math: don't clobber old libm.so on install [BZ #19822]

When installing glibc (w/mathvec enabled) in-place on a system with
a glibc w/out mathvec enabled, the install will clobber the existing
libm.so (e.g., /lib64/libm-2.21.so) with a linker script.  This is
because libm.so is a symlink to libm.so.6 which is a symlink to the
final libm-2.21.so file.  When the makefile writes the linker script
directly to libm.so, it gets clobbered.

The simple patch below to math/Makefile fixes this.  It is based on
the nptl Makefile, which does exactly the same thing in a safer way.

(cherry picked from commit f9378ac3773ffe998a2b3406568778ee9f77f759)

diff --git a/ChangeLog b/ChangeLog
index 8f5b28f9441cfc0fa5cb1cf56a1f8fafbb8f52cd..70553ea0d7c37fc66935bc31664677c844d9482c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-03-21  Dylan Alex Simon  <dylan-sourceware@dylex.net>
+
+       [BZ #19822]
+       * math/Makefile ($(inst_libdir)/libm.so): Write output to $@.tmp and
+       move it to the final $@ location.
+
 2016-03-15  Andreas Schwab  <schwab@suse.de>
 
        [BZ #19257]

diff --git a/NEWS b/NEWS
index 228a481aef7234fb5b7d64d0ca295843411d26c6..db5ee12bc9326031ddbc69ee29707fa8cc0a22d7 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@ The following bugs are resolved with this release:
   [19759] Don't inline mempcpy for x86
   [19762] Use HAS_ARCH_FEATURE with Fast_Rep_String
   [19792] MIPS: backtrace yields infinite backtrace with makecontext
+  [19822] libm.so install clobbers old version
 
 \f
 Version 2.23

diff --git a/math/Makefile b/math/Makefile
index 7d573a0074ff79c84c7fa2c95a148ad7f714515c..6aa87f95283a97ef6b537216c52a32b4d3c767ae 100644 (file)
--- a/math/Makefile
+++ b/math/Makefile
@@ -100,7 +100,8 @@ $(inst_libdir)/libm.so: $(common-objpfx)format.lds \
         cat $<; \
         echo 'GROUP ( $(slibdir)/libm.so$(libm.so-version) ' \
              'AS_NEEDED ( $(libdir)/libmvec_nonshared.a $(slibdir)/libmvec.so$(libmvec.so-version) ) )' \
-       ) > $@
+       ) > $@.new
+       mv -f $@.new $@
 endif
 
 # Rules for the test suite.