1284167 - Don't poke /proc on non-Linux systems

Status: RESOLVED FIXED

(Toolkit :: Telemetry, defect, P4)

Description

[Jan Beich]

While it's possible to retrieve some information about running CPU on BSD kernels via dmesg(8) or handpicking sysctls on x86 one is supposed to use CPUID instruction instead.

On FreeBSD there're procfs(5) and linprocfs(5). Only the latter provides "cpuinfo" file usually under /compat/linux/proc. linprocfs(5) is only available on x86 architectures and doesn't know about anthing more recent than SSE2.

Comment 1

[Jan Beich]

Attachment: Bug 1284167 - /proc is unreliable on non-Linux.

Review commit: https://reviewboard.mozilla.org/r/61990/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/61990/

Comment 2

[Milan Sreckovic [:milan] (needinfo for best results)]

https://reviewboard.mozilla.org/r/61990/#review58870

::: xpcom/base/nsSystemInfo.cpp:37
(Diff revision 1)
>  #ifdef MOZ_WIDGET_GTK
>  #include <gtk/gtk.h>
>  #include <dlfcn.h>
> +#endif
> +
> +#ifdef XP_LINUX

To not change things on Android, this can just be nested inside of #ifdef MOZ_WIDGET_GTK, i.e.,

#ifdef MOZ_WIDGET_GTK
...
#ifdef XP_LINUX
...
#endif
#endif

::: xpcom/base/nsSystemInfo.cpp:79
(Diff revision 1)
>  // system call to discover the appropriate value is not thread-safe,
>  // so we must call it before going multithreaded, but nsSystemInfo::Init
>  // only happens well after that point.
>  uint32_t nsSystemInfo::gUserUmask = 0;
>  
> -#if defined (MOZ_WIDGET_GTK)
> +#if defined (XP_LINUX)

We don't want this for Android, so the way to maintain the original intent and exclude something like FreeBSD, this should be:

#if defined (MOZ_WIDGET_GTK) && defined (XP_LINUX)

instead.

::: xpcom/base/nsSystemInfo.cpp:503
(Diff revision 1)
>    if (!sysctlbyname("machdep.cpu.stepping", &sysctlValue32, &len, NULL, 0)) {
>      cpuStepping = static_cast<int>(sysctlValue32);
>    }
>    MOZ_ASSERT(sizeof(sysctlValue32) == len);
>  
> -#elif defined (MOZ_WIDGET_GTK)
> +#elif defined (XP_LINUX)

Same as the above, we want:

#elif defined (MOZ_WIDGET_GTK) && defined (XP_LINUX)

instead.

Comment 3

[Jan Beich]

https://reviewboard.mozilla.org/r/61990/#review58870

> To not change things on Android, this can just be nested inside of #ifdef MOZ_WIDGET_GTK, i.e.,
> 
> #ifdef MOZ_WIDGET_GTK
> ...
> #ifdef XP_LINUX
> ...
> #endif
> #endif

But it's a platform-specific, not widget-specific code. I think, on Desktop it may work even with MOZ_WIDGET_QT.

Comment 4

[Jan Beich]

Comment on attachment 8767540 [details]
Bug 1284167 - /proc is unreliable on non-Linux.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/61990/diff/1-2/

Comment 5

[Milan Sreckovic [:milan] (needinfo for best results)]

Comment on attachment 8767540 [details]
Bug 1284167 - /proc is unreliable on non-Linux.

https://reviewboard.mozilla.org/r/61990/#review59174

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/fx-team/rev/cec1ab33c0d6
/proc is unreliable on non-Linux. r=milan

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/cec1ab33c0d6