143051d27SRobert Mustacchi.\" 243051d27SRobert Mustacchi.\" This file and its contents are supplied under the terms of the 343051d27SRobert Mustacchi.\" Common Development and Distribution License ("CDDL"), version 1.0. 443051d27SRobert Mustacchi.\" You may only use this file in accordance with the terms of version 543051d27SRobert Mustacchi.\" 1.0 of the CDDL. 643051d27SRobert Mustacchi.\" 743051d27SRobert Mustacchi.\" A full copy of the text of the CDDL should have accompanied this 843051d27SRobert Mustacchi.\" source. A copy of the CDDL is also available via the Internet at 943051d27SRobert Mustacchi.\" http://www.illumos.org/license/CDDL. 1043051d27SRobert Mustacchi.\" 1143051d27SRobert Mustacchi.\" 1243051d27SRobert Mustacchi.\" Copyright 2015 Joyent, Inc. 1343051d27SRobert Mustacchi.\" 14*a7d7cafeSRobert Mustacchi.Dd November 27, 2023 1543051d27SRobert Mustacchi.Dt LGRAB 3PROC 1643051d27SRobert Mustacchi.Os 1743051d27SRobert Mustacchi.Sh NAME 1843051d27SRobert Mustacchi.Nm Lgrab 1943051d27SRobert Mustacchi.Nd obtain a handle to control a thread 20*a7d7cafeSRobert Mustacchi.Sh LIBRARY 2143051d27SRobert Mustacchi.Lb libproc 22*a7d7cafeSRobert Mustacchi.Sh SYNOPSIS 2343051d27SRobert Mustacchi.In libproc.h 2443051d27SRobert Mustacchi.Ft "struct ps_lwphandle *" 2543051d27SRobert Mustacchi.Fo Lgrab 2643051d27SRobert Mustacchi.Fa "struct ps_prochandle *P" 2743051d27SRobert Mustacchi.Fa "lwpid_t lwpid" 2843051d27SRobert Mustacchi.Fa "int *perr" 2943051d27SRobert Mustacchi.Fc 3043051d27SRobert Mustacchi.Sh DESCRIPTION 3143051d27SRobert MustacchiThe 3243051d27SRobert Mustacchi.Fn Lgrab 3343051d27SRobert Mustacchifunction obtains a control handle to the thread identified by 3443051d27SRobert Mustacchi.Fa lwpid 3543051d27SRobert Mustacchiresiding under the process 3643051d27SRobert Mustacchi.Fa P . 3743051d27SRobert MustacchiThis handle is then passed as argument to other 3843051d27SRobert Mustacchi.Sy libproc 3972d3dbb9SYuri Pankovroutines. 4072d3dbb9SYuri PankovThe 4143051d27SRobert Mustacchi.Fa lwpid 4243051d27SRobert Mustacchican be obtained from the 4343051d27SRobert Mustacchi.Sy pr_lwpid 4443051d27SRobert Mustacchimember of the 4543051d27SRobert Mustacchi.Sy lwpstatus_t 4643051d27SRobert Mustacchistructure. 4743051d27SRobert Mustacchi.Pp 4843051d27SRobert MustacchiThe 4943051d27SRobert Mustacchi.Fa perr 5043051d27SRobert Mustacchiargument must point to a valid pointer that will be used to store an 5143051d27SRobert Mustacchierror code in the event that 5243051d27SRobert Mustacchi.Fn Lgrab 5372d3dbb9SYuri Pankovis unable to successfully obtain a handle to the process. 5472d3dbb9SYuri PankovThe possible errors are defined below in the 5543051d27SRobert Mustacchi.Sx ERRORS 5672d3dbb9SYuri Pankovsection. 5772d3dbb9SYuri PankovThe code may be transformed into a human readable string through the use of 5843051d27SRobert Mustacchi.Xr Lgrab_error 3PROC . 