
 #undef HAVE_READLINE_READLINE_H
 
-/* Define to 1 if you have the `readlink' function. */
-#undef HAVE_READLINK
-
 /* Define to 1 if you have the `readv' function. */
 #undef HAVE_READV
 
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index e3b60a773a..f9aec9494e 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -339,7 +339,6 @@ sub GenerateFiles
 		HAVE_READLINE_H             => undef,
 		HAVE_READLINE_HISTORY_H     => undef,
 		HAVE_READLINE_READLINE_H    => undef,
-		HAVE_READLINK               => undef,
 		HAVE_READV                  => undef,
 		HAVE_RL_COMPLETION_MATCHES  => undef,
 		HAVE_RL_COMPLETION_SUPPRESS_QUOTE        => undef,
-- 
2.30.2