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-Wstringop-truncation warnings
- From: Alan Modra <amodra at gmail dot com>
- To: binutils at sourceware dot org
- Date: Fri, 4 May 2018 19:02:48 +0930
- Subject: -Wstringop-truncation warnings
This patch is aimed at silencing gcc8 -Wstringop-truncation warnings.
Unfortunately adding __attribute__ ((__nonstring)) doesn't work in a
number of the places patched here, (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85643) so if you have
recent glibc headers installed you'll need to configure binutils with
--disable-werror to compile using gcc8 or gcc9.
include/
* ansidecl.h: Import from gcc.
* coff/internal.h (struct internal_scnhdr): Add ATTRIBUTE_NONSTRING
to s_name.
(struct internal_syment): Add ATTRIBUTE_NONSTRING to _n_name.
bfd/
* elf-linux-core.h (struct elf_external_linux_prpsinfo32_ugid32),
(struct elf_external_linux_prpsinfo32_ugid16),
(struct elf_external_linux_prpsinfo64_ugid32),
(struct elf_external_linux_prpsinfo64_ugid16): Add ATTRIBUTE_NONSTRING
to pr_fname and pr_psargs fields. Remove GCC diagnostic pragmas.
Move comment to..
* elf.c (elfcore_write_prpsinfo): ..here. Indent nested preprocessor
directives.
* elf32-arm.c (elf32_arm_nabi_write_core_note): Add ATTRIBUTE_NONSTRING
to data.
* elf32-ppc.c (ppc_elf_write_core_note): Likewise.
* elf32-s390.c (elf_s390_write_core_note): Likewise.
* elf64-s390.c (elf_s390_write_core_note): Likewise.
* elfxx-aarch64.c (_bfd_aarch64_elf_write_core_note): Likewise.
* elf64-x86-64.c (elf_x86_64_write_core_note): Add GCC diagnostic
pragmas.
* peXXigen.c (_bfd_XXi_swap_scnhdr_out): Use strnlen to avoid
false positive gcc-8 warning.
gas/
* config/obj-evax.c (shorten_identifier): Use memcpy in place
of strncpy.
* config/obj-macho.c (obj_mach_o_make_or_get_sect): Ensure
segname and sectname fields are NUL terminated.
diff --git a/bfd/cofflink.c b/bfd/cofflink.c
index fb1696afff..6ca547ce5b 100644
--- a/bfd/cofflink.c
+++ b/bfd/cofflink.c
@@ -1839,7 +1839,7 @@ _bfd_coff_link_input_bfd (struct coff_final_link_info *flaginfo, bfd *input_bfd)
case C_FCN:
if (obj_pe (input_bfd)
- && strcmp (isym.n_name, ".bf") != 0
+ && strncmp (isym.n_name, ".bf", sizeof isym.n_name) != 0
&& isym.n_scnum > 0)
{
/* For PE, .lf and .ef get their value left alone,
diff --git a/bfd/elf-linux-core.h b/bfd/elf-linux-core.h
index fa0690320a..f0c4b2fc35 100644
--- a/bfd/elf-linux-core.h
+++ b/bfd/elf-linux-core.h
@@ -21,25 +21,6 @@
#ifndef ELF_LINUX_CORE_H
#define ELF_LINUX_CORE_H
-/* gcc-8 warns (*) on all the strncpy calls in this file about
- possible string truncation. The "truncation" is not a bug. We
- have an external representation of structs with fields that are not
- necessarily NULL terminated and corresponding internal
- representation fields that are one larger so that they can always
- be NULL terminated.
- gcc versions between 4.2 and 4.6 do not allow pragma control of
- diagnostics inside functions, giving a hard error if you try to use
- the finer control available with later versions.
- gcc prior to 4.2 warns about diagnostic push and pop.
- gcc-5, gcc-6 and gcc-7 warn that -Wstringop-truncation is unknown,
- unless you also add #pragma GCC diagnostic ignored "-Wpragma".
- (*) Depending on your system header files! */
-
-#if GCC_VERSION >= 8000
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wstringop-truncation"
-#endif
-
/* External 32-bit structure for PRPSINFO. This structure is
ABI-defined, thus we choose to use char arrays here in order to
avoid dealing with different types in different architectures.
