596 lines
19 KiB
Python
596 lines
19 KiB
Python
# Pretty printers for the NPTL lock types.
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#
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# Copyright (C) 2016-2022 Free Software Foundation, Inc.
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# This file is part of the GNU C Library.
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#
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# The GNU C Library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# The GNU C Library 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 GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with the GNU C Library; if not, see
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# <https://www.gnu.org/licenses/>.
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"""This file contains the gdb pretty printers for the following types:
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* pthread_mutex_t
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* pthread_mutexattr_t
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* pthread_cond_t
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* pthread_condattr_t
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* pthread_rwlock_t
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* pthread_rwlockattr_t
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You can check which printers are registered and enabled by issuing the
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'info pretty-printer' gdb command. Printers should trigger automatically when
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trying to print a variable of one of the types mentioned above.
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"""
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from __future__ import print_function
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import gdb
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import gdb.printing
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from nptl_lock_constants import *
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MUTEX_TYPES = {
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PTHREAD_MUTEX_NORMAL: ('Type', 'Normal'),
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PTHREAD_MUTEX_RECURSIVE: ('Type', 'Recursive'),
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PTHREAD_MUTEX_ERRORCHECK: ('Type', 'Error check'),
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PTHREAD_MUTEX_ADAPTIVE_NP: ('Type', 'Adaptive')
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}
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class MutexPrinter(object):
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"""Pretty printer for pthread_mutex_t."""
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def __init__(self, mutex):
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"""Initialize the printer's internal data structures.
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Args:
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mutex: A gdb.value representing a pthread_mutex_t.
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"""
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data = mutex['__data']
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self.lock = data['__lock']
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self.count = data['__count']
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self.owner = data['__owner']
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self.kind = data['__kind']
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self.values = []
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self.read_values()
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def to_string(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_mutex_t.
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"""
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return 'pthread_mutex_t'
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def children(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_mutex_t.
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"""
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return self.values
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def read_values(self):
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"""Read the mutex's info and store it in self.values.
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The data contained in self.values will be returned by the Iterator
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created in self.children.
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"""
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self.read_type()
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self.read_status()
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self.read_attributes()
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self.read_misc_info()
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def read_type(self):
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"""Read the mutex's type."""
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mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK
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# mutex_type must be casted to int because it's a gdb.Value
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self.values.append(MUTEX_TYPES[int(mutex_type)])
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def read_status(self):
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"""Read the mutex's status.
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Architectures that support lock elision might not record the mutex owner
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ID in the __owner field. In that case, the owner will be reported as
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"Unknown".
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"""
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if self.kind == PTHREAD_MUTEX_DESTROYED:
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self.values.append(('Status', 'Destroyed'))
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elif self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP:
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self.read_status_robust()
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else:
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self.read_status_no_robust()
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def read_status_robust(self):
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"""Read the status of a robust mutex.
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In glibc robust mutexes are implemented in a very different way than
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non-robust ones. This method reads their locking status,
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whether it may have waiters, their registered owner (if any),
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whether the owner is alive or not, and the status of the state
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they're protecting.
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"""
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if self.lock == PTHREAD_MUTEX_UNLOCKED:
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self.values.append(('Status', 'Not acquired'))
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else:
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if self.lock & FUTEX_WAITERS:
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self.values.append(('Status',
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'Acquired, possibly with waiters'))
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else:
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self.values.append(('Status',
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'Acquired, possibly with no waiters'))
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if self.lock & FUTEX_OWNER_DIED:
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self.values.append(('Owner ID', '%d (dead)' % self.owner))
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else:
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self.values.append(('Owner ID', self.lock & FUTEX_TID_MASK))
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if self.owner == PTHREAD_MUTEX_INCONSISTENT:
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self.values.append(('State protected by this mutex',
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'Inconsistent'))
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elif self.owner == PTHREAD_MUTEX_NOTRECOVERABLE:
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self.values.append(('State protected by this mutex',
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'Not recoverable'))
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def read_status_no_robust(self):
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"""Read the status of a non-robust mutex.
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Read info on whether the mutex is acquired, if it may have waiters
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and its owner (if any).
