This simply utility makes it easy for scripts to read values from the device
tree. It is written in C and uses the same libfdt as the rest of the dtc
package.
What is it for:
- Reading fdt values from scripts
- Extracting fdt information within build systems
- Looking at particular values without having to dump the entire tree
To use it, specify the fdt binary file on command line followed by a list of
node, property pairs. The utility then looks up each node, finds the property
and displays the value.
Each value is printed on a new line.
fdtget tries to guess the type of each property based on its contents. This
is not always reliable, so you can use the -t option to force fdtget to decode
the value as a string, or byte, etc.
To read from stdin, use - as the file.
Usage:
fdtget <options> <dt file> [<node> <property>]...
Options:
-t <type> Type of data
-h Print this help
<type> s=string, i=int, u=unsigned, x=hex
Optional modifier prefix:
hh or b=byte, h=2 byte, l=4 byte (default)
Signed-off-by: Simon Glass <sjg@chromium.org>
This will allow callers to rebuild .dtb files when any of the /include/d
.dtsi files are modified, not just the top-level .dts file.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Commit a31e3ef83b introduced new libfdt
functions to append to existing properties. It also included a test case
for this, but neglected to update the Makefile and run_tests.sh script
to actually build and execute this testcase.
This patch corrects the oversight.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Some properties may contain multiple values, these values may need
to be added to the property respectively. this patch provides this
functionality. The main purpose of fdt_append_prop() is to append
the values to a existing property, or create a new property if it
dose not exist.
Signed-off-by: Minghuan Lian <Minghuan.Lian@freescale.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Elements of size 8, 16, 32, and 64 bits are supported. The new
/bits/ syntax was selected so as to not pollute the reserved
keyword space with uint8/uint16/... type names.
With this patch the following property assignment:
property = /bits/ 16 <0x1234 0x5678 0x0 0xffff>;
is equivalent to:
property = <0x12345678 0x0000ffff>;
It is now also possible to directly specify a 64 bit literal in a
cell list, also known as an array using:
property = /bits/ 64 <0xdeadbeef00000000>;
It is an error to attempt to store a literal into an element that is
too small to hold the literal, and the compiler will generate an
error when it detects this. For instance:
property = /bits/ 8 <256>;
Will fail to compile. It is also an error to attempt to place a
reference in a non 32-bit element.
The documentation has been changed to reflect that the cell list
is now an array of elements that can be of sizes other than the
default 32-bit cell size.
The sized_cells test tests the creation and access of 8, 16, 32,
and 64-bit sized elements. It also tests that the creation of two
properties, one with 16 bit elements and one with 32 bit elements
result in the same property contents.
Signed-off-by: Anton Staaf <robotboy@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
The load_blob() and save_blob() functions are very similar to the utilfdt
versions. This removes the duplicated code.
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
This adds higher-level libfdt operations for reading/writing an fdt
blob from/to a file, as well as a function to decode a data type string
as will be used by fdtget, fdtput.
This also adds a few tests for the simple type argument supported by
utilfdt_decode_type.
Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
With this patch the following property assignment:
property = <0x12345678 'a' '\r' 100>;
is equivalent to:
property = <0x12345678 0x00000061 0x0000000D 0x00000064>
Signed-off-by: Anton Staaf <robotboy@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
A number of the dtc testcases trigger the new "variable set but not
used" warning from gcc 4.6. That is they have variables which are
assigned, but then never read after that point.
In a couple of cases this is just because the variables aren't needed,
so this patch removes them. In subnode_offset.c, it's because one
pair of variables we clearly intended to test we don't actually test.
This patch also adds this missing check.
This patch makes the testsuite compile clean with gcc 4.6.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a "dtdiff" script to do a useful form diff of two
device trees. This automatically converts the tree to dts form (if
it's not already) and uses a new "-s" option in dtc to "sort" the
tree. That is, it sorts the reserve entries, it sorts the properties
within each node by name, and it sorts nodes by name within their
parent.
This gives a pretty sensible diff between the trees, which will ignore
semantically null internal rearrangements (directly diffing the dts
files can give a lot of noise due to the order changes).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When nodes are modified by merging device trees, nodes to be updated/merged can
be specified by a label. Specifying nodes by full path (instead of label)
doesn't quite work. This patch fixes that.
