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2015-05-25reprocess all libc/ldso symbolic relocations in dynamic linking stage 3Rich Felker-11/+43
commit f3ddd173806fd5c60b3f034528ca24542aecc5b9 introduced early relocations and subsequent reprocessing as part of the dynamic linker bootstrap overhaul, to allow use of arbitrary libc functions before the main application and libraries are loaded, but only reprocessed GOT/PLT relocation types. commit c093e2e8201524db0d638920e76bcb6b1d925f3a added reprocessing of non-GOT/PLT relocations to fix an actual regression that was observed on powerpc, but only for RELA format tables with out-of-line addends. REL table (inline addends at the relocation address) reprocessing is trickier because the first relocation pass clobbers the addends. this patch extends symbolic relocation reprocessing for libc/ldso to support all relocation types, whether REL or RELA format tables are used. it is believed not to alter behavior on any existing archs for the current dynamic linker and libc code. the motivations for this change are consistency and future-proofing. it ensures that behavior does not differ depending on whether REL or RELA tables are used, which could lead to undetected arch-specific bugs. it also ensures that, if in the future code depending on additional relocation types is added to, either at the source level or as part of the compiler runtime that gets pulled in (for example, soft-float with TLS for fenv), the new code will work properly. the implementation concept is simple: stage 2 of the dynamic linker counts the number of symbolic relocations in the libc/ldso REL table and allocates a VLA to save their addends into; stage 3 then uses the saved addends in place of the inline ones which were clobbered. for stack safety, a hard limit (currently 4k) is imposed on the number of such addends; this should be a couple orders of magnitude larger than the actual need. this number is not a runtime variable that could break fail-safety; it is constant for a given build.
2015-05-25move call to dynamic linker stage-3 into stage-2 functionRich Felker-12/+9
this move eliminates a duplicate "by-hand" symbol lookup loop from the stage-1 code and replaces it with a call to find_sym, which can be used once we're in stage 2. it reduces the size of the stage 1 code, which is helpful because stage 1 will become the crt start file for static-PIE executables, and it will allow stage 3 to access stage 2's automatic storage, which will be important in an upcoming commit.
2015-05-25mark mips crt code as codeRich Felker-0/+4
otherwise disassemblers treat it as data.
2015-05-25mark mips cancellable syscall code as codeRich Felker-0/+3
otherwise disassemblers treat it as data.
2015-05-25simplify/shrink relocation processing in dynamic linker stage 1Rich Felker-24/+16
the outer-loop approach made sense when we were also processing DT_JMPREL, which might be in REL or RELA form, to avoid major code duplication. commit 09db855b35709aa627d7055c57a98e1e471920ab removed processing of DT_JMPREL, and in the remaining two tables, the format (REL or RELA) is known by the name of the table. simply writing two versions of the loop results in smaller and simpler code.
2015-05-25remove processing of DT_JMPREL from dynamic linker stage 1 bootstrapRich Felker-1/+0
the DT_JMPREL relocation table necessarily consists entirely of JMP_SLOT (REL_PLT in internal nomenclature) relocations, which are symbolic; they cannot be resolved in stage 1, so there is no point in processing them.
2015-05-24fix stack alignment code in mips crt_arch.hRich Felker-2/+2
the instruction used to align the stack, "and $sp, $sp, -8", does not actually exist; it's expanded to 2 instructions using the 'at' (assembler temporary) register, and thus cannot be used in a branch delay slot. since alignment mod 16 commutes with subtracting 8, simply swapping these two operations fixes the problem. crt1.o was not affected because it's still being generated from a dedicated asm source file. dlstart.lo was not affected because the stack pointer it receives is already aligned by the kernel. but Scrt1.o was affected in cases where the dynamic linker gave it a misaligned stack pointer.
2015-05-22add .text section directive to all crt_arch.h files missing itRich Felker-0/+7
i386 and x86_64 versions already had the .text directive; other archs did not. normally, top-level (file scope) __asm__ starts in the .text section anyway, but problems were reported with some versions of clang, and it seems preferable to set it explicitly anyway, at least for the sake of consistency between archs.
2015-05-21remove outdated and misleading comment in iconv.cRich Felker-6/+0
the comment claimed that EUC/GBK/Big5 are not implemented, which has been incorrect since commit 19b4a0a20efc6b9df98b6a43536ecdd628ba4643.
2015-05-21in iconv_open, accept "CHAR" and "" as aliases for "UTF-8"Rich Felker-1/+2
while not a requirement, it's common convention in other iconv implementations to accept "CHAR" as an alias for nl_langinfo(CODESET), meaning the encoding used for char[] strings in the current locale, and also "" as an alternate form. supporting this is not costly and improves compatibility.
