diff options
| -rw-r--r-- | htl/Makefile | 1 | ||||
| -rw-r--r-- | htl/semaphoreP.h | 21 | ||||
| -rw-r--r-- | nptl/Makefile | 2 | ||||
| -rw-r--r-- | nptl/semaphoreP.h | 21 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_close.c | 56 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_open.c | 116 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_routines.c | 187 | ||||
| -rw-r--r-- | sysdeps/pthread/sem_routines.h | 27 |
8 files changed, 223 insertions, 208 deletions
diff --git a/htl/Makefile b/htl/Makefile index 9adc95e..c15c1b1 100644 --- a/htl/Makefile +++ b/htl/Makefile @@ -131,6 +131,7 @@ libpthread-routines := pt-attr pt-attr-destroy pt-attr-getdetachstate \ sem_close sem-destroy sem-getvalue sem-init sem_open \ sem-post sem-timedwait sem-trywait sem_unlink \ sem-wait sem-waitfast \ + sem_routines \ \ cancellation \ cthreads-compat \ diff --git a/htl/semaphoreP.h b/htl/semaphoreP.h index 3d6efcd..4b13f7b 100644 --- a/htl/semaphoreP.h +++ b/htl/semaphoreP.h @@ -21,27 +21,6 @@ #define SEM_SHM_PREFIX "sem." -/* Keeping track of currently used mappings. */ -struct inuse_sem -{ - dev_t dev; - ino_t ino; - int refcnt; - sem_t *sem; - char name[]; -}; - - -/* The search tree for existing mappings. */ -extern void *__sem_mappings attribute_hidden; - -/* Lock to protect the search tree. */ -extern int __sem_mappings_lock attribute_hidden; - - -/* Comparison function for search in tree with existing mappings. */ -extern int __sem_search (const void *a, const void *b) attribute_hidden; - static inline void __new_sem_open_init (struct new_sem *sem, unsigned value) { /* This always is a shared semaphore. */ diff --git a/nptl/Makefile b/nptl/Makefile index c49134b..8fb7fee 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -137,7 +137,7 @@ libpthread-routines = nptl-init nptlfreeres vars events version pt-interp \ pthread_once \ old_pthread_atfork \ pthread_getcpuclockid \ - sem_init sem_destroy \ + sem_init sem_destroy sem_routines \ sem_open sem_close sem_unlink \ sem_getvalue \ sem_wait sem_timedwait sem_clockwait sem_post \ diff --git a/nptl/semaphoreP.h b/nptl/semaphoreP.h index 3585af0..1b78614 100644 --- a/nptl/semaphoreP.h +++ b/nptl/semaphoreP.h @@ -22,27 +22,6 @@ #define SEM_SHM_PREFIX "sem." -/* Keeping track of currently used mappings. */ -struct inuse_sem -{ - dev_t dev; - ino_t ino; - int refcnt; - sem_t *sem; - char name[]; -}; - - -/* The search tree for existing mappings. */ -extern void *__sem_mappings attribute_hidden; - -/* Lock to protect the search tree. */ -extern int __sem_mappings_lock attribute_hidden; - - -/* Comparison function for search in tree with existing mappings. */ -extern int __sem_search (const void *a, const void *b) attribute_hidden; - static inline void __new_sem_open_init (struct new_sem *sem, unsigned value) { #if __HAVE_64B_ATOMICS diff --git a/sysdeps/pthread/sem_close.c b/sysdeps/pthread/sem_close.c index 8b6c9c6..6649196 100644 --- a/sysdeps/pthread/sem_close.c +++ b/sysdeps/pthread/sem_close.c @@ -17,65 +17,17 @@ <https://www.gnu.org/licenses/>. */ #include <errno.h> -#include <search.h> -#include <sys/mman.h> #include "semaphoreP.h" - -struct walk_closure -{ - sem_t *the_sem; - struct inuse_sem *rec; -}; - -static void -walker (const void *inodep, VISIT which, void *closure0) -{ - struct walk_closure *closure = closure0; - struct inuse_sem *nodep = *(struct inuse_sem **) inodep; - - if (nodep->sem == closure->the_sem) - closure->rec = nodep; -} - +#include <sem_routines.h> int sem_close (sem_t *sem) { - int result = 0; - - /* Get the lock. */ - lll_lock (__sem_mappings_lock, LLL_PRIVATE); - - /* Locate the entry for the mapping the caller provided. */ - struct inuse_sem *rec; - { - struct walk_closure closure = { .the_sem = sem, .rec = NULL }; - __twalk_r (__sem_mappings, walker, &closure); - rec = closure.rec; - } - if (rec != NULL) + if (!