[PATCH 4/4 v1.1] Use conf.list to generate spec array

[Siddhesh Poyarekar <siddhesh at redhat dot com>]

This patch also had to be updated due to 1/4 to update the comment in
conf.list.  Tested on x86_64.

Siddhesh

commit 218aad6c5df66ad432b9083db7e3f0cb4da686d6
Author: Siddhesh Poyarekar <siddhesh@redhat.com>
Date:   Wed Oct 1 14:36:03 2014 +0530

    Use conf.list to generate spec array
    
    This patch adds support to generate the spec array in getconf from the
    conf.list.  The generated code is mostly unchanged.  the only changes
    are due to the change in layout of the spec and val arrays in the ELF.
    
    The val array can also be auto-generated from conf.list once the
    remaining macros are added to it.
    
    	* posix/conf.list (SPEC:XBS5): Add sysconf prefix.
    	* posix/confstr.c: Define NEED_SPEC_ARRAY to 0.
    	* posix/posix-envs.def: Likewise.
    	* sysdeps/posix/sysconf.c: Likewise.
    	* posix/getconf.c: Define NEED_SPEC_ARRAY to 1.
    	(specs): Remove array.
    	* scripts/gen-conf.awk: Support generation of specs array.

diff --git a/posix/conf.list b/posix/conf.list
index 000b908..0a17666 100644
--- a/posix/conf.list
+++ b/posix/conf.list
@@ -1,7 +1,8 @@
 # Configuration variables identified by getconf.  The heading of each section
-# is of the format TYPE:PREFIX with the opening curly brace on the same line.
-# TYPE can either be SYSCONF, PATHCONF, CONFSTR or SPEC.  Variable names are
-# put one on each line with a curly brace on its own line ending the section.
+# is of the format TYPE:PREFIX:SC_PREFIX with the opening curly brace on the
+# same line.  TYPE can either be SYSCONF, PATHCONF, CONFSTR or SPEC.  In the
+# absence of SC_PREFIX, _SC is used as the SC_PREFIX.  Variable names are put
+# one on each line with a curly brace on its own line ending the section.
 
 SPEC:POSIX {
   V6_ILP32_OFF32
@@ -103,7 +104,7 @@ SYSCONF:POSIX {
   RAW_SOCKETS
 }
 
-SPEC:XBS5 {
+SPEC:XBS5:_SC_XBS5 {
   ILP32_OFF32
   ILP32_OFFBIG
   LP64_OFF64
diff --git a/posix/confstr.c b/posix/confstr.c
index 1accfee..0400d7f 100644
--- a/posix/confstr.c
+++ b/posix/confstr.c
@@ -21,7 +21,9 @@
 #include <string.h>
 #include <confstr.h>
 #include "../version.h"
-#include "confdefs.h"
+
+#define NEED_SPEC_ARRAY 0
+#include <confdefs.h>
 
 /* If BUF is not NULL and LEN > 0, fill in at most LEN - 1 bytes
    of BUF with the value corresponding to NAME and zero-terminate BUF.
diff --git a/posix/getconf.c b/posix/getconf.c
index 14d51d8..3c08688 100644
--- a/posix/getconf.c
+++ b/posix/getconf.c
@@ -26,6 +26,9 @@
 #include "../version.h"
 #define PACKAGE _libc_intl_domainname
 
+#define NEED_SPEC_ARRAY 1
+#include <confdefs.h>
+
 struct conf
   {
     const char *name;
@@ -387,23 +390,6 @@ static const struct conf vars[] =
   };
 
