[libcamera-devel] [PATCH v3] v4l2: v4l2_compat: Intercept open64, openat64, and mmap64
Paul Elder
paul.elder at ideasonboard.com
Thu Jun 18 12:08:11 CEST 2020
Some applications (eg. Firefox, Google Chrome, Skype) use open64,
openat64, and mmap64 instead of their non-64 versions that we currently
intercept. Intercept these calls as well. _LARGEFILE64_SOURCE needs to
be set so that the 64-bit symbols are available and not synonymous to
the non-64-bit versions on 64-bit systems.
Also, since we set _FILE_OFFSET_BITS to 32 to force the various open and
mmap symbols that we export to not be the 64-bit versions, our dlsym to
get the original open and mmap calls will not automatically be converted
to their 64-bit versions. Since we intercept both 32-bit and 64-bit
versions of open and mmap, we should be using the 64-bit version to
service both. Fetch the 64-bit versions of openat and mmap directly.
musl defines the 64-bit symbols as macros that are equivalent to the
non-64-bit symbols, so we put compile guards that check if the 64-bit
symbols are defined.
Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
Tested-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com> # Compile with musl
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
Changes in v3:
- add __open64_2 and __openat64_2
Changes in v2:
- squash intercept 64-bit calls and use 64-bit calls into
this one patch
- use off64_t instead of __off64_t
- add compile guard to get musl to play nicely with the 64-bit calls
coexisting with the non-64-bit calls
---
src/v4l2/meson.build | 1 +
src/v4l2/v4l2_camera_proxy.cpp | 2 +-
src/v4l2/v4l2_camera_proxy.h | 3 +-
src/v4l2/v4l2_compat.cpp | 47 ++++++++++++++++++++++++++++++++
src/v4l2/v4l2_compat_manager.cpp | 6 ++--
src/v4l2/v4l2_compat_manager.h | 5 ++--
6 files changed, 57 insertions(+), 7 deletions(-)
diff --git a/src/v4l2/meson.build b/src/v4l2/meson.build
index 0fb941e..f2e4aaf 100644
--- a/src/v4l2/meson.build
+++ b/src/v4l2/meson.build
@@ -15,6 +15,7 @@ v4l2_compat_cpp_args = [
# file operations, disable transparent large file support.
'-U_FILE_OFFSET_BITS',
'-D_FILE_OFFSET_BITS=32',
+ '-D_LARGEFILE64_SOURCE',
'-fvisibility=hidden',
]
diff --git a/src/v4l2/v4l2_camera_proxy.cpp b/src/v4l2/v4l2_camera_proxy.cpp
index d7f14e6..7425029 100644
--- a/src/v4l2/v4l2_camera_proxy.cpp
+++ b/src/v4l2/v4l2_camera_proxy.cpp
@@ -75,7 +75,7 @@ void V4L2CameraProxy::close()
}
void *V4L2CameraProxy::mmap(void *addr, size_t length, int prot, int flags,
- off_t offset)
+ off64_t offset)
{
LOG(V4L2Compat, Debug) << "Servicing mmap";
diff --git a/src/v4l2/v4l2_camera_proxy.h b/src/v4l2/v4l2_camera_proxy.h
index 7c65c88..27d3e50 100644
--- a/src/v4l2/v4l2_camera_proxy.h
+++ b/src/v4l2/v4l2_camera_proxy.h
@@ -11,6 +11,7 @@
#include <linux/videodev2.h>
#include <map>
#include <memory>
+#include <sys/mman.h>
#include <sys/types.h>
#include <vector>
@@ -28,7 +29,7 @@ public:
int open(bool nonBlocking);
void dup();
void close();
- void *mmap(void *addr, size_t length, int prot, int flags, off_t offset);
+ void *mmap(void *addr, size_t length, int prot, int flags, off64_t offset);
int munmap(void *addr, size_t length);
int ioctl(unsigned long request, void *arg);
diff --git a/src/v4l2/v4l2_compat.cpp b/src/v4l2/v4l2_compat.cpp
index 2a9a176..2e80de5 100644
--- a/src/v4l2/v4l2_compat.cpp
+++ b/src/v4l2/v4l2_compat.cpp
@@ -38,12 +38,31 @@ LIBCAMERA_PUBLIC int open(const char *path, int oflag, ...)
oflag, mode);
}
+#ifndef open64
+LIBCAMERA_PUBLIC int open64(const char *path, int oflag, ...)