__sem_remove_mapping (sem)) { - /* Check the reference counter. If it is going to be zero, free - all the resources. */ - if (--rec->refcnt == 0) - { - /* Remove the record from the tree. */ - (void) __tdelete (rec, &__sem_mappings, __sem_search); - - result = munmap (rec->sem, sizeof (sem_t)); - - free (rec); - } - } - else - { - /* This is no valid semaphore. */ - result = -1; __set_errno (EINVAL); + return -1; } - /* Release the lock. */ - lll_unlock (__sem_mappings_lock, LLL_PRIVATE); - - return result; + return 0; } diff --git a/sysdeps/pthread/sem_open.c b/sysdeps/pthread/sem_open.c index d666414..028d76a 100644 --- a/sysdeps/pthread/sem_open.c +++ b/sysdeps/pthread/sem_open.c @@ -16,127 +16,17 @@ License along with the GNU C Library; if not, see <https://www.gnu.org/licenses/>. */ -#include <errno.h> #include <fcntl.h> -#include <pthread.h> -#include <search.h> #include <semaphore.h> #include <stdarg.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> #include <unistd.h> #include <sys/mman.h> -#include <sys/stat.h> #include "semaphoreP.h" #include <shm-directory.h> +#include <sem_routines.h> #include <futex-internal.h> #include <libc-lock.h> -/* Comparison function for search of existing mapping. */ -int -attribute_hidden -__sem_search (const void *a, const void *b) -{ - const struct inuse_sem *as = (const struct inuse_sem *) a; - const struct inuse_sem *bs = (const struct inuse_sem *) b; - - if (as->ino != bs->ino) - /* Cannot return the difference the type is larger than int. */ - return as->ino < bs->ino ? -1 : (as->ino == bs->ino ? 0 : 1); - - if (as->dev != bs->dev) - /* Cannot return the difference the type is larger than int. */ - return as->dev < bs->dev ? -1 : (as->dev == bs->dev ? 0 : 1); - - return strcmp (as->name, bs->name); -} - - -/* The search tree for existing mappings. */ -void *__sem_mappings attribute_hidden; - -/* Lock to protect the search tree. */ -int __sem_mappings_lock attribute_hidden = LLL_LOCK_INITIALIZER; - - -/* Search for existing mapping and if possible add the one provided. */ -static sem_t * -check_add_mapping (const char *name, int fd, sem_t *existing) -{ - size_t namelen = strlen (name); - sem_t *result = SEM_FAILED; - - /* Get the information about the file. */ - struct stat64 st; - if (__fstat64 (fd, &st) == 0) - { - /* Get the lock. */ - lll_lock (__sem_mappings_lock, LLL_PRIVATE); - - /* Search for an existing mapping given the information we have. */ - struct inuse_sem *fake; - fake = (struct inuse_sem *) alloca (sizeof (*fake) + namelen); - memcpy (fake->name, name, namelen); - fake->dev = st.st_dev; - fake->ino = st.st_ino; - - struct inuse_sem **foundp = __tfind (fake, &__sem_mappings, - __sem_search); - if (foundp != NULL) - { - /* There is already a mapping. Use it. */ - result = (*foundp)->sem; - ++(*foundp)->refcnt; - } - else - { - /* We haven't found