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llvm-project/lldb/examples/interposing/darwin/fd_interposing/FDInterposing.cpp

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//===-- FDInterposing.cpp ---------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file helps with catching double close calls on unix integer file
// descriptors by interposing functions for all file descriptor create and
// close operations. A stack backtrace for every create and close function is
// maintained, and every create and close operation is logged. When a double
// file descriptor close is encountered, it will be logged.
//
// To enable the interposing in a darwin program, set the DYLD_INSERT_LIBRARIES
// environment variable as follows:
// For sh:
// DYLD_INSERT_LIBRARIES=/path/to/FDInterposing.dylib /path/to/executable
// For tcsh:
// (setenv DYLD_INSERT_LIBRARIES=/path/to/FDInterposing.dylib ;
// /path/to/executable)
//
// Other environment variables that can alter the default actions of this
// interposing shared library include:
//
// "FileDescriptorStackLoggingNoCompact"
//
// With this environment variable set, all file descriptor create and
// delete operations will be permanantly maintained in the event map.
// The default action is to compact the create/delete events by removing
// any previous file descriptor create events that are matched with a
// corresponding file descriptor delete event when the next valid file
// descriptor create event is detected.
//
// "FileDescriptorMinimalLogging"
//
// By default every file descriptor create and delete operation is logged
// (to STDOUT by default, see the "FileDescriptorLogFile"). This can be
// suppressed to only show errors and warnings by setting this environment
// variable (the value in not important).
//
// "FileDescriptorLogFile=<path>"
//
// By default logging goes to STDOUT_FILENO, but this can be changed by
// setting FileDescriptorLogFile. The value is a path to a file that
// will be opened and used for logging.
//===----------------------------------------------------------------------===//
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <execinfo.h>
#include <fcntl.h>
#include <libgen.h>
#include <mach-o/dyld-interposing.h>
#include <mach-o/dyld.h>
#include <map>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <string>
#include <sys/event.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <tr1/memory>
#include <unistd.h>
#include <vector>
//----------------------------------------------------------------------
/// \def DISALLOW_COPY_AND_ASSIGN(TypeName)
/// Macro definition for easily disallowing copy constructor and
/// assignment operators in C++ classes.
//----------------------------------------------------------------------
#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
TypeName(const TypeName &); \
const TypeName &operator=(const TypeName &)
extern "C" {
int accept$NOCANCEL(int, struct sockaddr *__restrict, socklen_t *__restrict);
int close$NOCANCEL(int);
int open$NOCANCEL(const char *, int, ...);
int __open_extended(const char *, int, uid_t, gid_t, int,
struct kauth_filesec *);
}
namespace fd_interposing {
//----------------------------------------------------------------------
// String class so we can get formatted strings without having to worry
// about the memory storage since it will allocate the memory it needs.
//----------------------------------------------------------------------
class String {
public:
String() : m_str(NULL) {}
String(const char *format, ...) : m_str(NULL) {
va_list args;
va_start(args, format);
vprintf(format, args);
va_end(args);
}
~String() { reset(); }
void reset(char *s = NULL) {
if (m_str)
::free(m_str);
m_str = s;
}
const char *c_str() const { return m_str; }
void printf(const char *format, ...) {
va_list args;
va_start(args, format);
vprintf(format, args);
va_end(args);
}
void vprintf(const char *format, va_list args) {
reset();
::vasprintf(&m_str, format, args);
}
void log(int log_fd) {
if (m_str && log_fd >= 0) {
const int len = strlen(m_str);
if (len > 0) {
write(log_fd, m_str, len);
const char last_char = m_str[len - 1];
if (!(last_char == '\n' || last_char == '\r'))
write(log_fd, "\n", 1);
}
}
}
protected:
char *m_str;
private:
DISALLOW_COPY_AND_ASSIGN(String);
};
//----------------------------------------------------------------------
// Type definitions
//----------------------------------------------------------------------
typedef std::vector<void *> Frames;
class FDEvent;
typedef std::vector<void *> Frames;
typedef std::tr1::shared_ptr<FDEvent> FDEventSP;
typedef std::tr1::shared_ptr<String> StringSP;
//----------------------------------------------------------------------
// FDEvent
//
// A class that describes a file desciptor event.
