how to find proc mounted or not using C libraries
 

Hi Friends,

I want to know how to find whether proc or sys is mounted using C libraries.

I came across this file in kernel source tree[1] which showed me some idea.

But i dont know from where the CONFIG_ACPI_PROCFS_POWER or CONFIG_ACPI_SYSFS_POWER defined.

I like to use them in my project[2] for finding whether proc is mounted or not because my project totally depends on proc.

[1]
http://git.kernel.org/?p=linux/kerne...9efbb7;hb=HEAD

[2]
http://webattery.sf.net


Thanks,

Alagunambi Welkin

Why don't you just try to open the files in the proc or sys filesystem? That will tell you if they are there and readable. The open will fail with ENOENT if the file doesn't exist.

Hi,

Thanks for your reply.

I can do what you told, but in some distributions they are using sysfs insted of procfs so inorder to find which file system is used I need solution.


Alagunambi Welkin

For those of us unacquainted with the differences, perhaps you could briefly explain them, and also how you would distinguish between them in some other context, such as with commandline tools, etc. This sounds like something that changed across kernel versions; maybe just checking the kernel version would suffice.
--- rod.

My reply was the solution. Try one. If it fails, try the other.

This is probably as good as any. There is also doco under ../Documentation in the source tree.

As of 2.6.29, both /proc and /sys are available in the kernel. I do not know if any distros turn one or the other off; I suppose that is possible in the kernel compilation but if true it seems it would break a lot of things.

I'm somewhat confused by this statement - both have been available "forever". At least since the 2.5 development kernels.

ya its true that both are available but the fact is procfs have only process details, but for hardware related stuffs sysfs is used if you can see the following link you can understand. But we can select procfs to have hardware details.

http://git.kernel.org/?p=linux/kerne...9efbb7;hb=HEAD

Here kernel developer clearly mentioned what are the headers to use when procfs has hardware details, or sysfs has hardware details.

Thanks every one for your kind information.


Alagunambi Welkin

Perhaps I should have phrased it a bit differently: "As of 2.6.29, both /proc and /sys are STILL available in the kernel..."

/proc has a lot of hardware information in it. /sys is more-or-less a reorganization of /proc, and the kernel developers insist that /sys is a more rational structure (I suppose that is true). Kernel developers are encouraging use of /sys rather than /proc, so at some point I suppose /proc will become deprecated. It is hard to see, however, how /proc will ever go away, given the extensive use that everyone makes of it.

But i still didnt get the answer how to find hardware details are in procfs or in sysfs