Re: (un)mount ramfs from C code

From: Tim Walberg
Date: Tue Sep 22 2009 - 15:59:59 EST


mount(2) (i.e. the system-call/library function) does not update /etc/mtab, IIRC...
mount(8) (the command-line utility) does...

In either case, I would expect the mount to show up in /proc/mounts (assuming
/proc is mounted).



On 09/22/2009 12:30 -0700, Brian McGrew wrote:
>> > You mean without using system(3), right? System call is how your program
>> > interacts with the outside world.
>> >
>> > The relevant system calls are:
>> > - mount(2): mount("none", "/mnt", "ramfs", 0, NULL);
>> > - umount(2): umount("/mnt");
>> >
>>
>> Thanks for the help! I'm getting there. Considering the following:
>>
>> If (mount("ramfs", rd_path, "ramfs", MS_NOEXEC | MS_NOSUID, "size=2000m") <
>> 0) {
>> strerror(errno);
>> } else {
>> std::cout << "mounted";
>> }
>>
>> Works great! Thank you. However, even though the filesystem is mounted and
>> /bin/mountpoint confirms it's a mountpoint, I do not see the mountpoint
>> listed in /etc/mtab.
>>
>> Also, according to what I've read about ramfs, the size is supposed to be
>> limited to size=, however, I can cat /dev/zero until the box it out of
>> memory (and swap).
>>
>> I think I'm just missing something and google's not helping a whole lot
>> since ramfs isn't the most popular subject today.
>>
>> Thanks,
>>
>> -b
>>
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