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(__linux__)
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
34static const char* process_name = "unknown";
35#ifdef HAVE_ANDROID_OS
36static int running_in_emulator = -1;
37#endif
38
39void 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(__linux__)
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
95const char* get_process_name(void) {
96    return process_name;
97}
98