# This is a shell archive.
# Remove everything above and including the cut line.
# Then run the rest of the file through sh.
#----cut here-----cut here-----cut here-----cut here----#
#!/bin/sh
# shar: Shell Archiver
# Run the following text with /bin/sh to create:
# README
# fcntl.patch
# This archive created: Tue Aug 18 14:16:48 1992
cat << \SHAR_EOF > README
README for fcntl.patch
This patch provides an almost complete implementation of the file locking
facilities provided by fcntl(). The only missing pieces are
- deadlock detection
- mandatory locks
Neither of these have a very high priority with me so I do not intend to
implement them soon.
This patch must be applied to Linux 0.97 Patch Level 1.
Apply it with:
cd /usr/src
patch -p0 <fcntl.patch 2>&1 | tee fcntlpatch.log
Enjoy!
Doug Evans, dje@sspiff.UUCP or dje@sspiff.ampr.ab.ca, 92Aug18
SHAR_EOF
cat << \SHAR_EOF > fcntl.patch
*** linux.pl1/fs/Makefile Sat Aug 1 15:44:01 1992
--- linux/fs/Makefile Sat Aug 8 00:02:15 1992
***************
*** 7,13 ****
#
# Note 2! The CFLAGS definitions are now in the main makefile...
! SUBDIRS =minix ext msdos
.c.s:
$(CC) $(CFLAGS) -S $<
--- 7,13 ----
#
# Note 2! The CFLAGS definitions are now in the main makefile...
! SUBDIRS =minix ext msdos # xenix
.c.s:
$(CC) $(CFLAGS) -S $<
***************
*** 18,24 ****
OBJS= open.o read_write.o inode.o file_table.o buffer.o super.o \
block_dev.o stat.o exec.o pipe.o namei.o fcntl.o ioctl.o \
! select.o fifo.o
all: fs.o fssubdirs
--- 18,24 ----
OBJS= open.o read_write.o inode.o file_table.o buffer.o super.o \
block_dev.o stat.o exec.o pipe.o namei.o fcntl.o ioctl.o \
! select.o fifo.o locks.o
all: fs.o fssubdirs
*** linux.pl1/fs/fcntl.c Tue Aug 18 12:51:57 1992
--- linux/fs/fcntl.c Tue Aug 18 13:11:57 1992
***************
*** 14,19 ****
--- 14,21 ----
#include <linux/string.h>
extern int sys_close(int fd);
+ extern int fcntl_getlk(unsigned int, struct flock *);
+ extern int fcntl_setlk(unsigned int, unsigned int, struct flock *);
static int dupfd(unsigned int fd, unsigned int arg)
{
***************
*** 56,85 ****
if (fd >= NR_OPEN || !(filp = current->filp[fd]))
return -EBADF;
switch (cmd) {
! case F_DUPFD:
! return dupfd(fd,arg);
! case F_GETFD:
! return (current->close_on_exec>>fd)&1;
! case F_SETFD:
! if (arg&1)
! current->close_on_exec |= (1<<fd);
! else
! current->close_on_exec &= ~(1<<fd);
! return 0;
! case F_GETFL:
! return filp->f_flags;
! case F_SETFL:
! filp->f_flags &= ~(O_APPEND | O_NONBLOCK);
! filp->f_flags |= arg & (O_APPEND | O_NONBLOCK);
! return 0;
! case F_GETLK: case F_SETLK: case F_SETLKW:
! return -ENOSYS;
! default:
! /* sockets need a few special fcntls. */
! if (S_ISSOCK (filp->f_inode->i_mode))
! {
! return (sock_fcntl (filp, cmd, arg));
! }
! return -EINVAL;
}
}
--- 58,89 ----
if (fd >= NR_OPEN || !(filp = current->filp[fd]))
return -EBADF;
switch (cmd) {
! case F_DUPFD:
! return dupfd(fd,arg);
! case F_GETFD:
! return (current->close_on_exec>>fd)&1;
! case F_SETFD:
! if (arg&1)
! current->close_on_exec |= (1<<fd);
! else
! current->close_on_exec &= ~(1<<fd);
! return 0;
! case F_GETFL:
! return filp->f_flags;
! case F_SETFL:
