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* reprocess libc/ldso RELA relocations in stage 3 of dynamic linkingRich Felker2015-05-181-1/+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.
* fix null pointer dereference in dcngettext under specific conditionsRich Felker2015-05-181-1/+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.
* eliminate costly tricks to avoid TLS access for current locale stateRich Felker2015-05-165-27/+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.
* in i386 __set_thread_area, don't assume %gs register is initially zeroRich Felker2015-05-161-4/+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.
* fix futimes legacy function with null tv pointerRich Felker2015-05-061-0/+1
| | | | | a null pointer is valid here and indicates that the current time should be used. based on patch by Felix Janda, simplified.
* fix stack protector crashes on x32 & powerpc due to misplaced TLS canaryRich Felker2015-05-063-3/+8
| | | | | | | | | | | | | | | | | | | 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.
* fix crash in x32 sigsetjmpRich Felker2015-05-021-0/+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.
* fix x32 __set_thread_area failure due to junk in upper bitsRich Felker2015-05-021-1/+1
| | | | | the kernel does not properly clear the upper bits of the syscall argument, so we have to do it before the syscall.
* complex: fix ctanh(+-0+i*nan) and ctanh(+-0+-i*inf)Szabolcs Nagy2015-05-012-2/+4
| | | | | These cases were incorrect in C11 as described by http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1886.htm
* fix mishandling of ENOMEM return case in internal getgrent_a functionRich Felker2015-05-011-1/+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.
* fix sh jmp_buf size to match ABIRich Felker2015-04-271-2/+2
| | | | | | | | | | | | | | | | | 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.
* fix build regression in aarch64 sigsetjmpRich Felker2015-04-241-2/+2
| | | | | at least some assembler versions do not accept the register name lr. use the name x30 instead.
* fix build regression in sh-nofpu subarch due to missing symbolRich Felker2015-04-241-0/+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.
* fix misalignment of dtv in static-linked programs with odd-sized TLSRich Felker2015-04-231-1/+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.
* remove dead store from static __init_tlsRich Felker2015-04-231-2/+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.
* make __init_tp function static when static linkingRich Felker2015-04-231-0/+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.
* fix regression in x86_64 math asm with old binutilsRich Felker2015-04-232-6/+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.
* minor optimization to pthread_spin_trylockRich Felker2015-04-222-2/+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.
* optimize spin lock not to dirty cache line while spinningRich Felker2015-04-221-1/+1
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* in visibility preinclude, remove overrides for stdin/stdout/stderrRich Felker2015-04-221-3/+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.
* fix inconsistent visibility for __hwcap and __sysinfo symbolsRich Felker2015-04-222-5/+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.
* remove additional libc struct accessor cruftRich Felker2015-04-221-12/+0
| | | | | commit f9cccfc16e58b39ee381fbdfb8688db3bb8e3555 left behind the part in libc.c; remove it too.
* remove useless visibility application from static-linking-only codeRich Felker2015-04-222-3/+2
| | | | | part of the goal here is to eliminate use of the ATTR_LIBC_VISIBILITY macro outside of libc.h, since it was never intended to be 'public'.
* remove libc.h dependency from otherwise-independent multibyte codeRich Felker2015-04-221-2/+4
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* remove cruft for libc struct accessor function and broken visibilityRich Felker2015-04-222-18/+0
| | | | | | | | | these were hacks to work around toolchains that could not properly optimize PIC accesses based on visibility and would generate GOT lookups even for hidden data, which broke the old dynamic linker. since commit f3ddd173806fd5c60b3f034528ca24542aecc5b9 it no longer matters; the dynamic linker does not assume accessibility of this data until stage 3.
* fix duplocale clobbering of new locale struct with memcpy of oldRich Felker2015-04-211-1/+2
| | | | | | | | | | | | | | | when the non-stub duplocale code was added as part of the locale framework in commit 0bc03091bb674ebb9fa6fe69e4aec1da3ac484f2, the old code to memcpy the old locale object to the new one was left behind. the conditional for the memcpy no longer makes sense, because the conditions are now always-true when it's reached, and the memcpy is wrong because it clobbers the new->messages_name pointer setup just above. since the messages_name and ctype_utf8 members have already been copied, all that remains is the cat[] array. these pointers are volatile, so using memcpy to copy them is formally wrong; use a for loop instead.
