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#include <stdlib.h>
#include <sys/mman.h>
#include <sys/uio.h>
#include "actual.h"
#include "utility/io.h"
#include "utility/logger.h"
#include "tracking/path_matcher.h"
#include "tracking/change_tracker.h"
// `true` signals the interposed functions to execute tracking logic
// `false` signals the interposed functions to do plain forwarding
static bool enabled = false;
static std::unique_ptr<utility::FileDescriptorGuard> fd_guard;
static std::unique_ptr<utility::Logger> logger;
static std::unique_ptr<tracking::PathMatcher> matcher;
static std::unique_ptr<tracking::ChangeTracker> tracker;
void initialize() __attribute__ ((constructor));
void initialize() {
if ( getenv("CHANGE_LOG_TARGET") != NULL ) {
fd_guard = std::make_unique<utility::FileDescriptorGuard>(
getenv("CHANGE_LOG_TARGET")
);
logger = std::make_unique<utility::Logger>(*fd_guard);
} else {
logger = std::make_unique<utility::Logger>(STDERR_FILENO);
}
if ( getenv("CHANGE_LOG_DIFF_CMD") != NULL ) {
tracker = std::make_unique<tracking::ChangeTracker>(
logger.get(), getenv("CHANGE_LOG_DIFF_CMD")
);
} else {
tracker = std::make_unique<tracking::ChangeTracker>(logger.get());
}
if ( getenv("CHANGE_LOG_IGNORE_PATTERN_PATH") != NULL ) {
matcher = std::make_unique<tracking::PathMatcher>(
getenv("CHANGE_LOG_IGNORE_PATTERN_PATH")
);
} else {
matcher = std::make_unique<tracking::PathMatcher>();
}
// tracking is only enabled when everything is initialized as both
// the actual tracking and the decision if a event should be tracked
// depend on `logger` and `tracker` being fully instantiated.
// In most cases this library will work correctly without delayed
// activation but e.g. `nvim` crashes as it performs tracked syscalls
// before `init` has been called.
enabled = true;
}
inline void track_write(const int fd) {
if ( enabled && fd != *fd_guard && utility::is_regular_file(fd) ) {
const auto path = utility::get_file_path(fd);
if ( !matcher->is_matching(path) ) {
tracker->track(path);
}
}
}
inline void track_write(const std::string& path) {
if ( enabled && utility::is_regular_file(path.c_str()) ) {
if ( !matcher->is_matching(path) ) {
tracker->track(path);
}
}
}
inline void track_rename(
const std::string& old_path, const std::string& new_path) {
if ( enabled ) {
if ( !matcher->is_matching(old_path) ) {
tracker->track(old_path);
if ( !matcher->is_matching(new_path) ) {
logger->append("renamed '", old_path, "' to '", new_path, "'");
}
}
}
}
inline void track_remove(const std::string& path) {
if ( enabled && utility::is_regular_file(path.c_str()) ) {
if ( !matcher->is_matching(path) ) {
logger->append("removed '", path, "'");
}
}
}
extern "C" {
int open(const char* path, int flags, mode_t mode) {
static actual::ptr<int, const char*, int, mode_t> actual_open{};
if ( !actual_open ) {
actual_open = actual::get_ptr<decltype(actual_open)>("open");
}
// `open` may reset the file contents when used with the `O_TRUNC` flag.
// e.g. this is how _emacs_ clears the file content prior to writing the
// new content.
// Normally `O_TRUNC` is defined in `fcntl.h` which we can not include
// as it defines the very c-function we are currently _overriding_.
//
if ( flags & 01000 ) {
track_write(path);
}
return actual_open(path, flags, mode);
}
ssize_t write(int fd, const void* buffer, size_t count) {
static actual::ptr<ssize_t, int, const void*, size_t> actual_write{};
if ( !actual_write ) {
actual_write = actual::get_ptr<decltype(actual_write)>("write");
}
track_write(fd);
return actual_write(fd, buffer, count);
}
ssize_t writev(int fd, const iovec* iov, int iovcnt) {
static actual::ptr<ssize_t, int, const iovec*, int> actual_writev{};
if ( !actual_writev ) {
actual_writev = actual::get_ptr<decltype(actual_writev)>("writev");
}
track_write(fd);
return actual_writev(fd, iov, iovcnt);
}
void* mmap(void* addr, size_t length, int prot, int flags, int fd, off_t offset) {
static actual::ptr<void*, void*, size_t, int, int, int, off_t> actual_mmap{};
if ( !actual_mmap ) {
actual_mmap = actual::get_ptr<decltype(actual_mmap)>("mmap");
}
if ( prot & PROT_WRITE ) {
track_write(fd);
}
return actual_mmap(addr, length, prot, flags, fd, offset);
}
int rename(const char* old_path, const char* new_path) {
static actual::ptr<int, const char*, const char*> actual_rename{};
if ( !actual_rename ) {
actual_rename = actual::get_ptr<decltype(actual_rename)>("rename");
}
track_rename(old_path, new_path);
return actual_rename(old_path, new_path);
}
int rmdir(const char* path) {
static actual::ptr<int, const char*> actual_rmdir{};
if ( !actual_rmdir ) {
actual_rmdir = actual::get_ptr<decltype(actual_rmdir)>("rmdir");
}
track_remove(path);
return actual_rmdir(path);
}
int unlink(const char* path) {
static actual::ptr<int, const char*> actual_unlink{};
if ( !actual_unlink ) {
actual_unlink = actual::get_ptr<decltype(actual_unlink)>("unlink");
}
track_remove(path);
return actual_unlink(path);
}
int unlinkat(int dirfd, const char* path, int flags) {
static actual::ptr<int, int, const char*, int> actual_unlinkat{};
if ( !actual_unlinkat ) {
actual_unlinkat = actual::get_ptr<decltype(actual_unlinkat)>("unlinkat");
}
// Normally `AT_FDCWD` is defined in `fcntl.h` which we can not include
// as it defines `open` which this library also aims to override.
//
if ( dirfd == -100 ) {
track_remove(path);
} else {
track_remove(utility::get_file_path(dirfd) + path);
}
return actual_unlinkat(dirfd, path, flags);
}
}
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