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"""
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lock_value = self.lock
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if self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP:
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lock_value &= 0xffffffff & ~(PTHREAD_MUTEX_PRIO_CEILING_MASK)
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if lock_value == PTHREAD_MUTEX_UNLOCKED:
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self.values.append(('Status', 'Not acquired'))
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else:
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if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP:
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waiters = self.lock & FUTEX_WAITERS
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owner = self.lock & FUTEX_TID_MASK
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else:
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# Mutex protocol is PP or none
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waiters = (self.lock != PTHREAD_MUTEX_LOCKED_NO_WAITERS)
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owner = self.owner
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if waiters:
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self.values.append(('Status',
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'Acquired, possibly with waiters'))
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else:
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self.values.append(('Status',
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'Acquired, possibly with no waiters'))
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if self.owner != 0:
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self.values.append(('Owner ID', owner))
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else:
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# Owner isn't recorded, probably because lock elision
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# is enabled.
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self.values.append(('Owner ID', 'Unknown'))
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def read_attributes(self):
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"""Read the mutex's attributes."""
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if self.kind != PTHREAD_MUTEX_DESTROYED:
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if self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP:
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self.values.append(('Robust', 'Yes'))
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else:
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self.values.append(('Robust', 'No'))
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# In glibc, robust mutexes always have their pshared flag set to
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# 'shared' regardless of what the pshared flag of their
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# mutexattr was. Therefore a robust mutex will act as shared
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# even if it was initialized with a 'private' mutexattr.
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if self.kind & PTHREAD_MUTEX_PSHARED_BIT:
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self.values.append(('Shared', 'Yes'))
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else:
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self.values.append(('Shared', 'No'))
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if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP:
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self.values.append(('Protocol', 'Priority inherit'))
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elif self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP:
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prio_ceiling = ((self.lock & PTHREAD_MUTEX_PRIO_CEILING_MASK)
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>> PTHREAD_MUTEX_PRIO_CEILING_SHIFT)
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self.values.append(('Protocol', 'Priority protect'))
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self.values.append(('Priority ceiling', prio_ceiling))
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else:
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# PTHREAD_PRIO_NONE
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self.values.append(('Protocol', 'None'))
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def read_misc_info(self):
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"""Read miscellaneous info on the mutex.
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For now this reads the number of times a recursive mutex was acquired
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by the same thread.
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"""
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mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK
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if mutex_type == PTHREAD_MUTEX_RECURSIVE and self.count > 1:
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self.values.append(('Times acquired by the owner', self.count))
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class MutexAttributesPrinter(object):
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"""Pretty printer for pthread_mutexattr_t.
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In the NPTL this is a type that's always casted to struct pthread_mutexattr
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which has a single 'mutexkind' field containing the actual attributes.
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"""
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def __init__(self, mutexattr):
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"""Initialize the printer's internal data structures.
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Args:
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mutexattr: A gdb.value representing a pthread_mutexattr_t.
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"""
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self.values = []
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try:
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mutexattr_struct = gdb.lookup_type('struct pthread_mutexattr')
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self.mutexattr = mutexattr.cast(mutexattr_struct)['mutexkind']
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self.read_values()
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except gdb.error:
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# libpthread doesn't have debug symbols, thus we can't find the
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# real struct type. Just print the union members.
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self.values.append(('__size', mutexattr['__size']))
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self.values.append(('__align', mutexattr['__align']))
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def to_string(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_mutexattr_t.
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"""
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return 'pthread_mutexattr_t'
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def children(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_mutexattr_t.
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"""
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return self.values
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def read_values(self):
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"""Read the mutexattr's info and store it in self.values.
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The data contained in self.values will be returned by the Iterator
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created in self.children.
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"""
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mutexattr_type = (self.mutexattr
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& 0xffffffff
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& ~PTHREAD_MUTEXATTR_FLAG_BITS
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& ~PTHREAD_MUTEX_NO_ELISION_NP)
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# mutexattr_type must be casted to int because it's a gdb.Value
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self.values.append(MUTEX_TYPES[int(mutexattr_type)])
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if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_ROBUST:
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self.values.append(('Robust', 'Yes'))
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else:
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self.values.append(('Robust', 'No'))
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if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_PSHARED:
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self.values.append(('Shared', 'Yes'))
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else:
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self.values.append(('Shared', 'No'))
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protocol = ((self.mutexattr & PTHREAD_MUTEXATTR_PROTOCOL_MASK) >>
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PTHREAD_MUTEXATTR_PROTOCOL_SHIFT)
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if protocol == PTHREAD_PRIO_NONE:
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self.values.append(('Protocol', 'None'))
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elif protocol == PTHREAD_PRIO_INHERIT:
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self.values.append(('Protocol', 'Priority inherit'))
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elif protocol == PTHREAD_PRIO_PROTECT:
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self.values.append(('Protocol', 'Priority protect'))
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class ConditionVariablePrinter(object):
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"""Pretty printer for pthread_cond_t."""
