1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <limits.h>
#include "libproc.h"
#include "Pcontrol.h"
#include "Pisadep.h"
#include "Putil.h"
#define BLKSIZE (8 * 1024)
/*
* Look for a SYSCALL instruction in the process's address space.
*/
int
Pscantext(struct ps_prochandle *P)
{
char mapfile[PATH_MAX];
int mapfd;
off_t offset; /* offset in text section */
off_t endoff; /* ending offset in text section */
uintptr_t sysaddr; /* address of SYSCALL instruction */
int syspri; /* priority of SYSCALL instruction */
int nbytes; /* number of bytes in buffer */
int n2bytes; /* number of bytes in second buffer */
int nmappings; /* current number of mappings */
prmap_t *pdp; /* pointer to map descriptor */
prmap_t *prbuf; /* buffer for map descriptors */
unsigned nmap; /* number of map descriptors */
uint32_t buf[2 * BLKSIZE / sizeof (uint32_t)]; /* text buffer */
uchar_t *p;
/* try the most recently-seen syscall address */
syspri = 0;
sysaddr = 0;
if (P->sysaddr != 0 &&
(syspri = Pissyscall(P, P->sysaddr)))
sysaddr = P->sysaddr;
/* try the previous instruction */
if (sysaddr == 0 || syspri != 1)
syspri = Pissyscall_prev(P, P->status.pr_lwp.pr_reg[R_PC],
&sysaddr);
if (sysaddr != 0 && syspri == 1) {
P->sysaddr = sysaddr;
return (0);
}
/* open the /proc/<pid>/map file */
(void) snprintf(mapfile, sizeof (mapfile), "%s/%d/map",
procfs_path, (int)P->pid);
if ((mapfd = open(mapfile, O_RDONLY)) < 0) {
dprintf("failed to open %s: %s\n", mapfile, strerror(errno));
return (-1);
}
/* allocate a plausible initial buffer size */
nmap = 50;
/* read all the map structures, allocating more space as needed */
for (;;) {
prbuf = malloc(nmap * sizeof (prmap_t));
if (prbuf == NULL) {
dprintf("Pscantext: failed to allocate buffer\n");
(void) close(mapfd);
return (-1);
}
nmappings = pread(mapfd, prbuf, nmap * sizeof (prmap_t), 0L);
if (nmappings < 0) {
dprintf("Pscantext: failed to read map file: %s\n",
strerror(errno));
free(prbuf);
(void) close(mapfd);
return (-1);
}
nmappings /= sizeof (prmap_t);
if (nmappings < nmap) /* we read them all */
break;
/* allocate a bigger buffer */
free(prbuf);
nmap *= 2;
}
(void) close(mapfd);
/*
* Scan each executable mapping looking for a syscall instruction.
* In dynamically linked executables, syscall instructions are
* typically only found in shared libraries. Because shared libraries
* are most often mapped at the top of the address space, we minimize
* our expected search time by starting at the last mapping and working
* our way down to the first mapping.
*/
for (pdp = &prbuf[nmappings - 1]; sysaddr == 0 && syspri != 1 &&
pdp >= prbuf; pdp--) {
offset = (off_t)pdp->pr_vaddr; /* beginning of text */
endoff = offset + pdp->pr_size;
/* avoid non-EXEC mappings; avoid the stack and heap */
if ((pdp->pr_mflags&MA_EXEC) == 0 ||
(endoff > P->status.pr_stkbase &&
offset < P->status.pr_stkbase + P->status.pr_stksize) ||
(endoff > P->status.pr_brkbase &&
offset < P->status.pr_brkbase + P->status.pr_brksize))
continue;
(void) lseek(P->asfd, (off_t)offset, 0);
if ((nbytes = read(P->asfd, buf, 2*BLKSIZE)) <= 0)
continue;
if (nbytes < BLKSIZE)
n2bytes = 0;
else {
n2bytes = nbytes - BLKSIZE;
nbytes = BLKSIZE;
}
p = (uchar_t *)buf;
/* search text for a SYSCALL instruction */
while (sysaddr == 0 && syspri != 1 && offset < endoff) {
if (nbytes <= 0) { /* shift buffers */
if ((nbytes = n2bytes) <= 0)
break;
(void) memcpy(buf,
&buf[BLKSIZE / sizeof (buf[0])],
nbytes);
n2bytes = 0;
p = (uchar_t *)buf;
if (nbytes == BLKSIZE &&
offset + BLKSIZE < endoff)
n2bytes = read(P->asfd,
&buf[BLKSIZE / sizeof (buf[0])],
BLKSIZE);
}
if (syspri = Pissyscall_text(P, p, nbytes))
sysaddr = offset;
p += sizeof (instr_t);
offset += sizeof (instr_t);
nbytes -= sizeof (instr_t);
}
}
free(prbuf);
if ((P->sysaddr = sysaddr) != 0)
return (0);
else
return (-1);
}
|
