[libvirt] [RFC] virfile: fix cast-align error
Use the correct type in order to fix the following error on s390x: In function 'virFileIsSharedFSType': ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type); Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..832d832696d5 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3466,7 +3466,7 @@ int virFilePrintf(FILE *fp, const char *msg, ...) static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + unsigned int *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3575,7 @@ virFileIsSharedFSType(const char *path, if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type); } VIR_DEBUG("Check if path %s with FS magic %lld is shared", -- 2.17.0
Marc Hartmayer <mhartmay@linux.ibm.com> [2018-10-08, 08:41PM +0200]:
Use the correct type in order to fix the following error on s390x:
In function 'virFileIsSharedFSType': ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..832d832696d5 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3466,7 +3466,7 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + unsigned int *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3575,7 @@ virFileIsSharedFSType(const char *path,
if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type); }
Using an unsigned int is fine as per statfs(2): NOTES The __fsword_t type used for various fields in the statfs structure defini‐ tion is a glibc internal type, not intended for public use. This leaves the programmer in a bit of a conundrum when trying to copy or compare these fields to local variables in a program. Using unsigned int for such vari‐ ables suffices on most systems. I would prefer an explicit cast though.
VIR_DEBUG("Check if path %s with FS magic %lld is shared", path, (long long int)sb.f_type);
Should we also fix this cast? Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com> -- IBM Systems Linux on Z & Virtualization Development -------------------------------------------------- IBM Deutschland Research & Development GmbH Schönaicher Str. 220, 71032 Böblingen Phone: +49 7031 16 1819 -------------------------------------------------- Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294
On 10/08/2018 08:41 PM, Marc Hartmayer wrote:
Use the correct type in order to fix the following error on s390x:
In function 'virFileIsSharedFSType': ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..832d832696d5 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3466,7 +3466,7 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + unsigned int *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3575,7 @@ virFileIsSharedFSType(const char *path,
if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type);
This won't fly on x86_64 where f_type is long. I think we can use __fsword_t directly.
}
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
Does that work for you? Michal
Michal Privoznik <mprivozn@redhat.com> [2018-10-09, 03:45PM +0200]:
On 10/08/2018 08:41 PM, Marc Hartmayer wrote:
Use the correct type in order to fix the following error on s390x:
In function 'virFileIsSharedFSType': ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..832d832696d5 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3466,7 +3466,7 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + unsigned int *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3575,7 @@ virFileIsSharedFSType(const char *path,
if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type);
This won't fly on x86_64 where f_type is long. I think we can use __fsword_t directly.
}
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
Does that work for you?
Hmm, __fsword_t is still a long int but the f_type member is defined as unsigned int in the userspace header. Also, I am against exposing any internal data types. virFileIsSharedFixFUSE could just return the value, the return value right now is not checked anyways.
Michal
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On 10/09/2018 04:39 PM, Bjoern Walk wrote:
Michal Privoznik <mprivozn@redhat.com> [2018-10-09, 03:45PM +0200]:
On 10/08/2018 08:41 PM, Marc Hartmayer wrote:
Use the correct type in order to fix the following error on s390x:
In function 'virFileIsSharedFSType': ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..832d832696d5 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3466,7 +3466,7 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + unsigned int *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3575,7 @@ virFileIsSharedFSType(const char *path,
if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type);
This won't fly on x86_64 where f_type is long. I think we can use __fsword_t directly.
}
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
Does that work for you?
Hmm, __fsword_t is still a long int but the f_type member is defined as unsigned int in the userspace header.
What header file are you looking at? From /usr/include/bits/statfs.h: struct statfs { __fsword_t f_type; __fsword_t f_bsize; /* ..... */ __fsid_t f_fsid; __fsword_t f_namelen; __fsword_t f_frsize; __fsword_t f_flags; __fsword_t f_spare[4]; };
Also, I am against exposing any internal data types.
It's not internal if it is exposed in a public header file.
virFileIsSharedFixFUSE could just return the value, the return value right now is not checked anyways.
