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authorAgustina Arzille <avarzille@riseup.net>2018-03-18 18:22:55 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2018-03-18 18:23:45 +0100
commitfb4cc8a0c2cc7ca710a2e1b21d33fcf7c5e3e8ba (patch)
tree0144983157b1b454724c37fe9e3e2b1e4aaa6629 /hurd
parent542c20a171cbc8cb63155fa6344708d26e9c446b (diff)
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hurd: Reimplement libc locks using mach's gsync
* hurd/Makefile (routines): Add hurdlock. * hurd/Versions (GLIBC_PRIVATE): Added new entry to export the above interface. (HURD_CTHREADS_0.3): Remove __libc_getspecific. * hurd/hurdpid.c: Include <lowlevellock.h> (_S_msg_proc_newids): Use lll_wait to synchronize. * hurd/hurdsig.c: (reauth_proc): Use __mutex_lock and __mutex_unlock. * hurd/setauth.c: Include <hurdlock.h>, use integer for synchronization. * mach/Makefile (lock-headers): Remove machine-lock.h. * mach/lock-intern.h: Include <lowlevellock.h> instead of <machine-lock.h>. (__spin_lock_t): New type. (__SPIN_LOCK_INITIALIZER): New macro. (__spin_lock, __spin_unlock, __spin_try_lock, __spin_lock_locked, __mutex_init, __mutex_lock_solid, __mutex_unlock_solid, __mutex_lock, __mutex_unlock, __mutex_trylock): Use lll to implement locks. * mach/mutex-init.c: Include <lowlevellock.h> instead of <cthreads.h>. (__mutex_init): Initialize with lll. * manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): New errno values. * sysdeps/mach/Makefile: Add libmachuser as dependencies for libs needing lll. * sysdeps/mach/hurd/bits/errno.h: Regenerate. * sysdeps/mach/hurd/cthreads.c (__libc_getspecific): Remove function. * sysdeps/mach/hurd/bits/libc-lock.h: Remove file. * sysdeps/mach/hurd/setpgid.c: Include <lowlevellock.h>. (__setpgid): Use lll for synchronization. * sysdeps/mach/hurd/setsid.c: Likewise with __setsid. * sysdeps/mach/bits/libc-lock.h: Include <tls.h> and <lowlevellock.h> instead of <cthreads.h>. (_IO_lock_inexpensive): New macro (__libc_lock_recursive_t, __rtld_lock_recursive_t): New structures. (__libc_lock_self0): New declaration. (__libc_lock_owner_self): New macro. (__libc_key_t): Remove type. (_LIBC_LOCK_INITIALIZER): New macro. (__libc_lock_define_initialized, __libc_lock_init, __libc_lock_fini, __libc_lock_fini_recursive, __rtld_lock_fini_recursive, __libc_lock_lock, __libc_lock_trylock, __libc_lock_unlock, __libc_lock_define_initialized_recursive, __rtld_lock_define_initialized_recursive, __libc_lock_init_recursive, __libc_lock_trylock_recursive, __libc_lock_lock_recursive, __libc_lock_unlock_recursive, __rtld_lock_initialize, __rtld_lock_trylock_recursive, __rtld_lock_lock_recursive, __rtld_lock_unlock_recursive __libc_once_define, __libc_mutex_unlock): Reimplement with lll. (__libc_lock_define_recursive, __rtld_lock_define_recursive, _LIBC_LOCK_RECURSIVE_INITIALIZER, _RTLD_LOCK_RECURSIVE_INITIALIZER): New macros. Include <libc-lockP.h> to reimplement libc_key* with pthread_key*. * hurd/hurdlock.c: New file. * hurd/hurdlock.h: New file. * mach/lowlevellock.h: New file
Diffstat (limited to 'hurd')
-rw-r--r--hurd/Makefile1
-rw-r--r--hurd/Versions9
-rw-r--r--hurd/hurdlock.c215
-rw-r--r--hurd/hurdlock.h125
-rw-r--r--hurd/hurdpid.c3
-rw-r--r--hurd/hurdsig.c4
-rw-r--r--hurd/setauth.c5
7 files changed, 356 insertions, 6 deletions
diff --git a/hurd/Makefile b/hurd/Makefile
index 2b318c9..7a787d2 100644
--- a/hurd/Makefile
+++ b/hurd/Makefile
@@ -54,6 +54,7 @@ routines = hurdstartup hurdinit \
vpprintf \
ports-get ports-set hurdports hurdmsg \
errno-loc \
+ hurdlock \
$(sig) $(dtable) $(inlines) port-cleanup report-wait xattr
sig = hurdsig hurdfault siginfo hurd-raise preempt-sig \
trampoline longjmp-ts catch-exc exc2signal hurdkill sigunwind \
diff --git a/hurd/Versions b/hurd/Versions
index 602391c..af6a0e4 100644
--- a/hurd/Versions
+++ b/hurd/Versions
@@ -147,6 +147,13 @@ libc {
# cthreads functions with stubs in libc
__cthread_keycreate; __cthread_getspecific; __cthread_setspecific;
- __libc_getspecific;
+ }
+
+ GLIBC_PRIVATE {
+ # Used by other libs.
