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1 /*
2  *
3  * Copyright 2016 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/transport/error_utils.h"
22 
23 #include <grpc/support/string_util.h>
24 #include "src/core/lib/iomgr/error_internal.h"
25 #include "src/core/lib/slice/slice_internal.h"
26 #include "src/core/lib/transport/status_conversion.h"
27 
recursively_find_error_with_field(grpc_error_handle error,grpc_error_ints which)28 static grpc_error_handle recursively_find_error_with_field(
29     grpc_error_handle error, grpc_error_ints which) {
30   intptr_t unused;
31   // If the error itself has a status code, return it.
32   if (grpc_error_get_int(error, which, &unused)) {
33     return error;
34   }
35   if (grpc_error_is_special(error)) return nullptr;
36   // Otherwise, search through its children.
37   uint8_t slot = error->first_err;
38   while (slot != UINT8_MAX) {
39     grpc_linked_error* lerr =
40         reinterpret_cast<grpc_linked_error*>(error->arena + slot);
41     grpc_error_handle result =
42         recursively_find_error_with_field(lerr->err, which);
43     if (result) return result;
44     slot = lerr->next;
45   }
46   return nullptr;
47 }
48 
grpc_error_get_status(grpc_error_handle error,grpc_millis deadline,grpc_status_code * code,grpc_slice * slice,grpc_http2_error_code * http_error,const char ** error_string)49 void grpc_error_get_status(grpc_error_handle error, grpc_millis deadline,
50                            grpc_status_code* code, grpc_slice* slice,
51                            grpc_http2_error_code* http_error,
52                            const char** error_string) {
53   // Fast path: We expect no error.
54   if (GPR_LIKELY(error == GRPC_ERROR_NONE)) {
55     if (code != nullptr) *code = GRPC_STATUS_OK;
56     if (slice != nullptr) {
57       // Normally, we call grpc_error_get_str(
58       //   error, GRPC_ERROR_STR_GRPC_MESSAGE, slice).
59       // We can fastpath since we know that:
60       // 1) Error is null
61       // 2) which == GRPC_ERROR_STR_GRPC_MESSAGE
62       // 3) The resulting slice is statically known.
63       // 4) Said resulting slice is of length 0 ("").
64       // This means 3 movs, instead of 10s of instructions and a strlen.
65       *slice = grpc_core::ExternallyManagedSlice("");
66     }
67     if (http_error != nullptr) {
68       *http_error = GRPC_HTTP2_NO_ERROR;
69     }
70     return;
71   }
72 
73   // Start with the parent error and recurse through the tree of children
74   // until we find the first one that has a status code.
75   grpc_error_handle found_error =
76       recursively_find_error_with_field(error, GRPC_ERROR_INT_GRPC_STATUS);
77   if (found_error == nullptr) {
78     /// If no grpc-status exists, retry through the tree to find a http2 error
79     /// code
80     found_error =
81         recursively_find_error_with_field(error, GRPC_ERROR_INT_HTTP2_ERROR);
82   }
83 
84   // If we found an error with a status code above, use that; otherwise,
85   // fall back to using the parent error.
86   if (found_error == nullptr) found_error = error;
87 
88   grpc_status_code status = GRPC_STATUS_UNKNOWN;
89   intptr_t integer;
90   if (grpc_error_get_int(found_error, GRPC_ERROR_INT_GRPC_STATUS, &integer)) {
91     status = static_cast<grpc_status_code>(integer);
92   } else if (grpc_error_get_int(found_error, GRPC_ERROR_INT_HTTP2_ERROR,
93                                 &integer)) {
94     status = grpc_http2_error_to_grpc_status(
95         static_cast<grpc_http2_error_code>(integer), deadline);
96   }
97   if (code != nullptr) *code = status;
98 
99   if (error_string != nullptr && status != GRPC_STATUS_OK) {
100     *error_string = gpr_strdup(grpc_error_std_string(error).c_str());
101   }
102 
103   if (http_error != nullptr) {
104     if (grpc_error_get_int(found_error, GRPC_ERROR_INT_HTTP2_ERROR, &integer)) {
105       *http_error = static_cast<grpc_http2_error_code>(integer);
106     } else if (grpc_error_get_int(found_error, GRPC_ERROR_INT_GRPC_STATUS,
107                                   &integer)) {
108       *http_error =
109           grpc_status_to_http2_error(static_cast<grpc_status_code>(integer));
110     } else {
111       *http_error = found_error == GRPC_ERROR_NONE ? GRPC_HTTP2_NO_ERROR
112                                                    : GRPC_HTTP2_INTERNAL_ERROR;
113     }
114   }
115 
116   // If the error has a status message, use it.  Otherwise, fall back to
117   // the error description.
118   if (slice != nullptr) {
119     if (!grpc_error_get_str(found_error, GRPC_ERROR_STR_GRPC_MESSAGE, slice)) {
120       if (!grpc_error_get_str(found_error, GRPC_ERROR_STR_DESCRIPTION, slice)) {
121         *slice = grpc_slice_from_static_string("unknown error");
122       }
123     }
124   }
125 }
126 
grpc_error_to_absl_status(grpc_error_handle error)127 absl::Status grpc_error_to_absl_status(grpc_error_handle error) {
128   grpc_status_code status;
129   // TODO(yashykt): This should be updated once we decide on how to use the
130   // absl::Status payload to capture all the contents of grpc_error.
131   grpc_slice message;
132   grpc_error_get_status(error, GRPC_MILLIS_INF_FUTURE, &status, &message,
133                         nullptr /* http_error */, nullptr /* error_string */);
134   return absl::Status(static_cast<absl::StatusCode>(status),
135                       absl::string_view(reinterpret_cast<const char*>(
136                                             GRPC_SLICE_START_PTR(message)),
137                                         GRPC_SLICE_LENGTH(message)));
138 }
139 
absl_status_to_grpc_error(absl::Status status)140 grpc_error_handle absl_status_to_grpc_error(absl::Status status) {
141   // Special error checks
142   if (status.ok()) {
143     return GRPC_ERROR_NONE;
144   }
145   return grpc_error_set_int(
146       GRPC_ERROR_CREATE_FROM_STRING_VIEW(status.message()),
147       GRPC_ERROR_INT_GRPC_STATUS, static_cast<grpc_status_code>(status.code()));
148 }
149 
grpc_error_has_clear_grpc_status(grpc_error_handle error)150 bool grpc_error_has_clear_grpc_status(grpc_error_handle error) {
151   intptr_t unused;
152   if (grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, &unused)) {
153     return true;
154   }
155   uint8_t slot = error->first_err;
156   while (slot != UINT8_MAX) {
157     grpc_linked_error* lerr =
158         reinterpret_cast<grpc_linked_error*>(error->arena + slot);
159     if (grpc_error_has_clear_grpc_status(lerr->err)) {
160       return true;
161     }
162     slot = lerr->next;
163   }
164   return false;
165 }
166