extern "C" int setpgid(pid_t pid, pid_t pgid)
{
DMTCP_PLUGIN_DISABLE_CKPT();
pid_t currPid = VIRTUAL_TO_REAL_PID (pid);
pid_t currPgid = VIRTUAL_TO_REAL_PID (pgid);
int retVal = _real_setpgid (currPid, currPgid);
DMTCP_PLUGIN_ENABLE_CKPT();
return retVal;
}
LIB_PRIVATE
int tgkill(int tgid, int tid, int sig)
{
// FIXME: Check the comments in kill()
// DMTCP_PLUGIN_DISABLE_CKPT();
int realTgid = VIRTUAL_TO_REAL_PID ( tgid );
int realTid = VIRTUAL_TO_REAL_PID ( tid );
int retVal = _real_tgkill ( realTgid, realTid, sig );
// DMTCP_PLUGIN_ENABLE_CKPT();
return retVal;
}
extern "C" int fcntl(int fd, int cmd, ...)
{
va_list ap;
// Handling the variable number of arguments
void *arg_in = NULL;
void *arg = NULL;
va_start( ap, cmd );
arg_in = va_arg(ap, void *);
va_end(ap);
arg = arg_in;
DMTCP_PLUGIN_DISABLE_CKPT();
if (cmd == F_SETOWN) {
pid_t virtualPid = VIRTUAL_TO_REAL_PID((pid_t) (unsigned long) arg_in);
arg = (void*) (unsigned long) virtualPid;
}
int result = _real_fcntl(fd, cmd, arg);
int retval = result;
if (cmd == F_GETOWN) {
retval = REAL_TO_VIRTUAL_PID(result);
}
DMTCP_PLUGIN_ENABLE_CKPT();
return retval;
}
extern "C" int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options)
{
int retval = 0;
struct timespec sleepTime = {0, 1000};
siginfo_t siginfop;
memset(&siginfop, 0, sizeof(siginfop));
/* waitid returns 0 in case of success as well as when WNOHANG is specified
* and we need to distinguish those two cases.man page for waitid says:
* If WNOHANG was specified in options and there were no children in a
* waitable state, then waitid() returns 0 immediately and the state of
* the siginfo_t structure pointed to by infop is unspecified. To
* distinguish this case from that where a child was in a waitable state,
* zero out the si_pid field before the call and check for a nonzero value
* in this field after the call returns.
*
* See comments above wait4()
*/
while (retval == 0) {
DMTCP_PLUGIN_DISABLE_CKPT();
pid_t currPid = VIRTUAL_TO_REAL_PID (id);
retval = _real_waitid (idtype, currPid, &siginfop, options | WNOHANG);
if (retval != -1) {
pid_t virtualPid = REAL_TO_VIRTUAL_PID ( siginfop.si_pid );
siginfop.si_pid = virtualPid;
if ( siginfop.si_code == CLD_EXITED || siginfop.si_code == CLD_KILLED )
dmtcp::VirtualPidTable::instance().erase(virtualPid);
}
DMTCP_PLUGIN_ENABLE_CKPT();
if ((options & WNOHANG) ||
retval == -1 ||
siginfop.si_pid != 0) {
break;
} else {
if (sleepTime.tv_sec == 0) {
sleepTime.tv_nsec *= 2;
if (sleepTime.tv_nsec >= 1000 * 1000 * 1000) {
sleepTime.tv_sec++;
sleepTime.tv_nsec = 0;
}
}
nanosleep(&sleepTime, NULL);
}
}
if (retval == 0 && infop != NULL) {
*infop = siginfop;
}
return retval;
}
extern "C" pid_t getpgid(pid_t pid)
{
DMTCP_PLUGIN_DISABLE_CKPT();
pid_t realPid = VIRTUAL_TO_REAL_PID (pid);
pid_t res = _real_getpgid (realPid);
pid_t origPgid = REAL_TO_VIRTUAL_PID (res);
DMTCP_PLUGIN_ENABLE_CKPT();
return origPgid;
}
// TODO: Add check for the below two functions in configure
int
sched_setattr(pid_t pid, const struct sched_attr *attr, unsigned int flags)
{
DMTCP_PLUGIN_DISABLE_CKPT();