//
// File descriptor events fall into one of two categories: create events
// and delete events.
//----------------------------------------------------------------------
class FDEvent {
public:
FDEvent(int fd, int err, const StringSP &string_sp, bool is_create,
const Frames &frames)
: m_string_sp(string_sp), m_frames(frames.begin(), frames.end()),
m_fd(fd), m_err(err), m_is_create(is_create) {}
~FDEvent() {}
bool IsCreateEvent() const { return m_is_create; }
bool IsDeleteEvent() const { return !m_is_create; }
Frames &GetFrames() { return m_frames; }
const Frames &GetFrames() const { return m_frames; }
int GetFD() const { return m_fd; }
int GetError() const { return m_err; }
void Dump(int log_fd) const;
void SetCreateEvent(FDEventSP &create_event_sp) {
m_create_event_sp = create_event_sp;
}
private:
// A shared pointer to a String that describes this event in
// detail (all args and return and error values)
StringSP m_string_sp;
// The frames for the stack backtrace for this event
Frames m_frames;
// If this is a file descriptor delete event, this might contain
// the correspoding file descriptor create event
FDEventSP m_create_event_sp;
// The file descriptor for this event
int m_fd;
// The error code (if any) for this event
int m_err;
// True if this event is a file descriptor create event, false
// if it is a file descriptor delete event
bool m_is_create;
};
//----------------------------------------------------------------------
// Templatized class that will save errno only if the "value" it is
// constructed with is equal to INVALID. When the class goes out of
// scope, it will restore errno if it was saved.
//----------------------------------------------------------------------
template <int INVALID> class Errno {
public:
// Save errno only if we are supposed to
Errno(int value)
: m_saved_errno((value == INVALID) ? errno : 0),
m_restore(value == INVALID) {}
// Restore errno only if we are supposed to
~Errno() {
if (m_restore)
errno = m_saved_errno;
}
// Accessor for the saved value of errno
int get_errno() const { return m_saved_errno; }
protected:
const int m_saved_errno;
const bool m_restore;
};
typedef Errno<-1> InvalidFDErrno;
typedef Errno<-1> NegativeErrorErrno;
typedef std::vector<FDEventSP> FDEventArray;
typedef std::map<int, FDEventArray> FDEventMap;
//----------------------------------------------------------------------
// Globals
//----------------------------------------------------------------------
// Global event map that contains all file descriptor events. As file
// descriptor create and close events come in, they will get filled
// into this map (protected by g_mutex). When a file descriptor close
// event is detected, the open event will be removed and placed into
// the close event so if something tries to double close a file
// descriptor we can show the previous close event and the file
// desctiptor event that created it. When a new file descriptor create
// event comes in, we will remove the previous one for that file
// desctiptor unless the environment variable
// "FileDescriptorStackLoggingNoCompact"
// is set. The file desctiptor history can be accessed using the
// get_fd_history() function.
static FDEventMap g_fd_event_map;
// A mutex to protect access to our data structures in g_fd_event_map
// and also our logging messages
static pthread_mutex_t g_mutex = PTHREAD_MUTEX_INITIALIZER;
// Log all file descriptor create and close events by default. Only log
// warnings and erros if the "FileDescriptorMinimalLogging" environment
// variable is set.
static int g_log_all_calls = 1;
// We compact the file descriptor events by default. Set the environment
// varible "FileDescriptorStackLoggingNoCompact" to keep a full history.
static int g_compact = 1;
// The current process ID
static int g_pid = -1;
static bool g_enabled = true;
//----------------------------------------------------------------------
// Mutex class that will lock a mutex when it is constructed, and unlock
// it when is goes out of scope
//----------------------------------------------------------------------
class Locker {
public:
Locker(pthread_mutex_t *mutex_ptr) : m_mutex_ptr(mutex_ptr) {
::pthread_mutex_lock(m_mutex_ptr);
}
// This allows clients to test try and acquire the mutex...
