| Message ID | 6bfa446eb7c351b5d867eb4158198231af724b11.1556650594.git.alistair.francis@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix some GCC 9 build warnings | expand |
Le 30/04/2019 à 22:09, Alistair Francis a écrit : > Fix this warning when building with GCC9 on Fedora 30: > In function ‘strncpy’, > inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, > inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, > inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: > /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] > 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > --- > linux-user/elfload.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > index c1a26021f8..cbb7fc10fa 100644 > --- a/linux-user/elfload.c > +++ b/linux-user/elfload.c > @@ -3206,7 +3206,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) /* * Using strncpy here is fine: at max-length, > * this field is not NUL-terminated. > */> (void) strncpy(psinfo->pr_fname, base_filename, > - sizeof(psinfo->pr_fname)); > + sizeof(psinfo->pr_fname) - 1); Read the comment above :) > > g_free(base_filename); > bswap_psinfo(psinfo); > @@ -3389,7 +3389,7 @@ static int fill_note_info(struct elf_note_info *info, > sizeof (*info->prstatus), info->prstatus); > fill_psinfo(info->psinfo, ts); > fill_note(&info->notes[1], "CORE", NT_PRPSINFO, > - sizeof (*info->psinfo), info->psinfo); > + sizeof(*info->psinfo) - 1, info->psinfo); Why? > fill_auxv_note(&info->notes[2], ts); > info->numnote = 3; > > Thanks, Laurent
On Tue, Apr 30, 2019 at 1:36 PM Laurent Vivier <laurent@vivier.eu> wrote: > > Le 30/04/2019 à 22:09, Alistair Francis a écrit : > > Fix this warning when building with GCC9 on Fedora 30: > > In function ‘strncpy’, > > inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, > > inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, > > inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: > > /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] > > 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > Signed-off-by: Alistair Francis <alistair.francis@wdc.com> > > --- > > linux-user/elfload.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/linux-user/elfload.c b/linux-user/elfload.c > > index c1a26021f8..cbb7fc10fa 100644 > > --- a/linux-user/elfload.c > > +++ b/linux-user/elfload.c > > @@ -3206,7 +3206,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) > > /* > * Using strncpy here is fine: at max-length, > > * this field is not NUL-terminated. > > */> (void) strncpy(psinfo->pr_fname, base_filename, > > - sizeof(psinfo->pr_fname)); > > + sizeof(psinfo->pr_fname) - 1); > > Read the comment above :) GCC can't read the comment though. The only other option I can think of is using a pragma, which I avoided using unless I had to. Would you prefer a pragma here? Or do you have a better solution? > > > > > g_free(base_filename); > > bswap_psinfo(psinfo); > > @@ -3389,7 +3389,7 @@ static int fill_note_info(struct elf_note_info *info, > > sizeof (*info->prstatus), info->prstatus); > > fill_psinfo(info->psinfo, ts); > > fill_note(&info->notes[1], "CORE", NT_PRPSINFO, > > - sizeof (*info->psinfo), info->psinfo); > > + sizeof(*info->psinfo) - 1, info->psinfo); > > Why? Same issue as above. Alistair > > > fill_auxv_note(&info->notes[2], ts); > > info->numnote = 3; > > > > > > Thanks, > Laurent
Le 30/04/2019 à 23:01, Alistair Francis a écrit : > On Tue, Apr 30, 2019 at 1:36 PM Laurent Vivier <laurent@vivier.eu> wrote: >> >> Le 30/04/2019 à 22:09, Alistair Francis a écrit : >>> Fix this warning when building with GCC9 on Fedora 30: >>> In function ‘strncpy’, >>> inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, >>> inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, >>> inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: >>> /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] >>> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); >>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> >>> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> >>> --- >>> linux-user/elfload.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c >>> index c1a26021f8..cbb7fc10fa 100644 >>> --- a/linux-user/elfload.c >>> +++ b/linux-user/elfload.c >>> @@ -3206,7 +3206,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) >> >> /* >> * Using strncpy here is fine: at max-length, >>> * this field is not NUL-terminated. >>> */> (void) strncpy(psinfo->pr_fname, base_filename, >>> - sizeof(psinfo->pr_fname)); >>> + sizeof(psinfo->pr_fname) - 1); >> >> Read the comment above :) > > GCC can't read the comment though. The only other option I can think > of is using a pragma, which I avoided using unless I had to. Would you > prefer a pragma here? Or do you have a better solution? > perhaps: memcpy(psinfo->pr_fname, base_filename, MIN(strlen(base_filename) + 1, sizeof(psinfo->pr_fname)); ? Thanks, Laurent
