Use posix-conf-vars.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 posix-conf-vars.list
once the remaining macros are added to it.

	* posix/posix-conf-vars.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-posix-conf-vars.awk: Support generation of specs
	array.

7 files changed, 49 insertions, 22 deletions

diff --git a/ChangeLog b/ChangeLog
index 94000ad7be..ff4b532bfa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2014-12-29  Siddhesh Poyarekar  <siddhesh@redhat.com>
 
+	* posix/posix-conf-vars.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-posix-conf-vars.awk: Support generation of specs
+	array.
+
 	* posix/posix-conf-vars.list: Add _POSIX sysconf namespace.
 	* sysdeps/posix/sysconf.c: Include posix-conf-vars.h.
 	(__sysconf): Use CONF_IS_* macros.
diff --git a/posix/confstr.c b/posix/confstr.c
index e4e0f4bdec..244a25c93f 100644
--- a/posix/confstr.c
+++ b/posix/confstr.c
@@ -21,6 +21,8 @@
 #include <string.h>
 #include <confstr.h>
 #include "../version.h"
+
+#define NEED_SPEC_ARRAY 0
 #include <posix-conf-vars.h>
 
 /* If BUF is not NULL and LEN > 0, fill in at most LEN - 1 bytes
diff --git a/posix/getconf.c b/posix/getconf.c
index 14d51d87ac..bcde4c58a1 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 <posix-conf-vars.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-conf-vars.list b/posix/posix-conf-vars.list
index 3e7e7cdaa9..601bc2fd33 100644
--- a/posix/posix-conf-vars.list
+++ b/posix/posix-conf-vars.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
@@ -104,7 +105,7 @@ SYSCONF POSIX {
   RAW_SOCKETS
 }
 
-SPEC XBS5 {
+SPEC XBS5 _SC_XBS5 {
   ILP32_OFF32
   ILP32_OFFBIG
   LP64_OFF64
diff --git a/posix/posix-envs.def b/posix/posix-envs.def
index 870d85a7db..fa271bbfc4 100644
--- a/posix/posix-envs.def
+++ b/posix/posix-envs.def
@@ -42,6 +42,7 @@
    defined.  These are called with arguments V5, V6, V7 before and
    after the relevant groups of environments.  */
 
+#define NEED_SPEC_ARRAY 0
 #include <posix-conf-vars.h>
 
 START_ENV_GROUP (V7)
diff --git a/scripts/gen-posix-conf-vars.awk b/scripts/gen-posix-conf-vars.awk
index 16e20fc100..0eca55d536 100644
--- a/scripts/gen-posix-conf-vars.awk
+++ b/scripts/gen-posix-conf-vars.awk
@@ -15,12 +15,19 @@ $1 ~ /^#/ || $0 ~ /^\s*$/ {
 $NF == "{" {
   type = $1
   prefix = $2
+
+  if (NF == 4)
+    sc_prefix = $3
+  else
+    sc_prefix = "_SC"
+
   next
 }
 
 $1 == "}" {
   prefix = ""
   type = ""
+  sc_prefix = ""
   next
 }
 
@@ -35,6 +42,7 @@ $1 == "}" {
   # CONFSTR: A configuration string
   # SYSCONF: A numeric value
   # SPEC: A specification
+  sc_prefixes[prefix][$1] = sc_prefix
   conf[prefix][$1] = type
 }
 
@@ -56,6 +64,26 @@ END {
 	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 posix-conf-vars.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 968c5cb367..0ea5382ba0 100644
--- a/sysdeps/posix/sysconf.c
+++ b/sysdeps/posix/sysconf.c
@@ -31,9 +31,9 @@
 #include <sys/types.h>
 #include <regex.h>
 
+#define NEED_SPEC_ARRAY 0
 #include <posix-conf-vars.h>
 
-
 #define NEED_CHECK_SPEC \
   (!defined _XBS5_ILP32_OFF32 || !defined _XBS5_ILP32_OFFBIG \
    || !defined _XBS5_LP64_OFF64 || !defined _XBS5_LPBIG_OFFBIG \