implementing accurate logarithms in different bases. This is based
on an approach bde coded up years ago.
This function should always be inlined; it will be used in only a few
places, and rudimentary tests show a 40% performance improvement in
implementations of log2() and log10() on amd64.
The kernel takes a reduced argument x and returns the same polynomial
approximation as e_log.c, but omitting the low-order term. The low-order
term is much larger than the rest of the approximation, so the caller of
the kernel function can scale it to the appropriate base in extra precision
and obtain a much more accurate answer than by using log(x)/log(b).
This includes support in the kernel, camcontrol(8), libcam and the mps(4)
driver for SMP passthrough.
The CAM SCSI probe code has been modified to fetch Inquiry VPD page 0x00
to determine supported pages, and will now fetch page 0x83 in addition to
page 0x80 if supported.
Add two new CAM CCBs, XPT_SMP_IO, and XPT_GDEV_ADVINFO. The SMP CCB is
intended for SMP requests and responses. The ADVINFO is currently used to
fetch cached VPD page 0x83 data from the transport layer, but is intended
to be extensible to fetch other types of device-specific data.
SMP-only devices are not currently represented in the CAM topology, and so
the current semantics are that the SIM will route SMP CCBs to either the
addressed device, if it contains an SMP target, or its parent, if it
contains an SMP target. (This is noted in cam_ccb.h, since it will change
later once we have the ability to have SMP-only devices in CAM's topology.)
smp_all.c,
smp_all.h: New helper routines for SMP. This includes
SMP request building routines, response parsing
routines, error decoding routines, and structure
definitions for a number of SMP commands.
libcam/Makefile: Add smp_all.c to libcam, so that SMP functionality
is available to userland applications.
camcontrol.8,
camcontrol.c: Add smp passthrough support to camcontrol. Several
new subcommands are now available:
'smpcmd' functions much like 'cmd', except that it
allows the user to send generic SMP commands.
'smprg' sends the SMP report general command, and
displays the decoded output. It will automatically
fetch extended output if it is available.
'smppc' sends the SMP phy control command, with any
number of potential options. Among other things,
this allows the user to reset a phy on a SAS
expander, or disable a phy on an expander.
'smpmaninfo' sends the SMP report manufacturer
information and displays the decoded output.
'smpphylist' displays a list of phys on an
expander, and the CAM devices attached to those
phys, if any.
cam.h,
cam.c: Add a status value for SMP errors
(CAM_SMP_STATUS_ERROR).
Add a missing description for CAM_SCSI_IT_NEXUS_LOST.
Add support for SMP commands to cam_error_string().
cam_ccb.h: Rename the CAM_DIR_RESV flag to CAM_DIR_BOTH. SMP
commands are by nature bi-directional, and we may
need to support bi-directional SCSI commands later.
Add the XPT_SMP_IO CCB. Since SMP commands are
bi-directional, there are pointers for both the
request and response.
Add a fill routine for SMP CCBs.
Add the XPT_GDEV_ADVINFO CCB. This is currently
used to fetch cached page 0x83 data from the
transport later, but is extensible to fetch many
other types of data.
cam_periph.c: Add support in cam_periph_mapmem() for XPT_SMP_IO
and XPT_GDEV_ADVINFO CCBs.
cam_xpt.c: Add support for executing XPT_SMP_IO CCBs.
cam_xpt_internal.h: Add fields for VPD pages 0x00 and 0x83 in struct
cam_ed.
scsi_all.c: Add scsi_get_sas_addr(), a function that parses
VPD page 0x83 data and pulls out a SAS address.
scsi_all.h: Add VPD page 0x00 and 0x83 structures, and a
prototype for scsi_get_sas_addr().
scsi_pass.c: Add support for mapping buffers in XPT_SMP_IO and
XPT_GDEV_ADVINFO CCBs.
scsi_xpt.c: In the SCSI probe code, first ask the device for
VPD page 0x00. If any VPD pages are supported,
that page is required to be implemented. Based on
the response, we may probe for the serial number
(page 0x80) or device id (page 0x83).
