Hide the definition of struct __sFILEX and add the needed
lock definitions to it. flockfile state is now allocated along with the rest of FILE. This eliminates the need for a separate allocation of flockfile state as well as eliminating the mutex/lock used to serialize its allocation.
This commit is contained in:
parent
3b5b529f2e
commit
45d8008748
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=73254
@ -68,13 +68,8 @@ struct __sbuf {
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int _size;
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};
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struct __file_lock;
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/* hold a buncha junk that would grow the ABI */
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struct __sFILEX {
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struct __file_lock *_mtlock; /* used for MT-safety */
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unsigned char *_up; /* saved _p when _p is doing ungetc data */
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};
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struct __sFILEX;
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/*
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* stdio state variables.
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@ -47,6 +47,9 @@
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#include <pthread.h>
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#include "un-namespace.h"
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#include "local.h"
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/*
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* Weak symbols for externally visible functions in this file:
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*/
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@ -55,18 +58,6 @@
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#pragma weak ftrylockfile=_ftrylockfile
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#pragma weak funlockfile=_funlockfile
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static int init_lock(FILE *);
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/*
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* The FILE lock structure. The FILE *fp is locked when the mutex
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* is locked.
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*/
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struct __file_lock {
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pthread_mutex_t fl_mutex;
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pthread_t fl_owner; /* current owner */
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int fl_count; /* recursive lock count */
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};
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/*
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* We need to retain binary compatibility for a while. So pretend
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* that _lock is part of FILE * even though it is dereferenced off
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@ -75,51 +66,13 @@ struct __file_lock {
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* code that has to change in the future (just remove this comment
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* and #define).
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*/
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#define _lock _extra->_mtlock
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/*
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* Allocate and initialize a file lock.
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*/
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static int
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init_lock(FILE *fp)
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{
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static pthread_mutex_t init_lock_mutex = PTHREAD_MUTEX_INITIALIZER;
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struct __file_lock *p;
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int ret;
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if ((p = malloc(sizeof(struct __file_lock))) == NULL)
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ret = -1;
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else {
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p->fl_mutex = PTHREAD_MUTEX_INITIALIZER;
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p->fl_owner = NULL;
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p->fl_count = 0;
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if (_pthread_mutex_lock(&init_lock_mutex) != 0) {
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free(p);
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return (-1);
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}
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if (fp->_lock != NULL) { /* lost the race */
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free(p);
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_pthread_mutex_unlock(&init_lock_mutex);
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return (0);
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}
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fp->_lock = p;
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_pthread_mutex_unlock(&init_lock_mutex);
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ret = 0;
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}
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return (ret);
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}
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#define _lock _extra
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void
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_flockfile(FILE *fp)
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{
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pthread_t curthread = _pthread_self();
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/*
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* Check if this is a real file with a valid lock, creating
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* the lock if needed:
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*/
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if ((fp->_file >= 0) &&
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((fp->_lock != NULL) || (init_lock(fp) == 0))) {
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if (fp->_lock->fl_owner == curthread)
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fp->_lock->fl_count++;
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else {
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@ -132,7 +85,6 @@ _flockfile(FILE *fp)
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fp->_lock->fl_count = 1;
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}
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}
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}
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/*
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* This can be overriden by the threads library if it is linked in.
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@ -149,11 +101,6 @@ _ftrylockfile(FILE *fp)
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pthread_t curthread = _pthread_self();
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int ret = 0;
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/*
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* Check if this is a real file with a valid lock, creating
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* the lock if needed:
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*/
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if (((fp->_lock != NULL) || (init_lock(fp) == 0))) {
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if (fp->_lock->fl_owner == curthread)
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fp->_lock->fl_count++;
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/*
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@ -166,9 +113,6 @@ _ftrylockfile(FILE *fp)
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}
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else
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ret = -1;
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}
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else
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ret = -1;
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return (ret);
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}
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@ -178,11 +122,9 @@ _funlockfile(FILE *fp)
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pthread_t curthread = _pthread_self();
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/*
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* Check if this is a real file with a valid lock owned
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* by the current thread:
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* Check if this file is owned by the current thread:
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*/
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if ((fp->_lock != NULL) &&
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(fp->_lock->fl_owner == curthread)) {
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if (fp->_lock->fl_owner == curthread) {
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/*
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* Check if this thread has locked the FILE
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* more than once:
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@ -39,6 +39,7 @@
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*/
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#include <sys/types.h> /* for off_t */
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#include <pthread.h>
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/*
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* Information local to this implementation of stdio,
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@ -67,6 +68,15 @@ extern int __vfprintf __P((FILE *, const char *, _BSD_VA_LIST_));
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extern int __sdidinit;
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/* hold a buncha junk that would grow the ABI */
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struct __sFILEX {
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unsigned char *_up; /* saved _p when _p is doing ungetc data */
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pthread_mutex_t fl_mutex; /* used for MT-safety */
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pthread_t fl_owner; /* current owner */
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int fl_count; /* recursive lock count */
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};
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/*
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* Return true iff the given FILE cannot be written now.
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*/
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