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Add FreeBSD support #102

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merged 1 commit into from
Aug 8, 2024
Merged

Add FreeBSD support #102

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9 changes: 9 additions & 0 deletions src/v4l2/api.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,7 @@ mod detail {
pub unsafe fn close(fd: std::os::raw::c_int) -> std::os::raw::c_int {
libc::close(fd)
}
#[cfg(any(target_os = "linux", target_os = "android"))]
pub unsafe fn ioctl(
fd: std::os::raw::c_int,
request: vidioc::_IOC_TYPE,
Expand All @@ -80,6 +81,14 @@ mod detail {
*/
libc::syscall(libc::SYS_ioctl, fd, request, argp) as std::os::raw::c_int
}
#[cfg(target_os = "freebsd")]
pub unsafe fn ioctl(
fd: std::os::raw::c_int,
request: vidioc::_IOC_TYPE,
argp: *mut std::os::raw::c_void,
) -> std::os::raw::c_int {
libc::ioctl(fd, request, argp)
}
pub unsafe fn mmap(
start: *mut std::os::raw::c_void,
length: usize,
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8 changes: 8 additions & 0 deletions src/v4l2/vidioc.rs
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Expand Up @@ -19,8 +19,16 @@ const _IOC_SIZESHIFT: u8 = _IOC_TYPESHIFT + _IOC_TYPEBITS;
const _IOC_DIRSHIFT: u8 = _IOC_SIZESHIFT + _IOC_SIZEBITS;

const _IOC_NONE: u8 = 0;

#[cfg(any(target_os = "linux", target_os = "android"))]
const _IOC_WRITE: u8 = 1;
#[cfg(target_os = "freebsd")]
const _IOC_WRITE: u8 = 2;

#[cfg(any(target_os = "linux", target_os = "android"))]
const _IOC_READ: u8 = 2;
#[cfg(target_os = "freebsd")]
const _IOC_READ: u8 = 1;

macro_rules! _IOC_TYPECHECK {
($type:ty) => {
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1 change: 1 addition & 0 deletions v4l2-sys/Cargo.toml
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Expand Up @@ -9,3 +9,4 @@ build = "build.rs"

[build-dependencies]
bindgen = "0.69.1"
pkg-config = "0.3.30"
10 changes: 10 additions & 0 deletions v4l2-sys/build.rs
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Expand Up @@ -4,8 +4,18 @@ use std::env;
use std::path::PathBuf;

fn main() {
let pkg_conf = pkg_config::Config::new()
.probe("libv4l2")
.expect("pkg-config has failed to find `libv4l2`");
Comment on lines +7 to +9
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Wasn't v4l2-sys to build purely against the kernel bindings? v4l-sys links against libv4l2. Can you clarify why this is needed here (i.e. does FreeBSD provide fallbacks here?).

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@vladmovchan vladmovchan Aug 12, 2024 •
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Location of linux/videodev2.h (included in wrapper.h) is generally speaking indeterminate.
It might reside outside of default include location, i.e. not in /usr/include.

pkg-config crate provides means to query include directories necessary to locate libv4l2 header files in pkgconf database:

$ pkgconf --cflags-only-I libv4l2
-I/usr/local/include
$

I don't think changes from this PR affected/changed linking in any way.

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It doesn't affect linking, but the question remains why the kernel-only package now relies on pkg-config and lib4l2 being available, just to locate standard Linux headers. That should at the very least require a comment otherwise, to explain that this build.rs is not interested in generating bindings to libv4l2.

There should be a different/better way that doesn't involve these implicit dependencies. @raymanfx what do you think?

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@vladmovchan vladmovchan Aug 12, 2024 •
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Sorry, I didn't realize the presence of linux/videodev2.h header file doesn't depend on the existence of libv4l2 in pkgconf database on Linux.

I prepared a PR to limit use of pkg-config to FreeBSD only avoid libv4l2 dependency added via pkg-config: #106

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Ah, understood, yeah it should be a Linux UAPI header (https://github.com/torvalds/linux/blob/master/include/uapi/linux/videodev2.h), but maybe FreeBSD provides it as part of the v4l2 package for compatibility? I'm not certain how FreeBSD works, but I think I found it here: https://www.freshports.org/multimedia/v4l_compat


let bindings = bindgen::Builder::default()
.header("wrapper.h")
.clang_args(
pkg_conf
.include_paths
.into_iter()
.map(|path| format!("-I{}", path.to_string_lossy())),
)
.generate()
.expect("Failed to generate bindings");

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