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Move the truncation code out of vn_open and into the open system call

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after the acquisition of any advisory locks. This fix corrects a case
in which a process tries to open a file with a non-blocking exclusive
lock. Even if it fails to get the lock it would still truncate the
file even though its open failed. With this change, the truncation
is done only after the lock is successfully acquired.

Obtained from:	 BSD/OS
This commit is contained in:
Kirk McKusick 2000-07-04 03:34:11 +00:00
parent 3764219663
commit e6796b67d9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=62550
16 changed files with 95 additions and 75 deletions
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5
sys/dev/ccd/ccd.c
View File

@ -1538,10 +1538,11 @@ ccdlookup(path, p, vpp)
{
struct nameidata nd;
struct vnode *vp;
int error;
int error, flags;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, path, p);
if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
flags = FREAD | FWRITE;
if ((error = vn_open(&nd, &flags, 0)) != 0) {
#ifdef DEBUG
if (ccddebug & CCDB_FOLLOW|CCDB_INIT)
printf("ccdlookup: vn_open error = %d\n", error);

4
sys/dev/vn/vn.c
View File

@ -539,13 +539,13 @@ vniocattach_file(vn, vio, dev, flag, p)
flags = FREAD|FWRITE;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_file, p);
error = vn_open(&nd, flags, 0);
error = vn_open(&nd, &flags, 0);
if (error) {
if (error != EACCES && error != EPERM && error != EROFS)
return (error);
flags &= ~FWRITE;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vn_file, p);
error = vn_open(&nd, flags, 0);
error = vn_open(&nd, &flags, 0);
if (error)
return (error);
}

5
sys/geom/geom_ccd.c
View File

@ -1538,10 +1538,11 @@ ccdlookup(path, p, vpp)
{
struct nameidata nd;
struct vnode *vp;
int error;
int error, flags;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, path, p);
if ((error = vn_open(&nd, FREAD|FWRITE, 0)) != 0) {
flags = FREAD | FWRITE;
if ((error = vn_open(&nd, &flags, 0)) != 0) {
#ifdef DEBUG
if (ccddebug & CCDB_FOLLOW|CCDB_INIT)
printf("ccdlookup: vn_open error = %d\n", error);

5
sys/kern/kern_acct.c
View File

@ -117,7 +117,7 @@ acct(a1, uap)
{
struct proc *p = curproc; /* XXX */
struct nameidata nd;
int error;
int error, flags;
/* Make sure that the caller is root. */
error = suser(p);
@ -131,7 +131,8 @@ acct(a1, uap)
if (SCARG(uap, path) != NULL) {
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, SCARG(uap, path),
p);
error = vn_open(&nd, FWRITE, 0);
flags = FWRITE;
error = vn_open(&nd, &flags, 0);
if (error)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);

5
sys/kern/kern_ktrace.c
View File

@ -253,7 +253,7 @@ ktrace(curp, uap)
int ops = KTROP(uap->ops);
int descend = uap->ops & KTRFLAG_DESCEND;
int ret = 0;
int error = 0;
int flags, error = 0;
struct nameidata nd;
curp->p_traceflag |= KTRFAC_ACTIVE;
@ -262,7 +262,8 @@ ktrace(curp, uap)
* an operation which requires a file argument.
*/
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, curp);
error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0);
flags = FREAD | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, 0);
if (error) {
curp->p_traceflag &= ~KTRFAC_ACTIVE;
return (error);

5
sys/kern/kern_linker.c
View File

@ -1175,7 +1175,7 @@ linker_search_path(const char *name)
struct nameidata nd;
struct proc *p = curproc; /* XXX */
char *cp, *ep, *result, **cpp;
int error, extlen, len;
int error, extlen, len, flags;
enum vtype type;
/* qualified at all? */
@ -1211,7 +1211,8 @@ linker_search_path(const char *name)
* and it's a regular file.
*/
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, result, p);
error = vn_open(&nd, FREAD, 0);
flags = FREAD;
error = vn_open(&nd, &flags, 0);
if (error == 0) {
NDFREE(&nd, NDF_ONLY_PNBUF);
type = nd.ni_vp->v_type;