Add support for the XPT_GDEV_ADVINFO CCB.
sys/conf/files: Add smp_all.c.
mps.c: Add support for passing in a uio in mps_map_command(),
so we can map a S/G list at once.
Add support for SMP passthrough commands in
mps_data_cb(). SMP is a special case, because the
first buffer in the S/G list is outbound and the
second buffer is inbound.
Add support for warning the user if the busdma code
comes back with more buffers than will work for the
command. This will, for example, help the user
determine why an SMP command failed if busdma comes
back with three buffers.
mps_pci.c: Add sys/uio.h.
mps_sas.c: Add the SAS address and the parent handle to the
list of fields we pull from device page 0 and cache
in struct mpssas_target. These are needed for SMP
passthrough.
Add support for the XPT_SMP_IO CCB. For now, this
CCB is routed to the addressed device if it supports
SMP, or to its parent if it does not and the parent
does. This is necessary because CAM does not
currently support SMP-only nodes in the topology.
Make SMP passthrough support conditional on
__FreeBSD_version >= 900026. This will make it
easier to MFC this change to the driver without
MFCing the CAM changes as well.
mps_user.c: Un-staticize mpi_init_sge() so we can use it for
the SMP passthrough code.
mpsvar.h: Add a uio and iovecs into struct mps_command for
SMP passthrough commands.
Add a cm_max_segs field to struct mps_command so
that we can warn the user if busdma comes back with
too many segments.
Clear the cm_reply when a command gets freed. If
it is not cleared, reply frames will eventually get
freed into the pool multiple times and corrupt the
pool. (This fix is from scottl.)
Add a prototype for mpi_init_sge().
sys/param.h: Bump __FreeBSD_version to 900026 for the for the
inclusion of the XPT_GDEV_ADVINFO and XPT_SMP_IO
CAM CCBs.
1) We need to allow the USB callback to free the USB transfer itself.
2) The USB transfer buffer should only be automatically freed when
freeing the USB transfer.
Fixed by: hselasky
Submitted by: Gustau Perez i Querol
Approved by: thompsa (mentor)
Explanation by Steve:
jn[f](n,x) for certain ranges of x uses downward recursion to compute
the value of the function. The recursion sequence that is generated is
proportional to the actual desired value, so a normalization step is
taken. This normalization is j0[f](x) divided by the zeroth sequence
member. As Bruce notes, near the zeros of j0[f](x) the computed value
can have giga-ULP inaccuracy. I found for the 1st zero of j0f(x) only
the leading decimal digit is correct. The solution to the issue is
fairly straight forward. The zeros of j0(x) and j1(x) never coincide,
so as j0(x) approaches a zero, the normalization constant switches to
j1[f](x) divided by the 2nd sequence member. The expectation is that
j1[f](x) is a more accurately computed value.
PR: bin/144306
Submitted by: Steven G. Kargl <kargl@troutmask.apl.washington.edu>
Reviewed by: bde
MFC after: 7 days
I've had a report of a sparc64 system where cc1 generates illegal
instructions. We still have to diagnose this properly, but instead of
hosing all sparc64 boxes out there, fall back to libgcc to prevent more
damage.
Reported by: Florian Smeets
you tag a socket with an uint32_t value. The cookie can then be
used by the kernel for various purposes, e.g. setting the skipto
rule or pipe number in ipfw (this is the reason SO_USER_COOKIE has
been implemented; however there is nothing ipfw-specific in its
implementation).
The ipfw-related code that uses the optopn will be committed separately.
This change adds a field to 'struct socket', but the struct is not
part of any driver or userland-visible ABI so the change should be
harmless.
See the discussion at
http://lists.freebsd.org/pipermail/freebsd-ipfw/2009-October/004001.html
Idea and code from Paul Joe, small modifications and manpage
changes by myself.
Submitted by: Paul Joe
MFC after: 1 week
After KVA space was increased to 512GB on amd64 it became impractical
to use PTEs as entries in the minidump map of dumped pages, because size
of that map alone would already be 1GB.
Instead, we now use PDEs as page map entries and employ two stage lookup
in libkvm: virtual address -> PDE -> PTE -> physical address. PTEs are
now dumped as regular pages. Fixed page map size now is 2MB.
libkvm keeps support for accessing amd64 minidumps of version 1.
