summaryrefslogtreecommitdiffstats
path: root/lib/libc_r/uthread/uthread_file.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/libc_r/uthread/uthread_file.c')
-rw-r--r--lib/libc_r/uthread/uthread_file.c468
1 files changed, 7 insertions, 461 deletions
diff --git a/lib/libc_r/uthread/uthread_file.c b/lib/libc_r/uthread/uthread_file.c
index e5a8484..cbedbc7 100644
--- a/lib/libc_r/uthread/uthread_file.c
+++ b/lib/libc_r/uthread/uthread_file.c
@@ -1,5 +1,6 @@
/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
+ * Copyright (c) 2001 Daniel Eischen <deischen@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -37,472 +38,17 @@
*
*/
#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/queue.h>
#include <pthread.h>
#include "pthread_private.h"
-/*
- * Weak symbols for externally visible functions in this file:
- */
-#pragma weak flockfile=_flockfile
-#pragma weak ftrylockfile=_ftrylockfile
-#pragma weak funlockfile=_funlockfile
-
-/*
- * The FILE lock structure. The FILE *fp is locked if the owner is
- * not NULL. If not locked, the file lock structure can be
- * reassigned to a different file by setting fp.
- */
-struct file_lock {
- LIST_ENTRY(file_lock) entry; /* Entry if file list. */
- TAILQ_HEAD(lock_head, pthread)
- l_head; /* Head of queue for threads */
- /* waiting on this lock. */
- FILE *fp; /* The target file. */
- pthread_t owner; /* Thread that owns lock. */
- int count; /* Lock count for owner. */
-};
-
-/*
- * The number of file lock lists into which the file pointer is
- * hashed. Ideally, the FILE structure size would have been increased,
- * but this causes incompatibility, so separate data structures are
- * required.
- */
-#define NUM_HEADS 128
-
-/*
- * This macro casts a file pointer to a long integer and right
- * shifts this by the number of bytes in a pointer. The shifted
- * value is then remaindered using the maximum number of hash
- * entries to produce and index into the array of static lock
- * structures. If there is a collision, a linear search of the
- * dynamic list of locks linked to each static lock is perfomed.
- */
-#define file_idx(_p) ((((u_long) _p) >> sizeof(void *)) % NUM_HEADS)
-
-/*
- * Global array of file locks. The first lock for each hash bucket is
- * allocated statically in the hope that there won't be too many
- * collisions that require a malloc and an element added to the list.
- */
-struct static_file_lock {
- LIST_HEAD(file_list_head, file_lock) head;
- struct file_lock fl;
-} flh[NUM_HEADS];
-
-/* Set to non-zero when initialisation is complete: */
-static int init_done = 0;
-
-/* Lock for accesses to the hash table: */
-static spinlock_t hash_lock = _SPINLOCK_INITIALIZER;
-
-/*
- * Find a lock structure for a FILE, return NULL if the file is
- * not locked:
- */
-static
-struct file_lock *
-find_lock(int idx, FILE *fp)
-{
- struct file_lock *p;
-
- /* Check if the file is locked using the static structure: */
- if (flh[idx].fl.fp == fp && flh[idx].fl.owner != NULL)
- /* Return a pointer to the static lock: */
- p = &flh[idx].fl;
- else {
- /* Point to the first dynamic lock: */
- p = LIST_FIRST(&flh[idx].head);
-
- /*
- * Loop through the dynamic locks looking for the
- * target file:
- */
- while (p != NULL && (p->fp != fp || p->owner == NULL))
- /* Not this file, try the next: */
- p = LIST_NEXT(p, entry);
- }
- return(p);
-}
-
-/*
- * Lock a file, assuming that there is no lock structure currently
- * assigned to it.
