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* size-optimize sh/fdpic dynamic entry pointRich Felker2015-09-221-0/+4
| | | | | | the __fdpic_fixup code is not needed for ET_DYN executables, which instead use reloctions, so we can omit it from the dynamic linker and static-pie entry point and save some code size.
* work around breakage in sh/fdpic __unmapself functionRich Felker2015-09-221-0/+5
| | | | | | | | | | | | the C implementation of __unmapself used for potentially-nommu sh assumed CRTJMP takes a function descriptor rather than a code address; however, the actual dynamic linker needs a code address, and so commit 7a9669e977e5f750cf72ccbd2614f8b72ce02c4c changed the definition of the macro in reloc.h. this commit puts the old macro back in a place where it only affects __unmapself. this is an ugly workaround and should be cleaned up at some point, but at least it's well isolated.
* add general fdpic support in dynamic linker and arch support for shRich Felker2015-09-225-17/+214
| | | | | | | | | | | | | | | | | | at this point not all functionality is complete. the dynamic linker itself, and main app if it is also loaded by the kernel, take advantage of fdpic and do not need constant displacement between segments, but additional libraries loaded by the dynamic linker follow normal ELF semantics for mapping still. this fully works, but does not admit shared text on nommu. in terms of actual functional correctness, dlsym's results are presently incorrect for function symbols, RTLD_NEXT fails to identify the caller correctly, and dladdr fails almost entirely. with the dynamic linker entry point working, support for static pie is automatically included, but linking the main application as ET_DYN (pie) probably does not make sense for fdpic anyway. ET_EXEC is equally relocatable but more efficient at representing relocations.
* factor symbol counting out of dladdr as its own functionRich Felker2015-09-211-19/+20
| | | | | | | | | | | | | the fdpic code will need to count symbols, and it may be useful elsewhere in the future too. counting is trivial as long as sysv hash is present, but for gnu-hash-only libraries it's complex. the behavior of the count is changed slightly: we now include symbols that are not accessible by the gnu hash table in the count. this may make dladdr slightly slower. if this is a problem, dladdr can subtract out the part that should not be accessible. unlike in the old code, subtracting this out is easy even in the fast path where sysv hash is available too.
* simplify dlstart code by using integer type for base addressRich Felker2015-09-211-8/+7
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* refactor some more dynamic linker load address computationsRich Felker2015-09-171-7/+7
| | | | these were just missed in the previous commits.
* remove some useless casts in dynamic linkerRich Felker2015-09-171-2/+2
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* add fdpic structs and reloc types for dynamic linkingRich Felker2015-09-171-0/+16
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* further refactoring of dynamic linker load address computationsRich Felker2015-09-171-2/+2
| | | | | | | these are in do_relocs. the first one was omitted in commit 301335a80b85f12c018e4acf1a2c28615e119f8d because it slightly changes code (using dso->base rather than cached local var base) and would have prevented easy verification. the other was an oversight.
* begin refactoring load address computations in dynamic linkerRich Felker2015-09-171-19/+22
| | | | | | | | | | | | | for ordinary ELF with fixed segment displacements, load address computation is simply adding the base load address. but for FDPIC, each segment has its own load address, and virtual addresses need to be adjusted according to the segment they fall in. abstracting this computation is the first step to making the dynamic linker ready for FDPIC. for this first commit, a macro is used rather than a function in order to facilitate correctness checking. I have verified that the generated code does not change on my i386 build.
* remove old dlstart stage-2 symbolic lookup code; add new genericRich Felker2015-09-171-14/+8
| | | | | | | | | | | | | | this new generic version of the stage-2 function lookup should work for any arch where static data is accessible via got-relative or pc-relative addressing, using approximately the technique described in the log message for commit 2907afb8dbd4c1d34825c3c9bd2b41564baca210. since all the mips-like archs that need got slots fo access static data have already transitioned to the new stage chaining scheme, the old dynamic symbol lookup code is now removed. aarch64, arm, and sh have not yet transitioned; with this commit, they are now using the new generic code.
