1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 #include <stdio.h>
17 #include <string.h>
18 #include <errno.h>
19 #include <sys/stat.h>
20 #include <sys/types.h>
21 #include <fcntl.h>
22 #include <unistd.h>
23
24 // This is the pathname to the sysfs file that enables and disables
25 // tracing on the qemu emulator.
26 #define SYS_QEMU_TRACE_STATE "/sys/qemu_trace/state"
27
28
29 // This is the pathname to the sysfs file that adds new (address, symbol)
30 // pairs to the trace.
31 #define SYS_QEMU_TRACE_SYMBOL "/sys/qemu_trace/symbol"
32
33 // The maximum length of a symbol name
34 #define MAX_SYMBOL_NAME_LENGTH (4 * 1024)
35
36 // Allow space in the buffer for the address plus whitespace.
37 #define MAX_BUF_SIZE (MAX_SYMBOL_NAME_LENGTH + 20)
38
39 // return 0 on success, or an error if the qemu driver cannot be opened
qemu_start_tracing()40 int qemu_start_tracing()
41 {
42 int fd = open(SYS_QEMU_TRACE_STATE, O_WRONLY);
43 if (fd < 0)
44 return fd;
45 write(fd, "1\n", 2);
46 close(fd);
47 return 0;
48 }
49
qemu_stop_tracing()50 int qemu_stop_tracing()
51 {
52 int fd = open(SYS_QEMU_TRACE_STATE, O_WRONLY);
53 if (fd < 0)
54 return fd;
55 write(fd, "0\n", 2);
56 close(fd);
57 return 0;
58 }
59
qemu_add_mapping(unsigned int addr,const char * name)60 int qemu_add_mapping(unsigned int addr, const char *name)
61 {
62 char buf[MAX_BUF_SIZE];
63
64 if (strlen(name) > MAX_SYMBOL_NAME_LENGTH)
65 return EINVAL;
66 int fd = open(SYS_QEMU_TRACE_SYMBOL, O_WRONLY);
67 if (fd < 0)
68 return fd;
69 sprintf(buf, "%x %s\n", addr, name);
70 write(fd, buf, strlen(buf));
71 close(fd);
72 return 0;
73 }
74
qemu_remove_mapping(unsigned int addr)75 int qemu_remove_mapping(unsigned int addr)
76 {
77 char buf[MAX_BUF_SIZE];
78
79 int fd = open(SYS_QEMU_TRACE_SYMBOL, O_WRONLY);
80 if (fd < 0)
81 return fd;
82 sprintf(buf, "%x\n", addr);
83 write(fd, buf, strlen(buf));
84 close(fd);
85 return 0;
86 }
87