From 607449506f197cc9514408908f41f22537a47a8c Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 10 Mar 2021 12:26:32 -0300 Subject: io: Add closefrom [BZ #10353] The function closes all open file descriptors greater than or equal to input argument. Negative values are clamped to 0, i.e, it will close all file descriptors. As indicated by the bug report, this is a common symbol provided by different systems (Solaris, OpenBSD, NetBSD, FreeBSD) and, although its has inherent issues with not taking in consideration internal libc file descriptors (such as syslog), this is also a common feature used in multiple projects [1][2][3][4][5]. The Linux fallback implementation iterates over /proc and close all file descriptors sequentially. Although it was raised the questioning whether getdents on /proc/self/fd might return disjointed entries when file descriptor are closed; it does not seems the case on my testing on multiple kernel (v4.18, v5.4, v5.9) and the same strategy is used on different projects [1][2][3][5]. Also, the interface is set a fail-safe meaning that a failure in the fallback results in a process abort. Checked on x86_64-linux-gnu and i686-linux-gnu on kernel 5.11 and 4.15. [1] https://github.com/systemd/systemd/blob/5238e9575906297608ff802a27e2ff9effa3b338/src/basic/fd-util.c#L217 [2] https://github.com/lxc/lxc/blob/ddf4b77e11a4d08f09b7b9cd13e593f8c047edc5/src/lxc/start.c#L236 [3] https://github.com/python/cpython/blob/9e4f2f3a6b8ee995c365e86d976937c141d867f8/Modules/_posixsubprocess.c#L220 [4] https://github.com/rust-lang/rust/blob/5f47c0613ed4eb46fca3633c1297364c09e5e451/src/libstd/sys/unix/process2.rs#L303-L308 [5] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82 --- sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist | 1 + sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist | 1 + sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist | 1 + sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist | 1 + 4 files changed, 4 insertions(+) (limited to 'sysdeps/unix/sysv/linux/powerpc') diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist index 3951054b61..959418aa48 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist @@ -2540,6 +2540,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist index 4c2adbd8ab..405b9b9c49 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist @@ -2573,6 +2573,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist index e9d30b1ed7..e60fe8917d 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist @@ -2309,6 +2309,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist index 81c1eac79c..0f86da7288 100644 --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist @@ -2604,6 +2604,7 @@ GLIBC_2.34 aio_write F GLIBC_2.34 aio_write64 F GLIBC_2.34 call_once F GLIBC_2.34 close_range F +GLIBC_2.34 closefrom F GLIBC_2.34 cnd_broadcast F GLIBC_2.34 cnd_destroy F GLIBC_2.34 cnd_init F -- cgit 1.4.1