1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * CDDL HEADER START
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7c478bd9Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*7c478bd9Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*7c478bd9Sstevel@tonic-gate  * with the License.
8*7c478bd9Sstevel@tonic-gate  *
9*7c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*7c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*7c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*7c478bd9Sstevel@tonic-gate  * and limitations under the License.
13*7c478bd9Sstevel@tonic-gate  *
14*7c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*7c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*7c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*7c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*7c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*7c478bd9Sstevel@tonic-gate  *
20*7c478bd9Sstevel@tonic-gate  * CDDL HEADER END
21*7c478bd9Sstevel@tonic-gate  */
22*7c478bd9Sstevel@tonic-gate /*
23*7c478bd9Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*7c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
25*7c478bd9Sstevel@tonic-gate  */
26*7c478bd9Sstevel@tonic-gate 
27*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*7c478bd9Sstevel@tonic-gate 
29*7c478bd9Sstevel@tonic-gate #include <stdio.h>
30*7c478bd9Sstevel@tonic-gate #include <stdlib.h>
31*7c478bd9Sstevel@tonic-gate #include <string.h>
32*7c478bd9Sstevel@tonic-gate #include <fcntl.h>
33*7c478bd9Sstevel@tonic-gate #include <unistd.h>
34*7c478bd9Sstevel@tonic-gate #include <string.h>
35*7c478bd9Sstevel@tonic-gate #include <errno.h>
36*7c478bd9Sstevel@tonic-gate 
37*7c478bd9Sstevel@tonic-gate #include "libproc.h"
38*7c478bd9Sstevel@tonic-gate #include "Pcontrol.h"
39*7c478bd9Sstevel@tonic-gate #include "Pisadep.h"
40*7c478bd9Sstevel@tonic-gate #include "Putil.h"
41*7c478bd9Sstevel@tonic-gate 
42*7c478bd9Sstevel@tonic-gate #define	BLKSIZE	(8 * 1024)
43*7c478bd9Sstevel@tonic-gate 
44*7c478bd9Sstevel@tonic-gate /*
45*7c478bd9Sstevel@tonic-gate  * Look for a SYSCALL instruction in the process's address space.
46*7c478bd9Sstevel@tonic-gate  */
47*7c478bd9Sstevel@tonic-gate int
48*7c478bd9Sstevel@tonic-gate Pscantext(struct ps_prochandle *P)
49*7c478bd9Sstevel@tonic-gate {
50*7c478bd9Sstevel@tonic-gate 	char mapfile[100];
51*7c478bd9Sstevel@tonic-gate 	int mapfd;
52*7c478bd9Sstevel@tonic-gate 	off_t offset;		/* offset in text section */
53*7c478bd9Sstevel@tonic-gate 	off_t endoff;		/* ending offset in text section */
54*7c478bd9Sstevel@tonic-gate 	uintptr_t sysaddr;	/* address of SYSCALL instruction */
55*7c478bd9Sstevel@tonic-gate 	int syspri;		/* priority of SYSCALL instruction */
56*7c478bd9Sstevel@tonic-gate 	int nbytes;		/* number of bytes in buffer */
57*7c478bd9Sstevel@tonic-gate 	int n2bytes;		/* number of bytes in second buffer */
58*7c478bd9Sstevel@tonic-gate 	int nmappings;		/* current number of mappings */
59*7c478bd9Sstevel@tonic-gate 	prmap_t *pdp;		/* pointer to map descriptor */
60*7c478bd9Sstevel@tonic-gate 	prmap_t *prbuf;		/* buffer for map descriptors */
61*7c478bd9Sstevel@tonic-gate 	unsigned nmap;		/* number of map descriptors */
62*7c478bd9Sstevel@tonic-gate 	uint32_t buf[2 * BLKSIZE / sizeof (uint32_t)];	/* text buffer */
63*7c478bd9Sstevel@tonic-gate 	uchar_t *p;
64*7c478bd9Sstevel@tonic-gate 
65*7c478bd9Sstevel@tonic-gate 	/* try the most recently-seen syscall address */