! filp->f_flags &= ~(O_APPEND | O_NONBLOCK);
! filp->f_flags |= arg & (O_APPEND | O_NONBLOCK);
! return 0;
! case F_GETLK:
! return fcntl_getlk(fd, (struct flock *) arg);
! case F_SETLK:
! return fcntl_setlk(fd, cmd, (struct flock *) arg);
! case F_SETLKW:
! return fcntl_setlk(fd, cmd, (struct flock *) arg);
! default:
! /* sockets need a few special fcntls. */
! if (S_ISSOCK (filp->f_inode->i_mode))
! return sock_fcntl (filp, cmd, arg);
! return -EINVAL;
}
}
*** linux.pl1/fs/open.c Tue Aug 18 12:51:57 1992
--- linux/fs/open.c Mon Aug 17 13:31:22 1992
***************
*** 17,22 ****
--- 17,24 ----
#include <linux/tty.h>
#include <asm/segment.h>
+ extern void fcntl_remove_locks(struct task_struct *, struct file *);
+
struct file_operations * chrdev_fops[MAX_CHRDEV] = {
NULL,
};
***************
*** 339,347 ****
}
static int
! close_fp (struct file *filp)
! {
! struct inode *inode;
if (filp->f_count == 0) {
printk("Close: file count is 0\n");
--- 341,349 ----
}
static int
! close_fp(struct file *filp)
! {
! struct inode * inode;
if (filp->f_count == 0) {
printk("Close: file count is 0\n");
***************
*** 348,359 ****
return 0;
}
if (filp->f_count > 1) {
filp->f_count--;
return 0;
}
!
! inode = filp->f_inode;
if (filp->f_op && filp->f_op->release)
filp->f_op->release(inode,filp);
--- 350,364 ----
return 0;
}
+ inode = filp->f_inode;
+ if (S_ISREG(inode->i_mode))
+ fcntl_remove_locks(current, filp);
+
if (filp->f_count > 1) {
filp->f_count--;
return 0;
}
!
if (filp->f_op && filp->f_op->release)
filp->f_op->release(inode,filp);
*** linux.pl1/fs/locks.c Tue Aug 11 14:27:34 1992
--- linux/fs/locks.c Tue Aug 18 13:18:51 1992
***************
*** 0 ****
--- 1,451 ----
+ /*
+ * linux/fs/locks.c
+ *
+ * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
+ * Doug Evans, 92Aug07, dje@sspiff.UUCP.
+ *
+ * FIXME: two things aren't handled yet:
+ * - deadlock detection/avoidance (of dubious merit, but since it's in
+ * the definition, I guess it should be provided eventually)
+ * - mandatory locks (requires lots of changes elsewhere)
+ *
+ * FIXME: Should vector locking operations through table based on filesystem
+ * type. NFS mounts obviously won't be able to use this code.
+ */
+
+ #include <asm/segment.h>
+
+ #include <linux/sched.h>
+ #include <linux/kernel.h>
+ #include <linux/errno.h>
+ #include <linux/stat.h>
+ #include <linux/fcntl.h>
+
+ #define OFFSET_MAX 0x7fffffff /* FIXME: move elsewhere? */
+
+ static int copy_flock(struct file *filp, struct file_lock *fl, struct flock *l);
+ static int conflict(struct file_lock *caller_fl, struct file_lock *sys_fl);
+ static int overlap(struct file_lock *fl1, struct file_lock *fl2);
+ static int lock_it(struct file *filp, struct file_lock *caller);
+ static int unlock_it(struct file *filp, struct file_lock *caller);
+ static struct file_lock *alloc_lock(struct file *filp, struct file_lock *template);
+ static void free_lock(struct file *filp, struct file_lock *fl);
+
+ static struct file_lock file_lock_table[NR_FILE_LOCKS];
+ static struct file_lock *file_lock_free_list;
+
+ /*
+ * Called at boot time to initialize the lock table ...
