1/*
2 * Copyright 2014 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 <errno.h>
18#include <stdlib.h>
19#include <ctype.h>
20
21#define LOG_TAG "ADebug"
22#include <cutils/atomic.h>
23#include <utils/Log.h>
24#include <utils/misc.h>
25
26#include <cutils/properties.h>
27
28#include <ADebug.h>
29#include <AStringUtils.h>
30#include <AUtils.h>
31
32#define UNUSED(x) ((void)(x))
33
34namespace android {
35
36//static
37long ADebug::GetLevelFromSettingsString(
38        const char *name, const char *value, long def) {
39    // split on ,
40    const char *next = value, *current;
41    while (next != NULL) {
42        current = next;
43        next = strchr(current, ',');
44        if (next != NULL) {
45            ++next;  // pass ,
46        }
47
48        while (isspace(*current)) {
49            ++current;
50        }
51        // check for :
52        const char *colon = strchr(current, ':');
53
54        // get level
55        char *end;
56        errno = 0;  // strtol does not clear errno, but it can be set for any return value
57        long level = strtol(current, &end, 10);
58        while (isspace(*end)) {
59            ++end;
60        }
61        if (errno != 0 || end == current || (end != colon && *end != '\0' && end != next)) {
62            // invalid level - skip
63            continue;
64        }
65        if (colon != NULL) {
66            // check if pattern matches
67            do {  // skip colon and spaces
68                ++colon;
69            } while (isspace(*colon));
70            size_t globLen = (next == NULL ? strlen(colon) : (next - 1 - colon));
71            while (globLen > 0 && isspace(colon[globLen - 1])) {
72                --globLen;  // trim glob
73            }
74
75            if (!AStringUtils::MatchesGlob(
76                    colon, globLen, name, strlen(name), true /* ignoreCase */)) {
77                continue;
78            }
79        }
80
81        // update value
82        def = level;
83    }
84    return def;
85}
86
87//static
88long ADebug::GetLevelFromProperty(
89        const char *name, const char *propertyName, long def) {
90    char value[PROPERTY_VALUE_MAX];
91    if (property_get(propertyName, value, NULL)) {
92        def = GetLevelFromSettingsString(name, value, def);
93    }
94    return def;
95}
96
97//static
98ADebug::Level ADebug::GetDebugLevelFromProperty(
99        const char *name, const char *propertyName, ADebug::Level def) {
100    long level = GetLevelFromProperty(name, propertyName, (long)def);
101    return (Level)min(max(level, (long)kDebugNone), (long)kDebugMax);
102}
103
104//static
105char *ADebug::GetDebugName(const char *name) {
106    char *debugName = strdup(name);
107    const char *terms[] = { "omx", "video", "audio" };
108    for (size_t i = 0; i < NELEM(terms) && debugName != NULL; i++) {
109        const char *term = terms[i];
110        const size_t len = strlen(term);
111        char *match = strcasestr(debugName, term);
112        if (match != NULL && (match == debugName || match[-1] == '.'
113                || match[len] == '.' || match[len] == '\0')) {
114            char *src = match + len;
115            if (match == debugName || match[-1] == '.') {
116                src += (*src == '.');  // remove trailing or double .
117            }
118            memmove(match, src, debugName + strlen(debugName) - src + 1);
119        }
120    }
121
122    return debugName;
123}
124
125//static
126bool ADebug::getExperimentFlag(
127        bool allow, const char *name, uint64_t modulo,
128        uint64_t limit, uint64_t plus, uint64_t timeDivisor) {
129    // see if this experiment should be disabled/enabled based on properties.
130    // default to 2 to allow 0/1 specification
131    const int undefined = 2;
132    long level = GetLevelFromProperty(name, "debug.stagefright.experiments", undefined);
133    if (level != undefined) {
134        ALOGI("experiment '%s': %s from property", name, level ? "ENABLED" : "disabled");
135        return allow && (level != 0);
136    }
137
138#ifndef ENABLE_STAGEFRIGHT_AUTO_EXPERIMENTS
139    UNUSED(modulo);
140    UNUSED(limit);
141    UNUSED(plus);
142    UNUSED(timeDivisor);
143    return false;
144#else
145    // Disable automatic experiments in "non-experimental" builds (that is, _all_ builds
146    // as there is no "experimental" build).
147    // TODO: change build type to enable automatic experiments in the future for some builds
148    char value[PROPERTY_VALUE_MAX];
149    if (property_get("ro.build.type", value, NULL)) {
150        if (strcmp(value, "experimental")) {
151            return false;
152        }
153    }
154
155    static volatile int32_t haveSerial = 0;
156    static uint64_t serialNum;
157    if (!android_atomic_acquire_load(&haveSerial)) {
158        // calculate initial counter value based on serial number
159        static char serial[PROPERTY_VALUE_MAX];
160        property_get("ro.serialno", serial, "0");
161        uint64_t num = 0; // it is okay for this number to overflow
162        for (size_t i = 0; i < NELEM(serial) && serial[i] != '\0'; ++i) {
163            const char &c = serial[i];
164            // try to use most letters of serialno
165            if (isdigit(c)) {
166                num = num * 10 + (c - '0');
167            } else if (islower(c)) {
168                num = num * 26 + (c - 'a');
169            } else if (isupper(c)) {
170                num = num * 26 + (c - 'A');
171            } else {
172                num = num * 256 + c;
173            }
174        }
175        serialNum = num;
176        android_atomic_release_store(1, &haveSerial);
177    }
178    ALOGD("serial: %llu, time: %lld", (long long unsigned)serialNum, (long long)time(NULL));
179    // MINOR: use modulo for counter and time, so that their sum does not
180    // roll over, and mess up the correlation between related experiments.
181    // e.g. keep (a mod 2N) = 0 impl (a mod N) = 0
182    time_t counter = (time(NULL) / timeDivisor) % modulo + plus + serialNum % modulo;
183    bool enable = allow && (counter % modulo < limit);
184    ALOGI("experiment '%s': %s", name, enable ? "ENABLED" : "disabled");
185    return enable;
186#endif
187}
188
189}  // namespace android
190
191