glibc 2.21 发布，安全修复和性能提升

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*?The?following?bugs?are?resolved?with?this?release:　　

　　
??6652,?10672,?12674,?12847,?12926,?13862,?14132,?14138,?14171,?14498,
　　
??15215,?15378,?15884,?16009,?16418,?16191,?16469,?16576,?16617,?16618,
　　
??16619,?16657,?16740,?16857,?17192,?17266,?17273,?17344,?17363,?17370,
　　
??17371,?17411,?17460,?17475,?17485,?17501,?17506,?17508,?17522,?17555,
　　
??17570,?17571,?17572,?17573,?17574,?17582,?17583,?17584,?17585,?17589,
　　
??17594,?17601,?17608,?17616,?17625,?17630,?17633,?17634,?17635,?17647,
　　
??17653,?17657,?17658,?17664,?17665,?17668,?17682,?17702,?17717,?17719,
　　
??17722,?17723,?17724,?17725,?17732,?17733,?17744,?17745,?17746,?17747,
　　
??17748,?17775,?17777,?17780,?17781,?17782,?17791,?17793,?17796,?17797,
　　
??17801,?17803,?17806,?17834,?17844,?17848,?17868,?17869,?17870,?17885,
　　
??17892.
　　

　　
*?CVE-2015-1472?Under?certain?conditions?wscanf?can?allocate?too?little
　　
??memory?for?the?to-be-scanned?arguments?and?overflow?the?allocated
　　
??buffer.??The?implementation?now?correctly?computes?the?required?buffer
　　
??size?when?using?malloc.
　　

　　
*?A?new?semaphore?algorithm?has?been?implemented?in?generic?C?code?for?all
　　
??machines.?Previous?custom?assembly?implementations?of?semaphore?were
　　
??difficult?to?reason?about?or?ensure?that?they?were?safe.?The?new?version
　　
??of?semaphore?supports?machines?with?64-bit?or?32-bit?atomic?operations.
　　
??The?new?semaphore?algorithm?is?used?by?sem_init,?sem_open,?sem_post,
　　
??sem_wait,?sem_timedwait,?sem_trywait,?and?sem_getvalue.
　　

　　
*?Port?to?Altera?Nios?II?has?been?contributed?by?Mentor?Graphics.
　　

　　
*?Optimized?strcpy,?stpcpy,?strncpy,?stpncpy,?strcmp,?and?strncmp
　　
??implementations?for?powerpc64/powerpc64le.
　　
??Implemented?by?Adhemerval?Zanella?(IBM).
　　

　　
*?Added?support?for?TSX?lock?elision?of?pthread?mutexes?on?powerpc32,?powerpc64
　　
??and?powerpc64le.??This?may?improve?lock?scaling?of?existing?programs?on
　　
??HTM?capable?systems.??The?lock?elision?code?is?only?enabled?with
　　
??--enable-lock-elision=yes.??Also,?the?TSX?lock?elision?implementation?for
　　
??powerpc?will?issue?a?transaction?abort?on?every?syscall?to?avoid?side
　　
??effects?being?visible?outside?transactions.
　　

　　
*?Optimized?strcpy,?stpcpy,?strchrnul?and?strrchr?implementations?for
　　
??AArch64.??Contributed?by?ARM?Ltd.
　　

　　
*?i386?memcpy?functions?optimized?with?SSE2?unaligned?load/store.
　　

　　
*?CVE-2104-7817?The?wordexp?function?could?ignore?the?WRDE_NOCMD?flag
　　
??under?certain?input?conditions?resulting?in?the?execution?of?a?shell?for
　　
??command?substitution?when?the?applicaiton?did?not?request?it.?The
　　
??implementation?now?checks?WRDE_NOCMD?immediately?before?executing?the
　　
??shell?and?returns?the?error?WRDE_CMDSUB?as?expected.
　　

　　
*?CVE-2012-3406?printf-style?functions?could?run?into?a?stack?overflow?when
　　
??processing?format?strings?with?a?large?number?of?format?specifiers.
　　

　　
*?CVE-2014-9402?The?nss_dns?implementation?of?getnetbyname?could?run?into?an
　　
??infinite?loop?if?the?DNS?response?contained?a?PTR?record?of?an?unexpected
　　
??format.
　　

　　
*?The?minimum?GCC?version?that?can?be?used?to?build?this?version?of?the?GNU
　　
??C?Library?is?GCC?4.6.??Older?GCC?versions,?and?non-GNU?compilers,?can
　　
??still?be?used?to?compile?programs?using?the?GNU?C?Library.
　　

　　
*?The?GNU?C?Library?is?now?built?with?-Werror?by?default.??This?can?be
　　
??disabled?by?configuring?with?--disable-werror.
　　

　　
*?New?locales:?tu_IN,?bh_IN,?raj_IN,?ce_RU.
　　

　　
*?The?obsolete?sigvec?function?has?been?removed.??This?was?the?original
　　
??4.2BSD?interface?that?inspired?the?POSIX.1?sigaction?interface,?which
　　
??programs?have?been?using?instead?for?about?25?years.??Of?course,?ABI
　　
??compatibility?for?old?binaries?using?sigvec?remains?intact.
　　

　　
*?Merged?gettext?0.19.3?into?the?intl?subdirectory.??This?fixes?building
　　
??with?newer?versions?of?bison.
　　

　　
*?Support?for?MIPS?o32?FPXX,?FP64A?and?FP64?ABI?Extensions.
　　
??The?original?MIPS?o32?hard-float?ABI?requires?an?FPU?where?double-precision
　　
??registers?overlay?two?consecutive?single-precision?registers.??MIPS32R2
　　
??introduced?a?new?FPU?mode?(FR=1)?where?double-precision?registers?extend?the
　　
??corresponding?single-precision?registers?which?is?incompatible?with?the
　　
??o32?hard-float?ABI.??The?MIPS?SIMD?ASE?and?the?MIPSR6?architecture?both
　　
??require?the?use?of?FR=1?making?a?transition?necessary.??New?o32?ABI
　　
??extensions?enable?users?to?migrate?over?time?from?the?original?o32?ABI
　　
??through?to?the?updated?o32?FP64?ABI.??To?achieve?this?the?dynamic?linker?now
　　
??tracks?the?ABI?of?any?loaded?object?and?verifies?that?new?objects?are
　　
??compatible.??Mode?transitions?will?also?be?requested?as?required?and
　　
??unsupportable?objects?will?be?rejected.??The?ABI?checks?include?both?soft?and
　　
??hard?float?ABIs?for?o32,?n32?and?n64.
　　

　　
??GCC?5?with?GNU?binutils?2.25?onwards:
　　
??It?is?strongly?recommended?that?all?o32?system?libraries?are?built?using?the
　　
??new?o32?FPXX?ABI?(-mfpxx)?to?facilitate?the?transition?as?this?is?compatible
　　
??with?the?original?and?all?new?o32?ABI?extensions.??Configure?a?MIPS?GCC
　　
??compiler?using?--with-fp-32=xx?to?set?this?by?default.