5
sys/kern/kern_sig.c
View File

@ -1598,7 +1598,7 @@ coredump(p)
register struct ucred *cred = p->p_ucred;
struct nameidata nd;
struct vattr vattr;
int error, error1;
int error, error1, flags;
char *name; /* name of corefile */
off_t limit;
@ -1621,7 +1621,8 @@ coredump(p)
name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid);
NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
flags = O_CREAT | FWRITE | O_NOFOLLOW;
error = vn_open(&nd, &flags, S_IRUSR | S_IWUSR);
free(name, M_TEMP);
if (error)
return (error);

5
sys/kern/link_aout.c
View File

@ -192,13 +192,14 @@ link_aout_load_file(linker_class_t lc, const char* filename, linker_file_t* resu
struct nameidata nd;
struct proc* p = curproc; /* XXX */
int error = 0;
int resid;
int resid, flags;
struct exec header;
aout_file_t af;
linker_file_t lf = 0;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
error = vn_open(&nd, FREAD, 0);
flags = FREAD;
error = vn_open(&nd, &flags, 0);
if (error)
return error;
NDFREE(&nd, NDF_ONLY_PNBUF);

5
sys/kern/link_elf.c
View File

@ -504,7 +504,7 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
Elf_Addr base_vaddr;
Elf_Addr base_vlimit;
int error = 0;
int resid;
int resid, flags;
elf_file_t ef;
linker_file_t lf;
Elf_Shdr *shdr;
@ -517,7 +517,8 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
lf = NULL;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
error = vn_open(&nd, FREAD, 0);
flags = FREAD;
error = vn_open(&nd, &flags, 0);
if (error)
return error;
NDFREE(&nd, NDF_ONLY_PNBUF);

5
sys/kern/link_elf_obj.c
View File

@ -504,7 +504,7 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
Elf_Addr base_vaddr;
Elf_Addr base_vlimit;
int error = 0;
int resid;
int resid, flags;
elf_file_t ef;
linker_file_t lf;
Elf_Shdr *shdr;
@ -517,7 +517,8 @@ link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* resu
lf = NULL;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename, p);
error = vn_open(&nd, FREAD, 0);
flags = FREAD;
error = vn_open(&nd, &flags, 0);
if (error)
return error;
NDFREE(&nd, NDF_ONLY_PNBUF);

36
sys/kern/vfs_extattr.c
View File

@ -968,9 +968,10 @@ open(p, uap)
syscallarg(int) mode;
} */ *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
register struct vnode *vp;
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
struct vattr vat;
int cmode, flags, oflags;
struct file *nfp;
int type, indx, error;
@ -988,7 +989,7 @@ open(p, uap)
cmode = ((SCARG(uap, mode) &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
p->p_dupfd = -indx - 1; /* XXX check for fdopen */
error = vn_open(&nd, flags, cmode);
error = vn_open(&nd, &flags, cmode);
if (error) {
ffree(fp);
if ((error == ENODEV || error == ENXIO) &&
@ -1011,6 +1012,7 @@ open(p, uap)
fp->f_flag = flags & FMASK;
fp->f_ops = &vnops;
fp->f_type = (vp->v_type == VFIFO ? DTYPE_FIFO : DTYPE_VNODE);
VOP_UNLOCK(vp, 0, p);
if (flags & (O_EXLOCK | O_SHLOCK)) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
@ -1022,22 +1024,30 @@ open(p, uap)
type = F_FLOCK;
if ((flags & FNONBLOCK) == 0)
type |= F_WAIT;
VOP_UNLOCK(vp, 0, p);
if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
(void) vn_close(vp, fp->f_flag, fp->f_cred, p);
ffree(fp);
fdp->fd_ofiles[indx] = NULL;
return (error);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0)
goto bad;
fp->f_flag |= FHASLOCK;
}
if (flags & O_TRUNC) {
VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
VATTR_NULL(&vat);
vat.va_size = 0;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
error = VOP_SETATTR(vp, &vat, p->p_ucred, p);
VOP_UNLOCK(vp, 0, p);
if (error)
goto bad;
}
/* assert that vn_open created a backing object if one is needed */
KASSERT(!vn_canvmio(vp) || vp->v_object != NULL,
("open: vmio vnode has no backing object after vn_open"));
VOP_UNLOCK(vp, 0, p);
p->p_retval[0] = indx;
return (0);
bad:
(void) vn_close(vp, fp->f_flag, fp->f_cred, p);
ffree(fp);
fdp->fd_ofiles[indx] = NULL;
return (error);
}
#ifdef COMPAT_43