66*7c478bd9Sstevel@tonic-gate 	syspri = 0;
67*7c478bd9Sstevel@tonic-gate 	sysaddr = 0;
68*7c478bd9Sstevel@tonic-gate 	if (P->sysaddr != 0 &&
69*7c478bd9Sstevel@tonic-gate 	    (syspri = Pissyscall(P, P->sysaddr)))
70*7c478bd9Sstevel@tonic-gate 		sysaddr = P->sysaddr;
71*7c478bd9Sstevel@tonic-gate 
72*7c478bd9Sstevel@tonic-gate 	/* try the previous instruction */
73*7c478bd9Sstevel@tonic-gate 	if (sysaddr == 0 || syspri != 1)
74*7c478bd9Sstevel@tonic-gate 		syspri = Pissyscall_prev(P, P->status.pr_lwp.pr_reg[R_PC],
75*7c478bd9Sstevel@tonic-gate 		    &sysaddr);
76*7c478bd9Sstevel@tonic-gate 
77*7c478bd9Sstevel@tonic-gate 	if (sysaddr != 0 && syspri == 1) {
78*7c478bd9Sstevel@tonic-gate 		P->sysaddr = sysaddr;
79*7c478bd9Sstevel@tonic-gate 		return (0);
80*7c478bd9Sstevel@tonic-gate 	}
81*7c478bd9Sstevel@tonic-gate 
82*7c478bd9Sstevel@tonic-gate 	/* open the /proc/<pid>/map file */
83*7c478bd9Sstevel@tonic-gate 	(void) sprintf(mapfile, "/proc/%d/map", (int)P->pid);
84*7c478bd9Sstevel@tonic-gate 	if ((mapfd = open(mapfile, O_RDONLY)) < 0) {
85*7c478bd9Sstevel@tonic-gate 		dprintf("failed to open %s: %s\n", mapfile, strerror(errno));
86*7c478bd9Sstevel@tonic-gate 		return (-1);
87*7c478bd9Sstevel@tonic-gate 	}
88*7c478bd9Sstevel@tonic-gate 
89*7c478bd9Sstevel@tonic-gate 	/* allocate a plausible initial buffer size */
90*7c478bd9Sstevel@tonic-gate 	nmap = 50;
91*7c478bd9Sstevel@tonic-gate 
92*7c478bd9Sstevel@tonic-gate 	/* read all the map structures, allocating more space as needed */
93*7c478bd9Sstevel@tonic-gate 	for (;;) {
94*7c478bd9Sstevel@tonic-gate 		prbuf = malloc(nmap * sizeof (prmap_t));
95*7c478bd9Sstevel@tonic-gate 		if (prbuf == NULL) {
96*7c478bd9Sstevel@tonic-gate 			dprintf("Pscantext: failed to allocate buffer\n");
97*7c478bd9Sstevel@tonic-gate 			(void) close(mapfd);
98*7c478bd9Sstevel@tonic-gate 			return (-1);
99*7c478bd9Sstevel@tonic-gate 		}
100*7c478bd9Sstevel@tonic-gate 		nmappings = pread(mapfd, prbuf, nmap * sizeof (prmap_t), 0L);
101*7c478bd9Sstevel@tonic-gate 		if (nmappings < 0) {
102*7c478bd9Sstevel@tonic-gate 			dprintf("Pscantext: failed to read map file: %s\n",
103*7c478bd9Sstevel@tonic-gate 			    strerror(errno));
104*7c478bd9Sstevel@tonic-gate 			free(prbuf);
105*7c478bd9Sstevel@tonic-gate 			(void) close(mapfd);
106*7c478bd9Sstevel@tonic-gate 			return (-1);
107*7c478bd9Sstevel@tonic-gate 		}
108*7c478bd9Sstevel@tonic-gate 		nmappings /= sizeof (prmap_t);
109*7c478bd9Sstevel@tonic-gate 		if (nmappings < nmap)	/* we read them all */
110*7c478bd9Sstevel@tonic-gate 			break;
111*7c478bd9Sstevel@tonic-gate 		/* allocate a bigger buffer */
112*7c478bd9Sstevel@tonic-gate 		free(prbuf);
113*7c478bd9Sstevel@tonic-gate 		nmap *= 2;
114*7c478bd9Sstevel@tonic-gate 	}
115*7c478bd9Sstevel@tonic-gate 	(void) close(mapfd);
116*7c478bd9Sstevel@tonic-gate 
117*7c478bd9Sstevel@tonic-gate 	/*
118*7c478bd9Sstevel@tonic-gate 	 * Scan each executable mapping looking for a syscall instruction.
119*7c478bd9Sstevel@tonic-gate 	 * In dynamically linked executables, syscall instructions are
120*7c478bd9Sstevel@tonic-gate 	 * typically only found in shared libraries.  Because shared libraries
121*7c478bd9Sstevel@tonic-gate 	 * are most often mapped at the top of the address space, we minimize
122*7c478bd9Sstevel@tonic-gate 	 * our expected search time by starting at the last mapping and working
123*7c478bd9Sstevel@tonic-gate 	 * our way down to the first mapping.