+ __lll_abstimed_wait; __lll_abstimed_xwait;
+ __lll_abstimed_lock; __lll_robust_lock;
+ __lll_robust_abstimed_lock; __lll_robust_trylock;
+ __lll_robust_unlock;
}
}
diff --git a/hurd/hurdlock.c b/hurd/hurdlock.c
new file mode 100644
index 0000000..c06b03c
--- /dev/null
+++ b/hurd/hurdlock.c
@@ -0,0 +1,215 @@
+/* Hurd helpers for lowlevellocks.
+ Copyright (C) 1999-2017 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/>. */
+
+#include "hurdlock.h"
+#include <hurd.h>
+#include <hurd/hurd.h>
+#include <time.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* Convert an absolute timeout in nanoseconds to a relative
+ timeout in milliseconds. */
+static inline int __attribute__ ((gnu_inline))
+compute_reltime (const struct timespec *abstime, clockid_t clk)
+{
+ struct timespec ts;
+ __clock_gettime (clk, &ts);
+
+ ts.tv_sec = abstime->tv_sec - ts.tv_sec;
+ ts.tv_nsec = abstime->tv_nsec - ts.tv_nsec;
+
+ if (ts.tv_nsec < 0)
+ {
+ --ts.tv_sec;
+ ts.tv_nsec += 1000000000;
+ }
+
+ return (ts.tv_sec < 0 ? -1 :
+ (int)(ts.tv_sec * 1000 + ts.tv_nsec / 1000000));
+}
+
+int __lll_abstimed_wait (void *ptr, int val,
+ const struct timespec *tsp, int flags, int clk)
+{
+ int mlsec = compute_reltime (tsp, clk);
+ return (mlsec < 0 ? KERN_TIMEDOUT :
+ lll_timed_wait (ptr, val, mlsec, flags));
+}
+
+int __lll_abstimed_xwait (void *ptr, int lo, int hi,
+ const struct timespec *tsp, int flags, int clk)
+{
+ int mlsec = compute_reltime (tsp, clk);
+ return (mlsec < 0 ? KERN_TIMEDOUT :
+ lll_timed_xwait (ptr, lo, hi, mlsec, flags));
+}
+
+int __lll_abstimed_lock (void *ptr,
+ const struct timespec *tsp, int flags, int clk)
+{
+ if (lll_trylock (ptr) == 0)
+ return (0);
+
+ while (1)
+ {
+ if (atomic_exchange_acq ((int *)ptr, 2) == 0)
+ return (0);
+ else if (tsp->tv_nsec < 0 || tsp->tv_nsec >= 1000000000)
+ return (EINVAL);
+
+ int mlsec = compute_reltime (tsp, clk);
+ if (mlsec < 0 || lll_timed_wait (ptr,
+ 2, mlsec, flags) == KERN_TIMEDOUT)
+ return (ETIMEDOUT);
+ }
+}
+
+/* Robust locks. */
+
+/* Test if a given process id is still valid. */
+static inline int valid_pid (int pid)
+{
+ task_t task = __pid2task (pid);
+ if (task == MACH_PORT_NULL)
+ return (0);
+
+ __mach_port_deallocate (__mach_task_self (), task);
+ return (1);
+}
+
+/* Robust locks have currently no support from the kernel; they
+ are simply implemented with periodic polling. When sleeping, the
+ maximum blocking time is determined by this constant. */
+#define MAX_WAIT_TIME 1500
+
+int __lll_robust_lock (void *ptr, int flags)
+{
+ int *iptr = (int *)ptr;
+ int id = __getpid ();
+ int wait_time = 25;
+ unsigned int val;
+
+ /* Try to set the lock word to our PID if it's clear. Otherwise,
+ mark it as having waiters. */
+ while (1)
+ {
+ val = *iptr;
+ if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+ return (0);
+ else if (atomic_compare_and_exchange_bool_acq (iptr,
+ val | LLL_WAITERS, val) == 0)
+ break;
+ }
+
+ for (id |= LLL_WAITERS ; ; )
+ {
+ val = *iptr;
+ if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+ return (0);
+ else if (val && !valid_pid (val & LLL_OWNER_MASK))
+ {
+ if (atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+ return (EOWNERDEAD);
+ }
+ else
+ {
+ lll_timed_wait (iptr, val, wait_time, flags);
+ if (wait_time < MAX_WAIT_TIME)
+ wait_time <<= 1;
+ }
+ }
+}
+
+int __lll_robust_abstimed_lock (void *ptr,
+ const struct timespec *tsp, int flags, int clk)
+{
+ int *iptr = (int *)ptr;
+ int id = __getpid ();
+ int wait_time = 25;
+ unsigned int val;
+
+ while (1)
+ {
+ val = *iptr;
+ if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+ return (0);
