On 04/09/2013 01:03 PM, Andrew Morton wrote:
cc: John Stultz <[email protected]>
I don't know if that address still works.
No, that email is no longer active. Thanks for noticing this.
From: David Rientjes <[email protected]>
Subject: fs, proc: truncate /proc/pid/comm writes to first TASK_COMM_LEN bytes
Currently, a write to a procfs file will return the number of bytes
successfully written. If the actual string is longer than this, the
remainder of the string will not be be written and userspace will complete
the operation by issuing additional write()s.
Hence
$ echo -n "abcdefghijklmnopqrs" > /proc/self/comm
results in
$ cat /proc/$$/comm
pqrs
since the final four bytes were written with a second write() since
TASK_COMM_LEN == 16. This is obviously an undesired result and not
equivalent to prctl(PR_SET_NAME). The implementation should not need to
know the definition of TASK_COMM_LEN.
That's embarrassing, thanks for catching it!
This patch truncates the string to the first TASK_COMM_LEN bytes and
returns the bytes written as the length of the string written so the
second write() is suppressed.
$ cat /proc/$$/comm
abcdefghijklmno
Signed-off-by: David Rientjes <[email protected]>
Cc: John Stultz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: John Stultz <[email protected]>
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