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Diffstat (limited to 'nptl/nptl-printers.py')
| -rw-r--r-- | nptl/nptl-printers.py | 593 |
1 files changed, 593 insertions, 0 deletions
diff --git a/nptl/nptl-printers.py b/nptl/nptl-printers.py new file mode 100644 index 0000000000..f64216fb57 --- /dev/null +++ b/nptl/nptl-printers.py @@ -0,0 +1,593 @@ +# Pretty printers for the NPTL lock types. +# +# Copyright (C) 2016 Free Software Foundation, Inc. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library 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 +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# <http://www.gnu.org/licenses/>. + +"""This file contains the gdb pretty printers for the following types: + + * pthread_mutex_t + * pthread_mutexattr_t + * pthread_cond_t + * pthread_condattr_t + * pthread_rwlock_t + * pthread_rwlockattr_t + +You can check which printers are registered and enabled by issuing the +'info pretty-printer' gdb command. Printers should trigger automatically when +trying to print a variable of one of the types mentioned above. +""" + +from __future__ import print_function + +import gdb +from nptl_lock_constants import * + +MUTEX_TYPES = { + PTHREAD_MUTEX_NORMAL: ('Type', 'Normal'), + PTHREAD_MUTEX_RECURSIVE: ('Type', 'Recursive'), + PTHREAD_MUTEX_ERRORCHECK: ('Type', 'Error check'), + PTHREAD_MUTEX_ADAPTIVE_NP: ('Type', 'Adaptive') +} + +class MutexPrinter(object): + """Pretty printer for pthread_mutex_t.""" + + def __init__(self, mutex): + """Initialize the printer's internal data structures. + + Args: + mutex: A gdb.value representing a pthread_mutex_t. + """ + + data = mutex['__data'] + self.lock = data['__lock'] + self.count = data['__count'] + self.owner = data['__owner'] + self.kind = data['__kind'] + self.values = [] + self.read_values() + + def to_string(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_mutex_t. + """ + + return 'pthread_mutex_t' + + def children(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_mutex_t. + """ + + return self.values + + def read_values(self): + """Read the mutex's info and store it in self.values. + + The data contained in self.values will be returned by the Iterator + created in self.children. + """ + + self.read_type() + self.read_status() + self.read_attributes() + self.read_misc_info() + + def read_type(self): + """Read the mutex's type.""" + + mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK + + # mutex_type must be casted to int because it's a gdb.Value + self.values.append(MUTEX_TYPES[int(mutex_type)]) + + def read_status(self): + """Read the mutex's status. + + For architectures which support lock elision, this method reads + whether the mutex appears as locked in memory (i.e. it may show it as + unlocked even after calling pthread_mutex_lock). + """ + + if self.kind == PTHREAD_MUTEX_DESTROYED: + self.values.append(('Status', 'Destroyed')) + elif self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP: + self.read_status_robust() + else: + self.read_status_no_robust() + + def read_status_robust(self): + """Read the status of a robust mutex. + + In glibc robust mutexes are implemented in a very different way than + non-robust ones. This method reads their locking status, + whether it may have waiters, their registered owner (if any), + whether the owner is alive or not, and the status of the state + they're protecting. + """ + + if self.lock == PTHREAD_MUTEX_UNLOCKED: + self.values.append(('Status', 'Unlocked')) + else: + if self.lock & FUTEX_WAITERS: + self.values.append(('Status', 'Locked, possibly with waiters')) + else: + self.values.append(('Status', + 'Locked, possibly with no waiters')) + + if self.lock & FUTEX_OWNER_DIED: + self.values.append(('Owner ID', '%d (dead)' % self.owner)) + else: + self.values.append(('Owner ID', self.lock & FUTEX_TID_MASK)) + + if self.owner == PTHREAD_MUTEX_INCONSISTENT: + self.values.append(('State protected by this mutex', + 'Inconsistent')) + elif self.owner == PTHREAD_MUTEX_NOTRECOVERABLE: + self.values.append(('State protected by this mutex', + 'Not recoverable')) + + def read_status_no_robust(self): + """Read the status of a non-robust mutex. + + Read info on whether the mutex is locked, if it may have waiters + and its owner (if any). + """ + + lock_value = self.lock + + if self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP: + lock_value &= ~(PTHREAD_MUTEX_PRIO_CEILING_MASK) + + if lock_value == PTHREAD_MUTEX_UNLOCKED: + self.values.append(('Status', 'Unlocked')) + else: + if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP: + waiters = self.lock & FUTEX_WAITERS + owner = self.lock & FUTEX_TID_MASK + else: + # Mutex protocol is PP or none + waiters = (self.lock != PTHREAD_MUTEX_LOCKED_NO_WAITERS) + owner = self.owner + + if waiters: + self.values.append(('Status', 'Locked, possibly with waiters')) + else: + self.values.append(('Status', + 'Locked, possibly with no waiters')) + + self.values.append(('Owner ID', owner)) + + def read_attributes(self): + """Read the mutex's attributes.""" + + if self.kind != PTHREAD_MUTEX_DESTROYED: + if self.kind & PTHREAD_MUTEX_ROBUST_NORMAL_NP: + self.values.append(('Robust', 'Yes')) + else: + self.values.append(('Robust', 'No')) + + # In glibc, robust mutexes always have their pshared flag set to + # 'shared' regardless of what the pshared flag of their + # mutexattr was. Therefore a robust mutex will act as shared + # even if it was initialized with a 'private' mutexattr. + if self.kind & PTHREAD_MUTEX_PSHARED_BIT: + self.values.append(('Shared', 'Yes')) + else: + self.values.append(('Shared', 'No')) + + if self.kind & PTHREAD_MUTEX_PRIO_INHERIT_NP: + self.values.append(('Protocol', 'Priority inherit')) + elif self.kind & PTHREAD_MUTEX_PRIO_PROTECT_NP: + prio_ceiling = ((self.lock & PTHREAD_MUTEX_PRIO_CEILING_MASK) + >> PTHREAD_MUTEX_PRIO_CEILING_SHIFT) + + self.values.append(('Protocol', 'Priority protect')) + self.values.append(('Priority ceiling', prio_ceiling)) + else: + # PTHREAD_PRIO_NONE + self.values.append(('Protocol', 'None')) + + def read_misc_info(self): + """Read miscellaneous info on the mutex. + + For now this reads the number of times a recursive mutex was locked + by the same thread. + """ + + mutex_type = self.kind & PTHREAD_MUTEX_KIND_MASK + + if mutex_type == PTHREAD_MUTEX_RECURSIVE and self.count > 1: + self.values.append(('Times locked recursively', self.count)) + +class MutexAttributesPrinter(object): + """Pretty printer for pthread_mutexattr_t. + + In the NPTL this is a type that's always casted to struct pthread_mutexattr + which has a single 'mutexkind' field containing the actual attributes. + """ + + def __init__(self, mutexattr): + """Initialize the printer's internal data structures. + + Args: + mutexattr: A gdb.value representing a pthread_mutexattr_t. + """ + + mutexattr_struct = gdb.lookup_type('struct pthread_mutexattr') + self.mutexattr = mutexattr.cast(mutexattr_struct)['mutexkind'] + self.values = [] + self.read_values() + + def to_string(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_mutexattr_t. + """ + + return 'pthread_mutexattr_t' + + def children(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_mutexattr_t. + """ + + return self.values + + def read_values(self): + """Read the mutexattr's info and store it in self.values. + + The data contained in self.values will be returned by the Iterator + created in self.children. + """ + + mutexattr_type = (self.mutexattr + & ~PTHREAD_MUTEXATTR_FLAG_BITS + & ~PTHREAD_MUTEX_NO_ELISION_NP) + + # mutexattr_type must be casted to int because it's a gdb.Value + self.values.append(MUTEX_TYPES[int(mutexattr_type)]) + + if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_ROBUST: + self.values.append(('Robust', 'Yes')) + else: + self.values.append(('Robust', 'No')) + + if self.mutexattr & PTHREAD_MUTEXATTR_FLAG_PSHARED: + self.values.append(('Shared', 'Yes')) + else: + self.values.append(('Shared', 'No')) + + protocol = ((self.mutexattr & PTHREAD_MUTEXATTR_PROTOCOL_MASK) >> + PTHREAD_MUTEXATTR_PROTOCOL_SHIFT) + + if protocol == PTHREAD_PRIO_NONE: + self.values.append(('Protocol', 'None')) + elif protocol == PTHREAD_PRIO_INHERIT: + self.values.append(('Protocol', 'Priority inherit')) + elif protocol == PTHREAD_PRIO_PROTECT: + self.values.append(('Protocol', 'Priority protect')) + +CLOCK_IDS = { + CLOCK_REALTIME: 'CLOCK_REALTIME', + CLOCK_MONOTONIC: 'CLOCK_MONOTONIC', + CLOCK_PROCESS_CPUTIME_ID: 'CLOCK_PROCESS_CPUTIME_ID', + CLOCK_THREAD_CPUTIME_ID: 'CLOCK_THREAD_CPUTIME_ID', + CLOCK_MONOTONIC_RAW: 'CLOCK_MONOTONIC_RAW', + CLOCK_REALTIME_COARSE: 'CLOCK_REALTIME_COARSE', + CLOCK_MONOTONIC_COARSE: 'CLOCK_MONOTONIC_COARSE' +} + +class ConditionVariablePrinter(object): + """Pretty printer for pthread_cond_t.""" + + def __init__(self, cond): + """Initialize the printer's internal data structures. + + Args: + cond: A gdb.value representing a pthread_cond_t. + """ + + data = cond['__data'] + self.total_seq = data['__total_seq'] + self.mutex = data['__mutex'] + self.nwaiters = data['__nwaiters'] + self.values = [] + self.read_values() + + def to_string(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_cond_t. + """ + + return 'pthread_cond_t' + + def children(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_cond_t. + """ + + return self.values + + def read_values(self): + """Read the condvar's info and store it in self.values. + + The data contained in self.values will be returned by the Iterator + created in self.children. + """ + + self.read_status() + self.read_attributes() + self.read_mutex_info() + + def read_status(self): + """Read the status of the condvar. + + This method reads whether the condvar is destroyed and how many threads + are waiting for it. + """ + + if self.total_seq == PTHREAD_COND_DESTROYED: + self.values.append(('Status', 'Destroyed')) + + self.values.append(('Threads waiting for this condvar', + self.nwaiters >> COND_NWAITERS_SHIFT)) + + def read_attributes(self): + """Read the condvar's attributes.""" + + clock_id = self.nwaiters & ((1 << COND_NWAITERS_SHIFT) - 1) + + # clock_id must be casted to int because it's a gdb.Value + self.values.append(('Clock ID', CLOCK_IDS[int(clock_id)])) + + shared = (self.mutex == PTHREAD_COND_SHARED) + + if shared: + self.values.append(('Shared', 'Yes')) + else: + self.values.append(('Shared', 'No')) + + def read_mutex_info(self): + """Read the data of the mutex this condvar is bound to. + + A pthread_cond_t's __data.__mutex member is a void * which + must be casted to pthread_mutex_t *. For shared condvars, this + member isn't recorded and has a value of ~0l instead. + """ + + if self.mutex and self.mutex != PTHREAD_COND_SHARED: + mutex_type = gdb.lookup_type('pthread_mutex_t') + mutex = self.mutex.cast(mutex_type.pointer()).dereference() + + self.values.append(('Mutex', mutex)) + +class ConditionVariableAttributesPrinter(object): + """Pretty printer for pthread_condattr_t. + + In the NPTL this is a type that's always casted to struct pthread_condattr, + which has a single 'value' field containing the actual attributes. + """ + + def __init__(self, condattr): + """Initialize the printer's internal data structures. + + Args: + condattr: A gdb.value representing a pthread_condattr_t. + """ + + condattr_struct = gdb.lookup_type('struct pthread_condattr') + self.condattr = condattr.cast(condattr_struct)['value'] + self.values = [] + self.read_values() + + def