platform_system_core/libprocinfo/process_map.cpp
Christopher Ferris 3bae40b279 Add ReadMapFileAsyncSafe function.
This is a function designed so that it doesn't do any allocations.
It's purpose is for testing allocation related code where doing an
allocation can disturb the test.

Added unit tests for the new code that disable memory allocations
before running.

Also, made the tests run in isolation mode since I added a bunch of
tests and this will keep the total runtime about the same as
before.

Bug: 137795072

Test: All unit tests pass.
Change-Id: I7645f1e9f88cdfbc57c8eebce80199b9cfae64c1
2019-08-23 10:07:44 -07:00

97 lines
2.7 KiB
C++

/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <procinfo/process_map.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <procinfo/process.h>
namespace android {
namespace procinfo {
bool ReadMapFileAsyncSafe(const char* map_file, void* buffer, size_t buffer_size,
const std::function<void(uint64_t, uint64_t, uint16_t, uint64_t, ino_t,
const char*)>& callback) {
if (buffer == nullptr || buffer_size == 0) {
return false;
}
int fd = open(map_file, O_RDONLY | O_CLOEXEC);
if (fd == -1) {
return false;
}
char* char_buffer = reinterpret_cast<char*>(buffer);
size_t start = 0;
size_t read_bytes = 0;
char* line = nullptr;
bool read_complete = false;
while (true) {
ssize_t bytes =
TEMP_FAILURE_RETRY(read(fd, char_buffer + read_bytes, buffer_size - read_bytes - 1));
if (bytes <= 0) {
if (read_bytes == 0) {
close(fd);
return bytes == 0;
}
// Treat the last piece of data as the last line.
char_buffer[start + read_bytes] = '\n';
bytes = 1;
read_complete = true;
}
read_bytes += bytes;
while (read_bytes > 0) {
char* newline = reinterpret_cast<char*>(memchr(&char_buffer[start], '\n', read_bytes));
if (newline == nullptr) {
break;
}
*newline = '\0';
line = &char_buffer[start];
start = newline - char_buffer + 1;
read_bytes -= newline - line + 1;
// Ignore the return code, errors are okay.
ReadMapFileContent(line, callback);
}
if (read_complete) {
close(fd);
return true;
}
if (start == 0 && read_bytes == buffer_size - 1) {
// The buffer provided is too small to contain this line, give up
// and indicate failure.
close(fd);
return false;
}
// Copy any leftover data to the front of the buffer.
if (start > 0) {
if (read_bytes > 0) {
memmove(char_buffer, &char_buffer[start], read_bytes);
}
start = 0;
}
}
}
} /* namespace procinfo */
} /* namespace android */