Locker(pthread_mutex_t *mutex_ptr, bool &lock_acquired) : m_mutex_ptr(NULL) {
lock_acquired = ::pthread_mutex_trylock(mutex_ptr) == 0;
if (lock_acquired)
m_mutex_ptr = mutex_ptr;
}
~Locker() {
if (m_mutex_ptr)
::pthread_mutex_unlock(m_mutex_ptr);
}
protected:
pthread_mutex_t *m_mutex_ptr;
};
static void log(const char *format, ...) __attribute__((format(printf, 1, 2)));
static void log(int log_fd, const FDEvent *event, const char *format, ...)
__attribute__((format(printf, 3, 4)));
static void backtrace_log(const char *format, ...)
__attribute__((format(printf, 1, 2)));
static void backtrace_error(const char *format, ...)
__attribute__((format(printf, 1, 2)));
static void log_to_fd(int log_fd, const char *format, ...)
__attribute__((format(printf, 2, 3)));
static inline size_t get_backtrace(Frames &frame_buffer,
size_t frames_to_remove) {
void *frames[2048];
int count = ::backtrace(&frames[0], sizeof(frames) / sizeof(void *));
if (count > frames_to_remove)
frame_buffer.assign(&frames[frames_to_remove], &frames[count]);
else
frame_buffer.assign(&frames[0], &frames[count]);
while (frame_buffer.back() < (void *)1024)
frame_buffer.pop_back();
return frame_buffer.size();
}
static int g_log_fd = STDOUT_FILENO;
static int g_initialized = 0;
const char *get_process_fullpath(bool force = false) {
static char g_process_fullpath[PATH_MAX] = {0};
if (force || g_process_fullpath[0] == '\0') {
// If DST is NULL, then return the number of bytes needed.
uint32_t len = sizeof(g_process_fullpath);
if (_NSGetExecutablePath(g_process_fullpath, &len) != 0)
strncpy(g_process_fullpath, "<error>", sizeof(g_process_fullpath));
}
return g_process_fullpath;
}
// Returns the current process ID, or -1 if inserposing not enabled for
// this process
static int get_interposed_pid() {
if (!g_enabled)
return -1;
const pid_t pid = getpid();
if (g_pid != pid) {
if (g_pid == -1) {
g_pid = pid;
log("Interposing file descriptor create and delete functions for %s "
"(pid=%i)\n",
get_process_fullpath(true), pid);
} else {
log("pid=%i: disabling interposing file descriptor create and delete "
"functions for child process %s (pid=%i)\n",
g_pid, get_process_fullpath(true), pid);
g_enabled = false;
return -1;
}
// Log when our process changes
}
return g_pid;
}
static int get_logging_fd() {
if (!g_enabled)
return -1;
if (!g_initialized) {
g_initialized = 1;
const pid_t pid = get_interposed_pid();
if (g_enabled) {
// Keep all stack info around for all fd create and delete calls.