+{
+ mode_t mode = 0;
+ if (oflag & O_CREAT || oflag & O_TMPFILE)
+ extract_va_arg(mode_t, mode, oflag);
+
+ return V4L2CompatManager::instance()->openat(AT_FDCWD, path,
+ oflag | O_LARGEFILE, mode);
+}
+#endif
+
/* _FORTIFY_SOURCE redirects open to __open_2 */
LIBCAMERA_PUBLIC int __open_2(const char *path, int oflag)
{
return open(path, oflag);
}
+#ifndef __open64_2
+LIBCAMERA_PUBLIC int __open64_2(const char *path, int oflag)
+{
+ return open(path, oflag);
+}
+#endif
+
LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...)
{
mode_t mode = 0;
@@ -53,11 +72,30 @@ LIBCAMERA_PUBLIC int openat(int dirfd, const char *path, int oflag, ...)
return V4L2CompatManager::instance()->openat(dirfd, path, oflag, mode);
}
+#ifndef openat64
+LIBCAMERA_PUBLIC int openat64(int dirfd, const char *path, int oflag, ...)
+{
+ mode_t mode = 0;
+ if (oflag & O_CREAT || oflag & O_TMPFILE)
+ extract_va_arg(mode_t, mode, oflag);
+
+ return V4L2CompatManager::instance()->openat(dirfd, path,
+ oflag | O_LARGEFILE, mode);
+}
+#endif
+
LIBCAMERA_PUBLIC int __openat_2(int dirfd, const char *path, int oflag)
{
return openat(dirfd, path, oflag);
}
+#ifndef __openat64_2
+LIBCAMERA_PUBLIC int __openat64_2(int dirfd, const char *path, int oflag)
+{
+ return openat(dirfd, path, oflag);
+}
+#endif
+
LIBCAMERA_PUBLIC int dup(int oldfd)
{
return V4L2CompatManager::instance()->dup(oldfd);
@@ -75,6 +113,15 @@ LIBCAMERA_PUBLIC void *mmap(void *addr, size_t length, int prot, int flags,
fd, offset);
}
+#ifndef mmap64
+LIBCAMERA_PUBLIC void *mmap64(void *addr, size_t length, int prot, int flags,
+ int fd, off64_t offset)
+{
+ return V4L2CompatManager::instance()->mmap(addr, length, prot, flags,
+ fd, offset);
+}
+#endif
+
LIBCAMERA_PUBLIC int munmap(void *addr, size_t length)
{
return V4L2CompatManager::instance()->munmap(addr, length);
diff --git a/src/v4l2/v4l2_compat_manager.cpp b/src/v4l2/v4l2_compat_manager.cpp
index 56533c4..8da3316 100644
--- a/src/v4l2/v4l2_compat_manager.cpp
+++ b/src/v4l2/v4l2_compat_manager.cpp
@@ -39,11 +39,11 @@ void get_symbol(T &func, const char *name)
V4L2CompatManager::V4L2CompatManager()
: cm_(nullptr)
{
- get_symbol(fops_.openat, "openat");
+ get_symbol(fops_.openat, "openat64");
get_symbol(fops_.dup, "dup");
get_symbol(fops_.close, "close");
get_symbol(fops_.ioctl, "ioctl");
- get_symbol(fops_.mmap, "mmap");
+ get_symbol(fops_.mmap, "mmap64");
get_symbol(fops_.munmap, "munmap");
}
@@ -200,7 +200,7 @@ int V4L2CompatManager::close(int fd)
}
void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
- int fd, off_t offset)
+ int fd, off64_t offset)
{
V4L2CameraProxy *proxy = getProxy(fd);
if (!proxy)
diff --git a/src/v4l2/v4l2_compat_manager.h b/src/v4l2/v4l2_compat_manager.h
index 14338a5..3d4e512 100644
--- a/src/v4l2/v4l2_compat_manager.h
+++ b/src/v4l2/v4l2_compat_manager.h
@@ -11,6 +11,7 @@
#include <fcntl.h>
#include <map>
#include <memory>
+#include <sys/mman.h>
#include <sys/types.h>
#include <vector>
@@ -30,7 +31,7 @@ public:
using close_func_t = int (*)(int fd);
using ioctl_func_t = int (*)(int fd, unsigned long request, ...);
using mmap_func_t = void *(*)(void *addr, size_t length, int prot,
- int flags, int fd, off_t offset);
+ int flags, int fd, off64_t offset);
using munmap_func_t = int (*)(void *addr, size_t length);
openat_func_t openat;
@@ -51,7 +52,7 @@ public:
int dup(int oldfd);
int close(int fd);
void *mmap(void *addr, size_t length, int prot, int flags,
- int fd, off_t offset);
+ int fd, off64_t offset);
int munmap(void *addr, size_t length);
int ioctl(int fd, unsigned long request, void *arg);
--
2.27.0
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