* new dlstart stage-2 chaining for x86_64 and x32Rich Felker2015-09-172-0/+10
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* new dlstart stage-2 chaining for powerpcRich Felker2015-09-171-0/+9
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* new dlstart stage-2 chaining for or1kRich Felker2015-09-171-0/+9
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* new dlstart stage-2 chaining for mipsRich Felker2015-09-171-0/+15
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* new dlstart stage-2 chaining for microblazeRich Felker2015-09-171-0/+7
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* introduce new symbol-lookup-free rcrt1/dlstart stage chainingRich Felker2015-09-172-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | previously, the call into stage 2 was made by looking up the symbol name "__dls2" (which was chosen short to be easy to look up) from the dynamic symbol table. this was no problem for the dynamic linker, since it always exports all its symbols. in the case of the static pie entry point, however, the dynamic symbol table does not contain the necessary symbol unless -rdynamic/-E was used when linking. this linking requirement is a major obstacle both to practical use of static-pie as a nommu binary format (since it greatly enlarges the file) and to upstream toolchain support for static-pie (adding -E to default linking specs is not reasonable). this patch replaces the runtime symbolic lookup with a link-time lookup via an inline asm fragment, which reloc.h is responsible for providing. in this initial commit, the asm is provided only for i386, and the old lookup code is left in place as a fallback for archs that have not yet transitioned. modifying crt_arch.h to pass the stage-2 function pointer as an argument was considered as an alternative, but such an approach would not be compatible with fdpic, where it's impossible to compute function pointers without already having performed relocations. it was also deemed desirable to keep crt_arch.h as simple/minimal as possible. in principle, archs with pc-relative or got-relative addressing of static variables could instead load the stage-2 function pointer from a static volatile object. that does not work for fdpic, and is not safe against reordering on mips-like archs that use got slots even for static functions, but it's a valid on i386 and many others, and could provide a reasonable default implementation in the future.
* remove attribute((const)) from pthread_self and errno location declsRich Felker2015-09-173-9/+0
| | | | | | | | | | | | | | | | | | | | | | this attribute was applied to pthread_self and the functions providing the locations for errno and h_errno as an optimization; however, it is subtly incorrect. as specified, it means the return value will always be the same, which is not true; it varies per-thread. this attribute also implies that the function does not depend on any state, and that calls to it can safely be reordered across any other code. however such reordering is unsafe for these functions: they break when reordered before initialization of the thread pointer. such breakage was actually observed when compiled by libfirm/cparser. to some extent the reordering problem could be solved with strong compiler barriers between the stages of early startup code, but the specified meaning of of attribute((const)) is sufficiently strong that a compiler would theoretically be justified inserting gratuitous calls to attribute((const)) const functions at random locations (e.g. to save the value in static storage for later use). this reverts commit cbf35978a9870fb1f5c73a852c986d4fcca6c2d4.
* add format argument attributes to gettext function prototypesKhem Raj2015-09-151-6/+14
| | | | | | | | | | their absence completely breaks format string warnings in programs with gettext message translations: -Wformat gives no results, and -Wformat-nonliteral produces spurious warnings. with gcc, the problem manifests only in standards-conforming profiles; otherwise gcc sets these attributes by default for the gettext family. with clang, the problem always manifests; clang has no such defaults.
* reindent powerpc's bits/termios.h to be consistent with other archsFelix Janda2015-09-151-140/+138
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* fix namespace violations in aarch64/bits/termios.hFelix Janda2015-09-151-7/+7
| | | | in analogy with commit a627eb35864d5c29a3c3300dfe83745ab1e7a00f
* add sh fdpic subarch variantsRich Felker2015-09-122-1/+20
| | | | | | | | | with this commit it should be possible to produce a working static-linked fdpic libc and application binaries for sh. the changes in reloc.h are largely unused at this point since dynamic linking is not supported, but the CRTJMP macro is used one place outside of dynamic linking, in __unmapself.
