/*
This file is part of drd, a thread error detector.
Copyright (C) 2006-2017 Bart Van Assche <bvanassche@acm.org>.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307, USA.
The GNU General Public License is contained in the file COPYING.
*/
#include "drd_clientobj.h"
#include "drd_error.h"
#include "drd_semaphore.h"
#include "drd_suppression.h"
#include "pub_tool_errormgr.h" // VG_(maybe_record_error)()
#include "pub_tool_libcassert.h" // tl_assert()
#include "pub_tool_libcprint.h" // VG_(printf)()
#include "pub_tool_machine.h" // VG_(get_IP)()
#include "pub_tool_mallocfree.h" // VG_(malloc), VG_(free)
#include "pub_tool_threadstate.h" // VG_(get_running_tid)()
/* Local functions. */
static void semaphore_cleanup(struct semaphore_info* p);
/* Local variables. */
static Bool s_trace_semaphore;
static ULong s_semaphore_segment_creation_count;
/* Function definitions. */
/** Push a segment at the end of the queue 'p->last_sem_post_seg'. */
static void drd_segment_push(struct semaphore_info* p, Segment* sg)
{
Word n;
tl_assert(sg);
n = VG_(addToXA)(p->last_sem_post_seg, &sg);
#if 0
VG_(message)(Vg_DebugMsg, "0x%lx push: added at position %ld/%ld\n",
p->a1, n, VG_(sizeXA)(p->last_sem_post_seg));
#endif
tl_assert(*(Segment**)VG_(indexXA)(p->last_sem_post_seg, n) == sg);
}
/** Pop a segment from the beginning of the queue 'p->last_sem_post_seg'. */
static Segment* drd_segment_pop(struct semaphore_info* p)
{
Word sz;
Segment* sg;
sz = VG_(sizeXA)(p->last_sem_post_seg);
#if 0
VG_(message)(Vg_DebugMsg, "0x%lx pop: removed from position %ld/%ld\n",
p->a1, sz - 1, sz);
#endif
sg = 0;
if (sz > 0)
{
sg = *(Segment**)VG_(indexXA)(p->last_sem_post_seg, sz - 1);
tl_assert(sg);
VG_(dropTailXA)(p->last_sem_post_seg, 1);
}
return sg;
}
/** Enable or disable tracing of semaphore actions. */
void DRD_(semaphore_set_trace)(const Bool trace_semaphore)
{
s_trace_semaphore = trace_semaphore;
}
/**
* Initialize the memory 'p' points at as a semaphore_info structure for the
* client semaphore at client address 'semaphore'.
*/
static
void drd_semaphore_initialize(struct semaphore_info* const p,
const Addr semaphore)
{
tl_assert(semaphore != 0);
tl_assert(p->a1 == semaphore);
tl_assert(p->type == ClientSemaphore);
p->cleanup = (void(*)(DrdClientobj*))semaphore_cleanup;
p->delete_thread = 0;
p->waits_to_skip = 0;
p->value = 0;
p->waiters = 0;
p->last_sem_post_tid = DRD_INVALID_THREADID;
p->last_sem_post_seg = VG_(newXA)(VG_(malloc), "drd.sg-stack",
VG_(free), sizeof(Segment*));
}
/**
* Free the memory that was allocated by semaphore_initialize(). Called by
* DRD_(clientobj_remove)().
*/
static void semaphore_cleanup(struct semaphore_info* p)
{
Segment* sg;
if (p->waiters > 0)
{
SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), p->a1 };
VG_(maybe_record_error)(VG_(get_running_tid)(),
SemaphoreErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Destruction of semaphore that is being waited"
" upon",
&sei);
}
while ((sg = drd_segment_pop(p)))
DRD_(sg_put)(sg);
VG_(deleteXA)(p->last_sem_post_seg);
}
/**
* Return a pointer to the structure with information about the specified
* client semaphore. Allocate a new structure if such a structure did not
* yet exist.