* remove dead case for F_SETLKW in fcntlRich Felker2015-04-211-1/+0
| | | | | | the first switch already returns in the F_SETLKW code path so it need not be handled in the second switch. moreover the code in the second switch is wrong for the F_SETLKW command: it's not cancellable.
* fix mmap leak in sem_open failure path for link callRich Felker2015-04-211-0/+1
| | | | | | | the leak was found by static analysis (reported by Alexander Monakov), not tested/observed, but seems to have occured both when failing due to O_EXCL, and in a race condition with O_CREAT but not O_EXCL where a semaphore by the same name was created concurrently.
* remove always-true conditional in dynamic linker TLSDESC processingRich Felker2015-04-211-1/+1
| | | | | | the allocating path which can fail is for dynamic TLS, which can only occur at runtime, and the check for runtime was already made in the outer conditional.
* remove redundant code in do_dlsym functionRich Felker2015-04-211-1/+1
| | | | | | | commit 637dd2d383cc1f63bf02a732f03786857b22c7bd introduced the checks for RTLD_DEFAULT and RTLD_NEXT here, claiming they fixed a regression, but the above conditional block clearly already covered these cases, and removing the checks produces no difference in the generated code.
* add optional global visibility overrideRich Felker2015-04-191-0/+40
| | | | | | | | | | | | this is implemented via the build system and does not affect source files. the idea is to use protected or hidden visibility to prevent the compiler from pessimizing function calls within a shared (or position-independent static) libc in the form of overhead setting up for a call through the PLT. the ld-time symbol binding via the -Bsymbolic-functions option already optimized out the PLT itself, but not the code in the caller needed to support a call through the PLT. on some archs this overhead can be substantial; on others it's trivial.
* remove invalid PLT calls from or1k asmRich Felker2015-04-192-3/+7
| | | | analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
* remove possible-textrels from powerpc asmRich Felker2015-04-192-2/+6
| | | | | | | these are perfectly fine with ld-time symbol binding, but otherwise result in textrels. they cannot be replaced with @PLT jump targets because the PLT thunks require a GOT register to be setup, so use a hidden alias instead.
* remove invalid PLT calls from microblaze asmRich Felker2015-04-192-2/+6
| | | | analogous to commit 646cb9a4a04e5ed78e2dd928bf9dc6e79202f609 for sh.
* remove invalid PLT calls from sh asmRich Felker2015-04-192-2/+6
| | | | | | these are perfectly fine with ld-time symbol binding, but if the calls go through a PLT thunk, they are invalid because the caller does not setup a GOT register. use a hidden alias to bypass the issue.
* remove potentially PIC-incompatible relocations from x86_64 and x32 asmRich Felker2015-04-186-7/+11
| | | | analogous to commit 8ed66ecbcba1dd0f899f22b534aac92a282f42d5 for i386.
* remove the last of possible-textrels from i386 asmRich Felker2015-04-186-4/+16
| | | | | | | | | | | | none of these are actual textrels because of ld-time binding performed by -Bsymbolic-functions, but I'm changing them with the goal of making ld-time binding purely an optimization rather than relying on it for semantic purposes. in the case of memmove's call to memcpy, making it explicit that the memmove asm is assuming the forward-copying behavior of the memcpy asm is desirable anyway; in case memcpy is ever changed, the semantic mismatch would be apparent while editing memmcpy.s.
* make dlerror state and message thread-local and dynamically-allocatedRich Felker2015-04-183-32/+65
| | | | | | | | | this fixes truncation of error messages containing long pathnames or symbol names. the dlerror state was previously required by POSIX to be global. the resolution of bug 97 relaxed the requirements to allow thread-safe implementations of dlerror with thread-local state and message buffer.
