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| author | Yu Watanabe <watanabe.yu+github@gmail.com> | 2021-01-19 08:47:39 +0900 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-01-19 08:47:39 +0900 |
| commit | 4c6dd238b81b7d5825a45b443cbe625ce365f086 (patch) | |
| tree | d237c682fd36af5225987872e88fa05f0205159f /man | |
| parent | ceed42830548a08d426af892d6ce55dc90070d41 (diff) | |
| parent | e37258406766efe53b161ee1d077872fda82ae1b (diff) | |
| download | systemd-4c6dd238b81b7d5825a45b443cbe625ce365f086.tar.gz | |
Merge pull request #18267 from lucaswerkmeister/truncate
Two StandardOutput=truncate:file improvements
Diffstat (limited to 'man')
| -rw-r--r-- | man/systemd.exec.xml | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index 9adb6a298e..663b15fa60 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -2430,8 +2430,19 @@ SystemCallErrorNumber=EPERM</programlisting> </para> <para><option>truncate:<replaceable>path</replaceable></option> is similar to - <option>file:<replaceable>path</replaceable></option> above, but it truncates the file when opening it. - </para> + <option>file:<replaceable>path</replaceable></option> above, but it truncates the file when opening + it. For units with multiple command lines, e.g. <varname>Type=oneshot</varname> services with + multiple <varname>ExecStart=</varname>, or services with <varname>ExecCondition=</varname>, + <varname>ExecStartPre=</varname> or <varname>ExecStartPost=</varname>, the output file is reopened + and therefore re-truncated for each command line. If the output file is truncated while another + process still has the file open, e.g. by an <varname>ExecReload=</varname> running concurrently with + an <varname>ExecStart=</varname>, and the other process continues writing to the file without + adjusting its offset, then the space between the file pointers of the two processes may be filled + with <constant>NUL</constant> bytes, producing a sparse file. Thus, + <option>truncate:<replaceable>path</replaceable></option> is typically only useful for units where + only one process runs at a time, such as services with a single <varname>ExecStart=</varname> and no + <varname>ExecStartPost=</varname>, <varname>ExecReload=</varname>, <varname>ExecStop=</varname> or + similar.</para> <para><option>socket</option> connects standard output to a socket acquired via socket activation. The semantics are similar to the same option of <varname>StandardInput=</varname>, see above.</para> |