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/iomgr/load_file.h"
22 
23 #include <errno.h>
24 #include <string.h>
25 
26 #include <grpc/support/alloc.h>
27 #include <grpc/support/log.h>
28 #include <grpc/support/string_util.h>
29 
30 #include "src/core/lib/gpr/string.h"
31 #include "src/core/lib/iomgr/block_annotate.h"
32 
grpc_load_file(const char * filename,int add_null_terminator,grpc_slice * output)33 grpc_error* grpc_load_file(const char* filename, int add_null_terminator,
34                            grpc_slice* output) {
35   unsigned char* contents = nullptr;
36   size_t contents_size = 0;
37   grpc_slice result = grpc_empty_slice();
38   FILE* file;
39   size_t bytes_read = 0;
40   grpc_error* error = GRPC_ERROR_NONE;
41 
42   GRPC_SCHEDULING_START_BLOCKING_REGION;
43   file = fopen(filename, "rb");
44   if (file == nullptr) {
45     error = GRPC_OS_ERROR(errno, "fopen");
46     goto end;
47   }
48   fseek(file, 0, SEEK_END);
49   /* Converting to size_t on the assumption that it will not fail */
50   contents_size = static_cast<size_t>(ftell(file));
51   fseek(file, 0, SEEK_SET);
52   contents = static_cast<unsigned char*>(
53       gpr_malloc(contents_size + (add_null_terminator ? 1 : 0)));
54   bytes_read = fread(contents, 1, contents_size, file);
55   if (bytes_read < contents_size) {
56     gpr_free(contents);
57     error = GRPC_OS_ERROR(errno, "fread");
58     GPR_ASSERT(ferror(file));
59     goto end;
60   }
61   if (add_null_terminator) {
62     contents[contents_size++] = 0;
63   }
64   result = grpc_slice_new(contents, contents_size, gpr_free);
65 
66 end:
67   *output = result;
68   if (file != nullptr) fclose(file);
69   if (error != GRPC_ERROR_NONE) {
70     grpc_error* error_out =
71         grpc_error_set_str(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
72                                "Failed to load file", &error, 1),
73                            GRPC_ERROR_STR_FILENAME,
74                            grpc_slice_from_copied_string(
75                                filename));  // TODO(ncteisen), always static?
76     GRPC_ERROR_UNREF(error);
77     error = error_out;
78   }
79   GRPC_SCHEDULING_END_BLOCKING_REGION_NO_EXEC_CTX;
80   return error;
81 }
82