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 <fcntl.h>
18 #include <stdlib.h>
19 #include <string.h>
20 #if defined(HAVE_PRCTL)
21 #include <sys/prctl.h>
22 #endif
23 #include <sys/stat.h>
24 #include <sys/types.h>
25 #include <unistd.h>
26
27 #include <cutils/process_name.h>
28 #ifdef HAVE_ANDROID_OS
29 #include <cutils/properties.h>
30 #endif
31
32 #define PROCESS_NAME_DEVICE "/sys/qemu_trace/process_name"
33
34 static const char* process_name = "unknown";
35 #ifdef HAVE_ANDROID_OS
36 static int running_in_emulator = -1;
37 #endif
38
set_process_name(const char * new_name)39 void set_process_name(const char* new_name) {
40 #ifdef HAVE_ANDROID_OS
41 char propBuf[PROPERTY_VALUE_MAX];
42 #endif
43
44 if (new_name == NULL) {
45 return;
46 }
47
48 // We never free the old name. Someone else could be using it.
49 int len = strlen(new_name);
50 char* copy = (char*) malloc(len + 1);
51 strcpy(copy, new_name);
52 process_name = (const char*) copy;
53
54 #if defined(HAVE_PRCTL)
55 if (len < 16) {
56 prctl(PR_SET_NAME, (unsigned long) new_name, 0, 0, 0);
57 } else {
58 prctl(PR_SET_NAME, (unsigned long) new_name + len - 15, 0, 0, 0);
59 }
60 #endif
61
62 #ifdef HAVE_ANDROID_OS
63 // If we know we are not running in the emulator, then return.
64 if (running_in_emulator == 0) {
65 return;
66 }
67
68 // If the "running_in_emulator" variable has not been initialized,
69 // then do it now.
70 if (running_in_emulator == -1) {
71 property_get("ro.kernel.qemu", propBuf, "");
72 if (propBuf[0] == '1') {
73 running_in_emulator = 1;
74 } else {
75 running_in_emulator = 0;
76 return;
77 }
78 }
79
80 // If the emulator was started with the "-trace file" command line option
81 // then we want to record the process name in the trace even if we are
82 // not currently tracing instructions (so that we will know the process
83 // name when we do start tracing instructions). We do not need to execute
84 // this code if we are just running in the emulator without the "-trace"
85 // command line option, but we don't know that here and this function
86 // isn't called frequently enough to bother optimizing that case.
87 int fd = open(PROCESS_NAME_DEVICE, O_RDWR);
88 if (fd < 0)
89 return;
90 write(fd, process_name, strlen(process_name) + 1);
91 close(fd);
92 #endif
93 }
94
get_process_name(void)95 const char* get_process_name(void) {
96 return process_name;
97 }
98