2015-05-20fix inconsistency in a_and and a_or argument types on x86[_64]Rich Felker-12/+12
conceptually, and on other archs, these functions take a pointer to int, but in the i386, x86_64, and x32 versions of atomic.h, they took a pointer to void instead.
2015-05-19inline llsc atomics when building for sh4aBobby Bingham-90/+128
If we're building for sh4a, the compiler is already free to use instructions only available on sh4a, so we can do the same and inline the llsc atomics. If we're building for an older processor, we still do the same runtime atomics selection as before.
2015-05-18reprocess libc/ldso RELA relocations in stage 3 of dynamic linkingRich Felker-1/+1
this fixes a regression on powerpc that was introduced in commit f3ddd173806fd5c60b3f034528ca24542aecc5b9. global data accesses on powerpc seem to be using a translation-unit-local GOT filled via R_PPC_ADDR32 relocations rather than R_PPC_GLOB_DAT. being a non-GOT relocation type, these were not reprocessed after adding the main application and its libraries to the chain, causing libc code not to see copy relocations in the main program, and therefore to use the pre-copy-relocation addresses for global data objects (like environ). the motivation for the dynamic linker only reprocessing GOT/PLT relocation types in stage 3 is that these types always have a zero addend, making them safe to process again even if the storage for the addend has been clobbered. other relocation types which can be used for address constants in initialized data objects may have non-zero addends which will be clobbered during the first pass of relocation processing if they're stored inline (REL form) rather than out-of-line (RELA form). powerpc generally uses only RELA, so this patch is sufficient to fix the regression in practice, but is not fully general, and would not suffice if an alternate toolchain generated REL for powerpc.
2015-05-18fix null pointer dereference in dcngettext under specific conditionsRich Felker-1/+1
if setlocale has not been called, the current locale's messages_name may be a null pointer. the code path where it's assumed to be non-null was only reachable if bindtextdomain had already been called, which is normally not done in programs which do not call setlocale, so the omitted check went unnoticed. patch from Void Linux, with description rewritten.
2015-05-16eliminate costly tricks to avoid TLS access for current locale stateRich Felker-27/+4
the code being removed used atomics to track whether any threads might be using a locale other than the current global locale, and whether any threads might have abstract 8-bit (non-UTF-8) LC_CTYPE active, a feature which was never committed (still pending). the motivations were to support early execution prior to setup of the thread pointer, to partially support systems (ancient kernels) where thread pointer setup is not possible, and to avoid high performance cost on archs where accessing the thread pointer may be very slow. since commit 19a1fe670acb3ab9ead0fe31859ca7d4fe40dd54, the thread pointer is always available, so these hacks are no longer needed. removing them greatly simplifies the affected code.
2015-05-16in i386 __set_thread_area, don't assume %gs register is initially zeroRich Felker-4/+9
commit f630df09b1fd954eda16e2f779da0b5ecc9d80d3 added logic to handle the case where __set_thread_area is called more than once by reusing the GDT slot already in the %gs register, and only setting up a new GDT slot when %gs is zero. this created a hidden assumption that %gs is zero when a new process image starts, which is true in practice on Linux, but does not seem to be documented ABI, and fails to hold under qemu app-level emulation. while it would in theory be possible to zero %gs in the entry point code, this code is shared between static and dynamic binaries, and dynamic binaries must not clobber the value of %gs already setup by the dynamic linker. the alternative solution implemented in this commit simply uses global data to store the GDT index that's selected. __set_thread_area should only be called in the initial thread anyway (subsequent threads get their thread pointer setup by __clone), but even if it were called by another thread, it would simply read and write back the same GDT index that was already assigned to the initial thread, and thus (in the x86 memory model) there is no data race.
2015-05-14make arm reloc.h CRTJMP macro compatible with thumbRich Felker-0/+5
compilers targeting armv7 may be configured to produce thumb2 code instead of arm code by default, and in the future we may wish to support targets where only the thumb instruction set is available. the instructions this patch omits in thumb mode are needed only for non-thumb versions of armv4 or earlier, which are not supported by any current compilers/toolchains and thus rather pointless to have. at some point these compatibility return sequences may be removed from all asm source files, and in that case it would make sense to remove them here too and remove the ifdef.
