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