a mapping. Install ione. */ - struct inuse_sem *newp; - - newp = (struct inuse_sem *) malloc (sizeof (*newp) + namelen); - if (newp != NULL) - { - /* If the caller hasn't provided any map it now. */ - if (existing == SEM_FAILED) - existing = (sem_t *) mmap (NULL, sizeof (sem_t), - PROT_READ | PROT_WRITE, MAP_SHARED, - fd, 0); - - newp->dev = st.st_dev; - newp->ino = st.st_ino; - newp->refcnt = 1; - newp->sem = existing; - memcpy (newp->name, name, namelen); - - /* Insert the new value. */ - if (existing != MAP_FAILED - && __tsearch (newp, &__sem_mappings, __sem_search) != NULL) - /* Successful. */ - result = existing; - else - /* Something went wrong while inserting the new - value. We fail completely. */ - free (newp); - } - } - - /* Release the lock. */ - lll_unlock (__sem_mappings_lock, LLL_PRIVATE); - } - - if (result != existing && existing != SEM_FAILED && existing != MAP_FAILED) - { - /* Do not disturb errno. */ - int save = errno; - munmap (existing, sizeof (sem_t)); - errno = save; - } - - return result; -} - - sem_t * sem_open (const char *name, int oflag, ...) { @@ -183,7 +73,7 @@ sem_open (const char *name, int oflag, ...) else /* Check whether we already have this semaphore mapped and create one if necessary. */ - result = check_add_mapping (name, fd, SEM_FAILED); + result = __sem_check_add_mapping (name, fd, SEM_FAILED); } else { @@ -294,7 +184,7 @@ sem_open (const char *name, int oflag, ...) /* Insert the mapping into the search tree. This also determines whether another thread sneaked by and already added such a mapping despite the fact that we created it. */ - result = check_add_mapping (name, fd, result); + result = __sem_check_add_mapping (name, fd, result); } /* Now remove the temporary name. This should never fail. If diff --git a/sysdeps/pthread/sem_routines.c b/sysdeps/pthread/sem_routines.c new file mode 100644 index 0000000..78d9364 --- /dev/null +++ b/sysdeps/pthread/sem_routines.c @@ -0,0 +1,187 @@ +/* Helper code for POSIX semaphore implementation. + Copyright (C) 2021 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 + <https://www.gnu.org/licenses/>. */ + +#include <search.h> +#include <semaphoreP.h> +#include <sys/mman.h> +#include <sem_routines.h> + +/* Keeping track of currently used mappings. */ +struct inuse_sem +{ + dev_t dev; + ino_t ino; + int refcnt; + sem_t *sem; + char name[]; +}; + +/* Comparison function for search of existing mapping. */ +static int +sem_search (const void *a, const void *b) +{ + const struct inuse_sem *as = (const struct inuse_sem *) a; + const struct inuse_sem *bs = (const struct inuse_sem *) b; + + if (as->ino != bs->ino) + /* Cannot return the difference the type is larger than int. */ + return as->ino < bs->ino ? -1 : (as->ino == bs->ino ? 0 : 1); + + if (as->dev != bs->dev) + /* Cannot return the difference the type is larger than int. */ + return as->dev < bs->dev ? -1 : (as->dev == bs->dev ? 