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* remove non-working pre-armv4t support from arm asmRich Felker2015-11-096-16/+2
| | | | | | | | | | | | | | | the idea of the three-instruction sequence being removed was to be able to return to thumb code when used on armv4t+ from a thumb caller, but also to be able to run on armv4 without the bx instruction available (in which case the low bit of lr would always be 0). however, without compiler support for generating such a sequence from C code, which does not exist and which there is unlikely to be interest in implementing, there is little point in having it in the asm, and it would likely be easier to add pre-armv4t support via enhanced linker handling of R_ARM_V4BX than at the compiler level. removing this code simplifies adding support for building libc in thumb2-only form (for cortex-m).
* use vfp mnemonics rather than hard-coded opcodes in arm setjmp/longjmpRich Felker2015-11-092-2/+10
| | | | | | | | | | | | | | | | | | the code to save/restore vfp registers needs to build even when the configured target does not have fpu; this is because code using vfp fpu (but with the standard soft-float EABI) may call a libc built for a soft-float only, and the EABI considers these registers call-saved when they exist. thus, extra directives are used to force the assembler to allow vfp instructions and to avoid marking the resulting object files as requiring vfp. moving away from using hard-coded opcode words is necessary in order to eventually support producing thumb2-only output for cortex-m. conditional execution of these instructions based on hwcap flags was already implemented. when building for arm (non-thumb) output, the only currently-supported configuration, this commit does not change the code emitted.
* use vfp mnemonics instead of p10 coprocessor ones in armhf fenv asmSzabolcs Nagy2015-11-051-10/+10
| | | | | mrc/mcr p10 coprocessor mnemonics are deprecated by some toolchains.
* convert arm memcpy asm to UAL, remove .word hacksRich Felker2015-11-051-22/+24
| | | | | contrary to commit 9367fe926196f407705bb07cd29c6e40eb1774dd, all relevant gas versions actually do support .syntax unified.
* remove external linkage from __simple_malloc definitionRich Felker2015-11-041-1/+1
| | | | | | | | this function is used only as a weak definition for malloc, for static linking in programs which do not call realloc or free. since it had external linkage and was thereby exported in libc.so's dynamic symbol table, --gc-sections was unable to drop it. this was merely an oversight; there's no reason for it to be external, so make it static.
* fix mremap memory synchronization and use of variadic argumentRich Felker2015-11-021-4/+11
| | | | | | | | | | | | since mremap with the MREMAP_FIXED flag is an operation that unmaps existing mappings, it needs to use the vm lock mechanism to ensure that any in-progress synchronization operations using vm identities from before the call have finished. also, the variadic argument was erroneously being read even if the MREMAP_FIXED flag was not passed. in practice this didn't break anything, but it's UB and in theory LTO could turn it into a hard error.
* prevent allocs than PTRDIFF_MAX via mremapDaniel Micay2015-11-021-1/+8
| | | | It's quite feasible for this to happen via MREMAP_MAYMOVE.
* use explicit __cp_cancel label in cancellable syscall asm for all archsRich Felker2015-11-028-28/+32
| | | | | | | | | | | | | previously, only archs that needed to do stack cleanup defined a __cp_cancel label for acting on cancellation in their syscall asm, and a default definition was provided by a weak alias to __cancel, the C function. this resulted in wrong codegen for arm on gcc versions affected by pr 68178 and possibly similar issues (like pr 66609) on other archs, and also created an inconsistency where the __cp_begin and __cp_end labels were treated as const data but __cp_cancel was treated as a function. this in turn caused incorrect code generation on archs where function pointers point to function descriptors rather than code (for now, only sh/fdpic).
* properly access mcontext_t program counter in cancellation handlerRich Felker2015-11-021-3/+4
| | | | | | | | | using the actual mcontext_t definition rather than an overlaid pointer array both improves correctness/readability and eliminates some ugly hacks for archs with 64-bit registers bit 32-bit program counter. also fix UB due to comparison of pointers not in a common array object.
