Re: [PATCH 01/11] tests: Fix signedness comparisons warnings

[Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org>]

On Tue, 13 Oct 2020 16:09:27 +1100
David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:

Hi,

eventually finding some time to come back to this:

> On Mon, Oct 12, 2020 at 05:19:38PM +0100, Andre Przywara wrote:
> > With -Wsign-compare, compilers warn about a mismatching signedness in
> > comparisons in various files in the tests/ directory.
> > 
> > For about half of the cases we can simply change the signed variable to
> > be of an unsigned type, because they will never need to store negative
> > values (which is the best fix of the problem).
> > 
> > In the remaining cases we can cast the signed variable to an unsigned
> > type, provided we know for sure it is not negative.
> > We see two different scenarios here:
> > - We either just explicitly checked for this variable to be positive
> >   (if (rc < 0) FAIL();), or
> > - We rely on a function returning only positive values in the "length"
> >   pointer if the function returned successfully: which we just checked.
> > 
> > At two occassions we compare with a constant "-1" (even though the
> > variable is unsigned), so we just change this to ~0U to create an
> > unsigned comparison value.
> > 
> > This fixes "make tests" (but not "make check" yet), when compiled
> > with -Wsign-compare.
> > 
> > Signed-off-by: Andre Przywara <andre.przywara-5wv7dgnIgG8@public.gmane.org>  
> 
> Oof, this is a big one.
> 
> > ---
> >  tests/dumptrees.c           | 2 +-
> >  tests/fs_tree1.c            | 2 +-
> >  tests/get_name.c            | 2 +-
> >  tests/integer-expressions.c | 2 +-
> >  tests/nopulate.c            | 3 ++-
> >  tests/overlay.c             | 2 +-
> >  tests/phandle_format.c      | 2 +-
> >  tests/property_iterate.c    | 2 +-
> >  tests/references.c          | 2 +-
> >  tests/set_name.c            | 4 ++--
> >  tests/subnode_iterate.c     | 2 +-
> >  tests/tests.h               | 2 +-
> >  tests/testutils.c           | 6 +++---
> >  13 files changed, 17 insertions(+), 16 deletions(-)
> > 
> > diff --git a/tests/dumptrees.c b/tests/dumptrees.c
> > index aecb326..49ef525 100644
> > --- a/tests/dumptrees.c
> > +++ b/tests/dumptrees.c
> > @@ -30,7 +30,7 @@ static struct {
> >  
> >  int main(int argc, char *argv[])
> >  {
> > -	int i;
> > +	unsigned int i;
> >  
> >  	if (argc != 2) {
> >  	    fprintf(stderr, "Missing output directory argument\n");
> > diff --git a/tests/fs_tree1.c b/tests/fs_tree1.c
> > index dff3880..978f6a3 100644
> > --- a/tests/fs_tree1.c
> > +++ b/tests/fs_tree1.c
> > @@ -54,7 +54,7 @@ static void mkfile(const char *name, void *data, size_t len)
> >  	rc = write(fd, data, len);
> >  	if (rc < 0)
> >  		FAIL("write(\"%s\"): %s", name, strerror(errno));
> > -	if (rc != len)
> > +	if ((unsigned)rc != len)
> >  		FAIL("write(\"%s\"): short write", name);
> >  	
