mirror of
https://github.com/ArduPilot/ardupilot
synced 2025-03-01 11:13:58 -04:00
63afcae8a7
Lua opens scripts to load them into memory, then the logger opens them after to stream them into the dataflash log. When loading multiple large Lua scripts from ROMFS, decompression takes a significant amount of time. This creates the opportunity for the Lua interpreter and logging threads to both be inside `AP_Filesystem_ROMFS::open()` decompressing a file. If this happens, the function can return the same `fd` for two different calls as the `fd` is chosen before decompression starts, but only marked as being used after that finishes. The read pointers then stomp on each other, so Lua loads garbled scripts (usually resulting in a syntax error) and the logger dumps garbled data. Fix the issue by locking before searching for a free record (or marking a record as free). Apply the same fix to directories as well. This doesn't protect against using the same `fd`/`dirp` from multiple threads, but that behavior is to be discouraged anyway and is not the root cause here.
82 lines
2.6 KiB
C++
82 lines
2.6 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "AP_Filesystem_config.h"
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#if AP_FILESYSTEM_ROMFS_ENABLED
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#include <AP_HAL/Semaphores.h>
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#include "AP_Filesystem_backend.h"
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class AP_Filesystem_ROMFS : public AP_Filesystem_Backend
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{
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public:
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// functions that closely match the equivalent posix calls
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int open(const char *fname, int flags, bool allow_absolute_paths = false) override;
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int close(int fd) override;
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int32_t read(int fd, void *buf, uint32_t count) override;
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int32_t write(int fd, const void *buf, uint32_t count) override;
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int fsync(int fd) override;
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int32_t lseek(int fd, int32_t offset, int whence) override;
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int stat(const char *pathname, struct stat *stbuf) override;
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int unlink(const char *pathname) override;
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int mkdir(const char *pathname) override;
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void *opendir(const char *pathname) override;
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struct dirent *readdir(void *dirp) override;
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int closedir(void *dirp) override;
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// return free disk space in bytes, -1 on error
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int64_t disk_free(const char *path) override;
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// return total disk space in bytes, -1 on error
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int64_t disk_space(const char *path) override;
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// set modification time on a file
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bool set_mtime(const char *filename, const uint32_t mtime_sec) override;
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/*
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load a full file. Use delete to free the data
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*/
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FileData *load_file(const char *filename) override;
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// unload data from load_file()
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void unload_file(FileData *fd) override;
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private:
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// protect searching for free file/dir records when opening/closing
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HAL_Semaphore record_sem;
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// only allow up to 4 files at a time
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static constexpr uint8_t max_open_file = 4;
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static constexpr uint8_t max_open_dir = 4;
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struct rfile {
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const uint8_t *data;
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uint32_t size;
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uint32_t ofs;
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} file[max_open_file];
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// allow up to 4 directory opens
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struct rdir {
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char *path;
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uint16_t ofs;
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struct dirent de;
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} dir[max_open_dir];
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};
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#endif // AP_FILESYSTEM_ROMFS_ENABLED
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