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Fix string/tester.c for GCC 7 -Wstringop-overflow=.

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GCC 7 has a -Wstringop-overflow= warning that includes warning for
strncat with a size specified that is larger than the size of the
buffer (which is dubious usage, but valid at runtime if in fact there
isn't an overflow with the particular buffer contents present).
string/tester.c tests such cases; this patch arranges for this warning
to be ignored around relevant strncat calls.

Tested compilation for aarch64 (GCC mainline) with
build-many-glibcs.py; did execution testing for x86_64 (GCC 5).

	* string/tester.c (test_strncat): Disable -Wstringop-overflow=
	around tests of strncat with large sizes.
This commit is contained in:
Joseph Myers
2017-01-04 23:33:31 +00:00
parent 3d7229c250
commit 3ecd616cc1
2 changed files with 60 additions and 0 deletions
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57
string/tester.c
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@ -353,28 +353,70 @@ test_strncat (void)
mechanism. */
it = "strncat";
(void) strcpy (one, "ijk");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
check (strncat (one, "lmn", 99) == one, 1); /* Returned value. */
DIAG_POP_NEEDS_COMMENT;
equal (one, "ijklmn", 2); /* Basic test. */
(void) strcpy (one, "x");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, "yz", 99);
DIAG_POP_NEEDS_COMMENT;
equal (one, "xyz", 3); /* Writeover. */
equal (one+4, "mn", 4); /* Wrote too much? */
(void) strcpy (one, "gh");
(void) strcpy (two, "ef");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, two, 99);
DIAG_POP_NEEDS_COMMENT;
equal (one, "ghef", 5); /* Basic test encore. */
equal (two, "ef", 6); /* Stomped on source? */
(void) strcpy (one, "");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, "", 99);
DIAG_POP_NEEDS_COMMENT;
equal (one, "", 7); /* Boundary conditions. */
(void) strcpy (one, "ab");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, "", 99);
DIAG_POP_NEEDS_COMMENT;
equal (one, "ab", 8);
(void) strcpy (one, "");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, "cd", 99);
DIAG_POP_NEEDS_COMMENT;
equal (one, "cd", 9);
(void) strcpy (one, "ab");
@ -387,7 +429,14 @@ test_strncat (void)
(void) strncat (one, "gh", 2);
equal (one, "abcdgh", 12); /* Count and length equal. */
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being larger than
the size of the buffer; this is deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
(void) strncat (one, "ij", (size_t)-1); /* set sign bit in count */
DIAG_POP_NEEDS_COMMENT;
equal (one, "abcdghij", 13);
int ntest = 14;
@ -406,8 +455,16 @@ test_strncat (void)
buf1[n2 + n3] = '\0';
strcpy (buf2 + n1, "123");
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about the size passed to strncat being
larger than the size of the buffer; this is
deliberately tested here.. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Wstringop-overflow=");
#endif
check (strncat (buf1 + n2, buf2 + n1, ~((size_t) 0) - n4)
== buf1 + n2, ntest);
DIAG_POP_NEEDS_COMMENT;
if (errors == olderrors)
for (size_t i = 0; i < sizeof (buf1); ++i)
{