Submit #2356 » 0001-Add-O_CLOEXEC-flag-to-open-2-and-fhopen-2.patch
| lib/libc/sys/open.2 | ||
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)open.2 8.2 (Berkeley) 11/16/93
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.\" $FreeBSD: src/lib/libc/sys/open.2,v 1.11.2.9 2001/12/14 18:34:01 ru Exp $
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.\" $DragonFly: src/lib/libc/sys/open.2,v 1.3 2005/07/29 23:16:04 hsu Exp $
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.\" $FreeBSD: src/lib/libc/sys/open.2,v 1.43 2011/03/25 14:01:18 kib Exp $
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.\"
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.Dd July 24, 2009
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.Dd March 25, 2011
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.Dt OPEN 2
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.Os
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.Sh NAME
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O_DIRECT eliminate or reduce cache effects
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O_FSYNC synchronous writes
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O_NOFOLLOW do not follow symlinks
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O_CLOEXEC set FD_CLOEXEC upon open
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.Ed
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.Pp
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Opening a file with
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it will minimize the impact the data has on the cache.
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Use of this flag can drastically reduce performance if not used with care.
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.Pp
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.Dv O_CLOEXEC
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may be used to set
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.Dv FD_CLOEXEC
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flag for the newly returned file descriptor.
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.Pp
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If successful,
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.Fn open
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and
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When a new file is created it is given the group of the directory
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which contains it.
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.Pp
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The new descriptor is set to remain open across
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Unless
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.Dv
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O_CLOEXEC
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flag was specified,
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the new descriptor is set to remain open across
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.Xr execve 2
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system calls; see
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.Xr close 2
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.Xr close 2 ,
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.Xr fcntl 2
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and
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.Xr fcntl 2 .
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.Dv O_CLOEXEC
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description.
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.Pp
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The system imposes a limit on the number of file descriptors
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open simultaneously by one process.
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| sys/kern/kern_descrip.c | ||
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* MPSAFE
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*/
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int
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falloc(struct lwp *lp, struct file **resultfp, int *resultfd)
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fallocf(struct lwp *lp, struct file **resultfp, int *resultfd, int flags)
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{
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static struct timeval lastfail;
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static int curfail;
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fp->f_ops = &badfileops;
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fp->f_seqcount = 1;
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fsetcred(fp, cred);
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if ((flags & O_CLOEXEC) != 0)
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fp->f_flag |= UF_EXCLOSE;
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spin_lock(&filehead_spin);
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nfiles++;
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LIST_INSERT_HEAD(&filehead, fp, f_list);
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return (error);
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}
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int
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falloc(struct lwp *lp, struct file **resultfp, int *resultfd)
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{
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return fallocf(lp, resultfp, resultfd, 0);
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}
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/*
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* Check for races against a file descriptor by determining that the
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* file pointer is still associated with the specified file descriptor,
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| sys/kern/vfs_syscalls.c | ||
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if ((oflags & O_ACCMODE) == O_ACCMODE)
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return (EINVAL);
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flags = FFLAGS(oflags);
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error = falloc(lp, &nfp, NULL);
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error = fallocf(lp, &nfp, NULL, flags);
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if (error)
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return (error);
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fp = nfp;
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* WARNING! no f_nchandle will be associated when fhopen()ing a
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* directory. XXX
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*/
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if ((error = falloc(td->td_lwp, &nfp, &indx)) != 0)
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if ((error = fallocf(td->td_lwp, &nfp, &indx, fmode)) != 0)
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goto bad;
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fp = nfp;
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| sys/sys/fcntl.h | ||
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/* Defined by POSIX 1003.1; BSD default, but must be distinct from O_RDONLY. */
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#define O_NOCTTY 0x8000 /* don't assign controlling terminal */
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#define O_CLOEXEC 0x10000 /* atomically set FD_CLOEXEC */
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/* Attempt to bypass the buffer cache */
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#define O_DIRECT 0x00010000
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| sys/sys/filedesc.h | ||
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int dupfdopen (struct filedesc *, int, int, int, int);
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int fdalloc (struct proc *p, int want, int *result);
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int fdavail (struct proc *p, int n);
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int fallocf(struct lwp *lp, struct file **resultfp, int *resultfd, int flags);
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int falloc (struct lwp *lp, struct file **resultfp, int *resultfd);
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void fsetfd (struct filedesc *fdp, struct file *fp, int fd);
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int fgetfdflags(struct filedesc *fdp, int fd, int *flagsp);
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