+ else if (atomic_compare_and_exchange_bool_acq (iptr,
+ val | LLL_WAITERS, val) == 0)
+ break;
+ }
+
+ for (id |= LLL_WAITERS ; ; )
+ {
+ val = *iptr;
+ if (!val && atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+ return (0);
+ else if (val && !valid_pid (val & LLL_OWNER_MASK))
+ {
+ if (atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+ return (EOWNERDEAD);
+ }
+ else
+ {
+ int mlsec = compute_reltime (tsp, clk);
+ if (mlsec < 0)
+ return (ETIMEDOUT);
+ else if (mlsec > wait_time)
+ mlsec = wait_time;
+
+ int res = lll_timed_wait (iptr, val, mlsec, flags);
+ if (res == KERN_TIMEDOUT)
+ return (ETIMEDOUT);
+ else if (wait_time < MAX_WAIT_TIME)
+ wait_time <<= 1;
+ }
+ }
+}
+
+int __lll_robust_trylock (void *ptr)
+{
+ int *iptr = (int *)ptr;
+ int id = __getpid ();
+ unsigned int val = *iptr;
+
+ if (!val)
+ {
+ if (atomic_compare_and_exchange_bool_acq (iptr, id, 0) == 0)
+ return (0);
+ }
+ else if (!valid_pid (val & LLL_OWNER_MASK) &&
+ atomic_compare_and_exchange_bool_acq (iptr, id, val) == 0)
+ return (EOWNERDEAD);
+
+ return (EBUSY);
+}
+
+void __lll_robust_unlock (void *ptr, int flags)
+{
+ unsigned int val = atomic_load_relaxed((unsigned int *)ptr);
+ while (1)
+ {
+ if (val & LLL_WAITERS)
+ {
+ lll_set_wake (ptr, 0, flags);
+ break;
+ }
+ else if (atomic_compare_exchange_weak_release ((unsigned int *)ptr, &val, 0))
+ break;
+ }
+}
diff --git a/hurd/hurdlock.h b/hurd/hurdlock.h
new file mode 100644
index 0000000..af57e25
--- /dev/null
+++ b/hurd/hurdlock.h
@@ -0,0 +1,125 @@
+/* Low-level lock implementation. High-level Hurd helpers.
+ Copyright (C) 1999-2017 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/>. */
+
+#ifndef _HURD_LOCK_H
+#define _HURD_LOCK_H 1
+
+#include <mach/lowlevellock.h>
+
+struct timespec;
+
+/* Flags for robust locks. */
+#define LLL_WAITERS (1U << 31)
+#define LLL_DEAD_OWNER (1U << 30)
+
+#define LLL_OWNER_MASK ~(LLL_WAITERS | LLL_DEAD_OWNER)
+
+/* Wait on 64-bit address PTR, without blocking if its contents
+ are different from the pair <LO, HI>. */
+#define lll_xwait(ptr, lo, hi, flags) \
+ __gsync_wait (__mach_task_self (), \
+ (vm_offset_t)ptr, lo, hi, 0, flags | GSYNC_QUAD)
+
+/* Same as 'lll_wait', but only block for MLSEC milliseconds. */
+#define lll_timed_wait(ptr, val, mlsec, flags) \
+ __gsync_wait (__mach_task_self (), \
+ (vm_offset_t)ptr, val, 0, mlsec, flags | GSYNC_TIMED)
+
+/* Same as 'lll_xwait', but only block for MLSEC milliseconds. */
+#define lll_timed_xwait(ptr, lo, hi, mlsec, flags) \
+ __gsync_wait (__mach_task_self (), (vm_offset_t)ptr, \
+ lo, hi, mlsec, flags | GSYNC_TIMED | GSYNC_QUAD)
+
+/* Same as 'lll_wait', but only block until TSP elapses,
+ using clock CLK. */
+extern int __lll_abstimed_wait (void *__ptr, int __val,
+ const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as 'lll_xwait', but only block until TSP elapses,
+ using clock CLK. */
+extern int __lll_abstimed_xwait (void *__ptr, int __lo, int __hi,
+ const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as 'lll_lock', but return with an error if TSP elapses,
+ using clock CLK. */
+extern int __lll_abstimed_lock (void *__ptr,
+ const struct timespec *__tsp, int __flags, int __clk);
+
+/* Acquire the lock at PTR, but return with an error if
+ the process containing the owner thread dies. */
+extern int __lll_robust_lock (void *__ptr, int __flags);
+
+/* Same as '__lll_robust_lock', but only block until TSP
+ elapses, using clock CLK. */
+extern int __lll_robust_abstimed_lock (void *__ptr,
+ const struct timespec *__tsp, int __flags, int __clk);
+
+/* Same as '__lll_robust_lock', but return with an error
+ if the lock cannot be acquired without blocking. */
