PLWP_GETXREGS(3PROC) Process Control Library Functions PLWP_GETXREGS(3PROC)

Plwp_getxregs, Plwp_freexregs, Plwp_setxregs, Lgetxregs, Lsetxregs — get and set extended register state

Process Control Library (libproc, -lproc)

#include <libproc.h>

int
Plwp_getxregs(struct ps_prochandle *P, lwpid_t lwpid, prxregset_t **xregsp, size_t *sizep);

int
Plwp_freexregs(struct ps_prochandle *P, lwpid_t lwpid, prxregset_t *xregs, size_t size);

int
Plwp_setxregs(struct ps_prochandle *P, lwpid_t lwpid, const prxregset_t *xregs);

int
Lgetxregs(struct ps_lwphandle *L, prxregset_t **xregsp, size_t *sizep);

int
Lsetxregs(struct ps_lwphandle *L, const prxregset_t *xregs);

The () and Plwp_setxregs() functions get and set the extended register state of the thread lwpid in the process handle P.

The extended register state is defined by the architecture. These registers may refer to optional registers that have become common on the platform, but are not part of the traditional ABI and thus not covered by functions such as Plwp_getregs(3PROC) and Plwp_getfpregs(3PROC). Support for the extended registers varies based on the architecture and varies based on the specific system. For example, on x86 based CPUs the xregs functionality requires the x86 xsave functionality to be supported.

The () function gets the extended register state information, allocates the appropriate sized buffer for it, and places a pointer to that buffer into xregs and updates sizep to indicate the size of the allocated structure. Due to the fact that hardware has varying sized extended register sets, the exact size of the structure can vary between different running systems and core files. It is also possible that some processor extensions are enabled at process runtime, leading for this to further be different between different processes on the same system. As such, all of the different platform instantiations of the prxregset_t end up generally being opaque structures that can be cast to something more specific that also includes its size.

The obtained prxregset_t in xregsp must be freed by the caller with the () function.

The () function sets the extended register state information in xregs for the process handle P.

Processes must be stopped prior to obtaining the register state of individual threads. Processes may be stopped with Pstop(3PROC).

The structure is described in proc(5).

One may not set the register values of a process that is not an active process, e.g. a process handle that refers to a file or a core file.

The () and () functions are equivalent to the Plwp_getxregs() and Plwp_setxregs() functions except that they operate on a specific thread identified by the handle L and only require that the thread in question be stopped. Data allocated with the Lgetxregs() functions should be freed with the Plwp_freexregs() function.

Upon successful completion, the Plwp_getxregs() and Plwp_setxregs() functions return and get or set the register state. Otherwise, is returned and is set to indicate the error.

For a full list of possible errors see the section in proc(5).

The Plwp_getxregs() and Plwp_setxregs() function will fail if:

The process handle P does not have any extended register state information. This generally happens because the platform does not support it.
The process handle P refers to a live process and it is not stopped.
There is no thread with id lwpid in the process handle P.
The Lgetxregs() and Lsetxregs() function will fail if:
The thread handle L does not have any extended register state information. This generally happens because the platform does not support it.
The thread handle L refers to a live process and the thread is not stopped.

See in libproc(3LIB).

libproc(3LIB), Plwp_getfpregs(3PROC), Plwp_getregs(3PROC), Plwp_setfpregs(3PROC), Plwp_setregs(3PROC), Pstop(3PROC), proc(5)

January 19, 2023 OmniOS