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Old 11-02-2008, 12:49 PM   #1
Sharon Olshanksy
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How to know where a flash disk that was discovered, is mounted(from C++ application)?


Hello, I have a question:

How to know where a flash disk that was discovered, is mounted(from C++ application)?

I write a project in C++/Linux (Debian), in which I have to identify when USB flash disk is insterted/removed, and when the flash disk is inserted,I have to read the files in the flash drive and copy them.

I found many ways to identify that the flash disk is insterted (I'm going to use usblib for that), but I haven't found a way to link between the data I get on the drive, to it's mapping in the file-system.

thanks,
Sharon
 
Old 11-02-2008, 01:06 PM   #2
Sergei Steshenko
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Quote:
Originally Posted by Sharon Olshanksy View Post
Hello, I have a question:

How to know where a flash disk that was discovered, is mounted(from C++ application)?

I write a project in C++/Linux (Debian), in which I have to identify when USB flash disk is insterted/removed, and when the flash disk is inserted,I have to read the files in the flash drive and copy them.

I found many ways to identify that the flash disk is insterted (I'm going to use usblib for that), but I haven't found a way to link between the data I get on the drive, to it's mapping in the file-system.

thanks,
Sharon
What about parsing stdout of 'mount' command ?
 
Old 11-02-2008, 01:34 PM   #3
Sergei Steshenko
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Actually, it's even simpler; from "man mount":

/etc/mtab table of mounted file systems
.
 
Old 11-02-2008, 04:16 PM   #4
ta0kira
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Neither of those are really reliable since neither will tell you if 1) something was mounted from chroot, 2) something was mounted when / was read-only, 3) something was mounted with -n. Really the only reliable way to check for mounts is /proc/mounts, but some of the /proc files won't give you a size, so you just have to read linearly until they're empty.
ta0kira

PS That's the Linux-only solution; Sergei's is more portable.

Last edited by ta0kira; 11-02-2008 at 04:18 PM.
 
Old 11-02-2008, 11:45 PM   #5
Sergei Steshenko
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Quote:
Originally Posted by ta0kira View Post
Neither of those are really reliable since neither will tell you if 1) something was mounted from chroot, 2) something was mounted when / was read-only, 3) something was mounted with -n. Really the only reliable way to check for mounts is /proc/mounts, but some of the /proc files won't give you a size, so you just have to read linearly until they're empty.
ta0kira

PS That's the Linux-only solution; Sergei's is more portable.
/etc/mtab and/or 'mount' can be good starting points; the next logical step would be to look into 'mount' source and see which library functions are used to report mounted media.

To make it portable, if possible, one would have to look into various 'mount' flavors (Linux, *BSD) - maybe the both use just POSIX-compliant functions.

OTOH, if /etc/mtab is present on all UNIXes and has the same format, maybe it's not worth bothering with 'mount' source code and library functions.

I hope the OP has enough inputs for now :-).
 
  


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