> >  	rc = close(fd);
> > diff --git a/tests/get_name.c b/tests/get_name.c
> > index 5a35103..7b757ec 100644
> > --- a/tests/get_name.c
> > +++ b/tests/get_name.c
> > @@ -39,7 +39,7 @@ static void check_name(void *fdt, const char *path)
> >  		FAIL("fdt_get_name(%s) returned \"%s\" instead of \"%s\"",
> >  		     path, getname, checkname);
> >  
> > -	if (len != strlen(getname))
> > +	if ((unsigned)len != strlen(getname))
> >  		FAIL("fdt_get_name(%s) returned length %d instead of %zd",
> >  		     path, len, strlen(getname));  
> 
> So, here you're relying on fdt_get_name() returning NULL in all the
> cases where it would return a negative len.  But.. this is test code,
> so we should actually verify that, rather than just assume it, and
> fail the test if len is negative here.
> 
> > diff --git a/tests/integer-expressions.c b/tests/integer-expressions.c
> > index 6f33d81..2f164d9 100644
> > --- a/tests/integer-expressions.c
> > +++ b/tests/integer-expressions.c
> > @@ -59,7 +59,7 @@ int main(int argc, char *argv[])
> >  	void *fdt;
> >  	const fdt32_t *res;
> >  	int reslen;
> > -	int i;
> > +	unsigned int i;
> >  
> >  	test_init(argc, argv);
> >  
> > diff --git a/tests/nopulate.c b/tests/nopulate.c
> > index 2ae1753..e06a0b3 100644
> > --- a/tests/nopulate.c
> > +++ b/tests/nopulate.c
> > @@ -43,7 +43,8 @@ static int nopulate_struct(char *buf, const char *fdt)
> >  int main(int argc, char *argv[])
> >  {
> >  	char *fdt, *fdt2, *buf;
> > -	int newsize, struct_start, struct_end_old, struct_end_new, delta;
> > +	int newsize, struct_end_old, struct_end_new, delta;
> > +	unsigned int struct_start;
> >  	const char *inname;
> >  	char outname[PATH_MAX];
> >  
> > diff --git a/tests/overlay.c b/tests/overlay.c
> > index 91afa72..c96f6f2 100644
> > --- a/tests/overlay.c
> > +++ b/tests/overlay.c
> > @@ -35,7 +35,7 @@ static int fdt_getprop_u32_by_poffset(void *fdt, const char *path,
> >  		return node_off;
> >  
> >  	val = fdt_getprop(fdt, node_off, name, &len);
> > -	if (!val || (len < (sizeof(uint32_t) * (poffset + 1))))
> > +	if (!val || ((unsigned)len < (sizeof(uint32_t) * (poffset + 1))))  
> 
> 
> Likewise here, we should extend the test to explicitly verify than len
> >= 0 in the !!val case.  
> 
> >  		return -FDT_ERR_NOTFOUND;
> >  
> >  	*out = fdt32_to_cpu(*(val + poffset));
> > diff --git a/tests/phandle_format.c b/tests/phandle_format.c
> > index d00618f..0febb32 100644
> > --- a/tests/phandle_format.c
> > +++ b/tests/phandle_format.c
> > @@ -45,7 +45,7 @@ int main(int argc, char *argv[])
> >  		FAIL("fdt_path_offset(/node4): %s", fdt_strerror(n4));
> >  
> >  	h4 = fdt_get_phandle(fdt, n4);
> > -	if ((h4 == 0) || (h4 == -1))
> > +	if ((h4 == 0) || (h4 == ~0U))  
> 
> I'm wondering if we should actually add an exported (inline) function
> to libfdt to do this test, since things like this are changed in a
> couple of places through this series.

