process_name.c revision 4f6e8d7a00cbeda1e70cc15be9c4af1018bdad53
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#define PROCESS_NAME_DEVICE "/sys/qemu_trace/process_name"
26
27static const char* process_name = "unknown";
28static int running_in_emulator = -1;
29
30void set_process_name(const char* new_name) {
31    char  propBuf[PROPERTY_VALUE_MAX];
32
33    if (new_name == NULL) {
34        return;
35    }
36
37    // We never free the old name. Someone else could be using it.
38    char* copy = (char*) malloc(strlen(new_name) + 1);
39    strcpy(copy, new_name);
40    process_name = (const char*) copy;
41
42    // If we know we are not running in the emulator, then return.
43    if (running_in_emulator == 0) {
44        return;
45    }
46
47    // If the "running_in_emulator" variable has not been initialized,
48    // then do it now.
49    if (running_in_emulator == -1) {
50        property_get("ro.kernel.qemu", propBuf, "");
51        if (propBuf[0] == '1') {
52            running_in_emulator = 1;
53        } else {
54            running_in_emulator = 0;
55            return;
56        }
57    }
58
59    // If the emulator was started with the "-trace file" command line option
60    // then we want to record the process name in the trace even if we are
61    // not currently tracing instructions (so that we will know the process
62    // name when we do start tracing instructions).  We do not need to execute
63    // this code if we are just running in the emulator without the "-trace"
64    // command line option, but we don't know that here and this function
65    // isn't called frequently enough to bother optimizing that case.
66    int fd = open(PROCESS_NAME_DEVICE, O_RDWR);
67    if (fd < 0)
68        return;
69    write(fd, process_name, strlen(process_name) + 1);
70    close(fd);
71}
72
73const char* get_process_name(void) {
74    return process_name;
75}
76