* add missing 'void' in prototypes of internal pthread functionsAlexander Monakov2015-04-181-6/+6
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* math: fix pow(+-0,-inf) not to raise divbyzero flagSzabolcs Nagy2015-04-183-3/+3
| | | | | | this reverts the commit f29fea00b5bc72d4b8abccba2bb1e312684d1fce which was based on a bug in C99 and POSIX and did not match IEEE-754 http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1515.pdf
* apply hidden visibility to tlsdesc accessor functionsRich Felker2015-04-175-0/+10
| | | | | | | these functions are never called directly; only their addresses are used, so PLT indirections should never happen unless a broken application tries to redefine them, but it's still best to make them hidden.
* comment fixes in aarch64 tlsdesc asmSzabolcs Nagy2015-04-171-4/+4
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* ensure debugger hook for dynamic linker does not point to a PLT slotRich Felker2015-04-171-2/+4
| | | | | this change is made in preparation to support linking without -Bsymbolic-functions.
* fix mips fesetenv(FE_DFL_ENV) againRich Felker2015-04-171-0/+1
| | | | | commit 5fc1487832e16aa2119e735a388d5f36c8c139e2 attempted to fix it, but neglected the fact that mips has branch delay slots.
* fix PLT call offset in sh dlsym asmRich Felker2015-04-171-3/+3
| | | | | | | | | | | the braf instruction's destination register is an offset from the address of the braf instruction plus 4 (or equivalently, the address of the next instruction after the delay slot). the code for dlsym was incorrectly computing the offset to pass using the address of the delay slot itself. in other places, a label was placed after the delay slot, but I find this confusing. putting the label on the branch instruction itself, and manually adding 4, makes it more clear which branch the offset in the constant pool goes with.
* fix sh build regressions in asmRich Felker2015-04-172-2/+2
| | | | | even hidden functions need @PLT symbol references; otherwise an absolute address is produced instead of a PC-relative one.
* fix sh __set_thread_area uninitialized return valueRich Felker2015-04-171-1/+2
| | | | | this caused the dynamic linker/startup code to abort when r0 happened to contain a negative value.
* redesign sigsetjmp so that signal mask is restored after longjmpRich Felker2015-04-1712-133/+177
| | | | | | | | | | | | | | | | | | | | | | | | | | | | the conventional way to implement sigsetjmp is to save the signal mask then tail-call to setjmp; siglongjmp then restores the signal mask and calls longjmp. the problem with this approach is that a signal already pending, or arriving between unmasking of signals and restoration of the saved stack pointer, will have its signal handler run on the stack that was active before siglongjmp was called. this can lead to unbounded stack usage when siglongjmp is used to leave a signal handler. in the new design, sigsetjmp saves its own return address inside the extended part of the sigjmp_buf (outside the __jmp_buf part used by setjmp) then calls setjmp to save a jmp_buf inside its own execution. it then tail-calls to __sigsetjmp_tail, which uses the return value of setjmp to determine whether to save the current signal mask or restore a previously-saved mask. as an added bonus, this design makes it so that siglongjmp and longjmp are identical. this is useful because the __longjmp_chk function we need to add for ABI-compatibility assumes siglongjmp and longjmp are the same, but for different reasons -- it was designed assuming either can access a flag just past the __jmp_buf indicating whether the signal masked was saved, and act on that flag. however, early versions of musl did not have space past the __jmp_buf for the non-sigjmp_buf version of jmp_buf, so our setjmp cannot store such a flag without risking clobbering memory on (very) old binaries.
* use hidden __tls_get_new for tls/tlsdesc lookup fallback casesRich Felker2015-04-144-5/+13
| | | | | | | | | | | | | | | previously, the dynamic tlsdesc lookup functions and the i386 special-ABI ___tls_get_addr (3 underscores) function called __tls_get_addr when the slot they wanted was not already setup; __tls_get_addr would then in turn also see that it's not setup and call __tls_get_new. calling __tls_get_new directly is both more efficient and avoids the issue of calling a non-hidden (public API/ABI) function from asm. for the special i386 function, a weak reference to __tls_get_new is used since this function is not defined when static linking (the code path that needs it is unreachable in static-linked programs).
* cleanup use of visibility attributes in pthread_cancel.cRich Felker2015-04-141-8/+9
| | | | | | | applying the attribute to a weak_alias macro was a hack. instead use a separate declaration to apply the visibility, and consolidate declarations together to avoid having visibility mess all over the file.
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-09 22:45:44 +0000