Message ID | 1520317081-5341-1-git-send-email-thuth@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
On 03/06/2018 07:18 AM, Thomas Huth wrote: > bootmap.h can currently only be included once - otherwise the linker > complains about multiple definitions of the "magic" strings. It's a > bad style to define string arrays in header files, so let's better > move these to the bootmap.c file instead where they are used. > > Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- > v2: > - Removed duplicated vol_desc_magic (copy-n-paste error) > > pc-bios/s390-ccw/bootmap.c | 20 ++++++++++++++++++++ > pc-bios/s390-ccw/bootmap.h | 19 ------------------- > 2 files changed, 20 insertions(+), 19 deletions(-) > > diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c > index 29bfd8c..fc2a9fe 100644 > --- a/pc-bios/s390-ccw/bootmap.c > +++ b/pc-bios/s390-ccw/bootmap.c > @@ -37,6 +37,26 @@ typedef struct ResetInfo { > > static ResetInfo save; > > +const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" > + "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; > + > +/* > + * Match two CCWs located after PSW and eight filler bytes. > + * From libmagic and arch/s390/kernel/head.S. > + */ > +const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00" > + "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40" > + "\x40\x40\x40\x40"; > + > +static inline bool is_iso_vd_valid(IsoVolDesc *vd) > +{ > + const uint8_t vol_desc_magic[] = "CD001"; > + > + return !memcmp(&vd->ident[0], vol_desc_magic, 5) && > + vd->version == 0x1 && > + vd->type <= VOL_DESC_TYPE_PARTITION; > +} > + > static void jump_to_IPL_2(void) > { > ResetInfo *current = 0; > diff --git a/pc-bios/s390-ccw/bootmap.h b/pc-bios/s390-ccw/bootmap.h > index c636626..07eb600 100644 > --- a/pc-bios/s390-ccw/bootmap.h > +++ b/pc-bios/s390-ccw/bootmap.h > @@ -375,9 +375,6 @@ static inline void read_iso_boot_image(uint32_t block_offset, void *load_addr, > "Failed to read boot image!"); > } > > -const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" > - "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; > - > #define ISO9660_MAX_DIR_DEPTH 8 > > typedef struct IsoDirHdr { > @@ -430,20 +427,12 @@ typedef struct IsoVolDesc { > } vd; > } __attribute__((packed)) IsoVolDesc; > > -const uint8_t vol_desc_magic[] = "CD001"; > #define VOL_DESC_TYPE_BOOT 0 > #define VOL_DESC_TYPE_PRIMARY 1 > #define VOL_DESC_TYPE_SUPPLEMENT 2 > #define VOL_DESC_TYPE_PARTITION 3 > #define VOL_DESC_TERMINATOR 255 > > -static inline bool is_iso_vd_valid(IsoVolDesc *vd) > -{ > - return !memcmp(&vd->ident[0], vol_desc_magic, 5) && > - vd->version == 0x1 && > - vd->type <= VOL_DESC_TYPE_PARTITION; > -} > - > typedef struct IsoBcValid { > uint8_t platform_id; > uint16_t reserved; > @@ -468,14 +457,6 @@ typedef struct IsoBcHdr { > uint8_t id[28]; > } __attribute__((packed)) IsoBcHdr; > > -/* > - * Match two CCWs located after PSW and eight filler bytes. > - * From libmagic and arch/s390/kernel/head.S. > - */ > -const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00" > - "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40" > - "\x40\x40\x40\x40"; > - > typedef struct IsoBcEntry { > uint8_t id; > union { >
On Tue, 6 Mar 2018 07:18:01 +0100 Thomas Huth <thuth@redhat.com> wrote: > bootmap.h can currently only be included once - otherwise the linker > complains about multiple definitions of the "magic" strings. It's a > bad style to define string arrays in header files, so let's better > move these to the bootmap.c file instead where they are used. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > v2: > - Removed duplicated vol_desc_magic (copy-n-paste error) > > pc-bios/s390-ccw/bootmap.c | 20 ++++++++++++++++++++ > pc-bios/s390-ccw/bootmap.h | 19 ------------------- > 2 files changed, 20 insertions(+), 19 deletions(-) Thanks, applied (without rebuild as this is no functional change).
On 03/06/2018 12:18 AM, Thomas Huth wrote: > bootmap.h can currently only be included once - otherwise the linker > complains about multiple definitions of the "magic" strings. My first thought when reading that was "Huh? bootmap.h has a proper[*] double-inclusion header guard, and therefore a second #include "bootmap.h" is a no-op - so how can including the header more than once cause a linker complaint?" [*] Well, proper if you overlook the fact that the name _PC_BIOS_S390_CCW_BOOTMAP_H starts with a leading underscore followed by uppercase, and is therefore violating namespace safety rules, as it could collide with a symbol reserved for the implementation > It's a > bad style to define string arrays in header files, so let's better > move these to the bootmap.c file instead where they are used. But I finally figured out what you really meant: if more than one .c file each include the header (and not my initial reading of a single .c file including the header more than once), then since the header was declaring non-static top-level variables, that does indeed cause linker errors. > > Signed-off-by: Thomas Huth <thuth@redhat.com> > --- > v2: > - Removed duplicated vol_desc_magic (copy-n-paste error) > > pc-bios/s390-ccw/bootmap.c | 20 ++++++++++++++++++++ > pc-bios/s390-ccw/bootmap.h | 19 ------------------- > 2 files changed, 20 insertions(+), 19 deletions(-) Your change is fine (moving the declaration into the one .c file that needs them), so no need to change this, but... > +++ b/pc-bios/s390-ccw/bootmap.h > @@ -375,9 +375,6 @@ static inline void read_iso_boot_image(uint32_t block_offset, void *load_addr, > "Failed to read boot image!"); > } > > -const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" > - "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; ...would adding 'static' here also solved the linker error (at the risk of possibly causing a compiler warning/error about unused variable)?