* add fdpic version of entry point code for shRich Felker2015-09-121-0/+29
| | | | | | | this version of the entry point is only suitable for static linking in ET_EXEC form. neither dynamic linking nor pie is supported yet. at some point in the future the fdpic and non-fdpic versions of this code may be unified but for now it's easiest to work with them separately.
* provide arch-generic fdpic self-relocation code for crt1 to useRich Felker2015-09-121-0/+28
| | | | | this file is intended to be included by crt_arch.h on fdpic-based targets and needs to be called from the entry point asm.
* make sh clone asm fdpic-compatibleRich Felker2015-09-122-3/+14
| | | | | | | | | | | clone calls back to a function pointer provided by the caller, which will actually be a pointer to a function descriptor on fdpic. the obvious solution is to have a separate version of clone for fdpic, but I have taken a simpler approach to go around the problem. instead of calling the pointed-to function from asm, a direct call is made to an internal C function which then calls the pointed-to function. this lets the C compiler generate the appropriate calling convention for an indirect call with no need for ABI-specific assembly.
* make sh crti/crtn init/fini fragments setup proper stack frameRich Felker2015-09-122-2/+14
| | | | | | for fdpic support is is essential that the got pointer be saved at a known, ABI-dictated offset from the frame pointer, since there is no way to recover it once it's lost.
* add sh relocation types needed for fdpic to elf.hRich Felker2015-09-121-0/+8
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* fix uninitialized scopeid in lookups from hosts file and ip literalsTimo Teräs2015-09-111-2/+2
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* fix missing earlyclobber flag in i386 a_ctz_64 asmRich Felker2015-09-091-1/+1
| | | | | | | | | this error was only found by reading the code, but it seems to have been causing gcc to produce wrong code in malloc: the same register was used for the output and the high word of the input. in principle this could have caused an infinite loop searching for an available bin, but in practice most x86 models seem to implement the "undefined" result of the bsf instruction as "unchanged".
* remove unused (and invalid) C version of sigsetjmpRich Felker2015-09-091-17/+0
| | | | | | | | | originally, the comment in this code was correct and it would likely work if the compiler generated a tail call to setjmp. however, commit 583e55122e767b1586286a0d9c35e2a4027998ab redesigned sigsetjmp and siglongjmp such that the old C implementation (which was not intended to be used) is not even conceptually correct. remove it in the interest of avoiding confusion when porting to new archs.
* fix breakage in nl_langinfo from previous commitRich Felker2015-09-091-1/+1
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* make nl_langinfo(CODESET) always return "UTF-8"Rich Felker2015-09-091-2/+1
| | | | | | | | | | | | | | | | | | | | | | | this restores the original behavior prior to the addition of the byte-based C locale and fixes what is effectively a regression in musl's property of always providing working UTF-8 support. commit 1507ebf837334e9e07cfab1ca1c2e88449069a80 introduced the codeset name "UTF-8-CODE-UNITS" for the byte-based C locale to represent that the semantic content is UTF-8 but that it is being processed as code units (bytes) rather than whole multibyte characters. however, many programs assume that the codeset name is usable with iconv and/or comes from a set of standard/widely-used names known to the application. such programs are likely to produce warnings or errors, run with reduced functionality, or mangle character data when run explicitly in the C locale. the standard places basically no requirements for the string returned by nl_langinfo(CODESET) and how it interacts with other interfaces, so returning "UTF-8" is permissible. moreover, it seems like the right thing to do, since the identity of the character encoding as "UTF-8" is independent of whether it is being processed as bytes of characters by the standard library functions.
* fix fclose of permanent (stdin/out/err) streamsRich Felker2015-09-091-2/+3
| | | | | | | | | | | | | | | | this fixes a bug reported by Nuno Gonçalves. previously, calling fclose on stdin or stdout resulted in deadlock at exit time, since __stdio_exit attempts to lock these streams to flush/seek them, and has no easy way of knowing that they were closed. conceptually, leaving a FILE stream locked on fclose is valid since, in the abstract machine, it ceases to exist. but to satisfy the implementation-internal assumption in __stdio_exit that it can access these streams unconditionally, we need to unlock them. it's also necessary that fclose leaves permanent streams in a state where __stdio_exit will not attempt any further operations on them. fortunately, the call to fflush already yields this property.