+ */
+
+ void fcntl_init_locks(void)
+ {
+ struct file_lock *fl;
+
+ for (fl = &file_lock_table[0]; fl < file_lock_table + NR_FILE_LOCKS - 1; fl++) {
+ fl->fl_next = fl + 1;
+ fl->fl_owner = NULL;
+ }
+ file_lock_table[NR_FILE_LOCKS - 1].fl_next = NULL;
+ file_lock_table[NR_FILE_LOCKS - 1].fl_owner = NULL;
+ file_lock_free_list = &file_lock_table[0];
+ }
+
+ int fcntl_getlk(unsigned int fd, struct flock *l)
+ {
+ struct flock flock;
+ struct file *filp;
+ struct file_lock *fl,file_lock;
+
+ if (fd >= NR_OPEN || !(filp = current->filp[fd]))
+ return -EBADF;
+ verify_area(l, sizeof(*l));
+ memcpy_fromfs(&flock, l, sizeof(flock));
+ if (flock.l_type == F_UNLCK)
+ return -EINVAL;
+ if (!copy_flock(filp, &file_lock, &flock))
+ return -EINVAL;
+
+ for (fl = filp->f_inode->i_flock; fl != NULL; fl = fl->fl_next) {
+ if (conflict(&file_lock, fl)) {
+ flock.l_pid = fl->fl_owner->pid;
+ flock.l_start = fl->fl_start;
+ flock.l_len = fl->fl_end == OFFSET_MAX ? 0 :
+ fl->fl_end - fl->fl_start + 1;
+ /* Note: this will always be SEEK_SET. */
+ flock.l_whence = fl->fl_whence;
+ flock.l_type = fl->fl_type;
+ memcpy_tofs(l, &flock, sizeof(flock));
+ return 0;
+ }
+ }
+
+ flock.l_type = F_UNLCK; /* no conflict found */
+ memcpy_tofs(l, &flock, sizeof(flock));
+ return 0;
+ }
+
+ /*
+ * This function implements both F_SETLK and F_SETLKW.
+ */
+
+ int fcntl_setlk(unsigned int fd, unsigned int cmd, struct flock *l)
+ {
+ struct file *filp;
+ struct file_lock *fl,file_lock;
+ struct flock flock;
+
+ /*
+ * Get arguments and validate them ...
+ */
+
+ if (fd >= NR_OPEN || !(filp = current->filp[fd]))
+ return -EBADF;
+ verify_area(l, sizeof(*l));
+ memcpy_fromfs(&flock, l, sizeof(flock));
+ if (!copy_flock(filp, &file_lock, &flock))
+ return -EINVAL;
+ switch (file_lock.fl_type) {
+ case F_RDLCK :
+ if (!(filp->f_mode & 1))
+ return -EBADF;
+ break;
+ case F_WRLCK :
+ if (!(filp->f_mode & 2))
+ return -EBADF;
+ break;
+ case F_UNLCK :
+ break;
+ }
+
+ /*
+ * F_UNLCK needs to be handled differently ...
+ */
+
+ if (file_lock.fl_type == F_UNLCK)
+ return unlock_it(filp, &file_lock);
+
+ /*
+ * Scan for a conflicting lock ...
+ */
+
+ repeat:
+ for (fl = filp->f_inode->i_flock; fl != NULL; fl = fl->fl_next) {
+ if (!conflict(&file_lock, fl))
+ continue;
+ /*
+ * File is locked by another process. If this is F_SETLKW
+ * wait for the lock to be released.
+ * FIXME: We need to check for deadlocks here.
+ */
+ if (cmd == F_SETLKW) {
+ interruptible_sleep_on(&fl->fl_wait);
+ goto repeat;
+ }
+ return -EAGAIN;
+ }
+
+ /*
+ * Lock doesn't conflict with any other lock ...
+ */
+
+ return lock_it(filp, &file_lock);
+ }
+
+ /*
+ * This function is called when the file is closed.
+ */
+
+ void fcntl_remove_locks(struct task_struct *task, struct file *filp)
+ {
+ struct file_lock *fl,*next;
+
+ for (fl = filp->f_inode->i_flock; fl != NULL; ) {
+ /*
+ * If this one is freed, <fl_next> gets clobbered when the
+ * entry is moved to the free list, so grab it now ...
+ */
+ next = fl->fl_next;
+ if (fl->fl_owner == task)
+ free_lock(filp, fl);
+ fl = next;
+ }
+ }
+
+ /*
+ * Verify a "struct flock" and copy it to a "struct file_lock" ...
+ * Result is a boolean indicating success.