* fix missing bss handling in FDPIC ELF loaderRich Felker2015-10-281-0/+13
| | | | | | | | when a library being loaded has bss (i.e. data segment with p_memsz>p_filesz), this region needs to be zeroed with a combination of memset and/or mmap. the regular ELF loader always did this but the FDPIC code path omitted it, leading to objects in bss having uninitialized/junk contents.
* getnameinfo: make size check not fail for bigger sizesHauke Mehrtens2015-10-261-2/+2
| | | | | | | | | | | | | | | | getnameinfo() compares the size of the given struct sockaddr with sizeof(struct sockaddr_in) and sizeof(struct sockaddr_in6) depending on the net family. When you add a sockaddr of size sizeof(struct sockaddr_storage) this function will fail because the size of the sockaddr is too big. Change the check that it only fails if the size is too small, but make it work when it is too big for example when someone calls this function with a struct sockaddr_storage and its size. This fixes a problem with IoTivity 1.0.0 and musl. glibc and bionic are only failing if it is smaller, net/freebsd implemented the != check. Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
* safely handle failure to open hosts, services, resolv.conf filesRich Felker2015-10-263-4/+29
| | | | | | | | | | | | | | | | | | | | previously, transient failures like fd exhaustion or other resource-related errors were treated the same as non-existence of these files, leading to fallbacks or false-negative results. in particular: - failure to open hosts resulted in fallback to dns, possibly yielding EAI_NONAME for a hostname that should be defined locally, or an unwanted result from dns that the hosts file was intended to replace. - failure to open services resulted in EAI_SERVICE. - failure to open resolv.conf resulted in querying localhost rather than the configured nameservers. now, only permanent errors trigger the fallback behaviors above; all other errors are reportable to the caller as EAI_SYSTEM.
* fix single-byte overflow of malloc'd buffer in getdelimRich Felker2015-10-241-1/+1
| | | | | | | | | | the buffer enlargement logic here accounted for the terminating null byte, but not for the possibility of hitting the delimiter in the buffer-refill code path that uses getc_unlocked, in which case two additional bytes (the delimiter and the null termination) are written without another chance to enlarge the buffer. this patch and the corresponding bug report are by Felix Janda.
* declare fpu usage to the assembler in arm hard-float asm filesSzabolcs Nagy2015-10-195-0/+6
| | | | | | | Some armhf gcc toolchains (built with --with-float=hard but without --with-fpu=vfp*) do not pass -mfpu=vfp to the assembler and then binutils rejects the UAL mnemonics for VFP unless there is an .fpu vfp directive in the asm source.
* add missing memory barrier to pthread_joinBobby Bingham2015-10-151-0/+1
| | | | | | | POSIX requires pthread_join to synchronize memory on success. The futex wait inside __timedwait_cp cannot handle this because it's not called in all cases. Also, in the case of a spurious wake, tid can become zero between the wake and when the joining thread checks it.
* fix dladdr treatment of function descriptors for fdpicRich Felker2015-10-151-9/+22
| | | | | | | | | | | | | | when determining which module an address belongs to, all function descriptor ranges must be checked first, in case the allocated memory falls inside another module's memory range. dladdr itself must also check addresses against function descriptors before doing a best-match search against the symbol table. even when doing the latter (e.g. for code addresses obtained from mcontext_t), also check whether the best-match was a function, and if so, replace the result with a function descriptor address. which is the nominal "base address" of the function and which the caller needs if it intends to subsequently call the matching function.
* fix visibility mismatch in dynamic linker stage 2 function definitionRich Felker2015-10-151-0/+1
| | | | | | | | | | | | | | | since commits 2907afb8dbd4c1d34825c3c9bd2b41564baca210 and 6fc30c2493fcfedec89e45088bea87766a1e3286, __dls2 is no longer called via symbol lookup, but instead uses relative addressing that needs to be resolved at link time. on some linker versions, and/or if -Bsymbolic-functions is not used, the linker may leave behind a dynamic relocation, which is not suitable for bootstrapping the dynamic linker, if the reference to __dls2 is marked hidden but the definition is not actually hidden. correcting the definition to use hidden visibility fixes the problem. the static-PIE entry point rcrt1 was likewise affected and is also fixed by this patch.