@@ -64,8 +45,8 @@ struct elf_external_linux_prpsinfo32_ugid32
char pr_ppid[4];
char pr_pgrp[4];
char pr_sid[4];
- char pr_fname[16]; /* Filename of executable. */
- char pr_psargs[80]; /* Initial part of arg list. */
+ char pr_fname[16] ATTRIBUTE_NONSTRING; /* Filename of executable. */
+ char pr_psargs[80] ATTRIBUTE_NONSTRING; /* Initial part of arg list. */
};
/* Helper function to copy an elf_internal_linux_prpsinfo in host
@@ -116,8 +97,8 @@ struct elf_external_linux_prpsinfo32_ugid16
char pr_ppid[4];
char pr_pgrp[4];
char pr_sid[4];
- char pr_fname[16]; /* Filename of executable. */
- char pr_psargs[80]; /* Initial part of arg list. */
+ char pr_fname[16] ATTRIBUTE_NONSTRING; /* Filename of executable. */
+ char pr_psargs[80] ATTRIBUTE_NONSTRING; /* Initial part of arg list. */
};
/* Helper function to copy an elf_internal_linux_prpsinfo in host
@@ -169,8 +150,8 @@ struct elf_external_linux_prpsinfo64_ugid32
char pr_ppid[4];
char pr_pgrp[4];
char pr_sid[4];
- char pr_fname[16]; /* Filename of executable. */
- char pr_psargs[80]; /* Initial part of arg list. */
+ char pr_fname[16] ATTRIBUTE_NONSTRING; /* Filename of executable. */
+ char pr_psargs[80] ATTRIBUTE_NONSTRING; /* Initial part of arg list. */
};
/* Helper function to copy an elf_internal_linux_prpsinfo in host
@@ -222,8 +203,8 @@ struct elf_external_linux_prpsinfo64_ugid16
char pr_ppid[4];
char pr_pgrp[4];
char pr_sid[4];
- char pr_fname[16]; /* Filename of executable. */
- char pr_psargs[80]; /* Initial part of arg list. */
+ char pr_fname[16] ATTRIBUTE_NONSTRING; /* Filename of executable. */
+ char pr_psargs[80] ATTRIBUTE_NONSTRING; /* Initial part of arg list. */
};
/* Helper function to copy an elf_internal_linux_prpsinfo in host
@@ -250,8 +231,4 @@ swap_linux_prpsinfo64_ugid16_out
strncpy (to->pr_psargs, from->pr_psargs, sizeof (to->pr_psargs));
}
-#if GCC_VERSION >= 8000
-#pragma GCC diagnostic pop
-#endif
-
#endif
diff --git a/bfd/elf.c b/bfd/elf.c
index bd9ffccee6..21bc4e7ac2 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -10508,9 +10508,22 @@ elfcore_write_note (bfd *abfd,
return buf;
}
+/* gcc-8 warns (*) on all the strncpy calls in this function about
+ possible string truncation. The "truncation" is not a bug. We
+ have an external representation of structs with fields that are not
+ necessarily NULL terminated and corresponding internal
+ representation fields that are one larger so that they can always
+ be NULL terminated.
+ gcc versions between 4.2 and 4.6 do not allow pragma control of
+ diagnostics inside functions, giving a hard error if you try to use
+ the finer control available with later versions.
+ gcc prior to 4.2 warns about diagnostic push and pop.
+ gcc-5, gcc-6 and gcc-7 warn that -Wstringop-truncation is unknown,
+ unless you also add #pragma GCC diagnostic ignored "-Wpragma".
+ (*) Depending on your system header files! */
#if GCC_VERSION >= 8000
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wstringop-truncation"
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wstringop-truncation"
#endif
char *
elfcore_write_prpsinfo (bfd *abfd,
@@ -10531,16 +10544,16 @@ elfcore_write_prpsinfo (bfd *abfd,
}
#if defined (HAVE_PRPSINFO_T) || defined (HAVE_PSINFO_T)
-#if defined (HAVE_PRPSINFO32_T) || defined (HAVE_PSINFO32_T)
+# if defined (HAVE_PRPSINFO32_T) || defined (HAVE_PSINFO32_T)
if (bed->s->elfclass == ELFCLASS32)
{
-#if defined (HAVE_PSINFO32_T)
+# if defined (HAVE_PSINFO32_T)
psinfo32_t data;
int note_type = NT_PSINFO;
-#else
+# else
prpsinfo32_t data;
int note_type = NT_PRPSINFO;
-#endif
+# endif
memset (&data, 0, sizeof (data));
strncpy (data.pr_fname, fname, sizeof (data.pr_fname));
@@ -10549,15 +10562,15 @@ elfcore_write_prpsinfo (bfd *abfd,
"CORE", note_type, &data, sizeof (data));
}
else
-#endif
+# endif
{
-#if defined (HAVE_PSINFO_T)
+# if defined (HAVE_PSINFO_T)
psinfo_t data;
int note_type = NT_PSINFO;
-#else
+# else
prpsinfo_t data;
int note_type = NT_PRPSINFO;
-#endif
+# endif
memset (&data, 0, sizeof (data));
strncpy (data.pr_fname, fname, sizeof (data.pr_fname));
@@ -10571,7 +10584,7 @@ elfcore_write_prpsinfo (bfd *abfd,
return NULL;
}
#if GCC_VERSION >= 8000
-#pragma GCC diagnostic pop
+# pragma GCC diagnostic pop
#endif
char *
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index a42db44b2f..5a3b58ff0d 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -2168,7 +2168,7 @@ elf32_arm_nabi_write_core_note (bfd *abfd, char *buf, int *bufsiz,
case NT_PRPSINFO:
{
- char data[124];
+ char data[124] ATTRIBUTE_NONSTRING;
va_list ap;
va_start (ap, note_type);
diff --git a/bfd/elf32-ppc.c b/bfd/elf32-ppc.c
index 7f4ed01f20..462c8af311 100644
--- a/bfd/elf32-ppc.c
+++ b/bfd/elf32-ppc.c
@@ -2405,7 +2405,7 @@ ppc_elf_write_core_note (bfd *abfd, char *buf, int *bufsiz, int note_type, ...)