2015-05-14make arm crt_arch.h compatible with thumb code generationRich Felker-4/+6
compilers targeting armv7 may be configured to produce thumb2 code instead of arm code by default, and in the future we may wish to support targets where only the thumb instruction set is available. the changes made here avoid operating directly on the sp register, which is not possible in thumb code, and address an issue with the way the address of _DYNAMIC is computed. previously, the relative address of _DYNAMIC was stored with an additional offset of -8 versus the pc-relative add instruction, since on arm the pc register evaluates to ".+8". in thumb code, it instead evaluates to ".+4". both are two (normal-size) instructions beyond "." in the current execution mode, so the numbered label 2 used in the relative address expression is simply moved two instructions ahead to be compatible with both instruction sets.
2015-05-12release 1.1.9v1.1.9Rich Felker-1/+40
2015-05-08fix netinet/ether.h for c++Szabolcs Nagy-0/+8
2015-05-06fix futimes legacy function with null tv pointerRich Felker-0/+1
a null pointer is valid here and indicates that the current time should be used. based on patch by Felix Janda, simplified.
2015-05-06fix stack protector crashes on x32 & powerpc due to misplaced TLS canaryRich Felker-3/+11
i386, x86_64, x32, and powerpc all use TLS for stack protector canary values in the default stack protector ABI, but the location only matched the ABI on i386 and x86_64. on x32, the expected location for the canary contained the tid, thus producing spurious mismatches (resulting in process termination) upon fork. on powerpc, the expected location contained the stdio_locks list head, so returning from a function after calling flockfile produced spurious mismatches. in both cases, the random canary was not present, and a predictable value was used instead, making the stack protector hardening much less effective than it should be. in the current fix, the thread structure has been expanded to have canary fields at all three possible locations, and archs that use a non-default location must define a macro in pthread_arch.h to choose which location is used. for most archs (which lack TLS canary ABI) the choice does not matter.
2015-05-02improve iswdigit macro to diagnose errorsRich Felker-2/+2
this is analogous to commit 2ca55a93f2a11185d72dcb69006fd2c30b5c3144 for the macros in ctype.h.
2015-05-02fix broken cancellation on x32 due to incorrect saved-PC offsetRich Felker-1/+1
2015-05-02fix crash in x32 sigsetjmpRich Felker-0/+1
the 64-bit push reads not only the 32-bit return address but also the first 32 signal mask bits. if any were nonzero, the return address obtained will be invalid. at some point storage of the return address should probably be moved to follow the saved mask so that there's plenty room and the same code can be used on x32 and regular x86_64, but for now I want a fix that does not risk breaking x86_64, and this simple re-zeroing works.
2015-05-02fix x32 __set_thread_area failure due to junk in upper bitsRich Felker-1/+1
the kernel does not properly clear the upper bits of the syscall argument, so we have to do it before the syscall.
2015-05-01fix dangling pointers in x32 syscall timespec fixup codeRich Felker-10/+23
the lifetime of compound literals is the block in which they appear. the temporary struct __timespec_kernel objects created as compound literals no longer existed at the time their addresses were passed to the kernel.
2015-05-01add IPTOS_CLASS_* macros to netinet/ip.hSzabolcs Nagy-0/+12
These macros were introduced in glibc 2.12 to follow RFC 2474 which deprecates "IP Precedence" in favor of "Class Selector Codepoints".
2015-05-01complex: fix ctanh(+-0+i*nan) and ctanh(+-0+-i*inf)Szabolcs Nagy-2/+4
These cases were incorrect in C11 as described by
2015-05-01fix integer overflow in elf.h macro SHF_EXCLUDERich Felker-1/+1
2015-05-01fix mishandling of ENOMEM return case in internal getgrent_a functionRich Felker-1/+2
due to an incorrect return statement in this error case, the previously blocked cancellation state was not restored and no result was stored. this could lead to invalid (read) accesses in the caller resulting in crashes or nonsensical result data in the event of memory exhaustion.
2015-04-30fix __syscall declaration with wrong visibility in syscall_arch.hSzabolcs Nagy-8/+3
remove __syscall declaration where it is not needed (aarch64, arm, microblaze, or1k) and add the hidden attribute where it is (mips).
2015-04-30aarch64: fix CRTJMP in reloc.hSzabolcs Nagy-1/+1
commit f3ddd173806fd5c60b3f034528ca24542aecc5b9 broke the build by using "bx" instead of "br".