// Otherwise we will remove the fd create call when a corresponding
// fd delete call is received
if (getenv("FileDescriptorStackLoggingNoCompact"))
g_compact = 0;
if (getenv("FileDescriptorMinimalLogging"))
g_log_all_calls = 0;
const char *log_path = getenv("FileDescriptorLogFile");
if (log_path)
g_log_fd = ::creat(log_path, 0660);
else
g_log_fd = STDOUT_FILENO;
// Only let this interposing happen on the first time this matches
// and stop this from happening so any child processes don't also
// log their file descriptors
::unsetenv("DYLD_INSERT_LIBRARIES");
} else {
log("pid=%i: logging disabled\n", getpid());
}
}
return g_log_fd;
}
void log_to_fd(int log_fd, const char *format, va_list args) {
if (format && format[0] && log_fd >= 0) {
char buffer[PATH_MAX];
const int count = ::vsnprintf(buffer, sizeof(buffer), format, args);
if (count > 0)
write(log_fd, buffer, count);
}
}
void log_to_fd(int log_fd, const char *format, ...) {
if (format && format[0]) {
va_list args;
va_start(args, format);
log_to_fd(log_fd, format, args);
va_end(args);
}
}
void log(const char *format, va_list args) {
log_to_fd(get_logging_fd(), format, args);
}
void log(const char *format, ...) {
if (format && format[0]) {
va_list args;
va_start(args, format);
log(format, args);
va_end(args);
}
}
void log(int log_fd, const FDEvent *event, const char *format, ...) {
if (format && format[0]) {
va_list args;
va_start(args, format);
log_to_fd(log_fd, format, args);
va_end(args);
}
if (event)
event->Dump(log_fd);
}
void FDEvent::Dump(int log_fd) const {
if (log_fd >= 0) {
log_to_fd(log_fd, "%s\n", m_string_sp->c_str());
if (!m_frames.empty())
::backtrace_symbols_fd(m_frames.data(), m_frames.size(), log_fd);
if (m_create_event_sp) {
log_to_fd(log_fd, "\nfd=%i was created with this event:\n", m_fd);
m_create_event_sp->Dump(log_fd);
log_to_fd(log_fd, "\n");
}
}
}
void backtrace_log(const char *format, ...) {
const int log_fd = get_logging_fd();
if (log_fd >= 0) {
if (format && format[0]) {
va_list args;
va_start(args, format);
log(format, args);
va_end(args);
}
Frames frames;
if (get_backtrace(frames, 2))
::backtrace_symbols_fd(frames.data(), frames.size(), log_fd);
}
}
void backtrace_error(const char *format, ...) {
const int pid = get_interposed_pid();
if (pid >= 0) {
const int log_fd = get_logging_fd();
if (log_fd >= 0) {
log("\nerror: %s (pid=%i): ", get_process_fullpath(), pid);
if (format && format[0]) {
va_list args;
va_start(args, format);
log(format, args);
va_end(args);
}
Frames frames;
if (get_backtrace(frames, 2))
::backtrace_symbols_fd(frames.data(), frames.size(), log_fd);
}
}
}
void save_backtrace(int fd, int err, const StringSP &string_sp,
bool is_create) {
Frames frames;
get_backtrace(frames, 2);
FDEventSP fd_event_sp(new FDEvent(fd, err, string_sp, is_create, frames));
FDEventMap::iterator pos = g_fd_event_map.find(fd);
if (pos != g_fd_event_map.end()) {
// We have history for this fd...
FDEventArray &event_array = g_fd_event_map[fd];
if (fd_event_sp->IsCreateEvent()) {
// The current fd event is a function that creates
// a descriptor, check in case last event was
// a create event.
if (event_array.back()->IsCreateEvent()) {
const int log_fd = get_logging_fd();
// Two fd create functions in a row, we missed
// a function that closes a fd...
log(log_fd, fd_event_sp.get(), "\nwarning: unmatched file descriptor "
"create event fd=%i (we missed a file "
"descriptor close event):\n",
fd);
} else if (g_compact) {
// We are compacting so we remove previous create event
// when we get the correspinding delete event
event_array.pop_back();
}
} else {
// The current fd event is a function that deletes
// a descriptor, check in case last event for this
// fd was a delete event (double close!)
if (event_array.back()->IsDeleteEvent()) {
const int log_fd = get_logging_fd();
// Two fd delete functions in a row, we must
// have missed some function that opened a descriptor
log(log_fd, fd_event_sp.get(), "\nwarning: unmatched file descriptor "
"close event for fd=%d (we missed the "
"file descriptor create event):\n",
fd);
} else if (g_compact) {
// Since this is a close event, we want to remember the open event
// that this close if for...