On 4/30/19 4:01 PM, Alistair Francis wrote: > On Tue, Apr 30, 2019 at 1:36 PM Laurent Vivier <laurent@vivier.eu> wrote: >> >> Le 30/04/2019 à 22:09, Alistair Francis a écrit : >>> Fix this warning when building with GCC9 on Fedora 30: >>> In function ‘strncpy’, >>> inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, >>> inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, >>> inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: >>> /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] >>> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); >>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> >> /* >> * Using strncpy here is fine: at max-length, >>> * this field is not NUL-terminated. >>> */> (void) strncpy(psinfo->pr_fname, base_filename, >>> - sizeof(psinfo->pr_fname)); >>> + sizeof(psinfo->pr_fname) - 1); >> >> Read the comment above :) > > GCC can't read the comment though. The only other option I can think > of is using a pragma, which I avoided using unless I had to. Would you > prefer a pragma here? Or do you have a better solution? psinfo is struct target_elf_prpsinfo, which we declare. Why not just use the QEMU_NONSTRING attribute in the declaration, to tell the compiler our exact intents (untested, but something like this): diff --git i/linux-user/elfload.c w/linux-user/elfload.c index c1a26021f8d..6ebb2eeb957 100644 --- i/linux-user/elfload.c +++ w/linux-user/elfload.c @@ -2872,7 +2872,7 @@ struct target_elf_prpsinfo { target_gid_t pr_gid; target_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; /* Lots missing */ - char pr_fname[16]; /* filename of executable */ + char pr_fname[16] QEMU_NONSTRING; /* filename of executable */ char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ };
On Tue, Apr 30, 2019 at 2:10 PM Eric Blake <eblake@redhat.com> wrote: > > On 4/30/19 4:01 PM, Alistair Francis wrote: > > On Tue, Apr 30, 2019 at 1:36 PM Laurent Vivier <laurent@vivier.eu> wrote: > >> > >> Le 30/04/2019 à 22:09, Alistair Francis a écrit : > >>> Fix this warning when building with GCC9 on Fedora 30: > >>> In function ‘strncpy’, > >>> inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, > >>> inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, > >>> inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: > >>> /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] > >>> 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); > >>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > >>> > > >> /* > >> * Using strncpy here is fine: at max-length, > >>> * this field is not NUL-terminated. > >>> */> (void) strncpy(psinfo->pr_fname, base_filename, > >>> - sizeof(psinfo->pr_fname)); > >>> + sizeof(psinfo->pr_fname) - 1); > >> > >> Read the comment above :) > > > > GCC can't read the comment though. The only other option I can think > > of is using a pragma, which I avoided using unless I had to. Would you > > prefer a pragma here? Or do you have a better solution? > > psinfo is struct target_elf_prpsinfo, which we declare. Why not just > use the QEMU_NONSTRING attribute in the declaration, to tell the > compiler our exact intents (untested, but something like this): > > diff --git i/linux-user/elfload.c w/linux-user/elfload.c > index c1a26021f8d..6ebb2eeb957 100644 > --- i/linux-user/elfload.c > +++ w/linux-user/elfload.c > @@ -2872,7 +2872,7 @@ struct target_elf_prpsinfo { > target_gid_t pr_gid; > target_pid_t pr_pid, pr_ppid, pr_pgrp, pr_sid; > /* Lots missing */ > - char pr_fname[16]; /* filename of executable */ > + char pr_fname[16] QEMU_NONSTRING; /* filename of > executable */ > char pr_psargs[ELF_PRARGSZ]; /* initial part of arg list */ > }; I didn't know about that property, that fixes it. Alistair > > > > > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3226 > Virtualization: qemu.org | libvirt.org >
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index c1a26021f8..cbb7fc10fa 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -3206,7 +3206,7 @@ static int fill_psinfo(struct target_elf_prpsinfo *psinfo, const TaskState *ts) * this field is not NUL-terminated. */ (void) strncpy(psinfo->pr_fname, base_filename, - sizeof(psinfo->pr_fname)); + sizeof(psinfo->pr_fname) - 1); g_free(base_filename); bswap_psinfo(psinfo); @@ -3389,7 +3389,7 @@ static int fill_note_info(struct elf_note_info *info, sizeof (*info->prstatus), info->prstatus); fill_psinfo(info->psinfo, ts); fill_note(&info->notes[1], "CORE", NT_PRPSINFO, - sizeof (*info->psinfo), info->psinfo); + sizeof(*info->psinfo) - 1, info->psinfo); fill_auxv_note(&info->notes[2], ts); info->numnote = 3;
Fix this warning when building with GCC9 on Fedora 30: In function ‘strncpy’, inlined from ‘fill_psinfo’ at /home/alistair/qemu/linux-user/elfload.c:3208:12, inlined from ‘fill_note_info’ at /home/alistair/qemu/linux-user/elfload.c:3390:5, inlined from ‘elf_core_dump’ at /home/alistair/qemu/linux-user/elfload.c:3539:9: /usr/include/bits/string_fortified.h:106:10: error: ‘__builtin_strncpy’ specified bound 16 equals destination size [-Werror=stringop-truncation] 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Alistair Francis <alistair.francis@wdc.com> --- linux-user/elfload.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)