*/
static
struct semaphore_info*
drd_semaphore_get_or_allocate(const Addr semaphore)
{
struct semaphore_info *p;
tl_assert(offsetof(DrdClientobj, semaphore) == 0);
p = &(DRD_(clientobj_get)(semaphore, ClientSemaphore)->semaphore);
if (p == 0)
{
tl_assert(offsetof(DrdClientobj, semaphore) == 0);
p = &(DRD_(clientobj_add)(semaphore, ClientSemaphore)->semaphore);
drd_semaphore_initialize(p, semaphore);
}
return p;
}
/**
* Return a pointer to the structure with information about the specified
* client semaphore, or null if no such structure was found.
*/
static struct semaphore_info* semaphore_get(const Addr semaphore)
{
tl_assert(offsetof(DrdClientobj, semaphore) == 0);
return &(DRD_(clientobj_get)(semaphore, ClientSemaphore)->semaphore);
}
/** Called before sem_init(). */
struct semaphore_info* DRD_(semaphore_init)(const Addr semaphore,
const Word pshared,
const UInt value)
{
struct semaphore_info* p;
Segment* sg;
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_init 0x%lx value %u",
DRD_(thread_get_running_tid)(), semaphore, value);
p = semaphore_get(semaphore);
if (p)
{
const ThreadId vg_tid = VG_(get_running_tid)();
SemaphoreErrInfo SEI = { DRD_(thread_get_running_tid)(), semaphore };
VG_(maybe_record_error)(vg_tid,
SemaphoreErr,
VG_(get_IP)(vg_tid),
"Semaphore reinitialization",
&SEI);
// Remove all segments from the segment stack.
while ((sg = drd_segment_pop(p)))
{
DRD_(sg_put)(sg);
}
}
else
{
#if defined(VGO_darwin)
const ThreadId vg_tid = VG_(get_running_tid)();
GenericErrInfo GEI = { DRD_(thread_get_running_tid)(), 0 };
VG_(maybe_record_error)(vg_tid,
GenericErr,
VG_(get_IP)(vg_tid),
"sem_init() is not yet supported on Darwin",
&GEI);
return NULL;
#else
p = drd_semaphore_get_or_allocate(semaphore);
#endif
}
tl_assert(p);
p->waits_to_skip = value;
p->value = value;
return p;
}
/** Called after sem_destroy(). */
void DRD_(semaphore_destroy)(const Addr semaphore)
{
struct semaphore_info* p;
p = semaphore_get(semaphore);
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_destroy 0x%lx value %u",
DRD_(thread_get_running_tid)(), semaphore,
p ? p->value : 0);
if (p == 0)
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = semaphore,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a semaphore",
&GEI);
return;
}
DRD_(clientobj_remove)(semaphore, ClientSemaphore);
}
/** Called after sem_open(). */
struct semaphore_info* DRD_(semaphore_open)(const Addr semaphore,
const HChar* name, const Word oflag,
const Word mode, const UInt value)
{
struct semaphore_info* p;
Segment* sg;
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_open 0x%lx name %s"
" oflag %#lx mode %#lo value %u",
DRD_(thread_get_running_tid)(),
semaphore, name, (UWord)oflag, (UWord)mode, value);
/* Return if the sem_open() call failed. */
if (! semaphore)
return NULL;
p = semaphore_get(semaphore);
if (p)
{
const ThreadId vg_tid = VG_(get_running_tid)();
SemaphoreErrInfo SEI = { DRD_(thread_get_running_tid)(), semaphore };
VG_(maybe_record_error)(vg_tid,
SemaphoreErr,
VG_(get_IP)(vg_tid),
"Semaphore reinitialization",
&SEI);
// Remove all segments from the segment stack.
