From ad35b6a6e99a0e0962d6a33e181784cada44c3c0 Mon Sep 17 00:00:00 2001
From: Darik Horn <dajhorn@vanadac.com>
Date: Thu, 14 Apr 2011 14:01:22 -0500
Subject: [PATCH] Remove the gawk dependency.

This reverts commit 1814251453c8140f50170ad29d9105c1273d7e08.

Demote the gawk call back to awk and ensure that stderr is attached.  GNU gawk
tolerates a missing stderr handle, but many utilities do not, which could be
why a regular awk call was unexplainably failing on some systems.

Use argv[0] instead of sh_path for consistency internally and with other Linux
drivers.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
---
 config/spl-build.m4      | 17 +----------------
 configure                | 34 ++--------------------------------
 module/spl/spl-generic.c | 26 +++++++++++++++-----------
 3 files changed, 18 insertions(+), 59 deletions(-)

diff --git a/config/spl-build.m4 b/config/spl-build.m4
index 97b38234bcb9..b25db38f3e30 100644
--- a/config/spl-build.m4
+++ b/config/spl-build.m4
@@ -211,25 +211,10 @@ AC_DEFUN([SPL_AC_KERNEL_CONFIG], [
 		** You must rebuild your kernel without this option.]), [])
 ])
 
-dnl #
-dnl # Explicitly check for gawk, we require it for the the usermode
-dnl # helper.  For some reason the standard awk command does not
-dnl # behave correctly when invoked from the usermode helper.
-dnl #
-AC_DEFUN([SPL_AC_GAWK], [
-	AS_IF([test "x$AWK" != xgawk], [
-                AC_MSG_ERROR([
-	*** Required util gawk missing.  Please install the required
-	*** gawk package for your distribution and try again.])
-	])
-])
-
 dnl #
 dnl # Default SPL user configuration
 dnl #
-AC_DEFUN([SPL_AC_CONFIG_USER], [
-	SPL_AC_GAWK
-])
+AC_DEFUN([SPL_AC_CONFIG_USER], [])
 
 dnl #
 dnl # Check for rpm+rpmbuild to build RPM packages.  If these tools
diff --git a/configure b/configure
index d05ff84aca91..1fb10af363dd 100755
--- a/configure
+++ b/configure
@@ -15719,22 +15719,7 @@ fi
 
 
  ;;
-                user)
-
-	if test "x$AWK" != xgawk; then
-
-                { { $as_echo "$as_me:$LINENO: error:
-	*** Required util gawk missing.  Please install the required
-	*** gawk package for your distribution and try again." >&5
-$as_echo "$as_me: error:
-	*** Required util gawk missing.  Please install the required
-	*** gawk package for your distribution and try again." >&2;}
-   { (exit 1); exit 1; }; }
-
-fi
-
-
-   ;;
+                user)      ;;
                 all)
 
 
@@ -19797,22 +19782,7 @@ fi
 
 
 
-
-
-	if test "x$AWK" != xgawk; then
-
-                { { $as_echo "$as_me:$LINENO: error:
-	*** Required util gawk missing.  Please install the required
-	*** gawk package for your distribution and try again." >&5
-$as_echo "$as_me: error:
-	*** Required util gawk missing.  Please install the required
-	*** gawk package for your distribution and try again." >&2;}
-   { (exit 1); exit 1; }; }
-
-fi
-
-
-   ;;
+                           ;;
 		srpm)                        ;;
                 *)
                 { $as_echo "$as_me:$LINENO: result: Error!" >&5
diff --git a/module/spl/spl-generic.c b/module/spl/spl-generic.c
index 680655d0f89a..65465414842b 100644
--- a/module/spl/spl-generic.c
+++ b/module/spl/spl-generic.c
@@ -414,21 +414,25 @@ EXPORT_SYMBOL(zone_get_hostid);
 
 #ifndef HAVE_KALLSYMS_LOOKUP_NAME
 /*
- * Because kallsyms_lookup_name() is no longer exported in the
- * mainline kernel we are forced to resort to somewhat drastic
- * measures.  This function replaces the functionality by performing
- * an upcall to user space where /proc/kallsyms is consulted for
- * the requested address.
+ * The kallsyms_lookup_name() kernel function is not an exported symbol in
+ * Linux 2.6.19 through 2.6.32 inclusive.
+ *
+ * This function replaces the functionality by performing an upcall to user
+ * space where /proc/kallsyms is consulted for the requested address.
+ *
  */
-#define GET_KALLSYMS_ADDR_CMD						\
-	"gawk '{ if ( $3 == \"kallsyms_lookup_name\") { print $1 } }' "	\
-	"/proc/kallsyms >/proc/sys/kernel/spl/kallsyms_lookup_name"
+
+#define GET_KALLSYMS_ADDR_CMD \
+	"exec 0</dev/null " \
+	"     1>/proc/sys/kernel/spl/kallsyms_lookup_name " \
+	"     2>/dev/null; " \
+	"awk  '{ if ( $3 == \"kallsyms_lookup_name\" ) { print $1 } }' " \
+	"     /proc/kallsyms "
 
 static int
 set_kallsyms_lookup_name(void)
 {
-	char sh_path[] = "/bin/sh";
-	char *argv[] = { sh_path,
+	char *argv[] = { "/bin/sh",
 	                 "-c",
 			 GET_KALLSYMS_ADDR_CMD,
 	                 NULL };
@@ -438,7 +442,7 @@ set_kallsyms_lookup_name(void)
 	                 NULL };
 	int rc;
 
-	rc = call_usermodehelper(sh_path, argv, envp, 1);
+	rc = call_usermodehelper(argv[0], argv, envp, 1);
 	if (rc)
 		printk("SPL: Failed user helper '%s %s %s', rc = %d\n",
 		       argv[0], argv[1], argv[2], rc);