Squash commits for public release

base/open_docs

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+The open() system call opens the file specified by pathname.  If the
+specified file does not exist, it may optionally (if O_CREAT is
+specified in flags) be created by open().
+
+The return value of open() is a file descriptor, a small, nonnegative
+integer that is used in subsequent system calls (read(2), write(2),
+lseek(2), fcntl(2), etc.) to refer to the open file.  The file
+descriptor returned by a successful call will be the lowest-numbered
+file descriptor not currently open for the process.
+
+By default, the new file descriptor is set to remain open across an
+execve(2) (i.e., the FD_CLOEXEC file descriptor flag described in
+fcntl(2) is initially disabled); the O_CLOEXEC flag, described below,
+can be used to change this default.  The file offset is set to the
+beginning of the file (see lseek(2)).
+
+A call to open() creates a new open file description, an entry in the
+system-wide table of open files.  The open file description records
+the file offset and the file status flags (see below).  A file
+descriptor is a reference to an open file description; this reference
+is unaffected if pathname is subsequently removed or modified to
+refer to a different file.  For further details on open file
+descriptions, see NOTES.
+
+The argument flags must include one of the following access modes:
+O_RDONLY, O_WRONLY, or O_RDWR.  These request opening the file read-
+only, write-only, or read/write, respectively.
+
+In addition, zero or more file creation flags and file status flags
+can be bitwise-or'd in flags.  The file creation flags are O_CLOEXEC,
+O_CREAT, O_DIRECTORY, O_EXCL, O_NOCTTY, O_NOFOLLOW, O_TMPFILE, and
+O_TRUNC.  The file status flags are all of the remaining flags listed
+below.  The distinction between these two groups of flags is that the
+file creation flags affect the semantics of the open operation
+itself, while the file status flags affect the semantics of
+subsequent I/O operations.  The file status flags can be retrieved
+and (in some cases) modified; see fcntl(2) for details.