36
sys/kern/vfs_syscalls.c
View File

@ -968,9 +968,10 @@ open(p, uap)
syscallarg(int) mode;
} */ *uap;
{
register struct filedesc *fdp = p->p_fd;
register struct file *fp;
register struct vnode *vp;
struct filedesc *fdp = p->p_fd;
struct file *fp;
struct vnode *vp;
struct vattr vat;
int cmode, flags, oflags;
struct file *nfp;
int type, indx, error;
@ -988,7 +989,7 @@ open(p, uap)
cmode = ((SCARG(uap, mode) &~ fdp->fd_cmask) & ALLPERMS) &~ S_ISTXT;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
p->p_dupfd = -indx - 1; /* XXX check for fdopen */
error = vn_open(&nd, flags, cmode);
error = vn_open(&nd, &flags, cmode);
if (error) {
ffree(fp);
if ((error == ENODEV || error == ENXIO) &&
@ -1011,6 +1012,7 @@ open(p, uap)
fp->f_flag = flags & FMASK;
fp->f_ops = &vnops;
fp->f_type = (vp->v_type == VFIFO ? DTYPE_FIFO : DTYPE_VNODE);
VOP_UNLOCK(vp, 0, p);
if (flags & (O_EXLOCK | O_SHLOCK)) {
lf.l_whence = SEEK_SET;
lf.l_start = 0;
@ -1022,22 +1024,30 @@ open(p, uap)
type = F_FLOCK;
if ((flags & FNONBLOCK) == 0)
type |= F_WAIT;
VOP_UNLOCK(vp, 0, p);
if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0) {
(void) vn_close(vp, fp->f_flag, fp->f_cred, p);
ffree(fp);
fdp->fd_ofiles[indx] = NULL;
return (error);
}
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if ((error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf, type)) != 0)
goto bad;
fp->f_flag |= FHASLOCK;
}
if (flags & O_TRUNC) {
VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
VATTR_NULL(&vat);
vat.va_size = 0;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
error = VOP_SETATTR(vp, &vat, p->p_ucred, p);
VOP_UNLOCK(vp, 0, p);
if (error)
goto bad;
}
/* assert that vn_open created a backing object if one is needed */
KASSERT(!vn_canvmio(vp) || vp->v_object != NULL,
("open: vmio vnode has no backing object after vn_open"));
VOP_UNLOCK(vp, 0, p);
p->p_retval[0] = indx;
return (0);
bad:
(void) vn_close(vp, fp->f_flag, fp->f_cred, p);
ffree(fp);
fdp->fd_ofiles[indx] = NULL;
return (error);
}
#ifdef COMPAT_43