5943051d27SRobert Mustacchi.Pp 6043051d27SRobert MustacchiThe handle to the thread is valid until the 6143051d27SRobert Mustacchi.Xr Lfree 3PROC 6272d3dbb9SYuri Pankovfunction is called, which also releases associated resources from the handle. 6372d3dbb9SYuri PankovOnly a single handle to a specific thread may exist at any time. 6472d3dbb9SYuri PankovIf the handle already exists and another caller attempts to grab 6572d3dbb9SYuri Pankovthat thread, it will result in an error. 6672d3dbb9SYuri PankovThe caller must call 6743051d27SRobert Mustacchi.Fn Lfree 6843051d27SRobert Mustacchibefore releasing the handle associated with 6943051d27SRobert Mustacchi.Fa P . 7043051d27SRobert Mustacchi.Pp 7143051d27SRobert MustacchiUnlike grabbing a process, grabbing a thread does not change the current 7272d3dbb9SYuri Pankovstate of the thread. 7372d3dbb9SYuri PankovIf it is running, it will remain running. 7472d3dbb9SYuri PankovIf it is stopped, it will remain stopped. 7543051d27SRobert Mustacchi.Sh RETURN VALUES 7643051d27SRobert MustacchiUpon successful completion, the 7743051d27SRobert Mustacchi.Fn Lgrab 7872d3dbb9SYuri Pankovfunction returns a pointer to the control handle for the specified thread. 7972d3dbb9SYuri PankovOtherwise, the 8043051d27SRobert Mustacchi.Dv NULL 8143051d27SRobert Mustacchipointer is returned and 8243051d27SRobert Mustacchi.Fa perr 8343051d27SRobert Mustacchiis set to indicate the error. 8443051d27SRobert Mustacchi.Sh ERRORS 8543051d27SRobert MustacchiThe 8643051d27SRobert Mustacchi.Fn Lgrab 8743051d27SRobert Mustacchifunction will fail if: 8843051d27SRobert Mustacchi.Bl -tag -width Er 8943051d27SRobert Mustacchi.It Er G_BUSY 9043051d27SRobert MustacchiAnother handle already exists for the thread identified by 9143051d27SRobert Mustacchi.Fa lwpid . 9243051d27SRobert MustacchiThe handle need not exist in the current process and may exist in 9343051d27SRobert Mustacchianother process. 9443051d27SRobert Mustacchi.It Er G_NOPROC 9543051d27SRobert MustacchiThe thread identified by 9643051d27SRobert Mustacchi.Fa lwpid 9743051d27SRobert Mustacchidoes not exist or has already become a zombie. 9843051d27SRobert Mustacchi.It Er G_STRANGE 9972d3dbb9SYuri PankovAn unanticipated system error occurred while trying to create the handle. 10072d3dbb9SYuri PankovWhen this occurs, then the value of 10143051d27SRobert Mustacchi.Sy errno 10272d3dbb9SYuri Pankovis meaningful. 10372d3dbb9SYuri PankovSee 10443051d27SRobert Mustacchi.Xr errno 3C 10543051d27SRobert Mustacchifor more information and 10643051d27SRobert Mustacchi.Xr Intro 2 10743051d27SRobert Mustacchifor the list of possible errors. 10843051d27SRobert Mustacchi.El 10943051d27SRobert Mustacchi.Sh INTERFACE STABILITY 11043051d27SRobert Mustacchi.Sy Uncommitted 11143051d27SRobert Mustacchi.Sh MT-LEVEL 11243051d27SRobert Mustacchi.Sy MT-Safe 11343051d27SRobert Mustacchi.Sh SEE ALSO 11443051d27SRobert Mustacchi.Xr errno 3C , 11543051d27SRobert Mustacchi.Xr libproc 3LIB , 11643051d27SRobert Mustacchi.Xr Lfree 3PROC , 11743051d27SRobert Mustacchi.Xr Lgrab_error 3PROC , 118bbf21555SRichard Lowe.Xr proc 5 119