v4l2: v4l2_compat: Intercept open64, openat64, and mmap64

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@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> # Compile with musl
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/src/v4l2/v4l2_compat.cpp b/src/v4l2/v4l2_compat.cpp
index 2a9a1762..fd73381d 100644
--- a/src/v4l2/v4l2_compat.cpp
+++ b/src/v4l2/v4l2_compat.cpp
@@ -44,6 +44,23 @@ LIBCAMERA_PUBLIC int __open_2(const char *path, int oflag)
 	return open(path, oflag);
 }
 
+#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);
+}
+
+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;
@@ -58,6 +75,23 @@ LIBCAMERA_PUBLIC int __openat_2(int dirfd, const char *path, int oflag)
 	return openat(dirfd, path, oflag);
 }
 
+#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);
+}
+
+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 +109,15 @@ 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);