Signed-off-by: John Bonesio <bones@secretlab.ca>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Current we check for various error codes with [ $x == "NN" ]. However
'==' is not actually a correct operator for the [ (test) command. It
should be either '=' for string comparison or '-eq' for integer
comparison. It appears that the bash builtin version of test
implements '==' though, so we were getting away with it, as long as
/bin/sh was bash - or the testsuite generated no errors.
This patch fixes the usage of test so that it should work on non-bash
shells.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The dtbs_equal_ordered test program is used to implement a number of
testcases. However, the test program itself has never been
particularly well tested. In addition there are testcases coming in
future for which it would be useful to have a corresponding
"dtbs_equal_unordered" which checks for equality of device trees, not
considering the internal ordering of elements. Finally, for some
tests we may want it would be useful to check trees for equality with
the PASS case being when they are *not* equal.
This patch addresses all of the above. A dtbs_equal_unordered is
added, and both it and the existing dtbs_equal_ordered program now
take a -n option to make the PASS case be where the trees are not
equal. A number of example trees with slight modifications from
test_tree1 are used to verify that both these programs correctly
identify when the tree is altered, and a dtb_reverse program is used
to verify that the unordered version does not depend on internal
ordering. These new testcases for the equality testing programs are
split out into a new test group in run_tests.sh.
dtbs_equal_unordered uses the new property iteration functions, and so
this also acts as further testing for those functions.
dtbs_equal_unordered will be useful for further testing the recently
added tree-merging code and its upcoming extensions.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch turns on a bunch of extra gcc warnings, most of which are
probably a good idea. Of the new warnings -Wnested-externs and
-Wstrict-prototypes need no code changes, we're already warning-clean.
The remaining one, -Wmissing-prototypes requires trivial changes in
some of the tests (making functions local).
This patch also rearranges the warnings flags into a separate make
variable for convenience, and turns on -Werror, to really encourage
people to keep the code warning-clean.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch allows the following construct:
/ {
property-a = "old";
property-b = "does not change";
};
/ {
property-a = "changed";
property-c = "new";
node-a {
};
};
Where the later device tree overrides the properties found in the
earlier tree. This is useful for laying down a template device tree
in an include file and modifying it for a specific board without having
to clone the entire tree.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
The somewhat embarrasing bug in the first version of my previous patch
would have been detected by valgrind. Thus reminded, I've run the
testsuite under valgrind and fixed any errors I found. This turned
out to be just some uninitialized buffers in test programs. The
fragments of uninitialized data aren't particularly important, but we
might as well squash the valgrind warnings, so that future valgrind
errors will stand out.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
At present, both the grammar and our internal data structures mean
that there can be only one label on a node or property. This is a
fairly arbitrary constraint, given that any number of value labels can
appear at the same point, and that in C you can have any number of
labels on the same statement.
This is pretty much a non-issue now, but it may become important with
some of the extensions that Grant and I have in mind. It's not that
hard to change, so this patch does so, allowing an arbitrary number of
labels on any given node or property. As usual a testcase is added
too.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
The only purpose of the dtc_references_dts0 testcase was to check
handling of references in the old dts v0 syntax. Since we no longer
support the old syntax, and the references_dts0.dts has been converted
to the new format, it's entirely redundant. This patch removes it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, nothing will stop you from re-using the same label string
multiple times in a dts, e.g.:
/ {
samelabel: prop1 = "foo";
samelabel: prop2 = "bar";
};
or
/ {
samelabel: prop1 = "foo";
samelabel: subnode {
};
};
When using node references by label, this could lead to confusing
results (with no warning), and in -Oasm mode will result in output
which the assembler will complain about (since it too will have
duplicate labels).
This patch, therefore, adds code to checks.c to give errors if you
attempt to re-use the same label. It treats all labels (node,
property, and value) as residing in the same namespace, since the
assembler will treat them so for -Oasm mode.
Testcases for the new code are also added.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, when in -Idts -Odtb or -Ifs -Odtb modes, dtc always
defaults to using 0 as the value for the boot_cpuid_phys header field.
That's correct quite often, but there are some systems where there is
no CPU with hardware ID of 0, or where we don't want to use the CPU
with hardware ID 0 at all (e.g. for AMP-style partitioning). The only
way to override this default currently, is with the -b command line
option.
