From 48a5bb7a26de6c3bea32d18c3e476dd2cedbcfd3 Mon Sep 17 00:00:00 2001 From: Laurent Bercot Date: Tue, 11 Feb 2020 01:38:05 +0000 Subject: Add bcnm-waitif doc --- doc/bcnm-waitif.html | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++ doc/index.html | 1 + 2 files changed, 88 insertions(+) create mode 100644 doc/bcnm-waitif.html diff --git a/doc/bcnm-waitif.html b/doc/bcnm-waitif.html new file mode 100644 index 0000000..ac95397 --- /dev/null +++ b/doc/bcnm-waitif.html @@ -0,0 +1,87 @@ + + + + + + bcnm: the bcnm-waitif program + + + + + + +

+s6
+Software
+skarnet.org +

+ +

The `bcnm-waitif` program

+ +

+bcnm-waitif waits until a set of network interfaces are in the desired state, +or a timeout occurs. Then it exits. It is typically used to avoid race conditions +in a service startup sequence. +

+ +

Interface

+ +

+     bcnm-waitif [ -u | -d ] [ -t timeout ] [ -k kbufsize ] mask interface...
+

+ +

bcnm-waitif reads the state of all the interfaces specified by +name as the interface... arguments.
If all the listed interfaces match the state defined in mask, +it exits 0.
Else, it waits for network interface state changes, and performs the +check again.
It loops until all the listed interfaces are in the desired state, +or a timeout (if defined) occurs.

+ +

mask meaning

+ +

+ mask is an unsigned integer representing a bitmask for the +flags to be tested. If several bits are given, the wanted state is the +conjunction of these flags: the condition will be true if all +those checks pass. +

+ +

1: the interface exists (the kernel knows about it)
2: the interface is UP (the administrator has activated it)
4: the interface is RUNNING (functional, not unplugged)

+ +

Options

+ +

-u : up. bcnm-waitif will wait until all +the states defined in mask are reached by all the interfaces +in interface.... This is the default.
-d : down. bcnm-waitif will wait until +none of the states defined in mask is true.
-t timeout : if the desired state +still has not been reached after timeout milliseconds, +bcnm-waitif will exit 99 with an error message. The default +is 0, meaning there is no timeout and the program can wait forever.
-k kbufsize : use kbufsize +bytes for the netlink socket buffer. Too small a buffer risks losing +state change events and reporting incorrect results. Too large a buffer +wastes memory. Default is 131072, which is probably on the large side.

+ +

Exit codes

+ +

0: success
99: timed out
100: wrong usage
111: system call failed

+ + + diff --git a/doc/index.html b/doc/index.html index bfc9f6b..24904a7 100644 --- a/doc/index.html +++ b/doc/index.html @@ -91,6 +91,7 @@ the previous versions of bcnm and the current one.

The bcnm-waitif program

Libraries