case NT_PRPSINFO:
{
- char data[128];
+ char data[128] ATTRIBUTE_NONSTRING;
va_list ap;
va_start (ap, note_type);
diff --git a/bfd/elf32-s390.c b/bfd/elf32-s390.c
index 18010c0b45..b3603bd865 100644
--- a/bfd/elf32-s390.c
+++ b/bfd/elf32-s390.c
@@ -3942,7 +3942,7 @@ elf_s390_write_core_note (bfd *abfd, char *buf, int *bufsiz,
case NT_PRPSINFO:
{
- char data[124] = { 0 };
+ char data[124] ATTRIBUTE_NONSTRING = { 0 };
const char *fname, *psargs;
va_start (ap, note_type);
diff --git a/bfd/elf64-s390.c b/bfd/elf64-s390.c
index 2d02e82c54..bfa02340ca 100644
--- a/bfd/elf64-s390.c
+++ b/bfd/elf64-s390.c
@@ -3751,7 +3751,7 @@ elf_s390_write_core_note (bfd *abfd, char *buf, int *bufsiz,
case NT_PRPSINFO:
{
- char data[136] = { 0 };
+ char data[136] ATTRIBUTE_NONSTRING = { 0 };
const char *fname, *psargs;
va_start (ap, note_type);
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index c1237bb2e4..a0ebd2cf69 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -439,6 +439,10 @@ elf_x86_64_grok_psinfo (bfd *abfd, Elf_Internal_Note *note)
}
#ifdef CORE_HEADER
+# if GCC_VERSION >= 8000
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wstringop-truncation"
+# endif
static char *
elf_x86_64_write_core_note (bfd *abfd, char *buf, int *bufsiz,
int note_type, ...)
@@ -524,6 +528,9 @@ elf_x86_64_write_core_note (bfd *abfd, char *buf, int *bufsiz,
}
/* NOTREACHED */
}
+# if GCC_VERSION >= 8000
+# pragma GCC diagnostic pop
+# endif
#endif
/* Functions for the x86-64 ELF linker. */
diff --git a/bfd/elfxx-aarch64.c b/bfd/elfxx-aarch64.c
index 08e7cd9684..45a732db2b 100644
--- a/bfd/elfxx-aarch64.c
+++ b/bfd/elfxx-aarch64.c
@@ -653,7 +653,7 @@ _bfd_aarch64_elf_write_core_note (bfd *abfd, char *buf, int *bufsiz, int note_ty
case NT_PRPSINFO:
{
- char data[136];
+ char data[136] ATTRIBUTE_NONSTRING;
va_list ap;
va_start (ap, note_type);
diff --git a/bfd/peXXigen.c b/bfd/peXXigen.c
index 32ce195a00..a62d126aff 100644
--- a/bfd/peXXigen.c
+++ b/bfd/peXXigen.c
@@ -1051,9 +1051,10 @@ _bfd_XXi_swap_scnhdr_out (bfd * abfd, void * in, void * out)
by ld --omagic, or by obcopy --writable-text. */
for (p = known_sections; p->section_name; p++)
- if (strcmp (scnhdr_int->s_name, p->section_name) == 0)
+ if (strncmp (scnhdr_int->s_name, p->section_name,
+ sizeof scnhdr_int->s_name) == 0)
{
- if (strcmp (scnhdr_int->s_name, ".text")
+ if (strncmp (scnhdr_int->s_name, ".text", sizeof scnhdr_int->s_name)
|| (bfd_get_file_flags (abfd) & WP_TEXT))
scnhdr_int->s_flags &= ~IMAGE_SCN_MEM_WRITE;
scnhdr_int->s_flags |= p->must_have;
@@ -1066,7 +1067,7 @@ _bfd_XXi_swap_scnhdr_out (bfd * abfd, void * in, void * out)
if (coff_data (abfd)->link_info
&& ! bfd_link_relocatable (coff_data (abfd)->link_info)
&& ! bfd_link_pic (coff_data (abfd)->link_info)
- && strcmp (scnhdr_int->s_name, ".text") == 0)
+ && strncmp (scnhdr_int->s_name, ".text", sizeof scnhdr_int->s_name) == 0)
{
/* By inference from looking at MS output, the 32 bit field
which is the combination of the number_of_relocs and
diff --git a/gas/config/obj-evax.c b/gas/config/obj-evax.c