- */
-static
-struct file_lock *
-do_lock(int idx, FILE *fp)
-{
- struct pthread *curthread = _get_curthread();
- struct file_lock *p;
-
- /* Check if the static structure is not being used: */
- if (flh[idx].fl.owner == NULL) {
- /* Return a pointer to the static lock: */
- p = &flh[idx].fl;
- }
- else {
- /* Point to the first dynamic lock: */
- p = LIST_FIRST(&flh[idx].head);
-
- /*
- * Loop through the dynamic locks looking for a
- * lock structure that is not being used:
- */
- while (p != NULL && p->owner != NULL)
- /* This one is used, try the next: */
- p = LIST_NEXT(p, entry);
- }
-
- /*
- * If an existing lock structure has not been found,
- * allocate memory for a new one:
- */
- if (p == NULL && (p = (struct file_lock *)
- malloc(sizeof(struct file_lock))) != NULL) {
- /* Add the new element to the list: */
- LIST_INSERT_HEAD(&flh[idx].head, p, entry);
- }
-
- /* Check if there is a lock structure to acquire: */
- if (p != NULL) {
- /* Acquire the lock for the running thread: */
- p->fp = fp;
- p->owner = curthread;
- p->count = 1;
- TAILQ_INIT(&p->l_head);
- }
- return(p);
-}
-
-void
-_flockfile_debug(FILE * fp, char *fname, int lineno)
-{
- struct pthread *curthread = _get_curthread();
- int idx = file_idx(fp);
- struct file_lock *p;
-
- /* Check if this is a real file: */
- if (fp->_file >= 0) {
- /* Lock the hash table: */
- _SPINLOCK(&hash_lock);
-
- /* Check if the static array has not been initialised: */
- if (!init_done) {
- /* Initialise the global array: */
- memset(flh,0,sizeof(flh));
-
- /* Flag the initialisation as complete: */
- init_done = 1;
- }
-
- /* Get a pointer to any existing lock for the file: */
- if ((p = find_lock(idx, fp)) == NULL) {
- /*
- * The file is not locked, so this thread can
- * grab the lock:
- */
- p = do_lock(idx, fp);
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
-
- /*
- * The file is already locked, so check if the
- * running thread is the owner:
- */
- } else if (p->owner == curthread) {
- /*
- * The running thread is already the
- * owner, so increment the count of
- * the number of times it has locked
- * the file:
- */
- p->count++;
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
- } else {
- /* Clear the interrupted flag: */
- curthread->interrupted = 0;
-
- /*
- * Prevent being context switched out while
- * adding this thread to the file lock queue.
- */
- _thread_kern_sig_defer();
-
- /*
- * The file is locked for another thread.
- * Append this thread to the queue of
- * threads waiting on the lock.
- */
- TAILQ_INSERT_TAIL(&p->l_head,curthread,qe);
- curthread->flags |= PTHREAD_FLAGS_IN_FILEQ;
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
-
- curthread->data.fp = fp;
-
- /* Wait on the FILE lock: */
- _thread_kern_sched_state(PS_FILE_WAIT, fname, lineno);
-
- if ((curthread->flags & PTHREAD_FLAGS_IN_FILEQ) != 0) {
- TAILQ_REMOVE(&p->l_head,curthread,qe);
- curthread->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
- }
-
- _thread_kern_sig_undefer();
-
- if (curthread->interrupted != 0 &&
- curthread->continuation != NULL)
- curthread->continuation((void *)curthread);
- }
- }
-}
+extern void _flockfile(FILE *);
void
-_flockfile(FILE * fp)
-{
- _flockfile_debug(fp, __FILE__, __LINE__);
-}
-
-int
-_ftrylockfile(FILE * fp)
-{
- struct pthread *curthread = _get_curthread();
- int ret = -1;
- int idx = file_idx(fp);
- struct file_lock *p;
-
- /* Check if this is a real file: */
- if (fp->_file >= 0) {
- /* Lock the hash table: */
- _SPINLOCK(&hash_lock);
-
- /* Get a pointer to any existing lock for the file: */
- if ((p = find_lock(idx, fp)) == NULL) {
- /*
- * The file is not locked, so this thread can
- * grab the lock:
- */
- p = do_lock(idx, fp);
-
- /*
- * The file is already locked, so check if the
- * running thread is the owner:
- */
- } else if (p->owner == curthread) {
- /*
- * The running thread is already the
- * owner, so increment the count of
- * the number of times it has locked
- * the file:
- */
- p->count++;
- } else {
- /*
- * The file is locked for another thread,
- * so this try fails.