On 08.03.2018 00:11, Eric Blake wrote: > On 03/06/2018 12:18 AM, Thomas Huth wrote: >> bootmap.h can currently only be included once - otherwise the linker >> complains about multiple definitions of the "magic" strings. > > My first thought when reading that was "Huh? bootmap.h has a proper[*] > double-inclusion header guard, and therefore a second #include > "bootmap.h" is a no-op - so how can including the header more than once > cause a linker complaint?" Sorry if the description was not precise enough ... but I think it's clear if you think about it twice ;-) > [*] Well, proper if you overlook the fact that the name > _PC_BIOS_S390_CCW_BOOTMAP_H starts with a leading underscore followed by > uppercase, and is therefore violating namespace safety rules, as it > could collide with a symbol reserved for the implementation Yeah, we've got a couple of these left. I recently added a task to the BiteSizedTasks page to clean those up. > Your change is fine (moving the declaration into the one .c file that > needs them), so no need to change this, but... > >> +++ b/pc-bios/s390-ccw/bootmap.h >> @@ -375,9 +375,6 @@ static inline void read_iso_boot_image(uint32_t >> block_offset, void *load_addr, >> "Failed to read boot image!"); >> } >> -const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" >> - "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; > > ...would adding 'static' here also solved the linker error (at the risk > of possibly causing a compiler warning/error about unused variable)? Yes, we would likely get a warning about unused variable instead, so that's not a real option. Thomas
diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c index 29bfd8c..fc2a9fe 100644 --- a/pc-bios/s390-ccw/bootmap.c +++ b/pc-bios/s390-ccw/bootmap.c @@ -37,6 +37,26 @@ typedef struct ResetInfo { static ResetInfo save; +const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" + "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; + +/* + * Match two CCWs located after PSW and eight filler bytes. + * From libmagic and arch/s390/kernel/head.S. + */ +const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00" + "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40" + "\x40\x40\x40\x40"; + +static inline bool is_iso_vd_valid(IsoVolDesc *vd) +{ + const uint8_t vol_desc_magic[] = "CD001"; + + return !memcmp(&vd->ident[0], vol_desc_magic, 5) && + vd->version == 0x1 && + vd->type <= VOL_DESC_TYPE_PARTITION; +} + static void jump_to_IPL_2(void) { ResetInfo *current = 0; diff --git a/pc-bios/s390-ccw/bootmap.h b/pc-bios/s390-ccw/bootmap.h index c636626..07eb600 100644 --- a/pc-bios/s390-ccw/bootmap.h +++ b/pc-bios/s390-ccw/bootmap.h @@ -375,9 +375,6 @@ static inline void read_iso_boot_image(uint32_t block_offset, void *load_addr, "Failed to read boot image!"); } -const uint8_t el_torito_magic[] = "EL TORITO SPECIFICATION" - "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"; - #define ISO9660_MAX_DIR_DEPTH 8 typedef struct IsoDirHdr { @@ -430,20 +427,12 @@ typedef struct IsoVolDesc { } vd; } __attribute__((packed)) IsoVolDesc; -const uint8_t vol_desc_magic[] = "CD001"; #define VOL_DESC_TYPE_BOOT 0 #define VOL_DESC_TYPE_PRIMARY 1 #define VOL_DESC_TYPE_SUPPLEMENT 2 #define VOL_DESC_TYPE_PARTITION 3 #define VOL_DESC_TERMINATOR 255 -static inline bool is_iso_vd_valid(IsoVolDesc *vd) -{ - return !memcmp(&vd->ident[0], vol_desc_magic, 5) && - vd->version == 0x1 && - vd->type <= VOL_DESC_TYPE_PARTITION; -} - typedef struct IsoBcValid { uint8_t platform_id; uint16_t reserved; @@ -468,14 +457,6 @@ typedef struct IsoBcHdr { uint8_t id[28]; } __attribute__((packed)) IsoBcHdr; -/* - * Match two CCWs located after PSW and eight filler bytes. - * From libmagic and arch/s390/kernel/head.S. - */ -const uint8_t linux_s390_magic[] = "\x02\x00\x00\x18\x60\x00\x00\x50\x02\x00" - "\x00\x68\x60\x00\x00\x50\x40\x40\x40\x40" - "\x40\x40\x40\x40"; - typedef struct IsoBcEntry { uint8_t id; union {
bootmap.h can currently only be included once - otherwise the linker complains about multiple definitions of the "magic" strings. It's a bad style to define string arrays in header files, so let's better move these to the bootmap.c file instead where they are used. Signed-off-by: Thomas Huth <thuth@redhat.com> --- v2: - Removed duplicated vol_desc_magic (copy-n-paste error) pc-bios/s390-ccw/bootmap.c | 20 ++++++++++++++++++++ pc-bios/s390-ccw/bootmap.h | 19 ------------------- 2 files changed, 20 insertions(+), 19 deletions(-)