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def __init__(self, cond):
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"""Initialize the printer's internal data structures.
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Args:
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cond: A gdb.value representing a pthread_cond_t.
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"""
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data = cond['__data']
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self.wrefs = data['__wrefs']
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self.values = []
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self.read_values()
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def to_string(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_cond_t.
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"""
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return 'pthread_cond_t'
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def children(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_cond_t.
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"""
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return self.values
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def read_values(self):
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"""Read the condvar's info and store it in self.values.
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The data contained in self.values will be returned by the Iterator
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created in self.children.
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"""
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self.read_status()
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self.read_attributes()
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def read_status(self):
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"""Read the status of the condvar.
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This method reads whether the condvar is destroyed and how many threads
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are waiting for it.
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"""
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self.values.append(('Threads known to still execute a wait function',
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self.wrefs >> PTHREAD_COND_WREFS_SHIFT))
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def read_attributes(self):
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"""Read the condvar's attributes."""
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if (self.wrefs & PTHREAD_COND_CLOCK_MONOTONIC_MASK) != 0:
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self.values.append(('Clock ID', 'CLOCK_MONOTONIC'))
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else:
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self.values.append(('Clock ID', 'CLOCK_REALTIME'))
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if (self.wrefs & PTHREAD_COND_SHARED_MASK) != 0:
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self.values.append(('Shared', 'Yes'))
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else:
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self.values.append(('Shared', 'No'))
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class ConditionVariableAttributesPrinter(object):
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"""Pretty printer for pthread_condattr_t.
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In the NPTL this is a type that's always casted to struct pthread_condattr,
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which has a single 'value' field containing the actual attributes.
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"""
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def __init__(self, condattr):
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"""Initialize the printer's internal data structures.
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Args:
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condattr: A gdb.value representing a pthread_condattr_t.
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"""
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self.values = []
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try:
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condattr_struct = gdb.lookup_type('struct pthread_condattr')
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self.condattr = condattr.cast(condattr_struct)['value']
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self.read_values()
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except gdb.error:
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# libpthread doesn't have debug symbols, thus we can't find the
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# real struct type. Just print the union members.
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self.values.append(('__size', condattr['__size']))
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self.values.append(('__align', condattr['__align']))
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def to_string(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_condattr_t.
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"""
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return 'pthread_condattr_t'
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def children(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_condattr_t.
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"""
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return self.values
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def read_values(self):
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"""Read the condattr's info and store it in self.values.
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The data contained in self.values will be returned by the Iterator
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created in self.children.
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"""
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clock_id = (self.condattr >> 1) & ((1 << COND_CLOCK_BITS) - 1)
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if clock_id != 0:
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self.values.append(('Clock ID', 'CLOCK_MONOTONIC'))
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else:
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self.values.append(('Clock ID', 'CLOCK_REALTIME'))
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if self.condattr & 1:
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self.values.append(('Shared', 'Yes'))
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else:
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self.values.append(('Shared', 'No'))
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class RWLockPrinter(object):
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"""Pretty printer for pthread_rwlock_t."""
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def __init__(self, rwlock):
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"""Initialize the printer's internal data structures.
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Args:
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rwlock: A gdb.value representing a pthread_rwlock_t.
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"""
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data = rwlock['__data']
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self.readers = data['__readers']
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self.cur_writer = data['__cur_writer']
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self.shared = data['__shared']
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self.flags = data['__flags']
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self.values = []
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self.read_values()
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def to_string(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_rwlock_t.
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"""
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return 'pthread_rwlock_t'
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def children(self):
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"""gdb API function.
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This is called from gdb when we try to print a pthread_rwlock_t.
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"""
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return self.values
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def read_values(self):
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"""Read the rwlock's info and store it in self.values.
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The data contained in self.values will be returned by the Iterator
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created in self.children.
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"""
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self.read_status()
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self.read_attributes()
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def read_status(self):
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"""Read the status of the rwlock."""
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if self.readers & PTHREAD_RWLOCK_WRPHASE:
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if self.readers & PTHREAD_RWLOCK_WRLOCKED:
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self.values.append(('Status', 'Acquired (Write)'))
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self.values.append(('Writer ID', self.cur_writer))
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else:
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self.values.append(('Status', 'Not acquired'))
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else:
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r = self.readers >> PTHREAD_RWLOCK_READER_SHIFT
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if r > 0:
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self.values.append(('Status', 'Acquired (Read)'))
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self.values.append(('Readers', r))
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else:
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self.values.append(('Status', 'Not acquired'))
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def read_attributes(self):
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"""Read the attributes of the rwlock."""
