Add utils directory for cross-subsystem tools to keep make files from having

to be sleazy and reach into other subsystems' directories.  First entry in
this directory is the PG_VERSION file interface, which must be used by the
backend and also the pg_version program (which is used by initdb).

src/Makefile

@@ -7,7 +7,7 @@
 #
 #
 # IDENTIFICATION
-#    $Header: /cvsroot/pgsql/src/Makefile,v 1.9 1996/10/21 06:56:55 bryanh Exp $
+#    $Header: /cvsroot/pgsql/src/Makefile,v 1.10 1996/11/11 13:51:20 bryanh Exp $
 #
 # NOTES
 #	objdir	- location of the objects and generated files (eg. obj)
@@ -31,6 +31,7 @@ XARGS = xargs
 	       you can build Postgres. ;\
 	  false ;\
 	fi
+	$(MAKE) -C utils $@
 	$(MAKE) -C backend $@
 	$(MAKE) -C libpq $@
 ifeq ($(HAVE_Cplusplus), true)

src/utils/Makefile

+#-------------------------------------------------------------------------
+#
+# Makefile--
+#    Makefile for utils
+#
+# IDENTIFICATION
+#    $Header: /cvsroot/pgsql/src/utils/Attic/Makefile,v 1.1 1996/11/11 13:51:55 bryanh Exp $
+#
+#-------------------------------------------------------------------------
+
+SRCDIR = ..
+include ../Makefile.global
+
+INCLUDE_OPT = -I../include
+
+CFLAGS+=$(INCLUDE_OPT)
+
+all: version.o
+
+depend dep:
+	$(CC) -MM $(INCLUDE_OPT) *.c >depend
+
+clean: 
+	rm -f version.o
+
+ifeq (depend,$(wildcard depend))
+include depend
+endif
+

src/utils/README

+The utils directory contains components that are used by multiple subsystems
+in the Postgres source tree.  We don't want subsystems reaching into other
+subsystems' directories and messing with the modularity of the system, so
+we gather any cross-subsystem utilities here.
+
+In particular, programs that form an interface between subsystems go here.

src/utils/version.c

+/*-------------------------------------------------------------------------
+ *
+ * version.c--
+ *    Routines to handle Postgres version number.
+ *
+ * Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *    $Header: /cvsroot/pgsql/src/utils/Attic/version.c,v 1.1 1996/11/11 13:51:57 bryanh Exp $
+ *
+ * NOTES
+ *	XXX eventually, should be able to handle version identifiers
+ *	of length != 4.
+ *
+ *  STANDALONE CODE - do not use error routines as this code is linked with
+ *  stuff that does not cinterface.a
+ *-------------------------------------------------------------------------
+ */
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "postgres.h"
+
+#include "storage/fd.h"	 /* for O_ */
+
+#include "version.h"    
+
+
+static void
+PathSetVersionFilePath(const char *path, char *filepathbuf) {
+/*----------------------------------------------------------------------------
+  PathSetVersionFilePath
+ 
+  Destructively change "filepathbuf" to contain the concatenation of "path"
+  and the name of the version file name.
+----------------------------------------------------------------------------*/
+    if (strlen(path) > (MAXPGPATH - sizeof(PG_VERFILE) - 1))
+        *filepathbuf = '\0';
+    else
+        sprintf(filepathbuf, "%s%c%s", path, SEP_CHAR, PG_VERFILE);
+}
+
+
+
+void
+ValidatePgVersion(const char *path, char **reason_p) {
+/*----------------------------------------------------------------------------
+    Determine whether the PG_VERSION file in directory <path> indicates
+    a data version compatible with the version of this program.
+ 
+    If compatible, return <*reason_p> == NULL.  Otherwise, malloc space,
+    fill it with a text string explaining how it isn't compatible (or why
+    we can't tell), and return a pointer to that space as <*reason_p>.
+-----------------------------------------------------------------------------*/
+    int	 fd;
+    char version[4];
+    char full_path[MAXPGPATH+1];
+#ifndef WIN32
+    struct stat	statbuf;
+#else    
+    struct _stat statbuf;
+#endif    
+    PathSetVersionFilePath(path, full_path);
+    
+    if (stat(full_path, &statbuf) < 0) {
+        *reason_p = malloc(200);
+        sprintf(*reason_p, "File '%s' does not exist.", full_path);
+    } else {
+        fd = open(full_path, O_RDONLY, 0);
+        if (fd < 0) {
+            *reason_p = malloc(200);
+            sprintf(*reason_p, "Unable to open file '%s'.  Errno = %s (%d).",
+                    full_path, strerror(errno), errno);
+        } else {
+            if (read(fd, version, 4) < 4 ||
+                !isascii(version[0]) || !isdigit(version[0]) ||
+                version[1] != '.' ||
+                !isascii(version[2]) || !isdigit(version[2]) ||
+                version[3] != '\n') {
+
+                *reason_p = malloc(200);
+                sprintf(*reason_p, "File '%s' does not have a valid format "
+                        "for a PG_VERSION file.", full_path);
+            } else {
+                if (version[2] != '0' + PG_VERSION ||
+                    version[0] != '0' + PG_RELEASE) {
+                    *reason_p = malloc(200);
+                    sprintf(*reason_p, 
+                            "Version number in file '%s' should be %d.%d, "
+                            "not %c.%c.",
+                            full_path, 
+                            PG_RELEASE, PG_VERSION, version[0], version[2]);
+                } else *reason_p = NULL;
+            }
+            close(fd);                
+        }
+    }
+}
+
+
+
+void
+SetPgVersion(const char *path, char **reason_p) {
+/*---------------------------------------------------------------------------
+  Create the PG_VERSION file in the directory <path>.
+  
+  If we fail, allocate storage, fill it with a text string explaining why,
+  and return a pointer to that storage as <*reason_p>.  If we succeed,
+  return *reason_p = NULL.
+---------------------------------------------------------------------------*/
+    int	fd;
+    char version[4];
+    char full_path[MAXPGPATH+1];
+    
+    PathSetVersionFilePath(path, full_path);
+    
+    fd = open(full_path, O_WRONLY|O_CREAT|O_EXCL, 0666);
+    if (fd < 0) {
+        *reason_p = malloc(100 + strlen(full_path));
+        sprintf(*reason_p, 
+                "Unable to create file '%s', errno from open(): %s (%d).",
+                full_path, strerror(errno), errno);
+    } else {
+        int rc;  /* return code from some function we call */
+
+        version[0] = '0' + PG_RELEASE;
+        version[1] = '.';
+        version[2] = '0' + PG_VERSION;
+        version[3] = '\n';
+        rc = write(fd, version, 4);
+        if (rc != 4) {
+            *reason_p = malloc(100 + strlen(full_path));
+            sprintf(*reason_p, 
+                    "Failed to write to file '%s', after it was already "
+                    "open.  Errno from write(): %s (%d)", 
+                    full_path, strerror(errno), errno);
+        } else *reason_p = NULL;
+        close(fd);
+    }
+}