while ((sg = drd_segment_pop(p)))
{
DRD_(sg_put)(sg);
}
}
else
{
p = drd_semaphore_get_or_allocate(semaphore);
}
tl_assert(p);
p->waits_to_skip = value;
p->value = value;
return p;
}
/** Called before sem_close(). */
void DRD_(semaphore_close)(const Addr semaphore)
{
struct semaphore_info* p;
p = semaphore_get(semaphore);
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_close 0x%lx value %u",
DRD_(thread_get_running_tid)(), semaphore,
p ? p->value : 0);
if (p == 0)
{
GenericErrInfo GEI = {
.tid = DRD_(thread_get_running_tid)(),
.addr = semaphore,
};
VG_(maybe_record_error)(VG_(get_running_tid)(),
GenericErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Not a semaphore",
&GEI);
return;
}
DRD_(clientobj_remove)(semaphore, ClientSemaphore);
}
/** Called before sem_wait(). */
void DRD_(semaphore_pre_wait)(const Addr semaphore)
{
struct semaphore_info* p;
tl_assert(semaphore < semaphore + 1);
p = drd_semaphore_get_or_allocate(semaphore);
tl_assert(p);
p->waiters++;
if ((Word)(p->waiters) <= 0)
{
SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), semaphore };
VG_(maybe_record_error)(VG_(get_running_tid)(),
SemaphoreErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Invalid semaphore",
&sei);
}
}
/**
* Called after sem_wait() finished.
* @note Some C libraries do not set the 'waited' value correctly.
*/
void DRD_(semaphore_post_wait)(const DrdThreadId tid, const Addr semaphore,
const Bool waited)
{
struct semaphore_info* p;
Segment* sg;
tl_assert(waited == 0 || waited == 1);
p = semaphore_get(semaphore);
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_wait 0x%lx value %u -> %u%s",
DRD_(thread_get_running_tid)(), semaphore,
p ? p->value : 0, p ? p->value - waited : 0,
waited ? "" : " (did not wait)");
if (p) {
p->waiters--;
p->value -= waited;
}
/*
* Note: if another thread destroyed and reinitialized a semaphore while
* the current thread was waiting in sem_wait, p->waiters may have been
* set to zero by drd_semaphore_initialize() after
* DRD_(semaphore_pre_wait)() has finished before
* DRD_(semaphore_post_wait)() has been called.
*/
if (p == NULL || (Int)(p->value) < 0 || (Word)(p->waiters) < 0)
{
SemaphoreErrInfo sei = { DRD_(thread_get_running_tid)(), semaphore };
VG_(maybe_record_error)(VG_(get_running_tid)(),
SemaphoreErr,
VG_(get_IP)(VG_(get_running_tid)()),
"Invalid semaphore",
&sei);
return;
}
if (!waited)
return;
if (p->waits_to_skip > 0)
p->waits_to_skip--;
else
{
sg = drd_segment_pop(p);
tl_assert(sg);
if (p->last_sem_post_tid != tid
&& p->last_sem_post_tid != DRD_INVALID_THREADID)
{
DRD_(thread_new_segment_and_combine_vc)(tid, sg);
}
else
DRD_(thread_new_segment)(tid);
s_semaphore_segment_creation_count++;
DRD_(sg_put)(sg);
}
}
/** Called before sem_post(). */
void DRD_(semaphore_pre_post)(const DrdThreadId tid, const Addr semaphore)
{
struct semaphore_info* p;
Segment* sg;
p = drd_semaphore_get_or_allocate(semaphore);
p->value++;
if (s_trace_semaphore)
DRD_(trace_msg)("[%u] sem_post 0x%lx value %u -> %u",
DRD_(thread_get_running_tid)(),
semaphore, p->value - 1, p->value);
p->last_sem_post_tid = tid;
sg = 0;
DRD_(thread_get_latest_segment)(&sg, tid);
tl_assert(sg);
drd_segment_push(p, sg);
DRD_(thread_new_segment)(tid);
s_semaphore_segment_creation_count++;
}
/** Called after sem_post() finished. */
void DRD_(semaphore_post_post)(const DrdThreadId tid, const Addr semaphore,
const Bool succeeded)
{
/*
* Note: it is hard to implement the sem_post() wrapper correctly in
* case sem_post() returns an error code. This is because handling this
* case correctly requires restoring the vector clock associated with
* the semaphore to its original value here. In order to do that without
* introducing a race condition, extra locking has to be added around
* each semaphore call. Such extra locking would have to be added in
* drd_pthread_intercepts.c. However, it is hard to implement
* synchronization in drd_pthread_intercepts.c in a portable way without
* calling already redirected functions.
*/
}
ULong DRD_(get_semaphore_segment_creation_count)(void)
{
return s_semaphore_segment_creation_count;
}