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
17 #include <string.h>
18 #include <cutils/process_name.h>
19 #include <cutils/properties.h>
20 #include <unistd.h>
21 #include <sys/types.h>
22 #include <sys/stat.h>
23 #include <fcntl.h>
24
25 #if defined(HAVE_PRCTL)
26 #include <sys/prctl.h>
27 #endif
28
29 #define PROCESS_NAME_DEVICE "/sys/qemu_trace/process_name"
30
31 static const char* process_name = "unknown";
32 static int running_in_emulator = -1;
33
set_process_name(const char * new_name)34 void set_process_name(const char* new_name) {
35 char propBuf[PROPERTY_VALUE_MAX];
36
37 if (new_name == NULL) {
38 return;
39 }
40
41 // We never free the old name. Someone else could be using it.
42 int len = strlen(new_name);
43 char* copy = (char*) malloc(len + 1);
44 strcpy(copy, new_name);
45 process_name = (const char*) copy;
46
47 #if defined(HAVE_PRCTL)
48 if (len < 16) {
49 prctl(PR_SET_NAME, (unsigned long) new_name, 0, 0, 0);
50 } else {
51 prctl(PR_SET_NAME, (unsigned long) new_name + len - 15, 0, 0, 0);
52 }
53 #endif
54
55 // If we know we are not running in the emulator, then return.
56 if (running_in_emulator == 0) {
57 return;
58 }
59
60 // If the "running_in_emulator" variable has not been initialized,
61 // then do it now.
62 if (running_in_emulator == -1) {
63 property_get("ro.kernel.qemu", propBuf, "");
64 if (propBuf[0] == '1') {
65 running_in_emulator = 1;
66 } else {
67 running_in_emulator = 0;
68 return;
69 }
70 }
71
72 // If the emulator was started with the "-trace file" command line option
73 // then we want to record the process name in the trace even if we are
74 // not currently tracing instructions (so that we will know the process
75 // name when we do start tracing instructions). We do not need to execute
76 // this code if we are just running in the emulator without the "-trace"
77 // command line option, but we don't know that here and this function
78 // isn't called frequently enough to bother optimizing that case.
79 int fd = open(PROCESS_NAME_DEVICE, O_RDWR);
80 if (fd < 0)
81 return;
82 write(fd, process_name, strlen(process_name) + 1);
83 close(fd);
84 }
85
get_process_name(void)86 const char* get_process_name(void) {
87 return process_name;
88 }
89