1 /*
2 * Copyright (C) 2017 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 "perfetto/ftrace_reader/format_parser.h"
18
19 #include <string.h>
20
21 #include <iosfwd>
22 #include <iostream>
23 #include <memory>
24 #include <regex>
25 #include <string>
26 #include <vector>
27
28 #include "perfetto/base/string_splitter.h"
29 #include "perfetto/base/utils.h"
30
31 namespace perfetto {
32 namespace {
33
34 #define MAX_FIELD_LENGTH 127
35 #define STRINGIFY(x) STRINGIFY2(x)
36 #define STRINGIFY2(x) #x
37
38 const char* kCommonFieldPrefix = "common_";
39
IsCommonFieldName(const std::string & name)40 bool IsCommonFieldName(const std::string& name) {
41 return name.compare(0, strlen(kCommonFieldPrefix), kCommonFieldPrefix) == 0;
42 }
43
IsCIdentifier(const std::string & s)44 bool IsCIdentifier(const std::string& s) {
45 for (const char c : s) {
46 if (!(std::isalnum(c) || c == '_'))
47 return false;
48 }
49 return !s.empty() && !std::isdigit(s[0]);
50 }
51
52 } // namespace
53
54 // For example:
55 // "int foo" -> "foo"
56 // "u8 foo[(int)sizeof(struct blah)]" -> "foo"
57 // "char[] foo[16]" -> "foo"
58 // "something_went_wrong" -> ""
59 // "" -> ""
GetNameFromTypeAndName(const std::string & type_and_name)60 std::string GetNameFromTypeAndName(const std::string& type_and_name) {
61 size_t right = type_and_name.size();
62 if (right == 0)
63 return "";
64
65 if (type_and_name[type_and_name.size() - 1] == ']') {
66 right = type_and_name.rfind('[');
67 if (right == std::string::npos)
68 return "";
69 }
70
71 size_t left = type_and_name.rfind(' ', right);
72 if (left == std::string::npos)
73 return "";
74 left++;
75
76 std::string result = type_and_name.substr(left, right - left);
77 if (!IsCIdentifier(result))
78 return "";
79
80 return result;
81 }
82
ParseFtraceEvent(const std::string & input,FtraceEvent * output)83 bool ParseFtraceEvent(const std::string& input, FtraceEvent* output) {
84 char buffer[MAX_FIELD_LENGTH + 1];
85
86 bool has_id = false;
87 bool has_name = false;
88
89 uint32_t id = 0;
90 std::string name;
91 std::vector<FtraceEvent::Field> common_fields;
92 std::vector<FtraceEvent::Field> fields;
93
94 for (base::StringSplitter ss(input, '\n'); ss.Next();) {
95 const char* line = ss.cur_token();
96 if (!has_id && sscanf(line, "ID: %d", &id) == 1) {
97 has_id = true;
98 continue;
99 }
100
101 if (!has_name &&
102 sscanf(line, "name: %" STRINGIFY(MAX_FIELD_LENGTH) "s", buffer) == 1) {
103 name = std::string(buffer);
104 has_name = true;
105 continue;
106 }
107
108 if (strcmp("format:", line) == 0) {
109 continue;
110 }
111
112 uint16_t offset = 0;
113 uint16_t size = 0;
114 int is_signed = 0;
115 if (sscanf(line,
116 "\tfield:%" STRINGIFY(MAX_FIELD_LENGTH) "[^;];\toffset: "
117 "%hu;\tsize: "
118 "%hu;\tsigned: %d;",
119 buffer, &offset, &size, &is_signed) == 4) {
120 std::string type_and_name(buffer);
121
122 FtraceEvent::Field field{type_and_name, offset, size, is_signed == 1};
123
124 if (IsCommonFieldName(GetNameFromTypeAndName(type_and_name))) {
125 common_fields.push_back(field);
126 } else {
127 fields.push_back(field);
128 }
129
130 continue;
131 }
132
133 if (strncmp(line, "print fmt:", 10) == 0) {
134 break;
135 }
136
137 if (output)
138 fprintf(stderr, "Cannot parse line: \"%s\"\n", line);
139 return false;
140 }
141
142 if (!has_id || !has_name || fields.empty()) {
143 if (output)
144 fprintf(stderr, "Could not parse format file: %s.\n",
145 !has_id ? "no ID found"
146 : !has_name ? "no name found" : "no fields found");
147 return false;
148 }
149
150 if (!output)
151 return true;
152
153 output->id = id;
154 output->name = name;
155 output->fields = std::move(fields);
156 output->common_fields = std::move(common_fields);
157
158 return true;
159 }
160
operator <<(::std::ostream & os,const FtraceEvent::Field & field)161 ::std::ostream& operator<<(::std::ostream& os,
162 const FtraceEvent::Field& field) {
163 PrintTo(field, &os);
164 return os;
165 }
166
167 // Allow gtest to pretty print FtraceEvent::Field.
PrintTo(const FtraceEvent::Field & field,::std::ostream * os)168 void PrintTo(const FtraceEvent::Field& field, ::std::ostream* os) {
169 *os << "FtraceEvent::Field(" << field.type_and_name << ", " << field.offset
170 << ", " << field.size << ", " << field.is_signed << ")";
171 }
172
173 } // namespace perfetto
174