int result = -1;
pid_t real_pid = 0;
if (pid != 0) {
real_pid = VIRTUAL_TO_REAL_PID(pid);
}
result = _real_sched_setattr(real_pid, attr, flags);
DMTCP_PLUGIN_ENABLE_CKPT();
return result;
}
int
sched_getparam(pid_t pid, struct sched_param *param)
{
DMTCP_PLUGIN_DISABLE_CKPT();
int result = -1;
pid_t real_pid = 0;
if (pid != 0) {
real_pid = VIRTUAL_TO_REAL_PID(pid);
}
result = _real_sched_getparam(real_pid, param);
DMTCP_PLUGIN_ENABLE_CKPT();
return result;
}
int
sched_getscheduler(pid_t pid)
{
DMTCP_PLUGIN_DISABLE_CKPT();
int result = -1;
pid_t real_pid = 0;
if (pid != 0) {
real_pid = VIRTUAL_TO_REAL_PID(pid);
}
result = _real_sched_getscheduler(real_pid);
DMTCP_PLUGIN_ENABLE_CKPT();
return result;
}
int
sched_setscheduler(pid_t pid, int policy, const struct sched_param *param)
{
DMTCP_PLUGIN_DISABLE_CKPT();
int result = -1;
pid_t real_pid = 0;
if (pid != 0) {
real_pid = VIRTUAL_TO_REAL_PID(pid);
}
result = _real_sched_setscheduler(real_pid, policy, param);
DMTCP_PLUGIN_ENABLE_CKPT();
return result;
}
int
sched_getaffinity(pid_t pid, size_t cpusetsize, cpu_set_t *mask)
{
DMTCP_PLUGIN_DISABLE_CKPT();
int result = -1;
pid_t real_pid = 0;
if (pid != 0) {
real_pid = VIRTUAL_TO_REAL_PID(pid);
}
result = _real_sched_getaffinity(real_pid, cpusetsize, mask);
DMTCP_PLUGIN_ENABLE_CKPT();
return result;
}
extern "C" pid_t tcsetpgrp(int fd, pid_t pgrp)
{
DMTCP_PLUGIN_DISABLE_CKPT();
pid_t currPgrp = VIRTUAL_TO_REAL_PID( pgrp );
// JTRACE( "Inside tcsetpgrp wrapper" ) (fd) (pgrp) (currPgrp);
pid_t realPid = _real_tcsetpgrp(fd, currPgrp);
pid_t virtualPid = REAL_TO_VIRTUAL_PID(realPid);
//JTRACE( "tcsetpgrp return value" ) (fd) (pgrp) (currPgrp) (retval);
DMTCP_PLUGIN_ENABLE_CKPT();
return virtualPid;
}
// FIXME: This function needs third argument newpathsize, or assume PATH_MAX
static void updateProcPathVirtualToReal(const char *path, char **newpath)
{
if (dmtcp::Util::strStartsWith(path, PROC_PREFIX)) {
int index = strlen(PROC_PREFIX);
char *rest;
pid_t virtualPid = strtol(&path[index], &rest, 0);
if (virtualPid > 0 && *rest == '/') {
pid_t realPid = VIRTUAL_TO_REAL_PID(virtualPid);
sprintf(*newpath, "/proc/%d%s", realPid, rest);
return;
}
}
*newpath = (char *)path;
}
extern "C" long ptrace (int request, pid_t pid, void* addr, void* data)
#endif
{
#ifndef ANDROID
va_list ap;
#endif
pid_t virtualPid;
pid_t realPid;
#ifndef ANDROID
void *addr;
void *data;
va_start(ap, request);
virtualPid = va_arg(ap, pid_t);
addr = va_arg(ap, void *);
data = va_arg(ap, void *);
va_end(ap);
#else
virtualPid = pid;
#endif
realPid = VIRTUAL_TO_REAL_PID(virtualPid);
long ptrace_ret = _real_ptrace(request, realPid, addr, data);
/*
* PTRACE_GETEVENTMSG (since Linux 2.5.46)
* Retrieve a message (as an unsigned long) about the ptrace event
* that just happened, placing it in the location data in the
* parent. For PTRACE_EVENT_EXIT this is the child's exit status.
* For PTRACE_EVENT_FORK, PTRACE_EVENT_VFORK and PTRACE_EVENT_CLONE
* this is the PID of the new process. Since Linux 2.6.18, the PID
* of the new process is also available for PTRACE_EVENT_VFORK_DONE.