+ */
+
+ static int copy_flock(struct file *filp, struct file_lock *fl, struct flock *l)
+ {
+ off_t start;
+
+ if (!filp->f_inode) /* just in case */
+ return 0;
+ if (!S_ISREG(filp->f_inode->i_mode))
+ return 0;
+ if (l->l_type != F_UNLCK && l->l_type != F_RDLCK && l->l_type != F_WRLCK)
+ return 0;
+ switch (l->l_whence) {
+ case 0 /*SEEK_SET*/ : start = 0; break;
+ case 1 /*SEEK_CUR*/ : start = filp->f_pos; break;
+ case 2 /*SEEK_END*/ : start = filp->f_inode->i_size; break;
+ default : return 0;
+ }
+ if ((start += l->l_start) < 0 || l->l_len < 0)
+ return 0;
+ fl->fl_type = l->l_type;
+ fl->fl_start = start; /* we record the absolute position */
+ fl->fl_whence = 0; /* FIXME: do we record <l_start> as passed? */
+ if (l->l_len == 0 || (fl->fl_end = start + l->l_len - 1) < 0)
+ fl->fl_end = OFFSET_MAX;
+ fl->fl_owner = current;
+ fl->fl_wait = NULL; /* just for cleanliness */
+ return 1;
+ }
+
+ /*
+ * Determine if lock <sys_fl> blocks lock <caller_fl> ...
+ */
+
+ static int conflict(struct file_lock *caller_fl, struct file_lock *sys_fl)
+ {
+ if (caller_fl->fl_owner == sys_fl->fl_owner)
+ return 0;
+ if (!overlap(caller_fl, sys_fl))
+ return 0;
+ switch (caller_fl->fl_type) {
+ case F_RDLCK :
+ return sys_fl->fl_type != F_RDLCK;
+ case F_WRLCK :
+ return 1; /* overlapping region not owned by caller */
+ }
+ return 0; /* shouldn't get here, but just in case */
+ }
+
+ static int overlap(struct file_lock *fl1, struct file_lock *fl2)
+ {
+ if (fl1->fl_start <= fl2->fl_start) {
+ return fl1->fl_end >= fl2->fl_start;
+ } else {
+ return fl2->fl_end >= fl1->fl_start;
+ }
+ }
+
+ /*
+ * Add a lock to a file ...
+ * Result is 0 for success or -ENOLCK.
+ *
+ * We try to be real clever here and always minimize the number of table
+ * entries we use. For example we merge adjacent locks whenever possible. This
+ * consumes a bit of cpu and code space, is it really worth it? Beats me.
+ *
+ * I've tried to keep the following as small and simple as possible. If you can
+ * make it smaller or simpler, please do. /dje 92Aug11
+ *
+ * WARNING: We assume the lock doesn't conflict with any other lock.
+ */
+
+ static int lock_it(struct file *filp, struct file_lock *caller)
+ {
+ struct file_lock *fl,*new;
+
+ /*
+ * It's easier if we allocate a slot for the lock first, and then
+ * release it later if we have to (IE: if it can be merged with
+ * another). This way the for() loop always knows that <caller> is an
+ * existing entry. This will cause the routine to fail unnecessarily
+ * in rare cases, but perfection can be pushed too far. :-)
+ */
+
+ if ((caller = alloc_lock(filp, caller)) == NULL)
+ return -ENOLCK;
+
+ /*
+ * First scan to see if we are changing/augmenting an existing lock ...
+ */
+
+ for (fl = filp->f_inode->i_flock; fl != NULL; fl = fl->fl_next) {
+ if (caller->fl_owner != fl->fl_owner)
+ continue;
+ if (caller == fl)
+ continue;
+ if (!overlap(caller, fl)) {
+ /*
+ * Detect adjacent regions (if same lock type) ...
+ */
+ if (caller->fl_type != fl->fl_type)
+ continue;
+ if (caller->fl_end + 1 == fl->fl_start) {
+ fl->fl_start = caller->fl_start;
+ free_lock(filp, caller);
+ caller = fl;
+ /* must continue, may overlap others now */
+ } else if (caller->fl_start - 1 == fl->fl_end) {
+ fl->fl_end = caller->fl_end;
+ free_lock(filp, caller);
+ caller = fl;
+ /* must continue, may overlap others now */
+ }
+ continue;
+ }
+ /*
+ * We've found an overlapping region. Is it a change of lock
+ * type, or are we changing the size of the locked space?