This patch improves dtc to instead base the default boot_cpuid_phys
value on the reg property of the first listed subnode of /cpus. This
means that dtc will get boot_cpuid_phys correct by default in a
greater proportion of cases (since the boot cpu is usually listed
first, and this way at least the boot_cpuid_phys default will match
some existing cpu node). If the node doesn't exist or has an invalid
'reg' property (missing or not 4 bytes in length), then
boot_cpuid_phys is set to 0.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, the Linux kernel, libfdt and dtc, when using flattened
device trees encode a node's phandle into a property named
"linux,phandle". The ePAPR specification, however - aiming as it is
to not be a Linux specific spec - requires that phandles be encoded in
a property named simply "phandle".
This patch adds support for this newer approach to dtc and libfdt.
Specifically:
- fdt_get_phandle() will now return the correct phandle if it
is supplied in either of these properties
- fdt_node_offset_by_phandle() will correctly find a node with
the given phandle encoded in either property.
- By default, when auto-generating phandles, dtc will encode
it into both properties for maximum compatibility. A new -H
option allows either only old-style or only new-style
properties to be generated.
- If phandle properties are explicitly supplied in the dts
file, dtc will not auto-generate ones in the alternate format.
- If both properties are supplied, dtc will check that they
have the same value.
- Some existing testcases are updated to use a mix of old and
new-style phandles, partially testing the changes.
- A new phandle_format test further tests the libfdt support,
and the -H option.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
I've just tested building dtc as an x86_64 binary on a 32-bit i386
host by using:
make CC="gcc -m64"
This patch fixes a handful of minor bugs thus discovered:
* There is a printf() type mismatch on 64-bit in value-labels.c
* For the tests which use libdl, we were using the GNU make feature
where it will find libdl.so given a dependency in the form '-ldl'.
But this built-in make logic doesn't know we're compiling 64-bit so
finds the 32-bit version of the library. We avoid using this and
instead explicitly pass -ldl to CC, which being the 64-bit version
does know where to look.
* To process dtc's asm output into .so files, run_tests.sh was
directly invoking the (default instance of) the assembler and linker.
Instead invoke these via the CC driver, and allow that to be overriden
from the make environment.
* The x86_64 assembler doesn't 0 fill with the .balign directive
(presumably it is NOP filling). That doesn't produce strictly
incorrect trees, but it is confusing and confounds are testcases which
do byte-by-byte comparison of the trees produced by asm output with
direct dtb output (which does 0 pad where necessary, of course). This
patch uses the optional second argument to .balign to force gas to
zero-fill instead.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
In one section, the run_tests script attempts to use the -e (interpret
escapes) option to echo. This option is not portable - for example
the echo built into dash, now the default /bin/sh on several
distributions does not support it and will just echo "-e" literally.
Since we don't actually use any of the escapes that -e enables, this
patch simply removes it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
When in -Odts mode, dtc will not produce correct output for
string-like properties which have more than one \0 character at the
end of the property's bytestring. In fact, it generates output which
is not syntactically correct. This patch fixes the bug, and adds a
testcase for future regressions here.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a testcase using asm output mode to check that labels
within property values are correctly processed.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds some testcases for dtc's -Oasm mode. Specifically it
checks that building the asm will result in the same device tree blob
in memory as -Odtb mode would produce, for a variety of trees. This
test uncovered two difficulties with our current -Oasm output, both of
which are addressed in this patch as well.
First, -Oasm output would only be correct if assembled for a
big-endian target. Usually that would be the case, when building
device trees into a firmware or similar. However this makes life
inconvenient for testing on a little-endian target, and one can think
up use cases where a program running on a little endian host might
want to embed a device tree for a big-endian target. This patch
therefore changes -Oasm output to use .byte directives instead of
.long throughout in order to generate byte-for-byte identical trees
regardless of the endianness of the assembler target.
Second, -Oasm output emitted several #define statements which were
then used in the innards of the output - i.e. it assumed the output
would be processed by cpp before being assembled. That may not be
convenient in all build environments, and in any case doesn't work
well with the above fix. So, -Oasm output no longer needs to be
preprocessed before assembling.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Build a libfdt shared library in addition to the existing .a that is
created. Symbol versioning is used from the libfdt/version.lds script.
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Currently, dtc will generate phandles for nodes which are referenced
elsewhere in the tree. phandles can also be explicitly assigned by
defining the linux,phandle property. However, there is no way,
currently to tell dtc to generate a phandle for a node if it is not
referenced elsewhere. This is inconvenient when it's expected that
later processing on the flat tree might add nodes which _will_
the node in question.