+extern int __lll_robust_trylock (void *__ptr);
+
+/* Wake one or more threads waiting on address PTR,
+ setting its value to VAL before doing so. */
+#define lll_set_wake(ptr, val, flags) \
+ __gsync_wake (__mach_task_self (), \
+ (vm_offset_t)ptr, val, flags | GSYNC_MUTATE)
+
+/* Release the robust lock at PTR. */
+extern void __lll_robust_unlock (void *__ptr, int __flags);
+
+/* Rearrange threads waiting on address SRC to instead wait on
+ DST, waking one of them if WAIT_ONE is non-zero. */
+#define lll_requeue(src, dst, wake_one, flags) \
+ __gsync_requeue (__mach_task_self (), (vm_offset_t)src, \
+ (vm_offset_t)dst, (boolean_t)wake_one, flags)
+
+/* The following are hacks that allow us to simulate optional
+ parameters in C, to avoid having to pass the clock id for
+ every one of these calls, defaulting to CLOCK_REALTIME if
+ no argument is passed. */
+
+#define lll_abstimed_wait(ptr, val, tsp, flags, ...) \
+ ({ \
+ const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ }; \
+ __lll_abstimed_wait ((ptr), (val), (tsp), (flags), \
+ __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]); \
+ })
+
+#define lll_abstimed_xwait(ptr, lo, hi, tsp, flags, ...) \
+ ({ \
+ const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ }; \
+ __lll_abstimed_xwait ((ptr), (lo), (hi), (tsp), (flags), \
+ __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]); \
+ })
+
+#define lll_abstimed_lock(ptr, tsp, flags, ...) \
+ ({ \
+ const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ }; \
+ __lll_abstimed_lock ((ptr), (tsp), (flags), \
+ __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]); \
+ })
+
+#define lll_robust_abstimed_lock(ptr, tsp, flags, ...) \
+ ({ \
+ const clockid_t __clk[] = { CLOCK_REALTIME, ##__VA_ARGS__ }; \
+ __lll_robust_abstimed_lock ((ptr), (tsp), (flags), \
+ __clk[sizeof (__clk) / sizeof (__clk[0]) - 1]); \
+ })
+
+
+#endif
diff --git a/hurd/hurdpid.c b/hurd/hurdpid.c
index e1dd093..33659cc 100644
--- a/hurd/hurdpid.c
+++ b/hurd/hurdpid.c
@@ -16,6 +16,8 @@
<http://www.gnu.org/licenses/>. */
#include <hurd.h>
+#include <lowlevellock.h>
+
pid_t _hurd_pid, _hurd_ppid, _hurd_pgrp;
int _hurd_orphaned;
@@ -66,6 +68,7 @@ _S_msg_proc_newids (mach_port_t me,
/* Notify any waiting user threads that the id change as been completed. */
++_hurd_pids_changed_stamp;
+ lll_wake (&_hurd_pids_changed_stamp, GSYNC_BROADCAST);
return 0;
}
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index ea76be7..fdadd5b 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -1362,14 +1362,14 @@ reauth_proc (mach_port_t new)
__mach_port_destroy (__mach_task_self (), ref);
/* Set the owner of the process here too. */
- mutex_lock (&_hurd_id.lock);
+ __mutex_lock (&_hurd_id.lock);
if (!_hurd_check_ids ())
HURD_PORT_USE (&_hurd_ports[INIT_PORT_PROC],
__proc_setowner (port,
(_hurd_id.gen.nuids
? _hurd_id.gen.uids[0] : 0),
!_hurd_id.gen.nuids));
- mutex_unlock (&_hurd_id.lock);
+ __mutex_unlock (&_hurd_id.lock);
(void) &reauth_proc; /* Silence compiler warning. */
}
diff --git a/hurd/setauth.c b/hurd/setauth.c
index deece20..025be58 100644
--- a/hurd/setauth.c
+++ b/hurd/setauth.c
@@ -18,14 +18,13 @@
#include <hurd.h>
#include <hurd/port.h>
#include <hurd/id.h>
+#include <hurdlock.h>
#include "set-hooks.h"
/* Things in the library which want to be run when the auth port changes. */
DEFINE_HOOK (_hurd_reauth_hook, (auth_t new_auth));
-#include <cthreads.h>
-static struct mutex reauth_lock = MUTEX_INITIALIZER;
-
+static unsigned int reauth_lock = LLL_INITIALIZER;
/* Set the auth port to NEW, and reauthenticate
everything used by the library. */