fd_event_sp->SetCreateEvent(event_array.back());
// We are compacting so we remove previous create event
// when we get the correspinding delete event
event_array.pop_back();
}
}
event_array.push_back(fd_event_sp);
} else {
g_fd_event_map[fd].push_back(fd_event_sp);
}
}
//----------------------------------------------------------------------
// socket() interpose function
//----------------------------------------------------------------------
extern "C" int socket$__interposed__(int domain, int type, int protocol) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::socket(domain, type, protocol);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String);
if (fd == -1)
description_sp->printf("pid=%i: socket (domain = %i, type = %i, protocol "
"= %i) => fd=%i errno = %i",
pid, domain, type, protocol, fd,
fd_errno.get_errno());
else
description_sp->printf(
"pid=%i: socket (domain = %i, type = %i, protocol = %i) => fd=%i",
pid, domain, type, protocol, fd);
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::socket(domain, type, protocol);
}
}
//----------------------------------------------------------------------
// socketpair() interpose function
//----------------------------------------------------------------------
extern "C" int socketpair$__interposed__(int domain, int type, int protocol,
int fds[2]) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
fds[0] = -1;
fds[1] = -1;
const int err = socketpair(domain, type, protocol, fds);
NegativeErrorErrno err_errno(err);
StringSP description_sp(
new String("pid=%i: socketpair (domain=%i, type=%i, protocol=%i, "
"{fd=%i, fd=%i}) -> err=%i",
pid, domain, type, protocol, fds[0], fds[1], err));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fds[0] >= 0)
save_backtrace(fds[0], err_errno.get_errno(), description_sp, true);
if (fds[1] >= 0)
save_backtrace(fds[1], err_errno.get_errno(), description_sp, true);
return err;
} else {
return socketpair(domain, type, protocol, fds);
}
}
//----------------------------------------------------------------------
// open() interpose function
//----------------------------------------------------------------------
extern "C" int open$__interposed__(const char *path, int oflag, int mode) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
int fd = -2;
StringSP description_sp(new String);
if (oflag & O_CREAT) {
fd = ::open(path, oflag, mode);
description_sp->printf(
"pid=%i: open (path = '%s', oflag = %i, mode = %i) -> fd=%i", pid,
path, oflag, mode, fd);
} else {
fd = ::open(path, oflag);
description_sp->printf("pid=%i: open (path = '%s', oflag = %i) -> fd=%i",
pid, path, oflag, fd);
}
InvalidFDErrno fd_errno(fd);
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::open(path, oflag, mode);
}
}
//----------------------------------------------------------------------
// open$NOCANCEL() interpose function
//----------------------------------------------------------------------
extern "C" int open$NOCANCEL$__interposed__(const char *path, int oflag,
int mode) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::open$NOCANCEL(path, oflag, mode);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String(
"pid=%i: open$NOCANCEL (path = '%s', oflag = %i, mode = %i) -> fd=%i",
pid, path, oflag, mode, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::open$NOCANCEL(path, oflag, mode);
}
}
//----------------------------------------------------------------------
// __open_extended() interpose function
//----------------------------------------------------------------------
extern "C" int __open_extended$__interposed__(const char *path, int oflag,
uid_t uid, gid_t gid, int mode,
struct kauth_filesec *fsacl) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::__open_extended(path, oflag, uid, gid, mode, fsacl);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(
new String("pid=%i: __open_extended (path='%s', oflag=%i, uid=%i, "
"gid=%i, mode=%i, fsacl=%p) -> fd=%i",
pid, path, oflag, uid, gid, mode, fsacl, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::__open_extended(path, oflag, uid, gid, mode, fsacl);
}
}
//----------------------------------------------------------------------
// kqueue() interpose function
//----------------------------------------------------------------------
extern "C" int kqueue$__interposed__(void) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::kqueue();