0 : 1); + + return strcmp (as->name, bs->name); +} + +/* The search tree for existing mappings. */ +static void *sem_mappings; + +/* Lock to protect the search tree. */ +static int sem_mappings_lock = LLL_LOCK_INITIALIZER; + + +/* Search for existing mapping and if possible add the one provided. */ +sem_t * +__sem_check_add_mapping (const char *name, int fd, sem_t *existing) +{ + size_t namelen = strlen (name); + sem_t *result = SEM_FAILED; + + /* Get the information about the file. */ + struct stat64 st; + if (__fstat64 (fd, &st) == 0) + { + /* Get the lock. */ + lll_lock (sem_mappings_lock, LLL_PRIVATE); + + /* Search for an existing mapping given the information we have. */ + struct inuse_sem *fake; + fake = (struct inuse_sem *) alloca (sizeof (*fake) + namelen); + memcpy (fake->name, name, namelen); + fake->dev = st.st_dev; + fake->ino = st.st_ino; + + struct inuse_sem **foundp = __tfind (fake, &sem_mappings, sem_search); + if (foundp != NULL) + { + /* There is already a mapping. Use it. */ + result = (*foundp)->sem; + ++(*foundp)->refcnt; + } + else + { + /* We haven't found a mapping. Install ione. */ + struct inuse_sem *newp; + + newp = (struct inuse_sem *) malloc (sizeof (*newp) + namelen); + if (newp != NULL) + { + /* If the caller hasn't provided any map it now. */ + if (existing == SEM_FAILED) + existing = (sem_t *) mmap (NULL, sizeof (sem_t), + PROT_READ | PROT_WRITE, MAP_SHARED, + fd, 0); + + newp->dev = st.st_dev; + newp->ino = st.st_ino; + newp->refcnt = 1; + newp->sem = existing; + memcpy (newp->name, name, namelen); + + /* Insert the new value. */ + if (existing != MAP_FAILED + && __tsearch (newp, &sem_mappings, sem_search) != NULL) + /* Successful. */ + result = existing; + else + /* Something went wrong while inserting the new + value. We fail completely. */ + free (newp); + } + } + + /* Release the lock. */ + lll_unlock (sem_mappings_lock, LLL_PRIVATE); + } + + if (result != existing && existing != SEM_FAILED && existing != MAP_FAILED) + { + /* Do not disturb errno. */ + int save = errno; + munmap (existing, sizeof (sem_t)); + errno = save; + } + + return result; +} + +struct walk_closure +{ + sem_t *the_sem; + struct inuse_sem *rec; +}; + +static void +walker (const void *inodep, VISIT which, void *closure0) +{ + struct walk_closure *closure = closure0; + struct inuse_sem *nodep = *(struct inuse_sem **) inodep; + + if (nodep->sem == closure->the_sem) + closure->rec = nodep; +} + +bool +__sem_remove_mapping (sem_t *sem) +{ + bool ret = true; + + /* Get the lock. */ + lll_lock (sem_mappings_lock, LLL_PRIVATE); + + /* Locate the entry for the mapping the caller provided. */ + struct inuse_sem *rec; + { + struct walk_closure closure = { .the_sem = sem, .rec = NULL }; + __twalk_r (sem_mappings, walker, &closure); + rec = closure.rec; + } + if (rec != NULL) + { + /* Check the reference counter. If it is going to be zero, free + all the resources. */ + if (--rec->refcnt == 0) + { + /* Remove the record from the tree. */ + __tdelete (rec, &sem_mappings, sem_search); + + if (munmap (rec->sem, sizeof (sem_t)) == -1) + ret = false; + + free (rec); + } + } + else + ret = false; + + /* Release the lock. */ + lll_unlock (sem_mappings_lock, LLL_PRIVATE); + + return ret; +} diff --git a/sysdeps/pthread/sem_routines.h b/sysdeps/pthread/sem_routines.h new file mode 100644 index 0000000..25d3e88 --- /dev/null +++ b/sysdeps/pthread/sem_routines.h @@ -0,0 +1,27 @@ +/* Helper code for POSIX semaphore implementation. + Copyright (C) 2021 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 + <https://www.gnu.org/licenses/>. */ + +#ifndef _SEM_ROUTINES_H +#define _SEM_ROUTINES_H + +sem_t * __sem_check_add_mapping (const char *name, int fd, sem_t *existing) + attribute_hidden; + +bool __sem_remove_mapping (sem_t *sem) attribute_hidden; + +#endif |