Support for 1GB pages is added.
Many thanks to Alan Cox for his guidance, numerous reviews, suggestions,
enhancments and corrections.
Reviewed by: alc [kernel part]
MFC after: 15 days
Not doing so may cause all sorts of random libraries to expose
libcompiler_rt's functions, which should of course not be done.
Discussed with: kan, kib
libcompiler_rt.a is a BSD licensed C language runtime, which implements
many routines which are linked into binaries on architectures where
certain functionality is missing (e.g. 64 bits mul/div on i386).
Unfortunately, libcompiler_rt cannot replace libgcc entirely. Certain
features, such as an unwinder for exception handling, are missing.
That's why only libgcc.a is replaced for now, because this one does seem
to be complete.
Tested by: rene (amd64), nwhitehorn (powerpc), droso (i386 exprun)
and many others. Thanks!
Obtained from: user/ed/compiler-rt
because there's inter-entry garbage, just scan forward
to find the next one. This allows us to handle a lot
of Zip archives that have been modified in-place.
Thanks to: Gleb Kurtsou for sending me a sample archive
I've noticed various terminal emulators that need to obtain a sane
default termios structure use very complex `hacks'. Even though POSIX
doesn't provide any functionality for this, extend our termios API with
cfmakesane(3), which is similar to the commonly supported cfmakeraw(3),
except that it fills the termios structure with sane defaults.
Change all code in our base system to use this function, instead of
depending on <sys/ttydefaults.h> to provide TTYDEF_*.
flag. [1]
- Note that also fchflags(2) will return EPERM for attempts to set or
unset the SF_SNAPSHOT flag.
Submitted by: Garrett Cooper [1]
MFC after: 1 week
Instead of only returning NULL when the entry is invalid and can't be
matched against the current database, also return it when it cannot open
the log files properly.
It's a bit more pedantic regarding .Bl list elements. This has an added
benefit of unbreaking the ipfw(8) manpage, where groff was silently
skipping one list element.
a silly rwlock deadlock problem, the deadlock is caused by writer
waiters, if a thread has already locked a reader lock, and wants to
acquire another reader lock, it will be blocked by writer waiters,
but we had already fixed it years ago.
functions set or get pthread_rwlock type, current supported types are:
PTHREAD_RWLOCK_PREFER_READER_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NP,
default is PTHREAD_RWLOCK_PREFER_WRITER_NONCECURSIVE_NP, this maintains
binary compatible with old code.
- Add missing check for ugd_actlen being too small.
- Add missing inclusion guard to usbvar.h header file.
- This also fixes buildworld breakage since r213852.
* libusb_strerror()
* libusb_get_driver[_np]()
* libusb_detach_kernel_driver[_np]()
- Factor out setting of non-blocking flag inside libusb.
- Add missing NULL check after libusb_get_device() call.
- Correct some wrong error codes due to copy and paste error.
PR: usb/150546
Submitted by: Robert Jenssen, Alexander Leidinger
Approved by: thompsa (mentor)
Remove or re-work support for the several features from the past:
- remove incomplete support for trimming slice/partition names
- remove mapping from old device names "sd" and "st"
- remove whitespace trimming
- remove unconditional skipping of leading 'r' in a device name
- skip leading 'n' or 'e' only if the following device name matches
a list of known devices that support no-rewind and eject-on-close
features; currently this is only sa(4)
- reflect the above changes in comments in code and in cam(3)
- remove a note cautioning against use of cam_get_device and
cam_open_device in cam(3)
Reviewed by: mjacob
'inline' to 'static inline'. Otherwise, a C99 compiler (such as clang)
will output an undefined symbol for those functions in the resulting
object file. (Even gcc will do this, when you use "-std=c99".)
This should fix the "undefined reference to `set4pixels'" errors that
some people were seeing during ports building, when their world was
compiled with clang.
Approved by: rpaulo (mentor)
and one under lib/msun/amd64. This avoids adding the identifiers to the
.text section, and moves them to the .comment section instead.
