1 /*
2 *
3 * Copyright 2015 gRPC authors.
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
19 #include <grpc/support/port_platform.h>
20
21 #include "src/core/lib/debug/trace.h"
22
23 #include <string.h>
24 #include <type_traits>
25
26 #include <grpc/grpc.h>
27 #include <grpc/support/alloc.h>
28 #include <grpc/support/log.h>
29
30 GPR_GLOBAL_CONFIG_DEFINE_STRING(
31 grpc_trace, "",
32 "A comma separated list of tracers that provide additional insight into "
33 "how gRPC C core is processing requests via debug logs.");
34
35 int grpc_tracer_set_enabled(const char* name, int enabled);
36
37 namespace grpc_core {
38
39 TraceFlag* TraceFlagList::root_tracer_ = nullptr;
40
Set(const char * name,bool enabled)41 bool TraceFlagList::Set(const char* name, bool enabled) {
42 TraceFlag* t;
43 if (0 == strcmp(name, "all")) {
44 for (t = root_tracer_; t; t = t->next_tracer_) {
45 t->set_enabled(enabled);
46 }
47 } else if (0 == strcmp(name, "list_tracers")) {
48 LogAllTracers();
49 } else if (0 == strcmp(name, "refcount")) {
50 for (t = root_tracer_; t; t = t->next_tracer_) {
51 if (strstr(t->name_, "refcount") != nullptr) {
52 t->set_enabled(enabled);
53 }
54 }
55 } else {
56 bool found = false;
57 for (t = root_tracer_; t; t = t->next_tracer_) {
58 if (0 == strcmp(name, t->name_)) {
59 t->set_enabled(enabled);
60 found = true;
61 }
62 }
63 // check for unknowns, but ignore "", to allow to GRPC_TRACE=
64 if (!found && 0 != strcmp(name, "")) {
65 gpr_log(GPR_ERROR, "Unknown trace var: '%s'", name);
66 return false; /* early return */
67 }
68 }
69 return true;
70 }
71
Add(TraceFlag * flag)72 void TraceFlagList::Add(TraceFlag* flag) {
73 flag->next_tracer_ = root_tracer_;
74 root_tracer_ = flag;
75 }
76
LogAllTracers()77 void TraceFlagList::LogAllTracers() {
78 gpr_log(GPR_DEBUG, "available tracers:");
79 TraceFlag* t;
80 for (t = root_tracer_; t != nullptr; t = t->next_tracer_) {
81 gpr_log(GPR_DEBUG, "\t%s", t->name_);
82 }
83 }
84
85 // Flags register themselves on the list during construction
TraceFlag(bool default_enabled,const char * name)86 TraceFlag::TraceFlag(bool default_enabled, const char* name) : name_(name) {
87 static_assert(std::is_trivially_destructible<TraceFlag>::value,
88 "TraceFlag needs to be trivially destructible.");
89 set_enabled(default_enabled);
90 TraceFlagList::Add(this);
91 }
92
93 } // namespace grpc_core
94
add(const char * beg,const char * end,char *** ss,size_t * ns)95 static void add(const char* beg, const char* end, char*** ss, size_t* ns) {
96 size_t n = *ns;
97 size_t np = n + 1;
98 char* s;
99 size_t len;
100 GPR_ASSERT(end >= beg);
101 len = static_cast<size_t>(end - beg);
102 s = static_cast<char*>(gpr_malloc(len + 1));
103 memcpy(s, beg, len);
104 s[len] = 0;
105 *ss = static_cast<char**>(gpr_realloc(*ss, sizeof(char**) * np));
106 (*ss)[n] = s;
107 *ns = np;
108 }
109
split(const char * s,char *** ss,size_t * ns)110 static void split(const char* s, char*** ss, size_t* ns) {
111 const char* c = strchr(s, ',');
112 if (c == nullptr) {
113 add(s, s + strlen(s), ss, ns);
114 } else {
115 add(s, c, ss, ns);
116 split(c + 1, ss, ns);
117 }
118 }
119
parse(const char * s)120 static void parse(const char* s) {
121 char** strings = nullptr;
122 size_t nstrings = 0;
123 size_t i;
124 split(s, &strings, &nstrings);
125
126 for (i = 0; i < nstrings; i++) {
127 if (strings[i][0] == '-') {
128 grpc_core::TraceFlagList::Set(strings[i] + 1, false);
129 } else {
130 grpc_core::TraceFlagList::Set(strings[i], true);
131 }
132 }
133
134 for (i = 0; i < nstrings; i++) {
135 gpr_free(strings[i]);
136 }
137 gpr_free(strings);
138 }
139
grpc_tracer_init(const char * env_var_name)140 void grpc_tracer_init(const char* env_var_name) {
141 (void)env_var_name; // suppress unused variable error
142 grpc_tracer_init();
143 }
144
grpc_tracer_init()145 void grpc_tracer_init() {
146 grpc_core::UniquePtr<char> value = GPR_GLOBAL_CONFIG_GET(grpc_trace);
147 parse(value.get());
148 }
149
grpc_tracer_shutdown(void)150 void grpc_tracer_shutdown(void) {}
151
grpc_tracer_set_enabled(const char * name,int enabled)152 int grpc_tracer_set_enabled(const char* name, int enabled) {
153 return grpc_core::TraceFlagList::Set(name, enabled != 0);
154 }
155