svn commit: r290878 - stable/9/sys/boot/common

[Garrett Cooper]

Author: ngie
Date: Sun Nov 15 20:20:03 2015
New Revision: 290878
URL: https://svnweb.freebsd.org/changeset/base/290878

Log:
  MFstable/10 r290877:
  
  MFC r289896:
  
  Make vers.c creation atomic by using a temporary file, then moving
  the temporary file to vers.c at the end of the script
  
  The previous logic wrote out to vers.c multiple times, so the file
  could be incorrectly interpreted as being completely written out
  after one of the echo calls with recursive make, when in reality it
  was only partially written.
  
  Also, in the event the build was interrupted when creating vers.c
  (small race window), it would have a leftover file that needed to
  be cleaned up before resuming the build.
  
  Sponsored by: EMC / Isilon Storage Division

Modified:
  stable/9/sys/boot/common/newvers.sh
Directory Properties:
  stable/9/   (props changed)
  stable/9/sys/   (props changed)
  stable/9/sys/boot/   (props changed)

Modified: stable/9/sys/boot/common/newvers.sh
==============================================================================
--- stable/9/sys/boot/common/newvers.sh	Sun Nov 15 20:14:54 2015	(r290877)
+++ stable/9/sys/boot/common/newvers.sh	Sun Nov 15 20:20:03 2015	(r290878)
@@ -32,12 +32,16 @@
 #
 #	@(#)newvers.sh	8.1 (Berkeley) 4/20/94
 
+tempfile=$(mktemp tmp.XXXXXX) || exit
+trap "rm -f $tempfile" EXIT INT TERM
+
 LC_ALL=C; export LC_ALL
 u=${USER-root} h=${HOSTNAME-`hostname`} t=`date`
 #r=`head -n 6 $1 | tail -n 1 | awk -F: ' { print $1 } '`
 r=`awk -F: ' /^[0-9]\.[0-9]+:/ { print $1; exit }' $1`
 
-echo "char bootprog_name[] = \"FreeBSD/${3} ${2}\";" > vers.c
-echo "char bootprog_rev[] = \"${r}\";" >> vers.c
-echo "char bootprog_date[] = \"${t}\";" >> vers.c
-echo "char bootprog_maker[] = \"${u}@${h}\";" >> vers.c
+echo "char bootprog_name[] = \"FreeBSD/${3} ${2}\";" > $tempfile
+echo "char bootprog_rev[] = \"${r}\";" >> $tempfile
+echo "char bootprog_date[] = \"${t}\";" >> $tempfile
+echo "char bootprog_maker[] = \"${u}@${h}\";" >> $tempfile
+mv $tempfile vers.c