to_string(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_condattr_t. + """ + + return 'pthread_condattr_t' + + def children(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_condattr_t. + """ + + return self.values + + def read_values(self): + """Read the condattr's info and store it in self.values. + + The data contained in self.values will be returned by the Iterator + created in self.children. + """ + + clock_id = self.condattr & ((1 << COND_NWAITERS_SHIFT) - 1) + + # clock_id must be casted to int because it's a gdb.Value + self.values.append(('Clock ID', CLOCK_IDS[int(clock_id)])) + + if self.condattr & 1: + self.values.append(('Shared', 'Yes')) + else: + self.values.append(('Shared', 'No')) + +class RWLockPrinter(object): + """Pretty printer for pthread_rwlock_t.""" + + def __init__(self, rwlock): + """Initialize the printer's internal data structures. + + Args: + rwlock: A gdb.value representing a pthread_rwlock_t. + """ + + data = rwlock['__data'] + self.readers = data['__nr_readers'] + self.queued_readers = data['__nr_readers_queued'] + self.queued_writers = data['__nr_writers_queued'] + self.writer_id = data['__writer'] + self.shared = data['__shared'] + self.prefers_writers = data['__flags'] + self.values = [] + self.read_values() + + def to_string(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_rwlock_t. + """ + + return 'pthread_rwlock_t' + + def children(self): + """gdb API function. + + This is called from gdb when we try to print a pthread_rwlock_t. + """ + + return self.values + + def read_values(self): + """Read the rwlock's info and store it in self.values. + + The data contained in self.values will be returned by the Iterator + created in self.children. + """ + + self.read_status() + self.read_attributes() + + def read_status(self): + """Read the status of the rwlock.""" + + # Right now pthread_rwlock_destroy doesn't do anything, so there's no + # way to check if an rwlock is destroyed. + + if self.writer_id: + self.values.append(('Status', 'Locked (Write)')) + self.values.append(('Writer ID', self.writer_id)) + elif self.readers: + self.values.append(('Status', 'Locked (Read)')) + self.values.append(('Readers', self.readers)) + else: + self.values.append(('Status', 'Unlocked')) + + self.values.append(('Queued readers', self.queued_readers)) + self.values.append(('Queued writers', self.queued_writers)) + + def read_attributes(self): + """Read the attributes of the rwlock.""" + + if self.shared: + self.values.append(('Shared', 'Yes')) + else: + self.values.append(('Shared', 'No')) + + if self.prefers_writers: + self.values.append(('Prefers', 'Writers')) + else: + self.values.append(('Prefers', 'Readers')) + +class RWLockAttributesPrinter(object): + """Pretty printer for pthread_rwlockattr_t. + + In the NPTL this is a type that's always casted to + struct pthread_rwlockattr, which has two fields ('lockkind' and 'pshared') + containing the actual attributes. + """ + + def __init__(self, rwlockattr): + """Initialize the printer's internal data structures. + + Args: + rwlockattr: A gdb.value representing a pthread_rwlockattr_t. + """ + + rwlockattr_struct = gdb.lookup_type('struct pthread_rwlockattr') + self.rwlockattr = rwlockattr.cast(rwlockattr_struct) + self.values = [] + self.read_values() + + 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 or + rwlock_type == PTHREAD_RWLOCK_PREFER_WRITER_NP): + # This is a known bug. Using PTHREAD_RWLOCK_PREFER_WRITER_NP will + # still make the rwlock prefer readers. + self.values.append(('Prefers', 'Readers')) + elif rwlock_type == PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP: + self.values.append(('Prefers', 'Writers')) + +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) + + gdb.printing.register_pretty_printer(objfile, printer) + +register(gdb.current_objfile()) |