index 642025f2ff..07a7067ebd 100644
--- a/gas/config/obj-evax.c
+++ b/gas/config/obj-evax.c
@@ -470,13 +470,13 @@ shorten_identifier (char *name)
newname [MAX_LABEL_LENGTH] = 0;
/* Now append the suffix of the original identifier, if any. */
if (suffix_length)
- strncpy (newname + MAX_LABEL_LENGTH - suffix_length,
- name + len - suffix_length,
- suffix_length);
- strncpy (newname + final_len, "_h", 2);
- strncpy (newname + final_len + 2 , crc_chars, 5);
- strncpy (newname + final_len + 2 + 5, encode_16 (len), 3);
- strncpy (newname + final_len + 2 + 5 + 3, encode_16 (sum), 3);
+ strncpy (newname + MAX_LABEL_LENGTH - suffix_length,
+ name + len - suffix_length,
+ suffix_length);
+ memcpy (newname + final_len, "_h", 2);
+ memcpy (newname + final_len + 2 , crc_chars, 5);
+ memcpy (newname + final_len + 2 + 5, encode_16 (len), 3);
+ memcpy (newname + final_len + 2 + 5 + 3, encode_16 (sum), 3);
if (!is_truncated_identifier (newname))
abort ();
return newname;
diff --git a/gas/config/obj-macho.c b/gas/config/obj-macho.c
index 4911907c9b..3ee98b9e5a 100644
--- a/gas/config/obj-macho.c
+++ b/gas/config/obj-macho.c
@@ -250,8 +250,10 @@ obj_mach_o_make_or_get_sect (char * segname, char * sectname,
bfd_section_name (stdoutput, sec),
bfd_errmsg (bfd_get_error ()));
- strncpy (msect->segname, segname, sizeof (msect->segname));
- strncpy (msect->sectname, sectname, sizeof (msect->sectname));
+ strncpy (msect->segname, segname, BFD_MACH_O_SEGNAME_SIZE);
+ msect->segname[BFD_MACH_O_SEGNAME_SIZE] = 0;
+ strncpy (msect->sectname, sectname, BFD_MACH_O_SECTNAME_SIZE);
+ msect->sectname[BFD_MACH_O_SECTNAME_SIZE] = 0;
msect->align = secalign;
msect->flags = sectype | secattr;
diff --git a/include/ansidecl.h b/include/ansidecl.h
index c11daffedb..406473ca9e 100644
--- a/include/ansidecl.h
+++ b/include/ansidecl.h
@@ -283,6 +283,15 @@ So instead we use the macro below and test it against specific values. */
# endif /* GNUC >= 4.9 */
#endif /* ATTRIBUTE_NO_SANITIZE_UNDEFINED */
+/* Attribute 'nonstring' was valid as of gcc 8. */
+#ifndef ATTRIBUTE_NONSTRING
+# if GCC_VERSION >= 8000
+# define ATTRIBUTE_NONSTRING __attribute__ ((__nonstring__))
+# else
+# define ATTRIBUTE_NONSTRING
+# endif
+#endif
+
/* We use __extension__ in some places to suppress -pedantic warnings
about GCC extensions. This feature didn't work properly before
gcc 2.8. */
diff --git a/include/coff/internal.h b/include/coff/internal.h
index 1879ddc0a0..a8efedb7c4 100644
--- a/include/coff/internal.h
+++ b/include/coff/internal.h
@@ -393,7 +393,7 @@ struct internal_aouthdr
struct internal_scnhdr
{
- char s_name[SCNNMLEN]; /* section name */
+ char s_name[SCNNMLEN] ATTRIBUTE_NONSTRING; /* section name */
/* Physical address, aliased s_nlib.
In the pei format, this field is the virtual section size
@@ -466,7 +466,7 @@ struct internal_syment
{
union
{
- char _n_name[SYMNMLEN]; /* old COFF version */
+ char _n_name[SYMNMLEN] ATTRIBUTE_NONSTRING; /* old COFF version */
struct
{
bfd_hostptr_t _n_zeroes; /* new == 0 */
--
Alan Modra
Australia Development Lab, IBM