Suggested by: bde
Approved by: rpaulo (mentor)
On anything modern, the C version, which processes a word at a time, is much
faster. The Intel optimization manual explicitly warns against using REP
prefixes with SCAS or CMPS, which is exactly what the assembler version
does.
A simple test on a Phenom II showed the C version, compiled with -O2, to be
about twice as fast determining the length of 100000 strings between 0 and
255 bytes long.
MFC after: 2 weeks
as they are slower than the generic version in C, at least on modern
hardware. This leaves us with just five implementations.
Suggested by: bde
Approved by: rpaulo (mentor)
r212976): order the incoming arguments to fscale as st(0), st(1), and
mark temp2 volatile (only in case of compilation with clang) to force
clang to pop it correctly. No binary change when compiled with gcc.
This fixes ldexp() when compiled with clang on amd64, which makes
drand48() and friends work correctly again, and this in turn fixes
perl's tempfile().
Reported by: Renato Botelho, Derek Tattersall
Approved by: rpaulo (mentor)
same null value, the code can not distinguish between them, to
fix the problem, now a destroyed object is assigned to a non-null
value, and it will be rejected by some pthread functions.
PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP is changed to number 1, so that
adaptive mutex can be statically initialized correctly.
it is incompatible with stack unwinding code, if they are invoked,
disable stack unwinding for current thread, and when thread is
exiting, print a warning message.
for them, two functions _pthread_cancel_enter and _pthread_cancel_leave
are added to let thread enter and leave a cancellation point, it also
makes it possible that other functions can be cancellation points in
libraries without having to be rewritten in libthr.
Reorder inline assembly arguments temp2, temp, value and texp to follow
the st(0), st(1), etc. style.
Also mark the temp2 variable as volatile to workaround another clang
bug.
This allows clang to buildworld FreeBSD/i386.
Submitted by: dim
the first line of a script exceeded MAXSHELLCMDLEN characters, then
exec_imgact_shell() silently truncated the line and passed on the truncated
interpreter name or argument. Now, exec_imgact_shell() will fail and return
ENOEXEC, which is the commonly used errno among Unix variants for this type
of error. (2) Previously, exec_imgact_shell()'s check on the length of the
interpreter's name was ineffective. In other words, exec_imgact_shell()
could not possibly fail and return ENAMETOOLONG. The reason being that the
length of the interpreter name had to exceed MAXSHELLCMDLEN characters in
order that ENAMETOOLONG be returned. But, the search for the end of the
interpreter name stops after at most MAXSHELLCMDLEN - 2 characters are
scanned. (In the end, this particular error is eventually discovered
outside of exec_imgact_shell() and ENAMETOOLONG is returned. So, the real
effect of this second change is that the error is detected earlier, in
exec_imgact_shell().)
Update the definition of MAXINTERP to the actual limit on the size of
the interpreter name that has been in effect since r142453 (from
2005).
In collaboration with: kib
whether asynchronous mode is turned on or not, this always gives us a
chance to decide whether thread should be canceled or not in
cancellation points.
acl_is_trivial_np(3) properly recognize the new trivial ACLs. From
the user point of view, that means "ls -l" no longer shows plus signs
for all the files when running ZFS v28.
files and directories were already added/removed in the upstream
repository, but were not added/removed here, when the previous snapshot
was imported.
Note: I did not import the file test/Lexer/conflict-marker.c, because it
contains merge conflict markers on purpose, which upsets our pre-commit
hooks.
Approved by: rpaulo (mentor)
defer-mode cancellation works, asynchrnous mode does not work because
it lacks of libuwind's support. stack unwinding is not enabled unless
LIBTHR_UNWIND_STACK is defined in Makefile.
For all libthr contexts, use ${MACHINE_CPUARCH}
for all libc contexts, use ${MACHINE_ARCH} if it exists, otherwise use
${MACHINE_CPUARCH}
Move some common code up a layer (the .PATH statement was the same in
all the arch submakefiles).
# Hope she hasn't busted powerpc64 with this...
add a wrapper for it in libc and rework the code in libthr, the
system call still can return EINTR, we keep this feature.