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if self.shared:
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self.values.append(('Shared', 'Yes'))
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else:
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self.values.append(('Shared', 'No'))
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if self.flags == PTHREAD_RWLOCK_PREFER_READER_NP:
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self.values.append(('Prefers', 'Readers'))
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elif self.flags == PTHREAD_RWLOCK_PREFER_WRITER_NP:
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self.values.append(('Prefers', 'Writers'))
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else:
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self.values.append(('Prefers', 'Writers no recursive readers'))
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class RWLockAttributesPrinter(object):
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"""Pretty printer for pthread_rwlockattr_t.
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In the NPTL this is a type that's always casted to
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struct pthread_rwlockattr, which has two fields ('lockkind' and 'pshared')
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containing the actual attributes.
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"""
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def __init__(self, rwlockattr):
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"""Initialize the printer's internal data structures.
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Args:
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rwlockattr: A gdb.value representing a pthread_rwlockattr_t.
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"""
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self.values = []
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try:
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rwlockattr_struct = gdb.lookup_type('struct pthread_rwlockattr')
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self.rwlockattr = rwlockattr.cast(rwlockattr_struct)
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self.read_values()
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except gdb.error:
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# libpthread doesn't have debug symbols, thus we can't find the
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# real struct type. Just print the union members.
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self.values.append(('__size', rwlockattr['__size']))
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self.values.append(('__align', rwlockattr['__align']))
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|
|
|
def to_string(self):
|
|
"""gdb API function.
|
|
|
|
This is called from gdb when we try to print a pthread_rwlockattr_t.
|
|
"""
|
|
|
|
return 'pthread_rwlockattr_t'
|
|
|
|
def children(self):
|
|
"""gdb API function.
|
|
|
|
This is called from gdb when we try to print a pthread_rwlockattr_t.
|
|
"""
|
|
|
|
return self.values
|
|
|
|
def read_values(self):
|
|
"""Read the rwlockattr's info and store it in self.values.
|
|
|
|
The data contained in self.values will be returned by the Iterator
|
|
created in self.children.
|
|
"""
|
|
|
|
rwlock_type = self.rwlockattr['lockkind']
|
|
shared = self.rwlockattr['pshared']
|
|
|
|
if shared == PTHREAD_PROCESS_SHARED:
|
|
self.values.append(('Shared', 'Yes'))
|
|
else:
|
|
# PTHREAD_PROCESS_PRIVATE
|
|
self.values.append(('Shared', 'No'))
|
|
|
|
if rwlock_type == PTHREAD_RWLOCK_PREFER_READER_NP:
|
|
self.values.append(('Prefers', 'Readers'))
|
|
elif rwlock_type == PTHREAD_RWLOCK_PREFER_WRITER_NP:
|
|
self.values.append(('Prefers', 'Writers'))
|
|
else:
|
|
self.values.append(('Prefers', 'Writers no recursive readers'))
|
|
|
|
def register(objfile):
|
|
"""Register the pretty printers within the given objfile."""
|
|
|
|
printer = gdb.printing.RegexpCollectionPrettyPrinter('glibc-pthread-locks')
|
|
|
|
printer.add_printer('pthread_mutex_t', r'^pthread_mutex_t$',
|
|
MutexPrinter)
|
|
printer.add_printer('pthread_mutexattr_t', r'^pthread_mutexattr_t$',
|
|
MutexAttributesPrinter)
|
|
printer.add_printer('pthread_cond_t', r'^pthread_cond_t$',
|
|
ConditionVariablePrinter)
|
|
printer.add_printer('pthread_condattr_t', r'^pthread_condattr_t$',
|
|
ConditionVariableAttributesPrinter)
|
|
printer.add_printer('pthread_rwlock_t', r'^pthread_rwlock_t$',
|
|
RWLockPrinter)
|
|
printer.add_printer('pthread_rwlockattr_t', r'^pthread_rwlockattr_t$',
|
|
RWLockAttributesPrinter)
|
|
|
|
if objfile == None:
|
|
objfile = gdb
|
|
|
|
gdb.printing.register_pretty_printer(objfile, printer)
|
|
|
|
register(gdb.current_objfile())
|