* implement arm eabi mem* functionsTimo Teräs2015-08-314-0/+36
| | | | | | | these functions are part of the ARM EABI, meaning compilers may generate references to them. known versions of gcc do not use them, but llvm does. they are not provided by libgcc, and the de facto standard seems to be that libc provides them.
* remove use of buggy .SECONDARY special target in makefileRich Felker2015-08-301-2/+0
| | | | | | | | | | | | | this functionality is affected by GNU make bug #30653, "intermediate files incorrectly pruned in parallel builds". on affected versions of make, parallel builds attempt to compile source files before alltypes.h is generated. as noted with commit a91ebdcfac6804714a1fe39f4375e2b4ebab085b, which added the use of .SECONDARY, suppression of removal of "intermediate" files does not seem to be needed at present. if it is needed in the future, it should be achievable by explicitly mentioning their names as targets or prerequisites.
* release 1.1.11 v1.1.11Rich Felker2015-08-302-1/+44
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* fix makefile suppression of intermediate file removalRich Felker2015-08-271-1/+1
| | | | | | | | | | | at one point, GNU make was removing crt/*.o after producing the copies in lib/ due to an arcane misfeature for handling "intermediate" files. the circumstances that caused this are no longer present in our makefile, but the previous workaround using .PRECIOUS was wrong and could result in corrupt/partial files being left behind during an interrupted build. using .SECONDARY is the correct, documented fix that will prevent deletion of "intermediate" files from ever resurfacing.
* Build process uses script to add CFI directives to x86 asmAlex Dowad2015-08-263-2/+254
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some functions implemented in asm need to use EBP for purposes other than acting as a frame pointer. (Notably, it is used for the 6th argument to syscalls with 6 arguments.) Without frame pointers, GDB can only show backtraces if it gets CFI information from a .debug_frame or .eh_frame ELF section. Rather than littering our asm with ugly .cfi directives, use an awk script to insert them in the right places during the build process, so GDB can keep track of where the current stack frame is relative to the stack pointer. This means GDB can produce beautiful stack traces at any given point when single-stepping through asm functions. Additionally, when registers are saved on the stack and later overwritten, emit ..cfi directives so GDB will know where they were saved relative to the stack pointer. This way, when you look back up the stack from within an asm function, you can still reliably print the values of local variables in the caller. If this awk script were to understand every possible wild and crazy contortion that an asm programmer can do with the stack and registers, and always emit the exact ..cfi directives needed for GDB to know what the register values were in the preceding stack frame, it would necessarily be as complex as a full x86 emulator. That way lies madness. Hence, we assume that the stack pointer will _only_ ever be adjusted using push/pop or else add/sub with a constant. We do not attempt to detect every possible way that a register value could be saved for later use, just the simple and common ways. Thanks to Szabolcs Nagy for suggesting numerous improvements to this code.
* getsubopt: don't include leading = in value stringSteven Barth2015-08-211-1/+1
| | | | | | | getsubopt incorrectly returns the delimiting = in the value string, this patch fixes it by increasing the pointer position by one. Signed-off-by: Steven Barth <cyrus@openwrt.org>
* mitigate performance regression in libc-internal locks on x86_64Rich Felker2015-08-162-2/+2
| | | | | | | | | commit 3c43c0761e1725fd5f89a9c028cbf43250abb913 fixed missing synchronization in the atomic store operation for i386 and x86_64, but opted to use mfence for the barrier on x86_64 where it's always available. however, in practice mfence is significantly slower than the barrier approach used on i386 (a nop-like lock orl operation). this commit changes x86_64 (and x32) to use the faster barrier.
* match historical behavior for tm_gmtoff member of struct tmNatanael Copa2015-08-144-12/+12
| | | | | | | | | | | | | | tm_gmtoff is a nonstandard field, but on historical systems which have this field, it stores the offset of the local time zone from GMT or UTC. this is the opposite of the POSIX extern long timezone object and the offsets used in POSIX-form TZ strings, which represent the offset from local time to UTC. previously we were storing these negated offsets in tm_gmtoff too. programs which only used this field indirectly via strftime were not affected since strftime performed the negation for presentation. however, some programs and libraries accesse tm_gmtoff directly and were obtaining negated time zone offsets.