One way one might attempt to do this is with the construct:
mynode: mynode {
linux,phandle = <&mynode>;
/* ... */
};
Though it's a trifle odd, there's really only one sensible meaning
which can be assigned to this construct: allocate a unique phandle to
"mynode" and put that in its linux,phandle property (as always).
Currently, however, dtc will choke on this self-reference. This patch
corrects this, making the construct above give the expected results.
It also ensures a more meaningful error message is given if you
attempt to process the nonsensical construct:
mynode: mynode {
linux,phandle = <&someothernode>;
/* ... */
};
The 'references' testcase is extended to cover this case, as well.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
There's currently an off-by-one bug in fdt_subnode_offset_namelen()
which causes it to keep searching after it's finished the subnodes of
the given parent, and into the subnodes of siblings of the original
node which come after it in the tree.
This patch fixes the bug. It also extends the subnode_offset testcase
(updating all of the 'test_tree1' example trees in the process) to
catch it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Now that all in-kernel-tree DTS files are properly /dts-v1/,
remove direct support for the older, un-numbered DTS
source file format.
Convert existing tests to /dts-v1/ and remove support
for the conversion tests themselves.
For now, though, the conversion tool still exists.
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Follows the model of the existing sub-Makefiles for dtc.
Adjust $(BIN) definition to represent installable bin programs
and use it as the list of installed programs rather than using
an enumerated list in the install target.
Adjust the tests/Makefile to clean up properly still.
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Kumar has already added alias expansion to fdt_path_offset().
However, in some circumstances it may be convenient for the user of
libfdt to explicitly get the string expansion of an alias. This patch
adds a function to do this, fdt_get_alias(), and uses it to implement
fdt_path_offset().
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
The current implementation of fdt_get_path() has a couple of bugs,
fixed by this patch.
First, contrary to its documentation, on success it returns the length
of the node's path, rather than 0. The testcase is correspondingly
wrong, and the patch fixes this as well.
Second, in some circumstances, it will return -FDT_ERR_BADOFFSET
instead of -FDT_ERR_NOSPACE when given insufficient buffer space.
Specifically this happens when there is insufficient space even to
hold the path's second last component. This behaviour is corrected,
and the testcase updated to check it.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
If the path doesn't start with '/' check to see if it matches some alias
under "/aliases" and substitute the matching alias value in the path
and retry the lookup.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
This patch marks various functions not shared between c files
'static', as they should be. There are a couple of functions in dtc,
and many in the testsuite.
This is *almost* enough to enable the -Wmissing-prototypes warning.
It's not quite enough, because there's a mess of junk in the flex
generated code which triggers that warning which I'm not yet sure how
to deal with.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adjusts the testsuite to run most of the tests for the tree
checking code on input in dtb form as well as dts form. Some checks
which only make sense for dts input (like reference handling) are
excluded, as are those which currently take dtb input because they
rely on things which cannot be lexically constructed in a dts file.
This shows up two small bugs in dtc, which are also corrected.
First, the name_properties test which was is supposed to remove
correctly formed 'name' properties (because they can be reconstructed
from tne node name) was instead removing 'name' properties even if
they weren't correct.
Secondly, when using dtb or fs input, the runtime tree in dtc did not
have the parent pointer initialized propertly because.built
internally. The appropriate initialization is added to the
add_child() function.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch turns on the -Wpointer-arith option in the dtc Makefile,
and fixes the resulting warnings due to using (void *) in pointer
arithmetic. While convenient, pointer arithmetic on void * is not
portable, so it's better that we avoid it, particularly in libfdt.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
I've recently worked with a FreeBSD developer, getting dtc and libfdt
working on FreeBSD. This showed up a number of portability problems
in the dtc package which this patch addresses. Changes are as
follows:
- the parent_offset and supernode_atdepth_offset testcases
used the glibc extension functions strchrnul() and strndupa(). Those
are removed, using slightly longer coding with standard C functions
instead.
- some other testcases had a #define _GNU_SOURCE for no
particular reason. This is removed.
- run_tests.sh has bash specific constructs removed, and the
interpreter changed to /bin/sh. This apparently now runs fine on
FreeBSD's /bin/sh, and I've also tested it with both ash and dash.
- convert-dtsv0-lexer.l has some extra #includes added. These
must have been included indirectly with Linux and glibc, but aren't on
FreeBSD.
