[libvirt] [PATCH v3 4/5] virpcimock.c: simplify getrealpath() usage
Daniel Henrique Barboza
danielhb413 at gmail.com
Thu Aug 29 19:19:01 UTC 2019
Previous patch had to add '/sys/kernel/' prefix in opendir() because
the path, which is being mocked, wasn't being considered due to
an 'if SYSFS_PCI_PREFIX' guarding the call to getrealpath().
In fact, all current getrealpath() callers are guarding it with a
conditional to ensure that the function will never be called with
a non-mocked path. In this case, an extra non-NULL verification is
needed for the 'newpath' string to use the variable - which is
counterintuitive, given that getrealpath() will always write the
'newpath' string in any non-error conditon.
However, simply removing the guard of all getrealpath() instances
causes an abort in init_env(). This happens because tests will
execute access() to non-mocked paths even before the
LIBVIRT_FAKE_ROOT_DIR variable is declared in the test files. We
don't need 'fakerootdir' to be created at this point though.
This patch does the following changes to simplify getrealpath()
usage:
- getrealpath() will now guard the init_env() call by checking if
both fakeroot isn't created and the required path is being mocked.
This ensures that we're not failing inside init_env() because
we're too early and LIBVIRT_FAKE_ROOT_DIR wasn't defined yet;
- remove all conditional guards to call getrealpath() from
access(), virMockStatRedirect(), open(), open_2(), opendir()
and virFileCanonicalizePath(). As a bonus, remove all ternary
conditionals with 'newpath';
- a new 'pathPrefixIsMocked()' helper to aggregate all the prefixes
we're mocking, making it easier to add/remove them. If a prefix
is added inside this function, we can be sure that all functions
are mocking them.
Signed-off-by: Daniel Henrique Barboza <danielhb413 at gmail.com>
---
tests/virpcimock.c | 63 +++++++++++++++++++++++++---------------------
1 file changed, 34 insertions(+), 29 deletions(-)
diff --git a/tests/virpcimock.c b/tests/virpcimock.c
index e362121899..69ee360e4c 100644
--- a/tests/virpcimock.c
+++ b/tests/virpcimock.c
@@ -45,8 +45,16 @@ static char *(*real_virFileCanonicalizePath)(const char *path);
*/
char *fakerootdir;
+/* To add a new mocked prefix in virpcimock:
+ * - add the prefix here as a define to make it easier to track what we
+ * are mocking;
+ * - add it to the 'pathPrefixIsMocked()' helper;
+ * - (optional) edit 'getrealpath()' if you need the resulting mocked
+ * path to be different than <fakerootdir>/path
+ */
# define SYSFS_PCI_PREFIX "/sys/bus/pci/"
-
+# define SYSFS_KERNEL_PREFIX "/sys/kernel/"
+# define DEV_VFIO_PREFIX "/dev/vfio/"
# define STDERR(...) \
fprintf(stderr, "%s %zu: ", __FUNCTION__, (size_t) __LINE__); \
@@ -251,11 +259,20 @@ pci_read_file(const char *path,
return ret;
}
+static bool
+pathPrefixIsMocked(const char *path)
+{
+ return STRPREFIX(path, SYSFS_PCI_PREFIX) ||
+ STRPREFIX(path, SYSFS_KERNEL_PREFIX) ||
+ STRPREFIX(path, DEV_VFIO_PREFIX);
+}
+
static int
getrealpath(char **newpath,
const char *path)
{
- init_env();
+ if (!fakerootdir && pathPrefixIsMocked(path))
+ init_env();
if (STRPREFIX(path, SYSFS_PCI_PREFIX)) {
if (virAsprintfQuiet(newpath, "%s/sys/bus/pci/%s",
@@ -264,9 +281,7 @@ getrealpath(char **newpath,
errno = ENOMEM;
return -1;
}
- } else if (STRPREFIX(path, "/sys/kernel/") ||
- STRPREFIX(path, "/dev/vfio/")) {
-
+ } else if (pathPrefixIsMocked(path)) {
if (virAsprintfQuiet(newpath, "%s/%s",
fakerootdir,
path) < 0) {
@@ -974,9 +989,6 @@ init_env(void)
{
VIR_AUTOFREE(char *) tmp = NULL;
- if (fakerootdir)
- return;
-
if (!(fakerootdir = getenv("LIBVIRT_FAKE_ROOT_DIR")))
ABORT("Missing LIBVIRT_FAKE_ROOT_DIR env variable\n");
@@ -1057,21 +1069,19 @@ access(const char *path, int mode)
init_syms();
- if (STRPREFIX(path, SYSFS_PCI_PREFIX) &&
- getrealpath(&newpath, path) < 0)
+ if (getrealpath(&newpath, path) < 0)
return -1;
- return real_access(newpath ? newpath : path, mode);
+ return real_access(newpath, mode);
}
static int
virMockStatRedirect(const char *path, char **newpath)
{
- if (STRPREFIX(path, SYSFS_PCI_PREFIX)) {
- if (getrealpath(newpath, path) < 0)
- return -1;
- }
+ if (getrealpath(newpath, path) < 0)
+ return -1;
+
return 0;
}
@@ -1084,8 +1094,7 @@ open(const char *path, int flags, ...)
init_syms();
- if (STRPREFIX(path, SYSFS_PCI_PREFIX) &&
- getrealpath(&newpath, path) < 0)
+ if (getrealpath(&newpath, path) < 0)
return -1;
if (flags & O_CREAT) {
@@ -1094,9 +1103,9 @@ open(const char *path, int flags, ...)
va_start(ap, flags);
mode = (mode_t) va_arg(ap, int);
va_end(ap);
- ret = real_open(newpath ? newpath : path, flags, mode);
+ ret = real_open(newpath, flags, mode);
} else {
- ret = real_open(newpath ? newpath : path, flags);
+ ret = real_open(newpath, flags);
}
/* Catch both: /sys/bus/pci/drivers/... and
@@ -1125,11 +1134,10 @@ __open_2(const char *path, int flags)
init_syms();
- if (STRPREFIX(path, SYSFS_PCI_PREFIX) &&
- getrealpath(&newpath, path) < 0)
+ if (getrealpath(&newpath, path) < 0)
return -1;
- ret = real___open_2(newpath ? newpath : path, flags);
+ ret = real___open_2(newpath, flags);
/* Catch both: /sys/bus/pci/drivers/... and
* /sys/bus/pci/device/.../driver/... */
@@ -1150,12 +1158,10 @@ opendir(const char *path)
init_syms();
- if ((STRPREFIX(path, SYSFS_PCI_PREFIX) ||
- STRPREFIX(path, "/sys/kernel/")) &&
- getrealpath(&newpath, path) < 0)
+ if (getrealpath(&newpath, path) < 0)
return NULL;
- return real_opendir(newpath ? newpath : path);
+ return real_opendir(newpath);
}
int
@@ -1173,11 +1179,10 @@ virFileCanonicalizePath(const char *path)
init_syms();
- if (STRPREFIX(path, SYSFS_PCI_PREFIX) &&
- getrealpath(&newpath, path) < 0)
+ if (getrealpath(&newpath, path) < 0)
return NULL;
- return real_virFileCanonicalizePath(newpath ? newpath : path);
+ return real_virFileCanonicalizePath(newpath);
}
# include "virmockstathelpers.c"
--
2.21.0
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