Date: Wed, 3 Sep 2025 08:23:05 -0700 From: Adrian Chadd <adrian@freebsd.org> To: =?UTF-8?Q?Eduardo_Morr=C3=A1s?= <emorras@emorras.eu> Cc: hackers@freebsd.org Subject: Re: Accesing vt(4) framebuffer Message-ID: <CAJ-VmoniUvHGom19s_hOnc%2BRzB%2BNTZZmSq%2BL0T8bgPskTryAzg@mail.gmail.com> In-Reply-To: <20250826160959.65024e9f008c30d46090b8ae@emorras.eu> References: <20250826160959.65024e9f008c30d46090b8ae@emorras.eu>
index | next in thread | previous in thread | raw e-mail
[-- Attachment #1 --] hi! We put code review requests in the tool at https://reviews.freebsd.org/ . If you've not heard back about this then please feel free to poke me directly. Having direct fb access from userland would be great. I thought we already did?! -adrian On Tue, 26 Aug 2025 at 07:10, Eduardo Morrás <emorras@emorras.eu> wrote: > > Hello, I'm developing a gui/widget over vt(4) framebuffer, no X11 nor > Wayland. > > For this I have created a new ioctl that allows access to framebuffer > information and change it's content. For this I modified > /usr/src/sys/dev/vt/hw/fb/vt_fb.c and .h, patches at end of this mail. > > Is this a correct way? Should I do it different? Any security problems? > > > Thanks, Good Day. > > > --- vt_fb.h_ORIG 2025-08-21 19:01:01.192050000 +0200 > +++ vt_fb.h 2025-08-21 19:04:58.447415000 +0200 > @@ -49,4 +49,20 @@ > vd_fb_ioctl_t vt_fb_ioctl; > vd_fb_mmap_t vt_fb_mmap; > > +#ifdef _KERNEL > +#include <sys/ioccom.h> > +#endif > + > +/* Struct to expose framebuffer to userland*/ > +struct vt_fb_userinfo { > + uint32_t width; > + uint32_t height; > + uint32_t depth; > + uint32_t stride; > + uint32_t size; > +}; > + > +/* IOCTL code to work with vt_fb_userinfo */ > +#define VT_FB_GETINFO _IOR('v', 1, struct vt_fb_userinfo) > + > #endif /* _DEV_VT_HW_FB_VT_FB_H_ */ > > > --- vt_fb.c_ORIG 2025-08-21 19:01:07.096190000 +0200 > +++ vt_fb.c 2025-08-21 19:10:22.228787000 +0200 > @@ -42,6 +42,8 @@ > #include <vm/vm.h> > #include <vm/pmap.h> > > +#include <sys/ioccom.h> /* Userland access framebuffer */ > + > static struct vt_driver vt_fb_driver = { > .vd_name = "fb", > .vd_init = vt_fb_init, > @@ -87,6 +89,24 @@ > *(uint32_t *)(sc->fb_vbase + o) = v; > } > > +static int > +vt_fb_userioctl(struct vt_device *vd, u_long cmd, caddr_t data) > +{ > + struct vt_fb_userinfo *ui = (struct vt_fb_userinfo *)data; > + struct fb_info *info = vd->vd_softc; > + > + if (cmd != VT_FB_GETINFO) > + return (ENOIOCTL); > + > + ui->width = info->fb_width; > + ui->height = info->fb_height; > + ui->depth = info->fb_bpp * 8; > + ui->stride = info->fb_stride; > + ui->size = info->fb_size; > + > + return (0); > +} > + > int > vt_fb_ioctl(struct vt_device *vd, u_long cmd, caddr_t data, struct thread > *td) > { > @@ -125,6 +145,10 @@ > return (ENOTTY); > memcpy((struct fb_rgboffs *)data, &info->fb_rgboffs, > sizeof(struct fb_rgboffs)); > + break; > + > + case VT_FB_GETINFO: /* userland framebuffer */ > + return vt_fb_userioctl(vd, cmd, data); > break; > > default: > > > --- --- > Eduardo Morrás <emorras@emorras.eu> > > [-- Attachment #2 --] <div dir="ltr"><div>hi!