glibc/include, branch vdso

stdlib: Do not use GLIBC_PRIVATE ABI for errno in libc_nonshared.a

2024-09-06T12:07:00Z

Using TLS directly introduces a GLIBC_PRIVATE ABI dependency into libc_nonshared.a, and thus indirectly into applications. Adding the !defined LIBC_NONSHARED condition deactivates direct TLS access, and libc_nonshared.a code switches to using __errno_location, like application code. Currently, this has no effect because there is no code in libc_nonshared.a that accesses errno. Reviewed-by: Carlos O'Donell

Define __libc_initial for the static libc

2024-08-09T14:17:14Z

Reviewed-by: Adhemerval Zanella

elf: Avoid re-initializing already allocated TLS in dlopen (bug 31717)

2024-08-05T16:26:52Z

The old code used l_init_called as an indicator for whether TLS initialization was complete. However, it is possible that TLS for an object is initialized, written to, and then dlopen for this object is called again, and l_init_called is not true at this point. Previously, this resulted in TLS being initialized twice, discarding any interim writes (technically introducing a use-after-free bug even). This commit introduces an explicit per-object flag, l_tls_in_slotinfo. It indicates whether _dl_add_to_slotinfo has been called for this object. This flag is used to avoid double-initialization of TLS. In update_tls_slotinfo, the first_static_tls micro-optimization is removed because preserving the initalization flag for subsequent use by the second loop for static TLS is a bit complicated, and another per-object flag does not seem to be worth it. Furthermore, the l_init_called flag is dropped from the second loop (for static TLS initialization) because l_need_tls_init on its own prevents double-initialization. The remaining l_init_called usage in resize_scopes and update_scopes is just an optimization due to the use of scope_has_map, so it is not changed in this commit. The isupper check ensures that libc.so.6 is TLS is not reverted. Such a revert happens if l_need_tls_init is not cleared in _dl_allocate_tls_init for the main_thread case, now that l_init_called is not checked anymore in update_tls_slotinfo in elf/dl-open.c. Reported-by: Jonathon Anderson Reviewed-by: Carlos O'Donell

Increase version number to 2.40

2024-07-21T16:23:25Z

Signed-off-by: Andreas K. Hüttel

posix: Sync tempname with gnulib

2024-04-10T17:53:39Z

The gnulib version contains an important change (9ce573cde), which fixes some problems with multithreading, entropy loss, and ASLR leak nfo. It also fixes an issue where getrandom is not being used on some new files generation (only for __GT_NOCREATE on first try). The 044bf893ac removed __path_search, which is now moved to another gnulib shared files (stdio-common/tmpdir.{c,h}). Tthis patch also fixes direxists to use __stat64_time64 instead of __xstat64, and move the include of pathmax.h for !_LIBC (since it is not used by glibc). The license is also changed from GPL 3.0 to 2.1, with permission from the authors (Bruno Haible and Paul Eggert). The sync also removed the clock fallback, since clock_gettime with CLOCK_REALTIME is expected to always succeed. It syncs with gnulib commit 323834962817af7b115187e8c9a833437f8d20ec. Checked on x86_64-linux-gnu. Co-authored-by: Bruno Haible Co-authored-by: Paul Eggert Reviewed-by: Bruno Haible

riscv: Enable multi-arg ifunc resolvers

2024-03-01T15:14:59Z

RISC-V is apparently the first architecture to pass more than one argument to ifunc resolvers. The helper macros in libc-symbols.h, __ifunc_resolver(), __ifunc(), and __ifunc_hidden(), are incompatible with this. These macros have an "arg" (non-final) parameter that represents the parameter signature of the ifunc resolver. The result is an inability to pass the required comma through in a single preprocessor argument. Rearrange the __ifunc_resolver() macro to be variadic, and pass the types as those variable parameters. Move the guts of __ifunc() and __ifunc_hidden() into new macros, __ifunc_args(), and __ifunc_args_hidden(), that pass the variable arguments down through to __ifunc_resolver(). Then redefine __ifunc() and __ifunc_hidden(), which are used in a bunch of places, to simply shuffle the arguments down into __ifunc_args[_hidden]. Finally, define a riscv-ifunc.h header, which provides convenience macros to those looking to write ifunc selectors that use both arguments. Signed-off-by: Evan Green Reviewed-by: Florian Weimer Signed-off-by: Palmer Dabbelt

arm: Use _dl_find_object on __gnu_Unwind_Find_exidx (BZ 31405)

2024-02-23T11:50:00Z

Instead of __dl_iterate_phdr. On ARM dlfo_eh_frame/dlfo_eh_count maps to PT_ARM_EXIDX vaddr start / length. On a Neoverse N1 machine with 160 cores, the following program: $ cat test.c #include #include #include enum { niter = 1024, ntimes = 128, }; static void * tf (void *arg) { int a = (int) arg; for (int i = 0; i < niter; i++) { void *p[ntimes]; for (int j = 0; j < ntimes; j++) p[j] = malloc (a * 128); for (int j = 0; j < ntimes; j++) free (p[j]); } return NULL; } int main (int argc, char *argv[]) { enum { nthreads = 16 }; pthread_t t[nthreads]; for (int i = 0; i < nthreads; i ++) assert (pthread_create (&t[i], NULL, tf, (void *) i) == 0); for (int i = 0; i < nthreads; i++) { void *r; assert (pthread_join (t[i], &r) == 0); assert (r == NULL); } return 0; } $ arm-linux-gnueabihf-gcc -fsanitize=address test.c -o test Improves from ~15s to 0.5s. Checked on arm-linux-gnueabihf.

string: Add hidden builtin definition for __strcpy_chk.

2024-02-06T08:17:04Z

Otherwise on at least x86_64 and s390x there is an unwanted PLT entry in libc.so when configured with --enable-fortify-source=3 and build with -Os. This is observed in elf/check-localplt Extra PLT reference: libc.so: __strcpy_chk The call to PLT entry is in inet/ruserpass.c. Reviewed-by: Adhemerval Zanella

Refer to C23 in place of C2X in glibc

2024-02-01T11:02:01Z

WG14 decided to use the name C23 as the informal name of the next revision of the C standard (notwithstanding the publication date in 2024). Update references to C2X in glibc to use the C23 name. This is intended to update everything *except* where it involves renaming files (the changes involving renaming tests are intended to be done separately). In the case of the _ISOC2X_SOURCE feature test macro - the only user-visible interface involved - support for that macro is kept for backwards compatibility, while adding _ISOC23_SOURCE. Tested for x86_64.

version.h, include/features.h: Bump version to 2.39

2024-01-31T00:29:11Z

Signed-off-by: Andreas K. Hüttel