Discussed on: thread
Reviewed by: jilles
objects inside one ELF section, which prevents the creation of a ELF
section with mixed data types. For example, gcc LTO use libelf to
create a .gnu_lto_XXX section that contains integers and a string
table, which doesn't work with our libelf implementation.
The changes made in this commit include:
* Allow Elf_Data type to be different than section type.
* Relax Elf_Data alignment check.
* Align each Elf_Data by their own alignment instead of section alignment.
MFC after: 1 month
This adds a new "arrow" key "delete" corresponding to the kD termcap value.
It only works if that is a sequence such as "\033[3~"; if it is "\177", the
em-delete-prev-char or ed-delete-prev-char from the single-character
mappings remains. It turns out that most terminals (xterm and alikes,
syscons in xterm mode) produce "\033[3~" by default so <Delete> has the
expected effect.
This also means that things need to be considerably misconfigured for
<Backspace> to perform a <Delete> action.
This allows the nfs_getrootfh() function to return the
correct file handle size to pxe.c for pxeboot. It also
results in NFSv2 no longer being used by default anywhere
in FreeBSD. If built with OLD_NFSV2 defined, the old
code that predated this patch will be built and NFSv2
will be used.
Tested by: danny at cs.huji.ac.il
MFC after: 2 weeks
module private type, when private type mutex is locked/unlocked, thread
critical region is entered or leaved. These changes makes fork()
async-signal safe which required by POSIX. Note that user's atfork handler
still needs to be async-signal safe, but it is not problem of libthr, it
is user's responsiblity.
some cases we want to improve:
1) if a thread signal got a signal while in cancellation point,
it is possible the TDP_WAKEUP may be eaten by signal handler
if the handler called some interruptibly system calls.
2) In signal handler, we want to disable cancellation.
3) When thread holding some low level locks, it is better to
disable signal, those code need not to worry reentrancy,
sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
1) libthr installs its signal handler if user code invokes sigaction
to install its handler, the user handler is recorded in internal
array.
2) when a signal is delivered, libthr's signal handler is invoke,
libthr checks if thread holds some low level lock or is in critical
region, if it is true, the signal is buffered, and all signals are
masked, once the thread leaves critical region, correct signal
mask is restored and buffered signal is processed.
3) before user signal handler is invoked, cancellation is temporarily
disabled, after user signal handler is returned, cancellation state
is restored, and pending cancellation is rescheduled.
their implementations aren't in the same files. Introduce LIBC_ARCH
and use that in preference to MACHINE_CPUARCH. Tested by amd64 and
powerpc64 builds (thanks nathanw@)
the separate .o for libc_pic.a. This prevents rtld from making the
symbol global.
Putting the stack_protector_compat.c into the public domain acknowledged
by kan.
Reviewed by: kan
MFC after: 2 weeks
atexit and __cxa_atexit handlers that are either installed by unloaded
dso, or points to the functions provided by the dso.
Use _rtld_addr_phdr to locate segment information from the address of
private variable belonging to the dso, supplied by crtstuff.c. Provide
utility function __elf_phdr_match_addr to do the match of address against
dso executable segment.
Call back into libthr from __cxa_finalize using weak
__pthread_cxa_finalize symbol to remove any atfork handler which
function points into unloaded object.
The rtld needs private __pthread_cxa_finalize symbol to not require
resolution of the weak undefined symbol at initialization time. This
cannot work, since rtld is relocated before sym_zero is set up.
Idea by: kan
Reviewed by: kan (previous version)
MFC after: 3 weeks
CLANG_PREFIX macro. This changes the default header search path when we
are building clang as part of cross-tools.
Submitted by: Dimitry Andric <dimitry at andric.com>
Reviewed by: freebsd-current
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
number of host CPUs and osreldate.
This eliminates the last sysctl(2) calls from the dynamically linked image
startup.
No objections from: kan
Tested by: marius (sparc64)
MFC after: 1 month
is acted upon, or when a thread calls pthread_exit(), the thread first
disables cancellation by setting its cancelability state to
PTHREAD_CANCEL_DISABLE and its cancelability type to
PTHREAD_CANCEL_DEFERRED. The cancelability state remains set to
PTHREAD_CANCEL_DISABLE until the thread has terminated.
