From e314c1fc4cbdf8d7172fb6f8b87b127b21dd26c0 Mon Sep 17 00:00:00 2001

From: John Reiser <jreiser@bitwagon.com>

Date: Tue, 5 Feb 2013 21:47:40 +0330

Subject: [PATCH 12/18] Factor out unnecessary logger calls (#875356)

Numerous invocations of logger bogged down os-prober on system with

large numbers of partitions. Refactored to reduce the total number of

unique invocations to increase speed.

Resolves: rhbz#875356

---

 common.sh         | 24 ++++++++++++++++--------

 linux-boot-prober | 11 +++++++++++

 os-prober         | 12 +++++++++++-

 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/common.sh b/common.sh

index 1dbf7a3..7fcae5a 100644

--- a/common.sh

+++ b/common.sh

@@ -62,10 +62,14 @@ cache_progname() {

   esac

 }

-log() {

-  cache_progname

-  logger -t "$progname" "$@"

-}

+# fd_logger: bind value now, possibly after assigning default. 

+eval '

+  log() {

+    cache_progname

+    echo "$progname: $@"  1>&'${fd_logger:=9}'

+  }

+'

+export fd_logger  # so subshells inherit current value by default

 error() {

   log "error: $@"

@@ -81,10 +85,14 @@ debug() {

   fi

 }

-result () {

-  log "result:" "$@"

-  echo "$@"

-}

+# fd_result: bind value now, possibly after assigning default.

+eval '

+  result() {

+    log "result:" "$@"

+    echo "$@"  1>&'${fd_result:=1}'

+  }

+'

+export fd_result  # so subshells inherit current value by default

 # shim to make it easier to use os-prober outside d-i

 if ! type mapdevfs >/dev/null 2>&1; then

diff --git a/linux-boot-prober b/linux-boot-prober

index 57bf245..3b89750 100755

--- a/linux-boot-prober

+++ b/linux-boot-prober

@@ -1,4 +1,12 @@

 #!/bin/sh

+

+# dash shell does not have "{varname}>&1" feature that bash shell has

+# for auto-assignment of new filedescriptors.

+# It is cumbersome to write the 'eval' to use our own variables in redirections.

+# Therefore use fixed numbers.

+export fd_result=3  # file descriptor for external results

+export fd_logger=9  # file descriptor for input to logger

+

 . /usr/share/os-prober/common.sh

 set -e

@@ -147,6 +155,7 @@ if ! mapped="$(mapdevfs "$partition")"; then

 	continue

 fi

+( (

 if ! grep -q "^$mapped " "$OS_PROBER_TMP/mounted-map"; then

 	for test in /usr/lib/linux-boot-probes/*; do

 		if [ -x $test ] && [ -f $test ]; then

@@ -186,3 +195,5 @@ else

 		fi

 	fi

 fi

+) 9>&1 | logger 1>&-  # fd_logger

+) 3>&1  # fd_result

diff --git a/os-prober b/os-prober

index f5052af..4b371d6 100755

--- a/os-prober

+++ b/os-prober

@@ -1,7 +1,14 @@

 #!/bin/sh

 set -e

-. /usr/share/os-prober/common.sh

+# dash shell does not have "{varname}>&1" feature that bash shell has

+# for auto-assignment of new filedescriptors.

+# It is cumbersome to write the 'eval' to use our own variables in redirections.

+# Therefore use fixed numbers.

+export fd_result=3  # file descriptor for external results

+export fd_logger=9  # file descriptor for input to logger

+

+ . /usr/share/os-prober/common.sh

 newns "$@"

 require_tmpdir

@@ -129,6 +136,7 @@ fi

 : >"$OS_PROBER_TMP/btrfs-vols"

+( (

 for partition in $(partitions); do

 	if ! mapped="$(mapdevfs "$partition")"; then

 		log "Device '$partition' does not exist; skipping"

@@ -193,3 +201,5 @@ for partition in $(partitions); do

 		fi

 	fi

 done

+) 9>&1 | logger 1>&-  # fd_logger

+) 3>&1  # fd_result

-- 

2.5.5