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String("pid=%i: kqueue () -> fd=%i", pid, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::kqueue();
}
}
//----------------------------------------------------------------------
// shm_open() interpose function
//----------------------------------------------------------------------
extern "C" int shm_open$__interposed__(const char *path, int oflag, int mode) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::shm_open(path, oflag, mode);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String(
"pid=%i: shm_open (path = '%s', oflag = %i, mode = %i) -> fd=%i", pid,
path, oflag, mode, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::shm_open(path, oflag, mode);
}
}
//----------------------------------------------------------------------
// accept() interpose function
//----------------------------------------------------------------------
extern "C" int accept$__interposed__(int socket, struct sockaddr *address,
socklen_t *address_len) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::accept(socket, address, address_len);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String(
"pid=%i: accept (socket=%i, ...) -> fd=%i", pid, socket, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::accept(socket, address, address_len);
}
}
//----------------------------------------------------------------------
// accept$NOCANCEL() interpose function
//----------------------------------------------------------------------
extern "C" int accept$NOCANCEL$__interposed__(int socket,
struct sockaddr *address,
socklen_t *address_len) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::accept$NOCANCEL(socket, address, address_len);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String(
"pid=%i: accept$NOCANCEL (socket=%i, ...) -> fd=%i", pid, socket, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::accept$NOCANCEL(socket, address, address_len);
}
}
//----------------------------------------------------------------------
// dup() interpose function
//----------------------------------------------------------------------
extern "C" int dup$__interposed__(int fd2) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int fd = ::dup(fd2);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(
new String("pid=%i: dup (fd2=%i) -> fd=%i", pid, fd2, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::dup(fd2);
}
}
//----------------------------------------------------------------------
// dup2() interpose function
//----------------------------------------------------------------------
extern "C" int dup2$__interposed__(int fd1, int fd2) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
// If "fd2" is already opened, it will be closed during the
// dup2 call below, so we need to see if we have fd2 in our
// open map and treat it as a close(fd2)
FDEventMap::iterator pos = g_fd_event_map.find(fd2);
StringSP dup2_close_description_sp(
new String("pid=%i: dup2 (fd1=%i, fd2=%i) -> will close (fd=%i)", pid,
fd1, fd2, fd2));
if (pos != g_fd_event_map.end() && pos->second.back()->IsCreateEvent())
save_backtrace(fd2, 0, dup2_close_description_sp, false);
const int fd = ::dup2(fd1, fd2);
InvalidFDErrno fd_errno(fd);
StringSP description_sp(new String("pid=%i: dup2 (fd1=%i, fd2=%i) -> fd=%i",
pid, fd1, fd2, fd));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fd >= 0)
save_backtrace(fd, fd_errno.get_errno(), description_sp, true);
return fd;
} else {
return ::dup2(fd1, fd2);
}
}
//----------------------------------------------------------------------
// close() interpose function
//----------------------------------------------------------------------
extern "C" int close$__interposed__(int fd) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int err = close(fd);
NegativeErrorErrno err_errno(err);
StringSP description_sp(new String);
if (err == -1)
description_sp->printf("pid=%i: close (fd=%i) => %i errno = %i (%s))",
pid, fd, err, err_errno.get_errno(),
strerror(err_errno.get_errno()));
else
description_sp->printf("pid=%i: close (fd=%i) => %i", pid, fd, err);
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (err == 0) {
if (fd >= 0)
save_backtrace(fd, err, description_sp, false);
} else if (err == -1) {
if (err_errno.get_errno() == EBADF && fd != -1) {
backtrace_error("close (fd=%d) resulted in EBADF:\n", fd);
