VerifySubs.cpp revision c1a4ab9c313d8a3d12007f2dbef7b5a6fa4ac2ef 
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/*
18 * Dalvik verification subroutines.
19 */
20#include "Dalvik.h"
21#include "analysis/CodeVerify.h"
22#include "libdex/InstrUtils.h"
23
24
25/*
26 * This is used when debugging to apply a magnifying glass to the
27 * verification of a particular method.
28 */
29bool dvmWantVerboseVerification(const Method* meth)
30{
31    return false;       /* COMMENT OUT to enable verbose debugging */
32
33    const char* cd = "Lcom/android/server/am/ActivityManagerService;";
34    const char* mn = "trimApplications";
35    const char* sg = "()V";
36    return (strcmp(meth->clazz->descriptor, cd) == 0 &&
37            dvmCompareNameDescriptorAndMethod(mn, sg, meth) == 0);
38}
39
40/*
41 * Output a code verifier warning message.  For the pre-verifier it's not
42 * a big deal if something fails (and it may even be expected), but if
43 * we're doing just-in-time verification it's significant.
44 */
45void dvmLogVerifyFailure(const Method* meth, const char* format, ...)
46{
47    va_list ap;
48    int logLevel;
49
50    if (gDvm.optimizing) {
51        return;
52        //logLevel = ANDROID_LOG_DEBUG;
53    } else {
54        logLevel = ANDROID_LOG_WARN;
55    }
56
57    va_start(ap, format);
58    LOG_PRI_VA(logLevel, LOG_TAG, format, ap);
59    if (meth != NULL) {
60        char* desc = dexProtoCopyMethodDescriptor(&meth->prototype);
61        LOG_PRI(logLevel, LOG_TAG, "VFY:  rejected %s.%s %s",
62            meth->clazz->descriptor, meth->name, desc);
63        free(desc);
64    }
65}
66
67/*
68 * Show a relatively human-readable message describing the failure to
69 * resolve a class.
70 *
71 * TODO: this is somewhat misleading when resolution fails because of
72 * illegal access rather than nonexistent class.
73 */
74void dvmLogUnableToResolveClass(const char* missingClassDescr,
75    const Method* meth)
76{
77    if (gDvm.optimizing) {
78        return;
79    }
80
81    std::string dotMissingClass = dvmHumanReadableDescriptor(missingClassDescr);
82    std::string dotFromClass = dvmHumanReadableDescriptor(meth->clazz->descriptor);
83    ALOGE("Could not find class '%s', referenced from method %s.%s",
84            dotMissingClass.c_str(), dotFromClass.c_str(), meth->name);
85}
86
87/*
88 * Extract the relative offset from a branch instruction.
89 *
90 * Returns "false" on failure (e.g. this isn't a branch instruction).
91 */
92bool dvmGetBranchOffset(const Method* meth, const InsnFlags* insnFlags,
93    int curOffset, s4* pOffset, bool* pConditional)
94{
95    const u2* insns = meth->insns + curOffset;
96
97    switch (*insns & 0xff) {
98    case OP_GOTO:
99        *pOffset = ((s2) *insns) >> 8;
100        *pConditional = false;
101        break;
102    case OP_GOTO_32:
103        *pOffset = insns[1] | (((u4) insns[2]) << 16);
104        *pConditional = false;
105        break;
106    case OP_GOTO_16:
107        *pOffset = (s2) insns[1];
108        *pConditional = false;
109        break;
110    case OP_IF_EQ:
111    case OP_IF_NE:
112    case OP_IF_LT:
113    case OP_IF_GE:
114    case OP_IF_GT:
115    case OP_IF_LE:
116    case OP_IF_EQZ:
117    case OP_IF_NEZ:
118    case OP_IF_LTZ:
119    case OP_IF_GEZ:
120    case OP_IF_GTZ:
121    case OP_IF_LEZ:
122        *pOffset = (s2) insns[1];
123        *pConditional = true;
124        break;
125    default:
126        return false;
127        break;
128    }
129
130    return true;
131}
132