[libcamera-devel] [PATCH] libcamera: Open files with O_CLOEXEC

[Umang Jain]

Hi Laurent,

Thank you for the patch

On 3/26/23 3:31 PM, Laurent Pinchart via libcamera-devel wrote:
> Files opened internally in libcamera without the O_CLOEXEC file will
> remain open upon a call to one of the exec(3) functions. As exec()
> doesn't destroy local or global objects, this can lead to various side
> effects. Avoid this by opening file descriptors with O_CLOEXEC for all
> internal files.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>

> ---
>   src/ipa/vimc/vimc.cpp                            | 2 +-
>   src/libcamera/base/file.cpp                      | 5 ++++-
>   src/libcamera/media_device.cpp                   | 2 +-
>   src/libcamera/pipeline/raspberrypi/dma_heaps.cpp | 2 +-
>   4 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/src/ipa/vimc/vimc.cpp b/src/ipa/vimc/vimc.cpp
> index d5fabaf13ec6..2c255778990a 100644
> --- a/src/ipa/vimc/vimc.cpp
> +++ b/src/ipa/vimc/vimc.cpp
> @@ -168,7 +168,7 @@ void IPAVimc::initTrace()
>   	if (ret)
>   		return;
>   
> -	ret = ::open(ipa::vimc::VimcIPAFIFOPath.c_str(), O_WRONLY);
> +	ret = ::open(ipa::vimc::VimcIPAFIFOPath.c_str(), O_WRONLY | O_CLOEXEC);
>   	if (ret < 0) {
>   		ret = errno;
>   		LOG(IPAVimc, Error) << "Failed to open vimc IPA test FIFO: "
> diff --git a/src/libcamera/base/file.cpp b/src/libcamera/base/file.cpp
> index fb3e276d6ccd..d1ab1aa57462 100644
> --- a/src/libcamera/base/file.cpp
> +++ b/src/libcamera/base/file.cpp
> @@ -163,6 +163,9 @@ bool File::exists() const
>    * attempt to create the file with initial permissions set to 0666 (modified by
>    * the process' umask).
>    *
> + * The file is opened with the O_CLOEXEC flag, and will be closed automatically
> + * when a new binary is executed with one of the exec(3) functions.
> + *
>    * The error() status is updated.
>    *
>    * \return True on success, false otherwise
> @@ -178,7 +181,7 @@ bool File::open(File::OpenMode mode)
>   	if (mode & OpenModeFlag::WriteOnly)
>   		flags |= O_CREAT;
>   
> -	fd_ = UniqueFD(::open(name_.c_str(), flags, 0666));
> +	fd_ = UniqueFD(::open(name_.c_str(), flags | O_CLOEXEC, 0666));
>   	if (!fd_.isValid()) {
>   		error_ = -errno;
>   		return false;
> diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp
> index 52c8e66e9e99..2949816b4a64 100644
> --- a/src/libcamera/media_device.cpp
> +++ b/src/libcamera/media_device.cpp
> @@ -477,7 +477,7 @@ int MediaDevice::open()
>   		return -EBUSY;
>   	}
>   
> -	fd_ = UniqueFD(::open(deviceNode_.c_str(), O_RDWR));
> +	fd_ = UniqueFD(::open(deviceNode_.c_str(), O_RDWR | O_CLOEXEC));
>   	if (!fd_.isValid()) {
>   		int ret = -errno;
>   		LOG(MediaDevice, Error)
> diff --git a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> index 6b644406c90f..317b1fc17161 100644
> --- a/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> +++ b/src/libcamera/pipeline/raspberrypi/dma_heaps.cpp
> @@ -37,7 +37,7 @@ namespace RPi {
>   DmaHeap::DmaHeap()
>   {
>   	for (const char *name : heapNames) {
> -		int ret = ::open(name, O_RDWR, 0);
> +		int ret = ::open(name, O_RDWR | O_CLOEXEC, 0);
>   		if (ret < 0) {
>   			ret = errno;
>   			LOG(RPI, Debug) << "Failed to open " << name << ": "