kmem(7)                                                      kmem(7)


       NAME
             kmem - perform I/O on kernel memory based on symbol name

       SYNOPSIS
             #include <sys/ksym.h>
             int ioctl(int kmemfd, MIOC_READKSYM, struct mioc_rksym *rks);
             int ioctl(int kmemfd, MIOC_IREADKSYM, struct mioc_rksym *rks);
             int ioctl(int kmemfd, MIOC_WRITEKSYM, struct mioc_rksym *rks);
             int ioctl(int kmemfd, MIOC_IWRITEKSYM, struct mioc_rksym *rks);

       DESCRIPTION
             When used with a valid file descriptor for /dev/kmem (kmemfd),
             these ioctl commands [see ioctl(2)] can be used to read or
             write kernel memory based on information provided in the
             mioc_rksym structure, which includes the following members:
               char *mirk_symname;/* symbol at whose address read will start */
               void *mirk_buf;/* buffer into which data will be written */
               size_t mirk_buflen;/* length (in bytes) of read buffer */

             The second argument to ioctl determines which I/O operation is
             being performed:

             MIOC_READKSYM      Read mirk_buflen bytes of kernel memory
                                starting at the address for mirk_symname
                                into mirk_buf.

             MIOC_IREADKSYM     Read sizeof(void *) bytes of kernel memory
                                starting at the address for mirk_symname
                                and use that as the address from which to
                                read mirk_buflen bytes of kernel memory
                                into mirk_buf.

             MIOC_WRITEKSYM     Write mirk_buflen bytes into kernel memory
                                starting at the address for mirk_symname
                                from mirk_buf.

             MIOC_IWRITEKSYM    Read sizeof(void *) bytes of kernel memory
                                starting at the address for mirk_symname
                                and use that as the address from which to
                                write mirk_buflen bytes of kernel memory
                                into mirk_buf.

       RETURN VALUES
             In addition to the error conditions listed on ioctl(2), these
             ioctl commands can fail for the following reasons:



                           Copyright 1994 Novell, Inc.               Page 1

      kmem(7)                                                      kmem(7)


            EBADF              kmemfd open for reading and this is
                               MIOC_WRITEKSYM or kmemfd open for writing
                               and this is MIOC_READKSYM

            EFAULT             Value of mirk_buflen results in attempt to
                               read outside kernel virtual address space,
                               or the third argument to ioctl is an
                               invalid pointer, or an invalid pointer is
                               given for the symbol name or buffer in the
                               mioc_rksym structure

            EINVAL             Second argument to ioctl is invalid

            ENAMETOOLONG       Symbol name is longer than MAXSYMNMLEN
                               characters

            ENOMATCH           Symbol names not found in the running
                               kernel (including loaded modules)

            ENXIO              kmemfd open on wrong minor device (that is,
                               not /dev/kmem)

      REFERENCES
            getksym(2), ioctl(2), nlist(3E)
























                          Copyright 1994 Novell, Inc.               Page 2