* aarch64: fix 64-bit syscall argument passingSzabolcs Nagy2015-08-111-4/+2
| | | | | | | | | On 32bit systems long long arguments are passed in a special way to some syscalls; this accidentally got copied to the AArch64 port. The following interfaces were broken: fallocate, fanotify, ftruncate, posix_fadvise, posix_fallocate, pread, pwrite, readahead, sync_file_range, truncate.
* fix failure of tempnam to null-terminate resultRich Felker2015-08-091-0/+1
| | | | | | | tempnam uses an uninitialized buffer which is filled using memcpy and __randname. It is therefore necessary to explicitly null-terminate it. based on patch by Felix Janda.
* mitigate blow-up of heap size under malloc/free contentionRich Felker2015-08-071-14/+14
| | | | | | | | | | | | | | | | | | | | | | | during calls to free, any free chunks adjacent to the chunk being freed are momentarily held in allocated state for the purpose of merging, possibly leaving little or no available free memory for other threads to allocate. under this condition, other threads will attempt to expand the heap rather than waiting to use memory that will soon be available. the race window where this happens is normally very small, but became huge when free chooses to use madvise to release unused physical memory, causing unbounded heap size growth. this patch drastically shrinks the race window for unwanted heap expansion by performing madvise with the bin lock held and marking the bin non-empty in the binmask before making the expensive madvise syscall. testing by Timo Teräs has shown this approach to be a suitable mitigation. more invasive changes to the synchronization between malloc and free would be needed to completely eliminate the problem. it's not clear whether such changes would improve or worsen typical-case performance, or whether this would be a worthwhile direction to take malloc development.
* fix missing synchronization in atomic store on i386 and x86_64Rich Felker2015-07-283-3/+3
| | | | | | | | | | | | | | | | | despite being strongly ordered, the x86 memory model does not preclude reordering of loads across earlier stores. while a plain store suffices as a release barrier, we actually need a full barrier, since users of a_store subsequently load a waiter count to determine whether to issue a futex wait, and using a stale count will result in soft (fail-to-wake) deadlocks. these deadlocks were observed in malloc and possible with stdio locks and other libc-internal locking. on i386, an atomic operation on the caller's stack is used as the barrier rather than performing the store itself using xchg; this avoids the need to read the cache line on which the store is being performed. mfence is used on x86_64 where it's always available, and could be used on i386 with the appropriate cpu model checks if it's shown to perform better.
* fix undefined left-shift of negative values in utf-8 state tableRich Felker2015-07-251-1/+1
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* fix atexit when it is called from an atexit handlerRich Felker2015-07-241-12/+9
| | | | | | | | | | | | | | | The old code accepted atexit handlers after exit, but did not run them reliably. C11 seems to explicitly allow atexit to fail (and report such failure) in this case, but this situation can easily come up in C++ if a destructor has a local static object with a destructor so it should be handled. Note that the memory usage can grow linearly with the overall number of registered atexit handlers instead of with the worst case list length. (This only matters if atexit handlers keep registering atexit handlers which should not happen in practice). Commit message/rationale based on text by Szabolcs Nagy.
* socket.h: cleanup/reorder mips and powerpc bits/socket.hRoman Yeryomin2015-07-212-18/+20
| | | | | | ....to be somewhat consistent and easily comparable with asm/socket.h Signed-off-by: Roman Yeryomin <roman@ubnt.com>
* socket.h: fix SO_* for mipsRoman Yeryomin2015-07-213-4/+9
| | | | Signed-off-by: Roman Yeryomin <roman@ubnt.com>
* mips: fix mcontext_t register array field nameFelix Fietkau2015-07-211-1/+1
| | | | | | glibc and uclibc use gregs instead of regs Signed-off-by: Felix Fietkau <nbd@openwrt.org>