* (addr is ignored.)
*/
if (ptrace_ret == 0 && request == PTRACE_GETEVENTMSG) {
unsigned long *ldata = (unsigned long*) data;
pid_t newRealPid = (pid_t) *ldata;
*ldata = (unsigned long) REAL_TO_VIRTUAL_PID(newRealPid);
}
return ptrace_ret;
}
extern "C" pid_t getsid(pid_t pid)
{
DMTCP_PLUGIN_DISABLE_CKPT();
pid_t currPid;
// If !pid then we ask SID of this process
if( pid )
currPid = VIRTUAL_TO_REAL_PID (pid);
else
currPid = _real_getpid();
pid_t res = _real_getsid (currPid);
pid_t origSid = REAL_TO_VIRTUAL_PID (res);
DMTCP_PLUGIN_ENABLE_CKPT();
return origSid;
}
pid_t wait4(pid_t pid, __WAIT_STATUS status, int options, struct rusage *rusage)
{
int stat;
int saved_errno = errno;
pid_t currPid;
pid_t virtualPid;
pid_t retval = 0;
struct timespec sleepTime = {0, 10*000};
if (status == NULL)
status = (__WAIT_STATUS) &stat;
while (retval == 0) {
DMTCP_PLUGIN_DISABLE_CKPT();
currPid = VIRTUAL_TO_REAL_PID(pid);
retval = _real_wait4(currPid, status, options | WNOHANG, rusage);
saved_errno = errno;
virtualPid = REAL_TO_VIRTUAL_PID(retval);
if (retval > 0 &&
(WIFEXITED(*(int*)status) || WIFSIGNALED(*(int*)status))) {
dmtcp::VirtualPidTable::instance().erase(virtualPid);
}
DMTCP_PLUGIN_ENABLE_CKPT();
if ((options & WNOHANG) || retval != 0) {
break;
} else {
if (sleepTime.tv_sec == 0) {
sleepTime.tv_nsec *= 2;
if (sleepTime.tv_nsec >= 1000 * 1000 * 1000) {
sleepTime.tv_sec++;
sleepTime.tv_nsec = 0;
}
}
nanosleep(&sleepTime, NULL);
}
}
errno = saved_errno;
return virtualPid;
}
// FIXME: This function needs third argument newpathsize, or assume PATH_MAX
// FIXME: This does a lot of copying even if "/proc" doesn't appear.
static void updateProcPathVirtualToReal(const char *path, char *newpath)
{
if (path == NULL || strlen(path) == 0) {
strcpy(newpath, "");
return;
}
if (dmtcp::Util::strStartsWith(path, "/proc/")) {
int index = 6;
char *rest;
pid_t virtualPid = strtol(&path[index], &rest, 0);
if (virtualPid > 0 && *rest == '/') {
pid_t realPid = VIRTUAL_TO_REAL_PID(virtualPid);
sprintf(newpath, "/proc/%d%s", realPid, rest);
} else {
strcpy(newpath, path);
}
} else {
strcpy(newpath, path);
}
return;
}
//need to forward user clone
extern "C" int __clone(int (*fn) (void *arg), void *child_stack, int flags,
void *arg, int *parent_tidptr, struct user_desc *newtls,
int *child_tidptr)
{
/*
* struct MtcpRestartThreadArg
*
* DMTCP requires the virtualTids of the threads being created during
* the RESTARTING phase. We use an MtcpRestartThreadArg structure to pass
* the virtualTid of the thread being created from MTCP to DMTCP.
*
* actual clone call: clone (fn, child_stack, flags, void *, ... )
* new clone call : clone (fn, child_stack, flags,
* (struct MtcpRestartThreadArg *), ...)
*
* DMTCP automatically extracts arg from this structure and passes that
* to the _real_clone call.
