glibc/libio/libioP.h, branch vdso

ungetc: Fix backup buffer leak on program exit [BZ #27821]

2024-08-15T17:56:13Z

If a file descriptor is left unclosed and is cleaned up by _IO_cleanup on exit, its backup buffer remains unfreed, registering as a leak in valgrind. This is not strictly an issue since (1) the program should ideally be closing the stream once it's not in use and (2) the program is about to exit anyway, so keeping the backup buffer around a wee bit longer isn't a real problem. Free it anyway to keep valgrind happy when the streams in question are the standard ones, i.e. stdout, stdin or stderr. Also, the _IO_have_backup macro checks for _IO_save_base, which is a roundabout way to check for a backup buffer instead of directly looking for _IO_backup_base. The roundabout check breaks when the main get area has not been used and user pushes a char into the backup buffer with ungetc. Fix this to use the _IO_backup_base directly. Signed-off-by: Siddhesh Poyarekar Reviewed-by: Carlos O'Donell

Revert "Allow glibc to be compiled without EXEC_PAGESIZE"

2024-04-22T21:00:18Z

This reverts commit 49aa652db810ebdca3a662ebd5b0468bd08ec688. This is still being discussed.

Allow glibc to be compiled without EXEC_PAGESIZE

2024-03-23T21:47:26Z

We would like to avoid statically defining any specific page size on aarch64-gnu, and instead make sure that everything uses the dynamic page size, available via vm_page_size and GLRO(dl_pagesize). There are currently a few places in glibc that require EXEC_PAGESIZE to be defined. Per Roland's suggestion [0], drop the static GLRO(dl_pagesize) initializers (for now, only if EXEC_PAGESIZE is not defined), and don't require EXEC_PAGESIZE definition for libio to enable mmap usage. [0]: https://mail.gnu.org/archive/html/bug-hurd/2011-10/msg00035.html Signed-off-by: Sergey Bugaev Message-ID: <20240323173301.151066-4-bugaevc@gmail.com>

Update copyright dates with scripts/update-copyrights

2024-01-01T18:53:40Z

Always do locking when accessing streams (bug 15142, bug 14697)

2023-07-03T07:55:43Z

Now that abort no longer calls fflush there is no reason to avoid locking the stdio streams anywhere. This fixes a conformance issue and potential heap corruption during exit.

libio: Remove the usage of __libc_IO_vtables

2023-03-27T16:57:55Z

Instead of using a special ELF section along with a linker script directive to put the IO vtables within the RELRO section, the libio vtables are all moved to an array marked as data.relro (so linker will place in the RELRO segment without the need of extra directives). To avoid static linking namespace issues and including all vtable referenced objects, all required function pointers are set to weak alias. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell

Move libc_freeres_ptrs and libc_subfreeres to hidden/weak functions

2023-03-27T16:57:55Z

They are both used by __libc_freeres to free all library malloc allocated resources to help tooling like mtrace or valgrind with memory leak tracking. The current scheme uses assembly markers and linker script entries to consolidate the free routine function pointers in the RELRO segment and to be freed buffers in BSS. This patch changes it to use specific free functions for libc_freeres_ptrs buffers and call the function pointer array directly with call_function_static_weak. It allows the removal of both the internal macros and the linker script sections. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell

C2x scanf binary constant handling

2023-03-02T19:10:37Z

C2x adds binary integer constants starting with 0b or 0B, and supports those constants for the %i scanf format (in addition to the %b format, which isn't yet implemented for scanf in glibc). Implement that scanf support for glibc. As with the strtol support, this is incompatible with previous C standard versions, in that such an input string starting with 0b or 0B was previously required to be parsed as 0 (with the rest of the input potentially matching subsequent parts of the scanf format string). Thus this patch adds 12 new __isoc23_* functions per long double format (12, 24 or 36 depending on how many long double formats the glibc configuration supports), with appropriate header redirection support (generally very closely following that for the __isoc99_* scanf functions - note that __GLIBC_USE (DEPRECATED_SCANF) takes precedence over __GLIBC_USE (C2X_STRTOL), so the case of GNU extensions to C89 continues to get old-style GNU %a and does not get this new feature). The function names would remain as __isoc23_* even if C2x ends up published in 2024 rather than 2023. When scanf %b support is added, I think it will be appropriate for all versions of scanf to follow C2x rules for inputs to the %b format (given that there are no compatibility concerns for a new format). Tested for x86_64 (full glibc testsuite). The first version was also tested for powerpc (32-bit) and powerpc64le (stdio-common/ and wcsmbs/ tests), and with build-many-glibcs.py.

Update copyright dates with scripts/update-copyrights

2023-01-06T21:14:39Z

Use PTR_MANGLE and PTR_DEMANGLE unconditionally in C sources

2022-10-18T15:04:10Z

In the future, this will result in a compilation failure if the macros are unexpectedly undefined (due to header inclusion ordering or header inclusion missing altogether). Assembler sources are more difficult to convert. In many cases, they are hand-optimized for the mangling and no-mangling variants, which is why they are not converted. sysdeps/s390/s390-32/__longjmp.c and sysdeps/s390/s390-64/__longjmp.c are special: These are C sources, but most of the implementation is in assembler, so the PTR_DEMANGLE macro has to be undefined in some cases, to match the assembler style. Reviewed-by: Adhemerval Zanella