Greg Buchholz <[EMAIL PROTECTED]> writes: > I've wondered about the > chain of events that occur when a program makes a call to read(). [...] > A call to > read() is really a wrapper around another glibc function called > io_read(). This function sends a message to the root translator with > the name of the target file and a request for a handle to a subroutine > which will be invoked to get the actual data.
I think you're a little confused. There should be no filenames involved at all in the read operation (that's just as true for the Hurd as for traditional Un*x). When you call *open*, you provide a filename. The filename is sent on either to the / filesystem (if it's an absolute filename), or to the filesystem responsible for your current working directory (for relative filenames). Additional translators may be encountered during the process. The result of a successful open is a *port* that represents the open file, and which is served by the filesystem/translator responsible for the file. read and write operations on the file result in messages sent to that port, no other servers should be involved. In the Hurd, a POSIX file descriptor is more or less a wrapper around such a Mach port. So the chain of events that occur when a program calls read() should be fairly simple (which of course doesn't imply that it is bad to describe it in an text on how the Hurd works). But the chain of events that occur when a program calls open() is more complex, and also more "Hurdish", i.e. it should reveal more about the Hurd way of doing things. Regards, /Niels