* fix strftime handling of out-of-range struct tm fieldsRich Felker2015-10-141-8/+12
| | | | | | | | | | strftime results are unspecified in this case, but should not invoke undefined behaviour. tm_wday, tm_yday, tm_mon and tm_year fields were used in signed int arithmetic that could overflow. based on patch by Szabolcs Nagy.
* fix integer overflows in time_t/struct tm conversion codeRich Felker2015-10-081-3/+3
| | | | | | | | | | as found and reported by Brian Mastenbrook, the expressions 400*qc_cycles and years+100 in __secs_to_tm were both subject to integer overflow for extreme values of the input t. this patch by Szabolcs Nagy fixes the code by switching to larger types, and matches the original intent I had in mind when writing this code.
* fix open_[w]memstream behavior when no writes take placeRich Felker2015-10-082-4/+18
| | | | | | | | | | | | | the specification for these functions requires that the buffer/size exposed to the caller be valid after any successful call to fflush or fclose on the stream. the implementation's approach is to update them only at flush time, but that misses the case where fflush or fclose is called without any writes having taken place, in which case the write flushing callback will not be called. to fix both the observable bug and the desired invariant, setup empty buffers at open time and fail the open operation if no memory is available.
* make nl_langinfo(CODESET) always return "ASCII" in byte-based C localeRich Felker2015-10-011-1/+1
| | | | | | | | | | | | | | | | | | | | | commit 844212d94f582c4e3c5055e0a1524931e89ebe76, which did not make it into any releases, changed nl_langinfo(CODESET) to always return "UTF-8", even in the byte-based C locale. this was problematic because application software was found to use the string match for "UTF-8" to activate its own UTF-8 processing. this both undermines the byte-based functionality of the C locale, and if mixed with with calls to the standard multibyte functions, which happened in practice, could result in severe mis-handling of input. the motive for the previous change was that, to avoid widespread compatibility problems, the string returned by nl_langinfo(CODESET) needs to be accepted by iconv and by third-party character conversion code. thus, the only remaining choice is "ASCII". this choice accurately represents the intent that high bytes do not have individual meaning in the C locale, but it does mean that iconv, when passed nl_langinfo(CODESET) in the C locale, will produce errors in cases where mbrtowc would have succeeded. for reference, glibc behaves similarly in this regard, so I don't think it will be a problem.
* fix mips fesetround failure to write back resulting modeRich Felker2015-10-011-0/+1
| | | | patch by Anand Takale.
* eliminate protected-visibility data in libc.so with vis.h preincludeRich Felker2015-09-291-0/+3
| | | | | | | | | | | | | | | some newer binutils versions print scary warnings about protected data because most gcc versions fail to produce the right address references/relocations for such data that might be subject to copy relocations. originally vis.h explicitly assigned default visibility to all public data symbols to avoid this issue, but commit b8dda24fe1caa901a99580f7a52defb95aedb67c removed this treatment for stdin/out/err to work around a gcc 3.x bug, and since they don't actually need it (because taking their addresses is not valid C). instead, a check for the gcc 3.x bug is added to the configure check for vis.h preinclude support; this feature will simply be disabled when using a buggy version of gcc.
* avoid attempting to lookup IP literals as hostnamesRich Felker2015-09-251-27/+32
| | | | | | | | | | | | | | | | previously, __lookup_ipliteral only checked its argument against the requested address family, so IPv4 literals passed through to __lookup_name if the caller asked for only IPv6 results, and likewise for IPv6 literals when the caller asked for only IPv4. this resulted in spurious DNS lookups that reportedly even succeeded with some nameservers. now, __lookup_ipliteral attempts to parse its argument as both IPv4 and IPv6, and returns an error (to stop further search) rather than 0 (no results yet) if the form of the argument mismatches the requested address family. based on patch by Julien Ramseier.
* make getaddrinfo return error if both host and service name are nullRich Felker2015-09-251-0/+2
| | | | | | this case is specified as a mandatory ("shall fail") error. based on patch by Julien Ramseier.
