cpu_info.c revision dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0 
1/* libs/cutils/cpu_info.c
2**
3** Copyright 2007, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include <cutils/cpu_info.h>
19#include <stdlib.h>
20#include <stdio.h>
21#include <string.h>
22
23// we cache the serial number here.
24// this is also used as a fgets() line buffer when we are reading /proc/cpuinfo
25static char serial_number[100] = { 0 };
26
27extern const char* get_cpu_serial_number(void)
28{
29    if (serial_number[0] == 0)
30    {
31        FILE* file;
32        char* chp, *end;
33        char* whitespace;
34        int length;
35
36        // read serial number from /proc/cpuinfo
37        file = fopen("proc/cpuinfo", "r");
38        if (! file)
39            return NULL;
40
41        while ((chp = fgets(serial_number, sizeof(serial_number), file)) != NULL)
42        {
43            // look for something like "Serial          : 999206122a03591c"
44
45            if (strncmp(chp, "Serial", 6) != 0)
46                continue;
47
48            chp = strchr(chp, ':');
49            if (!chp)
50                continue;
51
52             // skip colon and whitespace
53            while ( *(++chp) == ' ') {}
54
55            // truncate trailing whitespace
56            end = chp;
57            while (*end && *end != ' ' && *end != '\t' && *end != '\n' && *end != '\r')
58                ++end;
59            *end = 0;
60
61            whitespace = strchr(chp, ' ');
62            if (whitespace)
63                *whitespace = 0;
64            whitespace = strchr(chp, '\t');
65            if (whitespace)
66                *whitespace = 0;
67            whitespace = strchr(chp, '\r');
68            if (whitespace)
69                *whitespace = 0;
70            whitespace = strchr(chp, '\n');
71            if (whitespace)
72                *whitespace = 0;
73
74            // shift serial number to beginning of the buffer
75            memmove(serial_number, chp, strlen(chp) + 1);
76            break;
77        }
78
79        fclose(file);
80    }
81
82    return (serial_number[0] ? serial_number : NULL);
83}
84