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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-03-10 12:26:32 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-07-08 14:08:14 -0300 |
| commit | 607449506f197cc9514408908f41f22537a47a8c (patch) | |
| tree | 9d4304b8a8a1ccdef78a305433d845bcd3e08ae6 /io/Makefile | |
| parent | 286286283e9bdc7ef894306e2dbcf4c115b97ba2 (diff) | |
| download | glibc-607449506f197cc9514408908f41f22537a47a8c.zip glibc-607449506f197cc9514408908f41f22537a47a8c.tar.gz glibc-607449506f197cc9514408908f41f22537a47a8c.tar.bz2 | |
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
Diffstat (limited to 'io/Makefile')
| -rw-r--r-- | io/Makefile | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/io/Makefile b/io/Makefile index 1a16990..ebb7d56 100644 --- a/io/Makefile +++ b/io/Makefile @@ -56,7 +56,8 @@ routines := \ sendfile sendfile64 copy_file_range \ utimensat futimens file_change_detection \ fts64-time64 \ - ftw64-time64 + ftw64-time64 \ + closefrom others := pwd test-srcs := ftwtest ftwtest-time64 @@ -77,6 +78,7 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \ tst-lutimes \ tst-futimens \ tst-utimensat \ + tst-closefrom \ tests-time64 := \ tst-futimens-time64 \ |