 
-static const struct { const char *name; int num; } specs[] =
-  {
-    { "XBS5_ILP32_OFF32", _SC_XBS5_ILP32_OFF32 },
-    { "XBS5_ILP32_OFFBIG", _SC_XBS5_ILP32_OFFBIG },
-    { "XBS5_LP64_OFF64", _SC_XBS5_LP64_OFF64 },
-    { "XBS5_LPBIG_OFFBIG", _SC_XBS5_LPBIG_OFFBIG },
-    { "POSIX_V6_ILP32_OFF32", _SC_V6_ILP32_OFF32 },
-    { "POSIX_V6_ILP32_OFFBIG", _SC_V6_ILP32_OFFBIG },
-    { "POSIX_V6_LP64_OFF64", _SC_V6_LP64_OFF64 },
-    { "POSIX_V6_LPBIG_OFFBIG", _SC_V6_LPBIG_OFFBIG },
-    { "POSIX_V7_ILP32_OFF32", _SC_V7_ILP32_OFF32 },
-    { "POSIX_V7_ILP32_OFFBIG", _SC_V7_ILP32_OFFBIG },
-    { "POSIX_V7_LP64_OFF64", _SC_V7_LP64_OFF64 },
-    { "POSIX_V7_LPBIG_OFFBIG", _SC_V7_LPBIG_OFFBIG },
-  };
-static const int nspecs = sizeof (specs) / sizeof (specs[0]);
-
 extern const char *__progname;
 
 
diff --git a/posix/posix-envs.def b/posix/posix-envs.def
index 9047d0c..0b33e02 100644
--- a/posix/posix-envs.def
+++ b/posix/posix-envs.def
@@ -42,7 +42,8 @@
    defined.  These are called with arguments V5, V6, V7 before and
    after the relevant groups of environments.  */
 
-#include "confdefs.h"
+#define NEED_SPEC_ARRAY 0
+#include <confdefs.h>
 
 START_ENV_GROUP (V7)
 
diff --git a/scripts/gen-conf.awk b/scripts/gen-conf.awk
index 45a4d44..1370646 100644
--- a/scripts/gen-conf.awk
+++ b/scripts/gen-conf.awk
@@ -17,12 +17,17 @@ $2 == "{" {
   split ($1, arr, ":")
   type = arr[1]
   prefix = arr[2]
+  if (arr[3] != "")
+    sc_prefix = arr[3]
+  else
+    sc_prefix = "_SC"
   next
 }
 
 $1 == "}" {
   prefix = ""
   type = ""
+  sc_prefix = ""
   next
 }
 
@@ -37,6 +42,7 @@ $1 == "}" {
   # CONFSTR: A configuration string
   # SYSCONF: A numeric value
   # SPEC: A specification
+  sc_prefixes[prefix][$1] = sc_prefix
   conf[prefix][$1] = type
 }
 
@@ -58,6 +64,26 @@ ENDFILE {
 	printf "# endif\n"
       }
       printf "#endif\n\n"
+
+      # Build a name -> sysconf number associative array to print a C array at
+      # the end.
+      if (conf[p][c] == "SPEC") {
+	name = sprintf ("%s_%s", p, c)
+	num = sprintf ("%s_%s", sc_prefixes[p][c], c)
+	spec[name] = num
+      }
     }
   }
+
+  # Print the specification array.  Define the macro NEED_SPEC_ARRAY before
+  # including confdefs.h to make it available in the compilation unit.
+  print "#if NEED_SPEC_ARRAY"
+  print "static const struct { const char *name; int num; } specs[] ="
+  print "  {"
+  for (s in spec) {
+    printf "    { \"%s\", %s },\n", s, spec[s]
+  }
+  print "  };"
+  print "static const int nspecs = sizeof (specs) / sizeof (specs[0]);"
+  print "#endif"
 }
diff --git a/sysdeps/posix/sysconf.c b/sysdeps/posix/sysconf.c
index c7b748b..bff59f4 100644
--- a/sysdeps/posix/sysconf.c
+++ b/sysdeps/posix/sysconf.c
@@ -31,6 +31,7 @@
 #include <sys/types.h>
 #include <regex.h>
 
+#define NEED_SPEC_ARRAY 0
 #include <confdefs.h>

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