Sure, but since you claim the f_type member is an unsigned type, then we would hit the sign warning anyway. Also, not sure. If virFileIsSharedFixFUSE() is unable to tell the filesystem it should not touch the f_type at all. Michal
Michal Privoznik <mprivozn@redhat.com> [2018-10-09, 04:52PM +0200]:
What header file are you looking at? From /usr/include/bits/statfs.h:
It's s390x-specific hard-coded as an unsigned int.
Also, I am against exposing any internal data types.
It's not internal if it is exposed in a public header file.
virFileIsSharedFixFUSE could just return the value, the return value right now is not checked anyways.
Sure, but since you claim the f_type member is an unsigned type, then we would hit the sign warning anyway. Also, not sure. If virFileIsSharedFixFUSE() is unable to tell the filesystem it should not touch the f_type at all.
Ok, then I guess Daniel's solution is the most simple one. I'll have Marc send a v3 :) -- IBM Systems Linux on Z & Virtualization Development -------------------------------------------------- IBM Deutschland Research & Development GmbH Schönaicher Str. 220, 71032 Böblingen Phone: +49 7031 16 1819 -------------------------------------------------- Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen Registergericht: Amtsgericht Stuttgart, HRB 243294
On s390x the struct member f_type of statsfs is hard coded to 'unsigned int'. So let's try to determine the type by means of the GNU extension typeof. This fixes the following error: ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type); Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..6cde4ab6c23b 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3464,9 +3464,15 @@ int virFilePrintf(FILE *fp, const char *msg, ...) # define PROC_MOUNTS "/proc/mounts" +# ifdef __GNUC__ +typedef typeof(((struct statfs*)0)->f_type) f_type_type; +# else +typedef long f_type_type; +# endif + static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + f_type_type *f_type) { char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3581,7 @@ virFileIsSharedFSType(const char *path, if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type); } VIR_DEBUG("Check if path %s with FS magic %lld is shared", -- 2.17.0
On Tue, Oct 09, 2018 at 05:55:29PM +0200, Marc Hartmayer wrote:
On s390x the struct member f_type of statsfs is hard coded to 'unsigned int'. So let's try to determine the type by means of the GNU extension typeof.
This fixes the following error: ../../src/util/virfile.c:3578:38: error: cast increases required alignment of target type [-Werror=cast-align] virFileIsSharedFixFUSE(path, (long *) &sb.f_type);
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> --- src/util/virfile.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/util/virfile.c b/src/util/virfile.c index 2a7e87102a25..6cde4ab6c23b 100644 --- a/src/util/virfile.c +++ b/src/util/virfile.c @@ -3464,9 +3464,15 @@ int virFilePrintf(FILE *fp, const char *msg, ...)
# define PROC_MOUNTS "/proc/mounts"
+# ifdef __GNUC__ +typedef typeof(((struct statfs*)0)->f_type) f_type_type; +# else +typedef long f_type_type; +# endif
These games are rather overkill IMHO.
+ static int virFileIsSharedFixFUSE(const char *path, - long *f_type) + f_type_type *f_type)
Make this 'long long'
{ char *dirpath = NULL; const char **mounts = NULL; @@ -3575,7 +3581,7 @@ virFileIsSharedFSType(const char *path,
Add a local variable long long f_type; and then after the stat() call f_type = sb.f_type; and change everything that follows to use the local variable
if (sb.f_type == FUSE_SUPER_MAGIC) { VIR_DEBUG("Found FUSE mount for path=%s. Trying to fix it", path); - virFileIsSharedFixFUSE(path, (long *) &sb.f_type); + virFileIsSharedFixFUSE(path, &sb.f_type); }
VIR_DEBUG("Check if path %s with FS magic %lld is shared",
This also removes the need to cast to long long in this VIR_DEBUG call Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
participants (4)
-
Bjoern Walk -
Daniel P. Berrangé -
Marc Hartmayer -
Michal Privoznik