- */
- p = NULL;
- }
-
- /* Check if the lock was obtained: */
- if (p != NULL)
- /* Return success: */
- ret = 0;
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
-
- }
- return (ret);
-}
-
-void
-_funlockfile(FILE * fp)
+_flockfile_debug(FILE *fp, char *fname, int lineno)
{
- struct pthread *curthread = _get_curthread();
- int idx = file_idx(fp);
- struct file_lock *p;
-
- /* Check if this is a real file: */
- if (fp->_file >= 0) {
- /*
- * Defer signals to protect the scheduling queues from
- * access by the signal handler:
- */
- _thread_kern_sig_defer();
-
- /* Lock the hash table: */
- _SPINLOCK(&hash_lock);
-
- /*
- * Get a pointer to the lock for the file and check that
- * the running thread is the one with the lock:
- */
- if ((p = find_lock(idx, fp)) != NULL &&
- p->owner == curthread) {
- /*
- * Check if this thread has locked the FILE
- * more than once:
- */
- if (p->count > 1)
- /*
- * Decrement the count of the number of
- * times the running thread has locked this
- * file:
- */
- p->count--;
- else {
- /*
- * The running thread will release the
- * lock now:
- */
- p->count = 0;
-
- /* Get the new owner of the lock: */
- while ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
- /* Pop the thread off the queue: */
- TAILQ_REMOVE(&p->l_head,p->owner,qe);
- p->owner->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
- if (p->owner->interrupted == 0) {
- /*
- * This is the first lock for
- * the new owner:
- */
- p->count = 1;
-
- /* Allow the new owner to run: */
- PTHREAD_NEW_STATE(p->owner,PS_RUNNING);
-
- /* End the loop when we find a
- * thread that hasn't been
- * cancelled or interrupted;
- */
- break;
- }
- }
- }
- }
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
+ pthread_t curthread = _pthread_self();
- /*
- * Undefer and handle pending signals, yielding if
- * necessary:
- */
- _thread_kern_sig_undefer();
- }
+ curthread->lineno = lineno;
+ curthread->fname = fname;
+ _flockfile(fp);
}
-
-void
-_funlock_owned(pthread_t pthread)
-{
- int idx;
- struct file_lock *p, *next_p;
-
- /*
- * Defer signals to protect the scheduling queues from
- * access by the signal handler:
- */
- _thread_kern_sig_defer();
-
- /* Lock the hash table: */
- _SPINLOCK(&hash_lock);
-
- for (idx = 0; idx < NUM_HEADS; idx++) {
- /* Check the static file lock first: */
- p = &flh[idx].fl;
- next_p = LIST_FIRST(&flh[idx].head);
-
- while (p != NULL) {
- if (p->owner == pthread) {
- /*
- * The running thread will release the
- * lock now:
- */
- p->count = 0;
-
- /* Get the new owner of the lock: */
- while ((p->owner = TAILQ_FIRST(&p->l_head)) != NULL) {
- /* Pop the thread off the queue: */
- TAILQ_REMOVE(&p->l_head,p->owner,qe);
- p->owner->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
- if (p->owner->interrupted == 0) {
- /*
- * This is the first lock for
- * the new owner:
- */
- p->count = 1;
-
- /* Allow the new owner to run: */
- PTHREAD_NEW_STATE(p->owner,PS_RUNNING);
-
- /* End the loop when we find a
- * thread that hasn't been
- * cancelled or interrupted;
- */
- break;
- }
- }
- }
- p = next_p;
- if (next_p != NULL)
- next_p = LIST_NEXT(next_p, entry);
- }
- }
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
-
- /*
- * Undefer and handle pending signals, yielding if
- * necessary:
- */
- _thread_kern_sig_undefer();
-}
-
-void
-_flockfile_backout(pthread_t pthread)
-{
- int idx = file_idx(pthread->data.fp);
- struct file_lock *p;
-
- /*
- * Defer signals to protect the scheduling queues from
- * access by the signal handler:
- */
- _thread_kern_sig_defer();
-
- /*
- * Get a pointer to the lock for the file and check that
- * the running thread is the one with the lock:
- */
- if (((pthread->flags & PTHREAD_FLAGS_IN_FILEQ) != 0) &&
- ((p = find_lock(idx, pthread->data.fp)) != NULL)) {
- /* Lock the hash table: */
- _SPINLOCK(&hash_lock);
-
- /* Remove the thread from the queue: */
- TAILQ_REMOVE(&p->l_head, pthread, qe);
- pthread->flags &= ~PTHREAD_FLAGS_IN_FILEQ;
-
- /* Unlock the hash table: */
- _SPINUNLOCK(&hash_lock);
- }
-
- /*
- * Undefer and handle pending signals, yielding if necessary:
- */
- _thread_kern_sig_undefer();
-}
-
OpenPOWER on IntegriCloud