+ */
+ if (caller->fl_type != fl->fl_type) {
+ if (caller->fl_start > fl->fl_start && caller->fl_end < fl->fl_end) {
+ /*
+ * The new lock splits the old one in two ...
+ * <fl> is the bottom piece, <caller> is the
+ * new lock, and <new> is the top piece.
+ */
+ if ((new = alloc_lock(filp, fl)) == NULL) {
+ free_lock(filp, caller);
+ return -ENOLCK;
+ }
+ fl->fl_end = caller->fl_start - 1;
+ new->fl_start = caller->fl_end + 1;
+ return 0;
+ }
+ if (caller->fl_start <= fl->fl_start && caller->fl_end >= fl->fl_end) {
+ /*
+ * The new lock completely replaces old one ...
+ */
+ free_lock(filp, fl);
+ return 0;
+ }
+ if (caller->fl_end < fl->fl_end) {
+ fl->fl_start = caller->fl_end + 1;
+ /* must continue, may be more overlaps */
+ } else if (caller->fl_start > fl->fl_start) {
+ fl->fl_end = caller->fl_start - 1;
+ /* must continue, may be more overlaps */
+ } else {
+ printk("lock_it: program bug: unanticipated overlap\n");
+ free_lock(filp, caller);
+ return -ENOLCK;
+ }
+ } else { /* The new lock augments an existing lock ... */
+ int grew = 0;
+
+ if (caller->fl_start < fl->fl_start) {
+ fl->fl_start = caller->fl_start;
+ grew = 1;
+ }
+ if (caller->fl_end > fl->fl_end) {
+ fl->fl_end = caller->fl_end;
+ grew = 1;
+ }
+ free_lock(filp, caller);
+ caller = fl;
+ if (!grew)
+ return 0;
+ /* must continue, may be more overlaps */
+ }
+ }
+
+ /*
+ * New lock doesn't overlap any regions ...
+ * alloc_lock() has already been called, so we're done!
+ */
+
+ return 0;
+ }
+
+ /*
+ * Handle F_UNLCK ...
+ * Result is 0 for success, or -EINVAL or -ENOLCK.
+ * ENOLCK can happen when a lock is split into two.
+ */
+
+ static int unlock_it(struct file *filp, struct file_lock *caller)
+ {
+ int one_unlocked = 0;
+ struct file_lock *fl,*next;
+
+ for (fl = filp->f_inode->i_flock; fl != NULL; ) {
+ if (caller->fl_owner != fl->fl_owner || !overlap(caller, fl)) {
+ fl = fl->fl_next;
+ continue;
+ }
+ one_unlocked = 1;
+ if (caller->fl_start > fl->fl_start && caller->fl_end < fl->fl_end) {
+ /*
+ * Lock is split in two ...
+ * <fl> is the bottom piece, <next> is the top piece.
+ */
+ if ((next = alloc_lock(filp, fl)) == NULL)
+ return -ENOLCK;
+ fl->fl_end = caller->fl_start - 1;
+ next->fl_start = caller->fl_end + 1;
+ return 0;
+ }
+ if (caller->fl_start <= fl->fl_start && caller->fl_end >= fl->fl_end) {
+ /*
+ * <fl_next> gets clobbered when the entry is moved to
+ * the free list, so grab it now ...
+ */
+ next = fl->fl_next;
+ free_lock(filp, fl);
+ fl = next;
+ }
+ if (caller->fl_start == fl->fl_start && caller->fl_end == fl->fl_end)
+ return 0; /* no more to be found */
+ /* must continue, there may be more to unlock */
+ }
+
+ return one_unlocked ? 0 : -EINVAL;
+ }
+
+ static struct file_lock *alloc_lock(struct file *filp, struct file_lock *template)
+ {
+ struct file_lock *new;
+
+ if (file_lock_free_list == NULL)
+ return NULL; /* no available entry */
+ if (file_lock_free_list->fl_owner != NULL)
+ panic("alloc_lock: broken free list\n");
+
+ new = file_lock_free_list; /* remove from free list */
+ file_lock_free_list = file_lock_free_list->fl_next;
+
+ *new = *template;
+
+ new->fl_next = filp->f_inode->i_flock; /* insert into file's list */
+ filp->f_inode->i_flock = new;
+
+ new->fl_owner = current; /* FIXME: needed? */
+ new->fl_wait = NULL;
+ return new;
+ }
+
+ static void free_lock(struct file *filp, struct file_lock *fl)
+ {
+ struct file_lock **fl_p;
+
+ if (fl->fl_owner == NULL) /* sanity check */
+ panic("free_lock: broken lock list\n");
+
+ /*
+ * We only use a singly linked list to save some memory space
+ * (the only place we'd use a doubly linked list is here).