It has no effect if a cancellation cleanup handler or thread-specific
data destructor routine changes the cancelability state to
PTHREAD_CANCEL_ENABLE.
user in question (usually but not necessarily because we were called
with LOGIN_SETUSER). This plugs a hole where users could raise their
resource limits and expand their CPU mask.
MFC after: 3 weeks
a very bad one, since the shift does not actually overflow. This is
a better example (assuming uint64_t = unsigned long long):
~0LLU >> 9 = 0x7fffffffffffffLLU
~0LLU >> 9 << 10 = 0xfffffffffffffc00LLU
~0LLU >> 9 << 10 >> 10 = 0x3fffffffffffffLLU
switch. Since expand_number() does not accept negative numbers, switch
from int64_t to uint64_t; this makes it easier to check for overflow.
MFC after: 3 weeks
have to return ERANGE and terminate with NS_RETURN.
- When gethostbyname_r(3) and the friends end with an error,
set errno to the value nss backend returns, and return errno
value.
PR: kern/131623
MFC after: 2 weeks
o return the correct status in proc_wstatus()
o proc_read takes a void *
o correctly allocate the objs structure array
Sponsored by: The FreeBSD Foundation
Erwin fired up a ports build a couple of weeks ago and it seems the
following functions are not used by any of the 20k ports we have, which
makes me believe they don't have any purpose. Just remove them.
clang.
The general idea is that the vendor will not accept our compilation
patches and so disabling the warnings is the best way to go as it makes
future imports bearable.
Submitted by: Dimitry Andric <dimitry at andric.com>
Discussed with: das
* breakpoint setup support
* register query
* symbol to address mapping and vice-versa
* more misc utility functions based on their Solaris counterpart
Also, I've written some test cases.
Sponsored by: The FreeBSD Foundation
avoid a hang in the SSL case if the server sends a close notification
before we are done reading. In the non-SSL case, it can provide a
minor (but probably not noticeable) performance improvement for small
transfers.
MFC after: 3 weeks
-fno-rtti. The clang libaries that really use exceptions and virtual
functions can enable LLVM_REQUIRES_EH and LLVM_REQUIRES_RTTI
respectively. This saves space on the resulting binaries and follows
what's being done upstream.
Submitted by: Dimitry Andric <dimitry at andric.com>
to catch invalid signal numbers [1]. Use consistent style of
not assigning the return value to a local variable.
Reported by: Garrett Cooper <yanegomi gmail com> [1]
MFC after: 1 week
`_libelf_ar_open()` to a new compilation unit "libelf_ar_util.c"
to break the circular dependency between "elf_memory.o" and
"libelf_ar.o".
Obtained from: elftoolchain
MFC after: 1 month
favour of `elf_getshdrnum()`, `elf_getphdrnum()` and `elf_getshdrstrndx()`
respectively.
* Add new manual pages for `elf_getshdrstrndx()`, `elf_getphdrnum()` and
`elf_getshdrnum()`.
* Add a deprecation warning for `elf_getshstrndx()`, `elf_getphnum()` and
`elf_getshnum()`.
Obtained from: elftoolchain
MFC after: 1 month
types that don't have a fixed size.
- The *fsize() functions should return a size of 1, for variable length
types.
- Redefine symbol ELF_T_LAST to match the current end of the list.
Obtained from: elftoolchain
MFC after: 1 month
representations of ELF types.
The ELF(3) API allows applications to request a conversion that is
`in-place', i.e., with source and destinations data buffers being
the same. However, the file and memory sizes of ELF sections that
have additional internal structure, such as those of type `Elf_Note',
or `Elf_GNU_Hash_Header', can be determined only known after the
type-specific headers that comprise the first few words in these
sections are read and translated.
Pass in the size of destination buffer to type translation routines
in "libelf_convert.m4" and have these routines return an error code
if the translated data would not fit inside the destination buffer.
Obtained from: elftoolchain
MFC after: 1 month
when an output file has no program headers, set the 'e_phentsize'
field of the ELF executable header to zero.
Obtained from: elftoolchain
MFC after: 1 month