* fix localeconv field value for unavailable valuesRich Felker2015-09-241-14/+15
| | | | | | | per ISO C, CHAR_MAX, not -1, is the value used to indicate that a char field in struct lconv is unavailable. patch by Julien Ramseier.
* avoid reading uninitialized memory in __map_fileSzabolcs Nagy2015-09-241-2/+3
| | | | | | | The value of *size is not relevant in case of failure, but it's better not to copy garbage from the stack into it. (The compiler cannot see through the syscall, so optimization was not affected by the unspecified value).
* regcomp: propagate allocation failuresSzabolcs Nagy2015-09-241-1/+2
| | | | The error code of an allocating function was not checked in tre_add_tag.
* fix signal return for sh/fdpicRich Felker2015-09-233-4/+2
| | | | | | | | | | | | | | | | the restorer function pointer provided in the kernel sigaction structure is interpreted by the kernel as a raw code address, not a function descriptor. this commit moves the declarations of the __restore and __restore_rt symbols to ksigaction.h so that arch versions of the file can override them, and introduces a version for sh which declares them as objects rather than functions. an alternate solution would have been defining SA_RESTORER to 0 so that the functions are not used, but this both requires executable stack (since the sh kernel does not have a vdso page with permanent restorer functions) and crashes on qemu user-level emulation.
* fix dlsym RTLD_NEXT behavior for fdpicRich Felker2015-09-221-4/+28
| | | | | | | | | | | | | | lookup the dso an address falls in based on the loadmap and not just a base/length. fix the main app's fake loadmap used when loaded by a non-fdpic-aware loader so that it does not cover the whole memory space. function descriptor addresses are also matched for future use by dladdr, but reverse lookups of function descriptors via dladdr have not been implemented yet. some revisions may be needed in the future once reclaim_gaps supports fdpic, so that function descriptors allocated in reclaimed heap space do not get detected as belonging to the module whose gaps they were allocated in.
* fix dlsym lookup of function symbols on fdpicRich Felker2015-09-221-0/+6
| | | | | | | | | | | | | | previously these resolved to the code address rather than the address of the function descriptor. the conditions for accepting or rejecting symbols are quite inconsistent between the different points in the dynamic linker code where such decisions are made. this commit attempts to be at least as correct as anything already there, but does not improve consistency. it has been tested to correctly avoid symbols that are merely references to functions defined in other modules, at least in simple usage, but at some point all symbol lookup logic should be reviewed and refactored/unified.
* move calls to application init functions after crt1 entry pointRich Felker2015-09-222-1/+8
| | | | | | | | | | | | | | this change is needed to be compatible with fdpic, where some of the main application's relocations may be performed as part of the crt1 entry point. if we call init functions before passing control, these relocations will not yet have been performed, and the init code will potentially make use of invalid pointers. conceptually, no code provided by the application or third-party libraries should run before the application entry point. the difference is not observable to programs using the crt1 we provide, but it could come into play if custom entry point code is used, so it's better to be doing this right anyway.
* fix breakage in non-fdpic dynamic linker init/fini processingRich Felker2015-09-221-1/+1
| | | | | a mistaken #ifdef instead of #if caused conversion of code addresses to function descriptors to be performed even on non-fdpic.
* fix resolving interp string address on fdpic ldd commandRich Felker2015-09-221-2/+1
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* add real fdpic loading of shared librariesRich Felker2015-09-222-9/+58
| | | | | | previously, the normal ELF library loading code was used even for fdpic, so only the kernel-loaded dynamic linker and main app could benefit from separate placement of segments and shared text.
* add general fdpic support in dynamic linker and arch support for shRich Felker2015-09-223-14/+202
| | | | | | | | | | | | | | | | | | 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.
* introduce new symbol-lookup-free rcrt1/dlstart stage chainingRich Felker2015-09-171-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* 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 Felker2015-09-121-3/+9
| | | | | | | | | | | 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.
* fix uninitialized scopeid in lookups from hosts file and ip literalsTimo Teräs2015-09-111-2/+2
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* 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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