tree 1251dd3873f0a783050a2e8650c266eda127b00c
parent 35df34223b5d45db8b498def39bd720a8d3f810e
author William Lallemand <wlallemand@haproxy.org> 1664189679 +0200
committer William Lallemand <wlallemand@haproxy.org> 1665672622 +0200

MINOR: logs: startup-logs can use a shm for logging the reload

When compiled with USE_SHM_OPEN=1 the startup-logs are now able to use
an shm which is used to keep the logs when switching to mworker wait
mode. This allows to keep the failed reload logs.

When allocating the startup-logs at first start of the process, haproxy
will do a shm_open with a unique path using the PID of the process, the
file is unlink immediatly so we don't let unwelcomed files be. The fd
resulting from this shm is stored in the HAPROXY_STARTUPLOGS_FD
environment variable so it can be mmap again when switching to wait
mode.

When forking children, the process is copying the mmap to a a mallocated
ring so we never share the same memory section between the master and
the workers. When switching to wait mode, the shm is not used anymore as
it is also copied to a mallocated structure.

This allow to use the "show startup-logs" command over the master CLI,
to get the logs of the latest startup or reload. This way the logs of
the latest failed reload are also kept.

This is only activated on the linux-glibc target for now.