+ */
+
+ for (fl_p = &filp->f_inode->i_flock; *fl_p != NULL; fl_p = &(*fl_p)->fl_next) {
+ if (*fl_p == fl)
+ break;
+ }
+ if (*fl_p == NULL) {
+ printk("free_lock: lock is not in file's lock list\n");
+ } else {
+ *fl_p = (*fl_p)->fl_next;
+ }
+
+ fl->fl_next = file_lock_free_list; /* add to free list */
+ file_lock_free_list = fl;
+ fl->fl_owner = NULL; /* for sanity checks */
+
+ wake_up(&fl->fl_wait);
+ }
*** linux.pl1/fs/super.c Sat Aug 1 13:09:35 1992
--- linux/fs/super.c Mon Aug 17 13:54:39 1992
***************
*** 12,17 ****
--- 12,18 ----
#include <linux/minix_fs.h>
#include <linux/ext_fs.h>
#include <linux/msdos_fs.h>
+ /*#include <linux/xenix_fs.h>*/
#include <linux/kernel.h>
#include <linux/stat.h>
#include <linux/errno.h>
***************
*** 21,26 ****
--- 22,28 ----
int sync_dev(int dev);
void wait_for_keypress(void);
+ void fcntl_init_locks(void);
/* set_bit uses setb, as gas doesn't recognize setc */
#define set_bit(bitnr,addr) ({ \
***************
*** 35,42 ****
/* Move into include file later */
static struct file_system_type file_systems[] = {
{minix_read_super,"minix"},
! {ext_read_super,"ext"},
{msdos_read_super,"msdos"},
{NULL,NULL}
};
--- 37,45 ----
/* Move into include file later */
static struct file_system_type file_systems[] = {
+ /*{xenix_read_super,"xenix"},*/
{minix_read_super,"minix"},
! /*{ext_read_super,"ext"},*/
{msdos_read_super,"msdos"},
{NULL,NULL}
};
***************
*** 314,319 ****
--- 317,323 ----
panic("bad i-node size");
for(i=0;i<NR_FILE;i++)
file_table[i].f_count=0;
+ fcntl_init_locks();
if (MAJOR(ROOT_DEV) == 2) {
printk("Insert root floppy and press ENTER");
wait_for_keypress();
*** linux.pl1/include/linux/fcntl.h Tue Aug 18 13:04:28 1992
--- linux/include/linux/fcntl.h Tue Aug 18 13:02:31 1992
***************
*** 24,32 ****
#define F_SETFD 2 /* set f_flags */
#define F_GETFL 3 /* more flags (cloexec) */
#define F_SETFL 4
! #define F_GETLK 5 /* not implemented */
! #define F_SETLK 6
! #define F_SETLKW 7
#define F_SETOWN 8 /* for sockets. */
#define F_GETOWN 9 /* for sockets. */
--- 24,32 ----
#define F_SETFD 2 /* set f_flags */
#define F_GETFL 3 /* more flags (cloexec) */
#define F_SETFL 4
! #define F_GETLK 5 /* get conflicting lock */
! #define F_SETLK 6 /* set lock, don't wait */
! #define F_SETLKW 7 /* set lock, wait if necessary */
#define F_SETOWN 8 /* for sockets. */
#define F_GETOWN 9 /* for sockets. */
*** linux.pl1/include/linux/limits.h Tue Aug 18 12:52:50 1992
--- linux/include/linux/limits.h Mon Aug 17 13:34:52 1992
***************
*** 8,13 ****
--- 8,14 ----
#define NR_FILE 128
#define NR_SUPER 8
#define NR_HASH 997
+ #define NR_FILE_LOCKS 32
#define BLOCK_SIZE 1024
#define BLOCK_SIZE_BITS 10
#define MAX_CHRDEV 16
SHAR_EOF
# End of shell archive
exit 0