124*7c478bd9Sstevel@tonic-gate 	 */
125*7c478bd9Sstevel@tonic-gate 	for (pdp = &prbuf[nmappings - 1]; sysaddr == 0 && syspri != 1 &&
126*7c478bd9Sstevel@tonic-gate 	    pdp >= prbuf; pdp--) {
127*7c478bd9Sstevel@tonic-gate 
128*7c478bd9Sstevel@tonic-gate 		offset = (off_t)pdp->pr_vaddr;	/* beginning of text */
129*7c478bd9Sstevel@tonic-gate 		endoff = offset + pdp->pr_size;
130*7c478bd9Sstevel@tonic-gate 
131*7c478bd9Sstevel@tonic-gate 		/* avoid non-EXEC mappings; avoid the stack and heap */
132*7c478bd9Sstevel@tonic-gate 		if ((pdp->pr_mflags&MA_EXEC) == 0 ||
133*7c478bd9Sstevel@tonic-gate 		    (endoff > P->status.pr_stkbase &&
134*7c478bd9Sstevel@tonic-gate 		    offset < P->status.pr_stkbase + P->status.pr_stksize) ||
135*7c478bd9Sstevel@tonic-gate 		    (endoff > P->status.pr_brkbase &&
136*7c478bd9Sstevel@tonic-gate 		    offset < P->status.pr_brkbase + P->status.pr_brksize))
137*7c478bd9Sstevel@tonic-gate 			continue;
138*7c478bd9Sstevel@tonic-gate 
139*7c478bd9Sstevel@tonic-gate 		(void) lseek(P->asfd, (off_t)offset, 0);
140*7c478bd9Sstevel@tonic-gate 
141*7c478bd9Sstevel@tonic-gate 		if ((nbytes = read(P->asfd, buf, 2*BLKSIZE)) <= 0)
142*7c478bd9Sstevel@tonic-gate 			continue;
143*7c478bd9Sstevel@tonic-gate 
144*7c478bd9Sstevel@tonic-gate 		if (nbytes < BLKSIZE)
145*7c478bd9Sstevel@tonic-gate 			n2bytes = 0;
146*7c478bd9Sstevel@tonic-gate 		else {
147*7c478bd9Sstevel@tonic-gate 			n2bytes = nbytes - BLKSIZE;
148*7c478bd9Sstevel@tonic-gate 			nbytes  = BLKSIZE;
149*7c478bd9Sstevel@tonic-gate 		}
150*7c478bd9Sstevel@tonic-gate 
151*7c478bd9Sstevel@tonic-gate 		p = (uchar_t *)buf;
152*7c478bd9Sstevel@tonic-gate 
153*7c478bd9Sstevel@tonic-gate 		/* search text for a SYSCALL instruction */
154*7c478bd9Sstevel@tonic-gate 		while (sysaddr == 0 && syspri != 1 && offset < endoff) {
155*7c478bd9Sstevel@tonic-gate 			if (nbytes <= 0) {	/* shift buffers */
156*7c478bd9Sstevel@tonic-gate 				if ((nbytes = n2bytes) <= 0)
157*7c478bd9Sstevel@tonic-gate 					break;
158*7c478bd9Sstevel@tonic-gate 				(void) memcpy(buf,
159*7c478bd9Sstevel@tonic-gate 					&buf[BLKSIZE / sizeof (buf[0])],
160*7c478bd9Sstevel@tonic-gate 					nbytes);
161*7c478bd9Sstevel@tonic-gate 				n2bytes = 0;
162*7c478bd9Sstevel@tonic-gate 				p = (uchar_t *)buf;
163*7c478bd9Sstevel@tonic-gate 				if (nbytes == BLKSIZE &&
164*7c478bd9Sstevel@tonic-gate 				    offset + BLKSIZE < endoff)
165*7c478bd9Sstevel@tonic-gate 					n2bytes = read(P->asfd,
166*7c478bd9Sstevel@tonic-gate 						&buf[BLKSIZE / sizeof (buf[0])],
167*7c478bd9Sstevel@tonic-gate 						BLKSIZE);
168*7c478bd9Sstevel@tonic-gate 			}
169*7c478bd9Sstevel@tonic-gate 
170*7c478bd9Sstevel@tonic-gate 			if (syspri = Pissyscall_text(P, p, nbytes))
171*7c478bd9Sstevel@tonic-gate 				sysaddr = offset;
172*7c478bd9Sstevel@tonic-gate 
173*7c478bd9Sstevel@tonic-gate 			p += sizeof (instr_t);
174*7c478bd9Sstevel@tonic-gate 			offset += sizeof (instr_t);
175*7c478bd9Sstevel@tonic-gate 			nbytes -= sizeof (instr_t);
176*7c478bd9Sstevel@tonic-gate 		}
177*7c478bd9Sstevel@tonic-gate 	}
178*7c478bd9Sstevel@tonic-gate 
179*7c478bd9Sstevel@tonic-gate 	if ((P->sysaddr = sysaddr) != 0)
180*7c478bd9Sstevel@tonic-gate 		return (0);
181*7c478bd9Sstevel@tonic-gate 	else
182*7c478bd9Sstevel@tonic-gate 		return (-1);
183*7c478bd9Sstevel@tonic-gate }
184