PROC_RWMEM(9)          FreeBSD Kernel Developer's Manual         PROC_RWMEM(9)

NAME
     proc_rwmem, proc_readmem, proc_writemem - read from or write to a process
     address space

SYNOPSIS
     #include <sys/types.h>
     #include <sys/ptrace.h>

     int
     proc_rwmem(struct proc *p, struct uio *uio);

     ssize_t
     proc_readmem(struct thread *td, struct proc *p, vm_offset_t va,
         void *buf, size_t len);

     ssize_t
     proc_writemem(struct thread *td, struct proc *p, vm_offset_t va,
         void *buf, size_t len);

DESCRIPTION
     These functions are used to read to or write from the address space of
     the process p.  The proc_rwmem() function requires the caller to specify
     the I/O parameters using a struct uio, described in uio(9).  The
     proc_readmem() and proc_writemem() functions provide a simpler, less
     general interface which allows the caller to read into or write the
     kernel buffer buf of size len from or to the memory at offset va in the
     address space of p.  The operation is performed on behalf of thread td,
     which will most often be the current thread.

     These functions may sleep and thus may not be called with any non-
     sleepable locks held.  The process p must be held by the caller using
     PHOLD(9).

RETURN VALUES
     The proc_rwmem() function returns 0 on success.  EFAULT is returned if
     the specified user address is invalid, and ENOMEM is returned if the
     target pages could not be faulted in due to a resource shortage.

     The proc_readmem() and proc_writemem() functions return the number of
     bytes read or written, respectively.  This may be smaller than the number
     of bytes requested, for example if the request spans multiple pages in
     the process address space and one of them after the first is not mapped.
     Otherwise, -1 is returned.

SEE ALSO
     copyin(9), locking(9), PHOLD(9), uio(9)

AUTHORS
     This manual page was written by Mark Johnston <markj@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6        December 7, 2015        FreeBSD 13.1-RELEASE-p6