Add configure option for how read fails behave

Different platforms have different requirements for handling
hwmon sysfs access failures.

The default behavior is that a read failure leads to the daemon
exiting after some number of read failures.  This can be controlled
to then remove the object from the dbus on failure.  Now, it can
instead be controlled to return -errno on read failure.

This new behavior to set the value to -errno must be checked by
whatever mechanism is reporting the value.

Change-Id: I50b93aea56f22267da79c9571319f281e24a1e6f
Signed-off-by: Patrick Venture <venture@google.com>
3 files changed
tree: fede075880e005c2b9c13e9d2397162107699f75
  1. msl/
  2. test/
  3. .gitignore
  4. argument.cpp
  5. argument.hpp
  6. bootstrap.sh
  7. configure.ac
  8. env.cpp
  9. env.hpp
  10. fan_pwm.cpp
  11. fan_pwm.hpp
  12. fan_speed.cpp
  13. fan_speed.hpp
  14. hwmon.hpp
  15. interface.hpp
  16. LICENSE
  17. mainloop.cpp
  18. mainloop.hpp
  19. Makefile.am
  20. readd.cpp
  21. README.iio.md
  22. README.md
  23. sensorset.cpp
  24. sensorset.hpp
  25. sysfs.cpp
  26. sysfs.hpp
  27. targets.hpp
  28. thresholds.hpp
  29. util.hpp
README.md

Exposes generic hwmon entries as DBus objects.

To Build

To build this package, do the following steps:

    1. ./bootstrap.sh
    2. ./configure ${CONFIGURE_FLAGS}
    3. make

To full clean the repository again run `./bootstrap.sh clean`.

D-Bus bus names

To enable the use of Linux features like cgroups prioritization and
udev/systemd control, one instance of phosphor-hwmon is intended to
be run per hwmon sysfs class instance.

This requires an algorithm for selecting a stable, well-known D-Bus busname.

The algorithm is <PREFIX>-<ID>.Hwmon<N> where PREFIX is an autoconf
configurable prefix (BUSNAME_PREFIX, xyz.openbmc_project by default),
ID is a std::hash of the /sys/devices path backing the hwmon class
instance, and N is the implemented phosphor-hwmon D-Bus API version.