- the endian handling functions in libfdt_env.h, based on
endian.h and byteswap.h are replaced with some portable open-coded
versions. Unfortunately, these result in fairly crappy code when
compiled, but as far as I can determine there doesn't seem to be any
POSIX, SUS or de facto standard way of determining endianness at
compile time, nor standard names for byteswapping functions.
- some more endian handling, from testdata.h using the
problematic endian.h is simply removed, since it wasn't actually being
used anyway.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a testcase for the /include/ directive. It assembles
a sample dts file with many /include/ directives at a variety of
different lexical / grammatical contexts.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
On Wed, Jun 04, 2008 at 09:26:23AM -0500, Jon Loeliger wrote:
> David Gibson wrote:
>
>> But as I said that can be dealt with in the future without breaking
>> compatibility. Objection withdrawn.
>>
>
> And on that note, I officially implore Scott to
> re-submit his binary include patch!
Scott's original patch does still have some implementation details I
didn't like. So in the interests of saving time, I've addressed some
of those, added a testcase, and and now resubmitting my revised
version of Scott's patch.
dtc: Add support for binary includes.
A property's data can be populated with a file's contents
as follows:
node {
prop = /incbin/("path/to/data");
};
A subset of a file can be included by passing start and size parameters.
For example, to include bytes 8 through 23:
node {
prop = /incbin/("path/to/data", 8, 16);
};
As with /include/, non-absolute paths are looked for in the directory
of the source file that includes them.
Implementation revised, and a testcase added by David Gibson
Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Scott Wood <scottwood@freescale.com>
This patch adds an extra testcase to dtc to ensure that the
"reg_format" and "ranges_format" checks trigger as they should if a
'reg' or 'ranges' property appears in the root node.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, dtc generates a few gcc build warnings if built for a
64-bit target, due to the altered type of uint64_t and size_t. This
patch fixes the warnings (without generating new warnings for 32-bit).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Some of the helper scripts used to run testcases contain some
constructs that are bashisms. Or at least which don't work on dash,
the minimal shell used as /bin/sh on recent Ubuntu systems.
This patch removes these constructs so that the testsuite will pass
"out of the box" on systems where /bin/sh is dash.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds a new utility program, convert-dtsv0, to the dtc
sources. This program will convert dts files from v0 to v1,
preserving comments and spacing. It also includes some heuristics to
guess an appropriate base to use in the v1 output (so it will use hex
for the contents of reg properties and decimal for clock-frequency
properties, for example). They're limited and imperfect, but not
terrible.
The guts of the converter program is a modified version of the lexer
from dtc itself.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently, dtc will put the nonsense value 0xfeedbeef into the
boot_cpuid_phys field of an output blob, unless explicitly given
another value with the -b command line option. As well as being a
totally unuseful default value, this also means that dtc won't
properly preserve the boot_cpuid_phys field in -I dtb -O dtb mode.
This patch reworks things to improve the boot_cpuid handling. The new
semantics are that the output's boot_cpuid_phys value is:
the value given on the command line if -b is used
otherwise
the value from the input, if in -I dtb mode
otherwise
0
Implementation-wise we do the following:
- boot_cpuid_phys is added to struct boot_info, so that
structure now contains all of the blob's semantic information.
- dt_to_blob() and dt_to_asm() output the cpuid given in
boot_info
- dt_from_blob() fills in boot_info based on the input blob
- The other dt_from_*() functions just record 0, but we can
change this easily if e.g. we invent a way of specifying the boot cpu
in the source format.
- main() overrides the cpuid in the boot_info between input
and output if -b is given
We add some testcases to check this new behaviour.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Currently the Makefile.dtc and Makefile.libfdt fragments include a
number of things that seemed like they might be useful for other
projects embedding the pieces, or for a make dist target.
Well, we have no make dist target, it's become fairly unclear that
these things would actually be useful to embedders (the kernel
certainly doesn't use them), and it's a bunch of stuff with no current
users.
This patch, therefore, removes a bunch of unused definitions from the
Makefile fragments. It also removes a dependency declared in
Makefile.libfdt (of libfdt.a on the constituent .o files) which was
incorrect (wrong path), and if corrected would be redundant with the
similar dependency in the top-level makefile.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This patch adds some testcases checking corner cases of dtc's input
file handling. Specifically it checks that dtc works correctly when
given input via stdin, and it checks that dtc fails gracefully if
given a nonexistent input file (or directory, in the case of -Ifs
mode).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>