*
* IMPORTANT NOTE: While updating, this struct must be kept in sync
* with the struct of the same name in mtcp.c
*/
struct MtcpRestartThreadArg {
void * arg;
pid_t virtualTid;
} *mtcpRestartThreadArg;
pid_t virtualTid = -1;
if (!dmtcp_is_running_state()) {
mtcpRestartThreadArg = (struct MtcpRestartThreadArg *) arg;
arg = mtcpRestartThreadArg -> arg;
virtualTid = mtcpRestartThreadArg -> virtualTid;
if (virtualTid != VIRTUAL_TO_REAL_PID(virtualTid)) {
dmtcp::VirtualPidTable::instance().postRestart();
}
} else {
virtualTid = dmtcp::VirtualPidTable::instance().getNewVirtualTid();
dmtcp::VirtualPidTable::instance().writeVirtualTidToFileForPtrace(virtualTid);
}
// We have to use DMTCP-specific memory allocator because using glibc:malloc
// can interfere with user threads.
// We use JALLOC_HELPER_FREE to free this memory in two places:
// 1. later in this function in case of failure on call to __clone; and
// 2. near the beginnging of clone_start (wrapper for start_routine).
struct ThreadArg *threadArg =
(struct ThreadArg *) JALLOC_HELPER_MALLOC(sizeof (struct ThreadArg));
threadArg->fn = fn;
threadArg->arg = arg;
threadArg->virtualTid = virtualTid;
JTRACE("Calling libc:__clone");
pid_t tid = _real_clone(clone_start, child_stack, flags, threadArg,
parent_tidptr, newtls, child_tidptr);
if (dmtcp_is_running_state() && dmtcp::Util::isPtraced()) {
dmtcp::VirtualPidTable::instance().readVirtualTidFromFileForPtrace();
}
if (tid > 0) {
JTRACE("New thread created") (tid);
dmtcp::VirtualPidTable::instance().updateMapping(virtualTid, tid);
} else {
// Free memory previously allocated by calling JALLOC_HELPER_MALLOC
JALLOC_HELPER_FREE(threadArg);
virtualTid = tid;
}
return virtualTid;
}
extern "C" int kill(pid_t pid, int sig)
{
/* FIXME: When bash receives a SIGINT signal, the signal handler is
* called to process the signal. Once the processing is done, bash
* performs a longjmp to a much higher call frame. As a result, this
* call frame never gets a chance to return and hence we fail to
* perform DMTCP_PLUGIN_ENABLE_CKPT() WHICH RESULTS in the lock
* being held but never released. Thus later on, when the ckpt-thread
* tries to acquire this lock, it results in a deadlock.
*
* To avoid the deadlock, FOR NOW, we shouldn't call WRAPPER_...()
* calls in this function or any kill() family of wrappers.
*
* Potential Solution: If the signal sending process is among the
* potential signal receivers, it should MASK/BLOCK signal delivery
* right before sending the signal (before calling _real_kill()). Once
* the system call returns, it should then call
* DMTCP_PLUGIN_ENABLE_CKPT() AND THEN RESTore the signal mask to
* as it was prior to calling this wrapper. So this function will as
* follows:
* DMTCP_PLUGIN_DISABLE_CKPT();
* // if this process is a potential receiver of this signal
* if (pid == getpid() || pid == 0 || pid == -1 ||
* getpgrp() == abs(pid)) {
* <SAVE_SIGNAL_MASK>;
* <BLOCK SIGNAL 'sig'>;
* sigmaskAltered = true;
* }
* pid_t currPid = VIRTUAL_TO_REAL_PID(pid);
* int retVal = _real_kill(currPid, sig);
* DMTCP_PLUGIN_ENABLE_CKPT();
* if (sigmaskAltered) {
* <RESTORE_SIGNAL_MASK>
* }
* return retVal;
*
*
* This longjmp trouble can happen with any wrapper, whose execution my
* end up in a call to user-code i.e. if the call frame looks sth like:
* ...
* user_func1(...)
* ...
* DMTCP_WRAPPER(...)
* ...
* user_func2(...)
* ...
*
* Another potential way would be to put a wrapper around longjmp() in
* which the calling thread should release all the DMTCP-locks being
* held at the moment. This would require us to keep a count of lock()
* calls without a corresponding unlock() call. After the longjmp()
* call, one need to make sure that an unlock() call is requested only
* if there is a corresponding lock, because it might happen that
* longjmp() was harmless in the sense that, it didn't cause a
* callframe like the one mentioned above.
*
*/
// DMTCP_PLUGIN_DISABLE_CKPT();
pid_t currPid = VIRTUAL_TO_REAL_PID (pid);
int retVal = _real_kill (currPid, sig);
// DMTCP_PLUGIN_ENABLE_CKPT();
return retVal;
}