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/*
* 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 <dmabufinfo/dmabufinfo.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <filesystem>
#include <memory>
#include <string>
#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/parseint.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <procinfo/process_map.h>
namespace android {
namespace dmabufinfo {
static bool FileIsDmaBuf(const std::string& path) {
return ::android::base::StartsWith(path, "/dmabuf");
}
static bool ReadDmaBufFdInfo(pid_t pid, int fd, std::string* name, std::string* exporter,
uint64_t* count) {
std::string fdinfo = ::android::base::StringPrintf("/proc/%d/fdinfo/%d", pid, fd);
auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(fdinfo.c_str(), "re"), fclose};
if (fp == nullptr) {
LOG(ERROR) << "Failed to open dmabuf info from debugfs";
return false;
}
char* line = nullptr;
size_t len = 0;
while (getline(&line, &len, fp.get()) > 0) {
switch (line[0]) {
case 'c':
if (strncmp(line, "count:", 6) == 0) {
char* c = line + 6;
*count = strtoull(c, nullptr, 10);
}
break;
case 'e':
if (strncmp(line, "exp_name:", 9) == 0) {
char* c = line + 9;
*exporter = ::android::base::Trim(c);
}
break;
case 'n':
if (strncmp(line, "name:", 5) == 0) {
char* c = line + 5;
*name = ::android::base::Trim(std::string(c));
}
break;
}
}
free(line);
return true;
}
static bool ReadDmaBufFdRefs(pid_t pid, std::vector<DmaBuffer>* dmabufs) {
std::string fdpath = ::android::base::StringPrintf("/proc/%d/fd", pid);
for (auto& de : std::filesystem::directory_iterator(fdpath)) {
if (!std::filesystem::is_symlink(de.path())) {
continue;
}
std::string target;
if (!::android::base::Readlink(de.path().string(), &target)) {
LOG(ERROR) << "Failed to find target for symlink: " << de.path().string();
return false;
}
if (!FileIsDmaBuf(target)) {
continue;
}
int fd;
if (!::android::base::ParseInt(de.path().filename().string(), &fd)) {
LOG(ERROR) << "Dmabuf fd: " << de.path().string() << " is invalid";
return false;
}
// Set defaults in case the kernel doesn't give us the information
// we need in fdinfo
std::string name = "<unknown>";
std::string exporter = "<unknown>";
uint64_t count = 0;
if (!ReadDmaBufFdInfo(pid, fd, &name, &exporter, &count)) {
LOG(ERROR) << "Failed to read fdinfo for: " << de.path().string();
return false;
}
struct stat sb;
if (stat(de.path().c_str(), &sb) < 0) {
PLOG(ERROR) << "Failed to stat: " << de.path().string();
return false;
}
DmaBuffer& buf =
dmabufs->emplace_back(sb.st_ino, sb.st_blocks * 512, count, exporter, name);
buf.AddFdRef(pid);
}
return true;
}
static bool ReadDmaBufMapRefs(pid_t pid, std::vector<DmaBuffer>* dmabufs) {
std::string mapspath = ::android::base::StringPrintf("/proc/%d/maps", pid);
auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(mapspath.c_str(), "re"), fclose};
if (fp == nullptr) {
LOG(ERROR) << "Failed to open maps for pid: " << pid;
return false;
}
char* line = nullptr;
size_t len = 0;
// Process the map if it is dmabuf. Add map reference to existing object in 'dmabufs'
// if it was already found. If it wasn't create a new one and append it to 'dmabufs'
auto account_dmabuf = [&](uint64_t start, uint64_t end, uint16_t /* flags */,
uint64_t /* pgoff */, const char* name) {
// no need to look into this mapping if it is not dmabuf
if (!FileIsDmaBuf(std::string(name))) {
return;
}
// TODO (b/123532375) : Add inode number to the callback of ReadMapFileContent.
//
// Workaround: we know 'name' points to the name at the end of 'line'.
// We use that to backtrack and pick up the inode number from the line as well.
// start end flag pgoff mj:mn inode name
// 00400000-00409000 r-xp 00000000 00:00 426998 /dmabuf (deleted)
const char* p = name;
p--;
// skip spaces
while (p != line && *p == ' ') {
p--;
}
// walk backwards to the beginning of inode number
while (p != line && isdigit(*p)) {
p--;
}
uint64_t inode = strtoull(p, nullptr, 10);
auto buf = std::find_if(dmabufs->begin(), dmabufs->end(),
[&inode](const DmaBuffer& dbuf) { return dbuf.inode() == inode; });
if (buf != dmabufs->end()) {
buf->AddMapRef(pid);
return;
}
// We have a new buffer, but unknown count and name
DmaBuffer& dbuf = dmabufs->emplace_back(inode, end - start, 0, "<unknown>", "<unknown>");
dbuf.AddMapRef(pid);
};
while (getline(&line, &len, fp.get()) > 0) {
if (!::android::procinfo::ReadMapFileContent(line, account_dmabuf)) {
LOG(ERROR) << "Failed t parse maps for pid: " << pid;
return false;
}
}
free(line);
return true;
}
// Public methods
bool ReadDmaBufInfo(std::vector<DmaBuffer>* dmabufs, const std::string& path) {
auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
if (fp == nullptr) {
LOG(ERROR) << "Failed to open dmabuf info from debugfs";
return false;
}
char* line = nullptr;
size_t len = 0;
dmabufs->clear();
while (getline(&line, &len, fp.get()) > 0) {
// The new dmabuf bufinfo format adds inode number and a name at the end
// We are looking for lines as follows:
// size flags mode count exp_name ino name
// 01048576 00000002 00000007 00000001 ion 00018758 CAMERA
// 01048576 00000002 00000007 00000001 ion 00018758
uint64_t size, count;
char* exporter_name = nullptr;
ino_t inode;
char* name = nullptr;
int matched = sscanf(line, "%" SCNu64 "%*x %*x %" SCNu64 " %ms %lu %ms", &size, &count,
&exporter_name, &inode, &name);
if (matched < 4) {
continue;
}
dmabufs->emplace_back(inode, size, count, exporter_name, matched > 4 ? name : "");
free(exporter_name);
free(name);
}
free(line);
return true;
}
bool ReadDmaBufInfo(pid_t pid, std::vector<DmaBuffer>* dmabufs) {
dmabufs->clear();
if (!ReadDmaBufFdRefs(pid, dmabufs)) {
LOG(ERROR) << "Failed to read dmabuf fd references";
return false;
}
if (!ReadDmaBufMapRefs(pid, dmabufs)) {
LOG(ERROR) << "Failed to read dmabuf map references";
return false;
}
return true;
}
} // namespace dmabufinfo
} // namespace android
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