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| author | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2023-03-07 20:25:58 +0100 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2023-03-08 15:32:59 +0100 |
| commit | 8c51e1520ba96a0d19ddecccc57899eed2634750 (patch) | |
| tree | 3fcdcfc93e934258642a476c20efc420fb58d07e /man/threads-aware.xml | |
| parent | 1a87882635b921df2ee26ea5c9a3e3210e2fd077 (diff) | |
| download | systemd-8c51e1520ba96a0d19ddecccc57899eed2634750.tar.gz | |
man: add mention that libsystemd uses getenv()
See #26688: getenv() is not thread-safe, and could a possible source of
problems when a multi-threaded program calls setenv()/putenv()/unsetenv() in
parallel. It is not possible to avoid getenv() calls in general, since $PATH,
$LANG, $SHELL, $USER, $HOME, $TZ may need to be accessed at any time.
Add a warning to our docs so that people are aware of the issue.
Closes #26688. (Real fixes will need to be in glibc and gnome-shell or other
programs.)
The text is added to threads-aware.xml to be included in various places. By
including it in libsystemd-pkgconfig.xml, it is automatically added to all sd-*
pages. The text is also included explicitly in pages for a few other functions
which are call getenv().
Diffstat (limited to 'man/threads-aware.xml')
| -rw-r--r-- | man/threads-aware.xml | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/man/threads-aware.xml b/man/threads-aware.xml index fb38d07e1a..442e45bbbb 100644 --- a/man/threads-aware.xml +++ b/man/threads-aware.xml @@ -12,4 +12,12 @@ from any other, even if locking is used to ensure these threads don't operate on <para id="safe">All functions listed here are thread-safe and may be called in parallel from multiple threads.</para> +<para id='getenv'>The code described here uses +<citerefentry project='man-pages'><refentrytitle>getenv</refentrytitle><manvolnum>3</manvolnum></citerefentry>, +which is declared to be not multi-thread-safe. This means that the code calling the functions described +here must not call +<citerefentry project='man-pages'><refentrytitle>setenv</refentrytitle><manvolnum>3</manvolnum></citerefentry> +from a parallel thread. It is recommended to only do calls to <function>setenv()</function> +from an early phase of the program when no other threads have been started.</para> + </refsect1> |