Re: [libvirt] [PATCH 2/2] virpcimock: Mock __open_2()
On Thu, Aug 15, 2019 at 05:15:57PM +0200, Michal Privoznik wrote: Hold on to your hat, this is going to be a wild ride. As nearly nothing in glic, nor open() is a real function. Just look into s/glic/glibc/ bits/fcntl2.h and you'll see that open() is actually a thin wrapper that calls either __open_alias() or __open_2(). Now, before 801ebb5edb6 the open() done in virPCIDeviceConfigOpenInternal() had a constant oflags (we were opening the pci config with O_RDWR). And since we were not passing any mode nor O_CREAT the wrapper decided to call __open_alias() which was open() provided by our mock. So far so good. But after the referenced commit, the oflags is no longer compile time constant and therefore the wrapper calls __open_2() which we don't mock and thus the real __open_2() from glibc was called and thus we did try to open real path from host's /sys. This of course fails with variety of errors. Signed-off-by: Michal Privoznik --- tests/virpcimock.c | 29 + 1 file changed, 29 insertions(+) Thanks for tracking this down! Reviewed-by: Ján Tomko Jano signature.asc Description: PGP signature -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
Re: [libvirt] [PATCH 2/2] virpcimock: Mock __open_2()
On Thu, Aug 15, 2019 at 05:15:57PM +0200, Michal Privoznik wrote: > Hold on to your hat, this is going to be a wild ride. As nearly > nothing in glic, nor open() is a real function. Just look into > bits/fcntl2.h and you'll see that open() is actually a thin > wrapper that calls either __open_alias() or __open_2(). Now, > before 801ebb5edb6 the open() done in > virPCIDeviceConfigOpenInternal() had a constant oflags (we were > opening the pci config with O_RDWR). And since we were not > passing any mode nor O_CREAT the wrapper decided to call > __open_alias() which was open() provided by our mock. So far so > good. But after the referenced commit, the oflags is no longer > compile time constant and therefore the wrapper calls __open_2() > which we don't mock and thus the real __open_2() from glibc was > called and thus we did try to open real path from host's /sys. > This of course fails with variety of errors. > > Signed-off-by: Michal Privoznik > --- Reviewed-by: Erik Skultety -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
[libvirt] [PATCH 2/2] virpcimock: Mock __open_2()
Hold on to your hat, this is going to be a wild ride. As nearly
nothing in glic, nor open() is a real function. Just look into
bits/fcntl2.h and you'll see that open() is actually a thin
wrapper that calls either __open_alias() or __open_2(). Now,
before 801ebb5edb6 the open() done in
virPCIDeviceConfigOpenInternal() had a constant oflags (we were
opening the pci config with O_RDWR). And since we were not
passing any mode nor O_CREAT the wrapper decided to call
__open_alias() which was open() provided by our mock. So far so
good. But after the referenced commit, the oflags is no longer
compile time constant and therefore the wrapper calls __open_2()
which we don't mock and thus the real __open_2() from glibc was
called and thus we did try to open real path from host's /sys.
This of course fails with variety of errors.
Signed-off-by: Michal Privoznik
---
tests/virpcimock.c | 29 +
1 file changed, 29 insertions(+)
diff --git a/tests/virpcimock.c b/tests/virpcimock.c
index beb5e1490d..829d61cd3f 100644
--- a/tests/virpcimock.c
+++ b/tests/virpcimock.c
@@ -32,6 +32,7 @@
static int (*real_access)(const char *path, int mode);
static int (*real_open)(const char *path, int flags, ...);
+static int (*real___open_2)(const char *path, int flags);
static int (*real_close)(int fd);
static DIR * (*real_opendir)(const char *name);
static char *(*real_virFileCanonicalizePath)(const char *path);
@@ -805,6 +806,7 @@ init_syms(void)
VIR_MOCK_REAL_INIT(access);
VIR_MOCK_REAL_INIT(open);
+VIR_MOCK_REAL_INIT(__open_2);
VIR_MOCK_REAL_INIT(close);
VIR_MOCK_REAL_INIT(opendir);
VIR_MOCK_REAL_INIT(virFileCanonicalizePath);
@@ -932,6 +934,33 @@ open(const char *path, int flags, ...)
return ret;
}
+
+int
+__open_2(const char *path, int flags)
+{
+VIR_AUTOFREE(char *) newpath = NULL;
+int ret;
+
+init_syms();
+
+if (STRPREFIX(path, SYSFS_PCI_PREFIX) &&
+getrealpath(&newpath, path) < 0)
+return -1;
+
+ret = real___open_2(newpath ? newpath : path, flags);
+
+/* Catch both: /sys/bus/pci/drivers/... and
+ * /sys/bus/pci/device/.../driver/... */
+if (ret >= 0 && STRPREFIX(path, SYSFS_PCI_PREFIX) &&
+strstr(path, "driver") && add_fd(ret, path) < 0) {
+real_close(ret);
+ret = -1;
+}
+
+return ret;
+}
+
+
DIR *
opendir(const char *path)
{
--
2.21.0
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