GNU C Library 2.39 Released With New Tunables, stdbit.h For ISO C2X

In addition to this week's release of GNU Binutils 2.42, ending out January is the release of the GNU C Library 2.39. This C library "libc" update comes with several new features, security fixes, and other enhancements.

From more C2X enablement work to new functions for Linux systems and more, GNU C Library 2.39 is a big update. This Glibc update also fixes various security issues and other bugs. Some of the Glibc 2.39 highlights include:

- A new tunable "glibc.cpu.plt_rewrite" on x86-64 systems to enable PLT rewrite for rewriting indirect branches in PLT with direct branches.

- Syncing against the Shadow Stack interface found in the Linux 6.6+ kernel now that the kernel support is all squared away.

- The functions posix_spawnattr_getcgroup_np and posix_spawnattr_setcgroup_np have been added for Linux to set the cgroup v2 in the new process in a race-free manner.

- The pidfd_spawn and pidfd_swap functions for Linux that are similar to posix_spawn but return a file descriptor rather than process ID. For that, pidfd_getpid is also added for getting a process ID from a process file descriptor.

- The stdbit.h header has been added from ISO C2X.

- Libcrypt has been removed from the GNU C Library. Users should instead use libxcrypt.

- IA-64 Linux configurations are no longer supported with Itanium support having been removed from the Linux kernel.

- Various security fixes including for local privilege escalation issues.

- Many bug fixes.

More details on the GNU C Library 2.39 changes via the release announcement.