So I have this function for dtc, but this is in dtc.h, which is
internal, so not available here.
Since it's just two occasions in all of the tests, I just keep it
explicit, for simplicity.

I fixed the rest of the issues you mentioned, in this patch and all the
others. Will send an update in a jiffy.

Cheers,
Andre

> 
> >  		FAIL("/node4 has bad phandle 0x%x\n", h4);
> >  
> >  	if (phandle_format & PHANDLE_LEGACY)
> > diff --git a/tests/property_iterate.c b/tests/property_iterate.c
> > index 9a67f49..0b6af9b 100644
> > --- a/tests/property_iterate.c
> > +++ b/tests/property_iterate.c
> > @@ -23,7 +23,7 @@ static void test_node(void *fdt, int parent_offset)
> >  	uint32_t properties;
> >  	const fdt32_t *prop;
> >  	int offset, property;
> > -	int count;
> > +	unsigned int count;
> >  	int len;
> >  
> >  	/*
> > diff --git a/tests/references.c b/tests/references.c
> > index d18e722..cb1daaa 100644
> > --- a/tests/references.c
> > +++ b/tests/references.c
> > @@ -106,7 +106,7 @@ int main(int argc, char *argv[])
> >  	if ((h4 == 0x2000) || (h4 == 0x1) || (h4 == 0))
> >  		FAIL("/node4 has bad phandle, 0x%x", h4);
> >  
> > -	if ((h5 == 0) || (h5 == -1))
> > +	if ((h5 == 0) || (h5 == ~0U))
> >  		FAIL("/node5 has bad phandle, 0x%x", h5);
> >  	if ((h5 == h4) || (h5 == h2) || (h5 == h1))
> >  		FAIL("/node5 has duplicate phandle, 0x%x", h5);
> > diff --git a/tests/set_name.c b/tests/set_name.c
> > index a62cb58..cd2b9aa 100644
> > --- a/tests/set_name.c
> > +++ b/tests/set_name.c
> > @@ -39,7 +39,7 @@ static void check_set_name(void *fdt, const char *path, const char *newname)
> >  		FAIL("fdt_get_name(%s) returned \"%s\" instead of \"%s\"",
> >  		     path, getname, oldname);
> >  
> > -	if (len != strlen(getname))
> > +	if ((unsigned)len != strlen(getname))
> >  		FAIL("fdt_get_name(%s) returned length %d instead of %zd",
> >  		     path, len, strlen(getname));
> >  
> > @@ -56,7 +56,7 @@ static void check_set_name(void *fdt, const char *path, const char *newname)
> >  		FAIL("fdt_get_name(%s) returned \"%s\" instead of \"%s\"",
> >  		     path, getname, newname);
> >  
> > -	if (len != strlen(getname))
> > +	if ((unsigned)len != strlen(getname))  
> 
> Again, add explicit negative check.
> 
> >  		FAIL("fdt_get_name(%s) returned length %d instead of %zd",
> >  		     path, len, strlen(getname));
> >  }
> > diff --git a/tests/subnode_iterate.c b/tests/subnode_iterate.c
> > index 2dc9b2d..2553a51 100644
> > --- a/tests/subnode_iterate.c
> > +++ b/tests/subnode_iterate.c
> > @@ -23,7 +23,7 @@ static void test_node(void *fdt, int parent_offset)
> >  	uint32_t subnodes;
> >  	const fdt32_t *prop;
> >  	int offset;
> > -	int count;
> > +	unsigned int count;
> >  	int len;
> >  
> >  	/* This property indicates the number of subnodes to expect */
> > diff --git a/tests/tests.h b/tests/tests.h
> > index 1017366..bf8f23c 100644
> > --- a/tests/tests.h
> > +++ b/tests/tests.h
> > @@ -83,7 +83,7 @@ void cleanup(void);
> >  void check_mem_rsv(void *fdt, int n, uint64_t addr, uint64_t size);
> >  
> >  void check_property(void *fdt, int nodeoffset, const char *name,
> > -		    int len, const void *val);
> > +		    unsigned int len, const void *val);
> >  #define check_property_cell(fdt, nodeoffset, name, val) \
> >  	({ \
> >  		fdt32_t x = cpu_to_fdt32(val);			      \
> > diff --git a/tests/testutils.c b/tests/testutils.c
> > index 5e494c5..ff215fc 100644
> > --- a/tests/testutils.c
> > +++ b/tests/testutils.c
> > @@ -88,7 +88,7 @@ void check_mem_rsv(void *fdt, int n, uint64_t addr, uint64_t size)
> >  }
> >  
> >  void check_property(void *fdt, int nodeoffset, const char *name,
> > -		    int len, const void *val)
> > +		    unsigned int len, const void *val)
> >  {
> >  	const struct fdt_property *prop;
> >  	int retlen, namelen;
> > @@ -112,13 +112,13 @@ void check_property(void *fdt, int nodeoffset, const char *name,
> >  	propname = fdt_get_string(fdt, nameoff, &namelen);
> >  	if (!propname)
> >  		FAIL("Couldn't get property name: %s", fdt_strerror(namelen));
> > -	if (namelen != strlen(propname))
> > +	if ((unsigned)namelen != strlen(propname))  
> 
> 
> And here.
> >  		FAIL("Incorrect prop name length: %d instead of %zd",
> >  		     namelen, strlen(propname));
> >  	if (!streq(propname, name))
> >  		FAIL("Property name mismatch \"%s\" instead of \"%s\"",
> >  		     propname, name);
> > -	if (proplen != retlen)
> > +	if (proplen != (unsigned)retlen)  
> 
> And here.
> 
> >  		FAIL("Length retrieved for \"%s\" by fdt_get_property()"
> >  		     " differs from stored length (%d != %d)",
> >  		     name, retlen, proplen);  
>