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v4l2: compat_manager: Move file operations to new struct FileOperations

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Create a new FileOperations structure to hold all the dynamically-loaded
C library file operations. The file operations are now exposed publicly,
to prepare for usage of mmap in the V4L2CameraProxy.

A new template helper function is added to retrieve a symbol with
dlsym() with proper casting to simplify the V4L2CompatManager
constructor.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
This commit is contained in:
Laurent Pinchart 2020-01-04 22:58:35 +02:00
parent b4415f1c98
commit 7088041a80
2 changed files with 41 additions and 27 deletions
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34
src/v4l2/v4l2_compat_manager.cpp
View file

@ -28,15 +28,23 @@ using namespace libcamera;
LOG_DEFINE_CATEGORY(V4L2Compat)
namespace {
template<typename T>
void get_symbol(T &func, const char *name)
{
func = reinterpret_cast<T>(dlsym(RTLD_NEXT, name));
}
} /* namespace */
V4L2CompatManager::V4L2CompatManager()
: cm_(nullptr), initialized_(false)
{
openat_func_ = (openat_func_t)dlsym(RTLD_NEXT, "openat");
dup_func_ = (dup_func_t )dlsym(RTLD_NEXT, "dup");
close_func_ = (close_func_t )dlsym(RTLD_NEXT, "close");
ioctl_func_ = (ioctl_func_t )dlsym(RTLD_NEXT, "ioctl");
mmap_func_ = (mmap_func_t )dlsym(RTLD_NEXT, "mmap");
munmap_func_ = (munmap_func_t)dlsym(RTLD_NEXT, "munmap");
get_symbol(fops_.openat, "openat");
get_symbol(fops_.dup, "dup");
get_symbol(fops_.close, "close");
get_symbol(fops_.ioctl, "ioctl");
get_symbol(fops_.mmap, "mmap");
get_symbol(fops_.munmap, "munmap");
}
V4L2CompatManager::~V4L2CompatManager()
@ -141,7 +149,7 @@ int V4L2CompatManager::getCameraIndex(int fd)
int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mode)
{
int fd = openat_func_(dirfd, path, oflag, mode);
int fd = fops_.openat(dirfd, path, oflag, mode);
if (fd < 0)
return fd;
@ -160,7 +168,7 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
return fd;
}
close_func_(fd);
fops_.close(fd);
unsigned int camera_index = static_cast<unsigned int>(ret);
@ -182,7 +190,7 @@ int V4L2CompatManager::openat(int dirfd, const char *path, int oflag, mode_t mod
int V4L2CompatManager::dup(int oldfd)
{
int newfd = dup_func_(oldfd);
int newfd = fops_.dup(oldfd);
if (newfd < 0)
return newfd;
@ -205,7 +213,7 @@ int V4L2CompatManager::close(int fd)
return 0;
}
return close_func_(fd);
return fops_.close(fd);
}
void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
@ -213,7 +221,7 @@ void *V4L2CompatManager::mmap(void *addr, size_t length, int prot, int flags,
{
V4L2CameraProxy *proxy = getProxy(fd);
if (!proxy)
return mmap_func_(addr, length, prot, flags, fd, offset);
return fops_.mmap(addr, length, prot, flags, fd, offset);
void *map = proxy->mmap(length, prot, flags, offset);
if (map == MAP_FAILED)
@ -227,7 +235,7 @@ int V4L2CompatManager::munmap(void *addr, size_t length)
{
auto device = mmaps_.find(addr);
if (device == mmaps_.end())
return munmap_func_(addr, length);
return fops_.munmap(addr, length);
V4L2CameraProxy *proxy = device->second;
@ -244,7 +252,7 @@ int V4L2CompatManager::ioctl(int fd, unsigned long request, void *arg)
{
V4L2CameraProxy *proxy = getProxy(fd);
if (!proxy)
return ioctl_func_(fd, request, arg);
return fops_.ioctl(fd, request, arg);
return proxy->ioctl(request, arg);
}