FDEventMap::iterator pos = g_fd_event_map.find(fd);
if (pos != g_fd_event_map.end()) {
log(get_logging_fd(), pos->second.back().get(),
"\nfd=%d was previously %s with this event:\n", fd,
pos->second.back()->IsCreateEvent() ? "opened" : "closed");
}
}
}
return err;
} else {
return close(fd);
}
}
//----------------------------------------------------------------------
// close$NOCANCEL() interpose function
//----------------------------------------------------------------------
extern "C" int close$NOCANCEL$__interposed__(int fd) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
const int err = close$NOCANCEL(fd);
NegativeErrorErrno err_errno(err);
StringSP description_sp(new String);
if (err == -1)
description_sp->printf(
"pid=%i: close$NOCANCEL (fd=%i) => %i errno = %i (%s))", pid, fd, err,
err_errno.get_errno(), strerror(err_errno.get_errno()));
else
description_sp->printf("pid=%i: close$NOCANCEL (fd=%i) => %i", pid, fd,
err);
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (err == 0) {
if (fd >= 0)
save_backtrace(fd, err, description_sp, false);
} else if (err == -1) {
if (err_errno.get_errno() == EBADF && fd != -1) {
backtrace_error("close$NOCANCEL (fd=%d) resulted in EBADF\n:", fd);
FDEventMap::iterator pos = g_fd_event_map.find(fd);
if (pos != g_fd_event_map.end()) {
log(get_logging_fd(), pos->second.back().get(),
"\nfd=%d was previously %s with this event:\n", fd,
pos->second.back()->IsCreateEvent() ? "opened" : "closed");
}
}
}
return err;
} else {
return close$NOCANCEL(fd);
}
}
//----------------------------------------------------------------------
// pipe() interpose function
//----------------------------------------------------------------------
extern "C" int pipe$__interposed__(int fds[2]) {
const int pid = get_interposed_pid();
if (pid >= 0) {
Locker locker(&g_mutex);
fds[0] = -1;
fds[1] = -1;
const int err = pipe(fds);
const int saved_errno = errno;
StringSP description_sp(new String(
"pid=%i: pipe ({fd=%i, fd=%i}) -> err=%i", pid, fds[0], fds[1], err));
if (g_log_all_calls)
description_sp->log(get_logging_fd());
if (fds[0] >= 0)
save_backtrace(fds[0], saved_errno, description_sp, true);
if (fds[1] >= 0)
save_backtrace(fds[1], saved_errno, description_sp, true);
errno = saved_errno;
return err;
} else {
return pipe(fds);
}
}
//----------------------------------------------------------------------
// get_fd_history()
//
// This function allows runtime access to the file descriptor history.
//
// @param[in] log_fd
// The file descriptor to log to
//
// @param[in] fd
// The file descriptor whose history should be dumped
//----------------------------------------------------------------------
extern "C" void get_fd_history(int log_fd, int fd) {
// "create" below needs to be outside of the mutex locker scope
if (log_fd >= 0) {
bool got_lock = false;
Locker locker(&g_mutex, got_lock);
if (got_lock) {
FDEventMap::iterator pos = g_fd_event_map.find(fd);
log_to_fd(log_fd, "Dumping file descriptor history for fd=%i:\n", fd);
if (pos != g_fd_event_map.end()) {
FDEventArray &event_array = g_fd_event_map[fd];
const size_t num_events = event_array.size();
for (size_t i = 0; i < num_events; ++i)
event_array[i]->Dump(log_fd);
} else {
log_to_fd(log_fd, "error: no file descriptor events found for fd=%i\n",
fd);
}
} else {
log_to_fd(log_fd, "error: fd event mutex is locked...\n");
}
}
}
//----------------------------------------------------------------------
// Interposing
//----------------------------------------------------------------------
// FD creation routines
DYLD_INTERPOSE(accept$__interposed__, accept);
DYLD_INTERPOSE(accept$NOCANCEL$__interposed__, accept$NOCANCEL);
DYLD_INTERPOSE(dup$__interposed__, dup);
DYLD_INTERPOSE(dup2$__interposed__, dup2);
DYLD_INTERPOSE(kqueue$__interposed__, kqueue);
DYLD_INTERPOSE(open$__interposed__, open);
DYLD_INTERPOSE(open$NOCANCEL$__interposed__, open$NOCANCEL);
DYLD_INTERPOSE(__open_extended$__interposed__, __open_extended);
DYLD_INTERPOSE(pipe$__interposed__, pipe);
DYLD_INTERPOSE(shm_open$__interposed__, shm_open);
DYLD_INTERPOSE(socket$__interposed__, socket);
DYLD_INTERPOSE(socketpair$__interposed__, socketpair);
// FD deleting routines
DYLD_INTERPOSE(close$__interposed__, close);
DYLD_INTERPOSE(close$NOCANCEL$__interposed__, close$NOCANCEL);
} // namespace fd_interposing
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