</div><div><br></div><div>We put code review requests in the tool at <a href="https://reviews.freebsd.org/">https://reviews.freebsd.org/</a>; . If you've not heard back about this</div><div>then please feel free to poke me directly.</div><div><br></div><div>Having direct fb access from userland would be great. I thought we already did?!</div><div><br></div><div><br></div><div><br></div><div>-adrian</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Tue, 26 Aug 2025 at 07:10, Eduardo Morrás <<a href="mailto:emorras@emorras.eu">emorras@emorras.eu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br> Hello, I'm developing a gui/widget over vt(4) framebuffer, no X11 nor<br> Wayland.<br> <br> For this I have created a new ioctl that allows access to framebuffer<br> information and change it's content. For this I modified <br> /usr/src/sys/dev/vt/hw/fb/vt_fb.c and .h, patches at end of this mail.<br> <br> Is this a correct way? Should I do it different? Any security problems?<br> <br> <br> Thanks, Good Day.<br> <br> <br> --- vt_fb.h_ORIG 2025-08-21 19:01:01.192050000 +0200<br> +++ vt_fb.h 2025-08-21 19:04:58.447415000 +0200<br> @@ -49,4 +49,20 @@<br> vd_fb_ioctl_t vt_fb_ioctl;<br> vd_fb_mmap_t vt_fb_mmap;<br> <br> +#ifdef _KERNEL<br> +#include <sys/ioccom.h><br> +#endif<br> +<br> +/* Struct to expose framebuffer to userland*/<br> +struct vt_fb_userinfo {<br> + uint32_t width;<br> + uint32_t height;<br> + uint32_t depth;<br> + uint32_t stride;<br> + uint32_t size;<br> +};<br> +<br> +/* IOCTL code to work with vt_fb_userinfo */<br> +#define VT_FB_GETINFO _IOR('v', 1, struct vt_fb_userinfo)<br> +<br> #endif /* _DEV_VT_HW_FB_VT_FB_H_ */<br> <br> <br> --- vt_fb.c_ORIG 2025-08-21 19:01:07.096190000 +0200<br> +++ vt_fb.c 2025-08-21 19:10:22.228787000 +0200<br> @@ -42,6 +42,8 @@<br> #include <vm/vm.h><br> #include <vm/pmap.h><br> <br> +#include <sys/ioccom.h> /* Userland access framebuffer */<br> +<br> static struct vt_driver vt_fb_driver = {<br> .vd_name = "fb",<br> .vd_init = vt_fb_init,<br> @@ -87,6 +89,24 @@<br> *(uint32_t *)(sc->fb_vbase + o) = v;<br> }<br> <br> +static int<br> +vt_fb_userioctl(struct vt_device *vd, u_long cmd, caddr_t data)<br> +{<br> + struct vt_fb_userinfo *ui = (struct vt_fb_userinfo *)data;<br> + struct fb_info *info = vd->vd_softc;<br> +<br> + if (cmd != VT_FB_GETINFO)<br> + return (ENOIOCTL);<br> +<br> + ui->width = info->fb_width;<br> + ui->height = info->fb_height;<br> + ui->depth = info->fb_bpp * 8;<br> + ui->stride = info->fb_stride;<br> + ui->size = info->fb_size;<br> +<br> + return (0);<br> +}<br> +<br> int<br> vt_fb_ioctl(struct vt_device *vd, u_long cmd, caddr_t data, struct thread *td)<br> {<br> @@ -125,6 +145,10 @@<br> return (ENOTTY);<br> memcpy((struct fb_rgboffs *)data, &info->fb_rgboffs,<br> sizeof(struct fb_rgboffs));<br> + break;<br> +<br> + case VT_FB_GETINFO: /* userland framebuffer */<br> + return vt_fb_userioctl(vd, cmd, data);<br> break;<br> <br> default:<br> <br> <br> --- ---<br> Eduardo Morrás <<a href="mailto:emorras@emorras.eu" target="_blank">emorras@emorras.eu</a>><br> <br> </blockquote></div>help
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAJ-VmoniUvHGom19s_hOnc%2BRzB%2BNTZZmSq%2BL0T8bgPskTryAzg>