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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     27 
     28 #include <stdio.h>
     29 #include <stdlib.h>
     30 #include <unistd.h>
     31 #include <fcntl.h>
     32 #include <string.h>
     33 #include <errno.h>
     34 #include <sys/types.h>
     35 #include <signal.h>
     36 #include <libproc.h>
     37 
     38 static	int	start(char *);
     39 static	int	lwpstart(int *, const lwpstatus_t *, const lwpsinfo_t *);
     40 
     41 static	char	*command;
     42 static	const char *lwps;
     43 static	struct	ps_prochandle *P;
     44 
     45 int
     46 main(int argc, char **argv)
     47 {
     48 	int	rc = 0;
     49 
     50 	if ((command = strrchr(argv[0], '/')) != NULL)
     51 		command++;
     52 	else
     53 		command = argv[0];
     54 
     55 	if (argc <= 1) {
     56 		(void) fprintf(stderr, "usage:\t%s pid[/lwps] ...\n", command);
     57 		(void) fprintf(stderr, "  (set stopped processes or lwps "
     58 		    "running)\n");
     59 		return (2);
     60 	}
     61 
     62 	while (--argc > 0)
     63 		rc += start(*++argv);
     64 
     65 	return (rc);
     66 }
     67 
     68 static int
     69 start(char *arg)
     70 {
     71 	int gcode;
     72 	int rc = 0;
     73 
     74 	if ((P = proc_arg_xgrab(arg, NULL, PR_ARG_PIDS, PGRAB_FORCE |
     75 	    PGRAB_RETAIN | PGRAB_NOSTOP, &gcode, &lwps)) == NULL) {
     76 		(void) fprintf(stderr, "%s: cannot control %s: %s\n",
     77 		    command, arg, Pgrab_error(gcode));
     78 		return (1);
     79 	}
     80 
     81 	/*
     82 	 * If the victim is stopped because of a job control signal, we
     83 	 * need to send it SIGCONT to get it moving again, otherwise
     84 	 * the agent will not be able to run, and so will not be able to
     85 	 * exit the process.
     86 	 */
     87 	(void) kill(Pstatus(P)->pr_pid, SIGCONT);
     88 
     89 	/*
     90 	 * if the agent already exists, Pcreate_agent will adopt the
     91 	 * extant agent so that we can destroy it
     92 	 */
     93 	if (Pstatus(P)->pr_lwp.pr_flags & PR_AGENT) {
     94 		if (Pcreate_agent(P) != 0) {
     95 			(void) fprintf(stderr,
     96 			    "%s: cannot remove agent from %s: %s\n",
     97 			    command, arg, strerror(errno));
     98 
     99 			Prelease(P, 0);
    100 			return (1);
    101 		}
    102 
    103 		Pdestroy_agent(P);
    104 	}
    105 
    106 	if (lwps != NULL) {
    107 		/*
    108 		 * The user provided an lwp specification. Let's consider the
    109 		 * lwp specification as a mask.  We iterate over all lwps in the
    110 		 * process and set running every lwp, which matches the mask.
    111 		 * If there is no lwp matching the mask or an error occured
    112 		 * during the iteration, set the return code to 1 as indication
    113 		 * of an error.  We need to unset run-on-last-close flag,
    114 		 * otherwise *all* lwps could be set running after detaching
    115 		 * from the process and not only lwps, which were selected.
    116 		 */
    117 		int lwpcount = 0;
    118 
    119 		(void) Punsetflags(P, PR_RLC);
    120 		(void) Plwp_iter_all(P, (proc_lwp_all_f *)lwpstart, &lwpcount);
    121 
    122 		if (lwpcount == 0) {
    123 			(void) fprintf(stderr, "%s: cannot control %s:"
    124 			    " no matching LWPs found\n", command, arg);
    125 			rc = 1;
    126 		} else if (lwpcount == -1)
    127 			rc = 1;
    128 	} else {
    129 		(void) Psetrun(P, 0, 0);	/* Set the process running. */
    130 	}
    131 
    132 	/*
    133 	 * Prelease could change the tracing flags or leave the victim hung
    134 	 * so we free the handle by hand.
    135 	 */
    136 	Pfree(P);
    137 	return (rc);
    138 }
    139 
    140 /* ARGSUSED */
    141 static int
    142 lwpstart(int *lwpcount, const lwpstatus_t *status, const lwpsinfo_t *info)
    143 {
    144 	struct ps_lwphandle *L;
    145 	int gcode;
    146 
    147 	if (proc_lwp_in_set(lwps, info->pr_lwpid)) {
    148 		/*
    149 		 * There is a race between the callback from the iterator and
    150 		 * grabbing of the lwp.  If the lwp has already exited, Lgrab
    151 		 * will return the error code G_NOPROC.  It's not a real error,
    152 		 * only if there is no lwp matching the specification.
    153 		 */
    154 		if ((L = Lgrab(P, info->pr_lwpid, &gcode)) != NULL) {
    155 			(void) Lsetrun(L, 0, 0);
    156 			Lfree(L);
    157 			if (*lwpcount >= 0)
    158 				(*lwpcount)++;
    159 		} else if (gcode != G_NOPROC) {
    160 			(void) fprintf(stderr, "%s: cannot control %d/%d: %s\n",
    161 			    command, (int)Pstatus(P)->pr_pid,
    162 			    (int)info->pr_lwpid, Lgrab_error(gcode));
    163 			*lwpcount = -1;
    164 		}
    165 	}
    166 	return (0);
    167 }
    168