MFC 338603:
Correct ELF header parsing code to prevent invalid ELF sections from
disclosing memory.

Submitted by: markj
Reported by: Thomas Barabosch, Fraunhofer FKIE
Approved by: so
Security: FreeBSD-SA-18:12.elf
Security: CVE-2018-6924
Sponsored by: The FreeBSD Foundation

MFC r313496:
Increase a chance of devfs_close() calling d_close cdevsw method.

MFC r300142:
Ensure that ftruncate(2) is performed synchronously when file is
opened in O_SYNC mode, at least for UFS.

MFC r298809, r298817
Minor spelling fixes.

MFC r294596:
Limit the accesses to file' f_advice member to VREG vnodes only.
Recheck that f_advice is not NULL after lock is taken.

Approved by: re (marius)

MFC r287599:
Correct handling of open("name", O_DIRECTORY | O_CREAT).

PR: 202892

MFC r286106:
Provide a prefaulting for the userspace i/o buffers, disabled by default.

MFC r283601:
Add V_MNTREF flag, to indicate that caller of vn_start*_write() already
owns a reference on the mount point, and the functions can consume it.

MFC r276008:
Add VN_OPEN_NAMECACHE flag for vn_open_cred(9), which requests that
the created file name was cached. Use the flag for core dumps.

MFC r275897:
Set NOCACHE flag for CREATE namei() calls, do not specially handle
MAKEENTRY in VOP_LOOKUP().

MFC r275744:
Only sleep interruptible while waiting for suspension end when
filesystem specified VFCF_SBDRY flag, i.e. for NFS.

MFC r274501:
In vfs_write_suspend_umnt(), if suspension cannot be established, do
not forget to restore write ops count when returning the error.

MFC r272534:
Add IO_RANGELOCKED flag for vn_rdwr(9), which specifies that vnode is
not locked, but range is.

MFC r272538:
Slightly reword comment. Move code, which is described by the
comment, after it.

MFC r270993:

Fix up proc_realparent to always return correct process.

Prior to the change it would always return initproc for non-traced processes.

This fixes a regression in inferior().

Approved by: re (marius)

MFC r268612:
Add helper helper vfs_write_suspend_umnt().

Fix the bug in the FFS unmount, when suspension failed, the ufs
extattrs were not reinitialized.

MFC r268606:
Generalize vn_get_ino() to allow filesystems to use custom vnode
producer. Convert inline copies of vn_get_ino() in msdosfs and cd9660
into the uses of vn_get_ino_gen().

MFC r267491:
Use vn_io_fault for the writes from core dumping code.

MFC r267564:
In msdosfs_setattr(), add a check for result of the utimes(2) permissions test.
Refactor the permission checks for utimes(2).

MFC r259522:
If vn_open_vnode() succeeded in opening the vnode, but subsequent
advisory lock cannot be obtained, prevent double-close of the vnode in
vn_close() called from the fdrop(), by resetting file' f_ops methods.

MFC r258039:
Avoid overflow for the page counts.

MFC r258365:
Revert back to use int for the page counts.
Rearrange the checks to correctly handle overflowing address arithmetic.

MFC r257898:
Change VFS_PROLOGUE() to evaluate the mp once, convert
MNTK_SHARED_WRITES and MNTK_EXTENDED_SHARED tests into inline functions.

MFC r287599:
Correct handling of open("name", O_DIRECTORY | O_CREAT).

PR: 202892

MFC r286106:
Provide a prefaulting for the userspace i/o buffers, disabled by default.

MFC r283601:
Add V_MNTREF flag, to indicate that caller of vn_start*_write() already
owns a reference on the mount point, and the functions can consume it.

MFC r276008:
Add VN_OPEN_NAMECACHE flag for vn_open_cred(9), which requests that
the created file name was cached. Use the flag for core dumps.

MFC r275897:
Set NOCACHE flag for CREATE namei() calls, do not specially handle
MAKEENTRY in VOP_LOOKUP().

MFC r275744:
Only sleep interruptible while waiting for suspension end when
filesystem specified VFCF_SBDRY flag, i.e. for NFS.

MFC r274501:
In vfs_write_suspend_umnt(), if suspension cannot be established, do
not forget to restore write ops count when returning the error.

MFC r272534:
Add IO_RANGELOCKED flag for vn_rdwr(9), which specifies that vnode is
not locked, but range is.

MFC r272538:
Slightly reword comment. Move code, which is described by the
comment, after it.

MFC r270993:

Fix up proc_realparent to always return correct process.

Prior to the change it would always return initproc for non-traced processes.

This fixes a regression in inferior().

Approved by: re (marius)

MFC r268612:
Add helper helper vfs_write_suspend_umnt().

Fix the bug in the FFS unmount, when suspension failed, the ufs
extattrs were not reinitialized.

MFC r268606:
Generalize vn_get_ino() to allow filesystems to use custom vnode
producer. Convert inline copies of vn_get_ino() in msdosfs and cd9660
into the uses of vn_get_ino_gen().

MFC r267491:
Use vn_io_fault for the writes from core dumping code.

MFC r267564:
In msdosfs_setattr(), add a check for result of the utimes(2) permissions test.
Refactor the permission checks for utimes(2).

MFC r259522:
If vn_open_vnode() succeeded in opening the vnode, but subsequent
advisory lock cannot be obtained, prevent double-close of the vnode in
vn_close() called from the fdrop(), by resetting file' f_ops methods.

MFC r258039:
Avoid overflow for the page counts.

MFC r258365:
Revert back to use int for the page counts.
Rearrange the checks to correctly handle overflowing address arithmetic.

MFC r257898:
Change VFS_PROLOGUE() to evaluate the mp once, convert
MNTK_SHARED_WRITES and MNTK_EXTENDED_SHARED tests into inline functions.