2015-04-27fix sh jmp_buf size to match ABIRich Felker-3/+3
while the sh port is still experimental and subject to ABI instability, this is not actually an application/libc boundary ABI change. it only affects third-party APIs where jmp_buf is used in a shared structure at the ABI boundary, because nothing anywhere near the end of the jmp_buf object (which includes the oversized sigset_t) is accessed by libc. both glibc and uclibc have 15-slot jmp_buf for sh. presumably the smaller version was used in musl because the slots for fpu status register and thread pointer register (gbr) were incorrect and must not be restored by longjmp, but the size should have been preserved, as it's generally treated as a libc-agnostic ABI property for the arch, and having extra slots free in case we ever need them for something is useful anyway.
2015-04-27fix name of sh crt asm directoryRich Felker-0/+0
2015-04-24fix build regression in aarch64 sigsetjmpRich Felker-2/+2
at least some assembler versions do not accept the register name lr. use the name x30 instead.
2015-04-24fix ldso name for sh-nofpu subarchRich Felker-1/+7
previously it was using the same name as the default ABI with hard float (floating point args and return value in registers). the test __SH_FPU_ANY__ || __SH4__ matches what's used in the configure script already, and seems correct under casual review against gcc's config/sh.h, but may need tweaks. the logic for predefined macros for sh, and what they all mean, is very complex. eventually this should be documented in comments here. configure already rejects "half-hard" configurations on sh where double=float since these do not conform to Annex F and are not suitable for musl, so these do not need to be considered here.
2015-04-24fix build regression in sh-nofpu subarch due to missing symbolRich Felker-0/+3
commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 switched sigsetjmp to use the new hidden ___setjmp symbol for setjmp, but the nofpu variant of setjmp.s was not updated to match.
2015-04-24fix failure of sh reloc.h to properly detect endianness for ldso nameRich Felker-0/+2
versions of reloc.h that rely on endian macros much include endian.h to ensure they are available.
2015-04-23fix misalignment of dtv in static-linked programs with odd-sized TLSRich Felker-1/+2
both static and dynamic linked versions of the __copy_tls function have a hidden assumption that the alignment of the beginning or end of the memory passed is suitable for storing an array of pointers for the dtv. pthread_create satisfies this requirement except when libc.tls_size is misaligned, which cannot happen with dynamic linking due to way update_tls_size computes the total size, but could happen with static linking and odd-sized TLS.
2015-04-23remove dead store from static __init_tlsRich Felker-2/+0
commit dab441aea240f3b7c18a26d2ef51979ea36c301c, which made thread pointer init mandatory for all programs, rendered this store obsolete by removing the early-return path for static programs with no TLS.
2015-04-23make __init_tp function static when static linkingRich Felker-0/+3
this slightly reduces the code size cost of TLS/thread-pointer for static linking since __init_tp can be inlined into its only caller and removed. this is analogous to the handling of __init_libc in __libc_start_main, where the function only has external linkage when it needs to be called from the dynamic linker.
2015-04-23add dependency of dlstart.lo on crt_arch.h to MakefileRich Felker-1/+1
2015-04-23fix regression in x86_64 math asm with old binutilsRich Felker-6/+6
the implicit-operand form of fucomip is rejected by binutils 2.19 and perhaps other versions still in use. writing both operands explicitly fixes the issue. there is no change to the resulting output. commit a732e80d33b4fd6f510f7cec4f5573ef5d89bc4e was the source of this regression.
2015-04-22fix syntax errors in configure scriptRich Felker-2/+2
2015-04-22minor optimization to pthread_spin_trylockRich Felker-2/+4
use CAS instead of swap since it's lighter for most archs, and keep EBUSY in the lock value so that the old value obtained by CAS can be used directly as the return value for pthread_spin_trylock.
2015-04-22optimize spin lock not to dirty cache line while spinningRich Felker-1/+1
2015-04-22in visibility preinclude, remove overrides for stdin/stdout/stderrRich Felker-3/+0
the motivation for this change is that the extra declaration (with or without visibility) using "struct _IO_FILE" instead of "FILE" seems to trigger a bug in gcc 3.x where it considers the types mismatched. however, this change also results in slightly better code and it is valid because (1) these three objects are constant, and (2) applying the & operator to any of them is invalid C, since they are not even specified to be objects. thus it does not matter if the application and libc see different addresses for them, as long as the (initial, unchanging) value is seen the same by both.
2015-04-22fix inconsistent visibility for __hwcap and __sysinfo symbolsRich Felker-5/+3
these are used as hidden by asm files (and such use is the whole reason they exist), but their actual definitions were not hidden.
2015-04-22remove additional libc struct accessor cruftRich Felker-12/+0
commit f9cccfc16e58b39ee381fbdfb8688db3bb8e3555 left behind the part in libc.c; remove it too.