- 29 10月, 2012 1 次提交
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由 Rich Felker 提交于
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- 28 10月, 2012 1 次提交
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由 Rich Felker 提交于
for conformance, two functions should not have the same address. a conforming program could use the addresses of getc and fgetc in ways that assume they are distinct. normally i would just use a wrapper, but these functions are so small and performance-critical that an extra layer of function call could make the one that's a wrapper nearly twice as slow, so I'm just duplicating the code instead.
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- 27 10月, 2012 3 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
-lpcc only works if -nostdlib is not passed, so it's useless. instead, use -print-file-name to look up the full pathname for libpcc.a, and check whether that succeeds before trying to link with the result. also, silence pcc's junk printed on stdout during tests.
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由 Rich Felker 提交于
in old versions of pcc, the directory containing libpcc.a was not in the library path, and other options like -print-file-name may have been needed to locate it. however, -print-file-name itself seems to have been added around the same time that the directory was added to the search path, and moreover, I see no evidence that older versions of pcc are capable of building a working musl shared library. thus, it seems reasonable to just test whether -lpcc is accepted.
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- 26 10月, 2012 2 次提交
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由 Rich Felker 提交于
on x86 and some other archs, functions which make function calls which might go through a PLT incur a significant overhead cost loading the GOT register prior to making the call. this load is utterly useless in musl, since all calls are bound at library-creation time using -Bsymbolic-functions, but the compiler has no way of knowing this, and attempts to set the default visibility to protected have failed due to bugs in GCC and binutils. this commit simply manually assigns hidden/protected visibility, as appropriate, to a few internal-use-only functions which have many callers, or which have callers that are hot paths like getc/putc. it shaves about 5k off the i386 libc.so with -Os. many of the improvements are in syscall wrappers, where the benefit is just size and performance improvement is unmeasurable noise amid the syscall overhead. however, stdio may be measurably faster. if in the future there are toolchains that can do the same thing globally without introducing linking bugs, it might be worth considering removing these workarounds.
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由 Rich Felker 提交于
pcc wrongly passes any option beginning with -m to the linker, and will break at link time if these options were added to CFLAGS. testing linking lets us catch this at configure time and skip them.
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- 25 10月, 2012 3 次提交
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由 Rich Felker 提交于
these functions must behave as if they obtain the lock via flockfile to satisfy POSIX requirements. since another thread can provably hold the lock when they are called, they must wait to obtain the lock before they can return, even if the correct return value could be obtained without locking. in the case of fclose and freopen, failure to do so could cause correct (albeit obscure) programs to crash or otherwise misbehave; in the case of feof, ferror, and fwide, failure to obtain the lock could sometimes return incorrect results. in any case, having these functions proceed and return while another thread held the lock was wrong.
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由 Rich Felker 提交于
1. don't open /dev/null just as a basis to copy flags; use shared __fmodeflags function to get the right file flags for the mode. 2. handle the case (probably invalid, but whatever) case where the original stream's file descriptor was closed; previously, the logic re-closed it. 3. accept the "e" mode flag for close-on-exec; update dup3 to fallback to using dup2 so we can simply call __dup3 instead of putting fallback logic in freopen itself.
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由 Rich Felker 提交于
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- 23 10月, 2012 1 次提交
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由 Rich Felker 提交于
gcc seems to be generating identical or near-identical code for both versions, but the newer code is more expressive of what it's doing.
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- 22 10月, 2012 4 次提交
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由 Rich Felker 提交于
the W* namespace is not reserved, so the nonstandard ones must be moved under extension features. also WNOHANG and WUNTRACED were missing.
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由 Rich Felker 提交于
the behavior of putenv is left undefined if the argument does not contain an equal sign, but traditional implementations behave this way and gnulib replaces putenv if it doesn't do this.
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由 Rich Felker 提交于
this will prevent gnulib from wrapping our strtod to handle this useless feature.
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由 Rich Felker 提交于
signal mask was not being restored after fork, but instead blocked again.
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- 21 10月, 2012 1 次提交
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由 nsz 提交于
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- 20 10月, 2012 4 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
this was broken during the early dynamic-linked TLS commits, which rearranged some of the code for handling new relocation types.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
__release_ptc() is only valid in the parent; if it's performed in the child, the lock will be unlocked early then double-unlocked later, corrupting the lock state.
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- 19 10月, 2012 10 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
with this commit, based on testing with patches to qemu which are not yet upstream,
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由 Rich Felker 提交于
this is necessary to allow $CC with arguments in it
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由 Rich Felker 提交于
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由 Rich Felker 提交于
since it did not set the return-value register, the caller could wrongly interpret this as failure.
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由 Rich Felker 提交于
these macros are supported by more compilers
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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由 Rich Felker 提交于
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由 Rich Felker 提交于
since we target systems without overcommit, special care should be taken that system() and popen(), like posix_spawn(), do not fail in processes whose commit charges are too high to allow ordinary forking. this in turn requires special precautions to ensure that the parent process's signal handlers do not end up running in the shared-memory child, where they could corrupt the state of the parent process. popen has also been updated to use pipe2, so it does not have a fd-leak race in multi-threaded programs. since pipe2 is missing on older kernels, (non-atomic) emulation has been added. some silly bugs in the old code should be gone too.
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- 18 10月, 2012 2 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
only @PLT relocations are considered functions for purposes of -Bsymbolic-functions, so always use @PLT. it should not hurt in the static-linked case.
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- 17 10月, 2012 1 次提交
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由 Rich Felker 提交于
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- 16 10月, 2012 3 次提交
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由 Rich Felker 提交于
based on strstr. passes gnulib tests and a few quick checks of my own.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
despite documentation that makes it sound a lot different, the only ABI-constraint difference between TLS variants II and I seems to be that variant II stores the initial TLS segment immediately below the thread pointer (i.e. the thread pointer points to the end of it) and variant I stores the initial TLS segment above the thread pointer, requiring the thread descriptor to be stored below. the actual value stored in the thread pointer register also tends to have per-arch random offsets applied to it for silly micro-optimization purposes. with these changes applied, TLS should be basically working on all supported archs except microblaze. I'm still working on getting the necessary information and a working toolchain that can build TLS binaries for microblaze, but in theory, static-linked programs with TLS and dynamic-linked programs where only the main executable uses TLS should already work on microblaze. alignment constraints have not yet been heavily tested, so it's possible that this code does not always align TLS segments correctly on archs that need TLS variant I.
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- 15 10月, 2012 3 次提交
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由 Rich Felker 提交于
usage of vfork creates a situation where a process of lower privilege may momentarily have write access to the memory of a process of higher privilege. consider the case of a multi-threaded suid program which is calling posix_spawn in one thread while another thread drops the elevated privileges then runs untrusted (relative to the elevated privilege) code as the original invoking user. this untrusted code can then potentially modify the data the child process will use before calling exec, for example changing the pathname or arguments that will be passed to exec. note that if vfork is implemented as fork, the lock will not be held until the child execs, but since memory is not shared it does not matter.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
this change brings the behavior in line with the static-linked code, which seems to be correct.
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- 14 10月, 2012 1 次提交
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由 Rich Felker 提交于
with this change, pcc-built musl libc.so seems to work correctly. the problem is that pcc generates GOT lookups for external-linkage symbols even if they are hidden, rather than using GOT-relative addressing. the entire reason we're using hidden visibility on the __libc object is to make it accessible prior to relocations -- not to mention inexpensive to access. unfortunately, the workaround makes it even more expensive on pcc. when the pcc issue is fixed, an appropriate version test should be added so new pcc can use the much more efficient variant.
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