37
sys/kern/vfs_vnops.c
View File

@ -98,25 +98,25 @@ struct filterops vn_rwfiltops[] = {
* due to the NDINIT being done elsewhere.
*/
int
vn_open(ndp, fmode, cmode)
vn_open(ndp, flagp, cmode)
register struct nameidata *ndp;
int fmode, cmode;
int *flagp, cmode;
{
register struct vnode *vp;
register struct proc *p = ndp->ni_cnd.cn_proc;
register struct ucred *cred = p->p_ucred;
struct vnode *vp;
struct proc *p = ndp->ni_cnd.cn_proc;
struct ucred *cred = p->p_ucred;
struct vattr vat;
struct vattr *vap = &vat;
int mode, error;
int mode, fmode, error;
fmode = *flagp;
if (fmode & O_CREAT) {
ndp->ni_cnd.cn_nameiop = CREATE;
ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF;
if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
ndp->ni_cnd.cn_flags |= FOLLOW;
bwillwrite();
error = namei(ndp);
if (error)
if ((error = namei(ndp)) != 0)
return (error);
if (ndp->ni_vp == NULL) {
VATTR_NULL(vap);
@ -127,12 +127,11 @@ vn_open(ndp, fmode, cmode)
VOP_LEASE(ndp->ni_dvp, p, cred, LEASE_WRITE);
error = VOP_CREATE(ndp->ni_dvp, &ndp->ni_vp,
&ndp->ni_cnd, vap);
vput(ndp->ni_dvp);
if (error) {
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(ndp->ni_dvp);
return (error);
}
vput(ndp->ni_dvp);
ASSERT_VOP_UNLOCKED(ndp->ni_dvp, "create");
ASSERT_VOP_LOCKED(ndp->ni_vp, "create");
fmode &= ~O_TRUNC;
@ -154,8 +153,7 @@ vn_open(ndp, fmode, cmode)
ndp->ni_cnd.cn_nameiop = LOOKUP;
ndp->ni_cnd.cn_flags =
((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
error = namei(ndp);
if (error)
if ((error = namei(ndp)) != 0)
return (error);
vp = ndp->ni_vp;
}
@ -187,18 +185,7 @@ vn_open(ndp, fmode, cmode)
goto bad;
}
}
if (fmode & O_TRUNC) {
VOP_UNLOCK(vp, 0, p); /* XXX */
VOP_LEASE(vp, p, cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); /* XXX */
VATTR_NULL(vap);
vap->va_size = 0;
error = VOP_SETATTR(vp, vap, cred, p);
if (error)
goto bad;
}
error = VOP_OPEN(vp, fmode, cred, p);
if (error)
if ((error = VOP_OPEN(vp, fmode, cred, p)) != 0)
goto bad;
/*
* Make sure that a VM object is created for VMIO support.
@ -210,10 +197,12 @@ vn_open(ndp, fmode, cmode)
if (fmode & FWRITE)
vp->v_writecount++;
*flagp = fmode;
return (0);
bad:
NDFREE(ndp, NDF_ONLY_PNBUF);
vput(vp);
*flagp = fmode;
return (error);
}

2
sys/sys/vnode.h
View File

@ -579,7 +579,7 @@ int debug_vn_lock __P((struct vnode *vp, int flags, struct proc *p,
const char *filename, int line));
#define vn_lock(vp,flags,p) debug_vn_lock(vp,flags,p,__FILE__,__LINE__)
#endif
int vn_open __P((struct nameidata *ndp, int fmode, int cmode));
int vn_open __P((struct nameidata *ndp, int *flagp, int cmode));
void vn_pollevent __P((struct vnode *vp, int events));
void vn_pollgone __P((struct vnode *vp));
int vn_pollrecord __P((struct vnode *vp, struct proc *p, int events));

5
sys/ufs/ufs/ufs_extattr.c
View File

@ -307,7 +307,7 @@ ufs_extattrctl(struct mount *mp, int cmd, char *attrname,
struct vnode *vp;
char local_attrname[UFS_EXTATTR_MAXEXTATTRNAME]; /* inc null */
char *filename;
int error, len;
int error, len, flags;
if ((error = suser_xxx(p->p_cred->pc_ucred, p, 0)))
return (error);
@ -329,7 +329,8 @@ ufs_extattrctl(struct mount *mp, int cmd, char *attrname,
filename = (char *) arg;
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, filename, p);
error = vn_open(&nd, FREAD|FWRITE, 0);
flags = FREAD | FWRITE;
error = vn_open(&nd, &flags, 0);
if (error)
return (error);

5
sys/ufs/ufs/ufs_quota.c
View File

@ -393,12 +393,13 @@ quotaon(p, mp, type, fname)
struct vnode *vp, **vpp;
struct vnode *nextvp;
struct dquot *dq;
int error;
int error, flags;
struct nameidata nd;
vpp = &ump->um_quotas[type];
NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, fname, p);
error = vn_open(&nd, FREAD|FWRITE, 0);
flags = FREAD | FWRITE;
error = vn_open(&nd, &flags, 0);
if (error)
return (error);
NDFREE(&nd, NDF_ONLY_PNBUF);