PROCFS

The ChorusOS operating system provides a /proc file system derived from the FreeBSD 4.1 implementation of /proc. Due to major differences in the implementation of the two systems, only a subset of the FreeBSD /proc file system has been retained. However, due to enhancements of the process model introduced by the ChorusOS operating system, such as the support of multi-threaded processes, extensions have been introduced to reflect the multi-threaded nature of the processes.

Such a file system is usually mounted, by convention, under the /proc directory. This directory is then populated and depopulated dynamically and automatically depending on the life cycle of the processes. ChorusOS actors are not reflected in this file system. Upon process creation (using fork() or posix_spawn()) an entry whose name is derived from the process identifier is created in the /proc directory. This per-process entry is in turn a directory whose layout is almost identical from one process to another. Threads running in this process are also represented by a regular file in the /proc file system (on a basis of one-to-one correspondence).

PROCFS API

The API supported by the PROCFS file system are similar to those exported by the UFS file system, although many of calls that do not have any significance when applied to a process will return with an error code. The list of entries that are supported below each process are listed in the following table.