On 2025/05/08 23:44, John Johansen wrote: > On 5/8/25 05:55, Tetsuo Handa wrote: >> On 2025/05/08 17:25, John Johansen wrote: >>> That is fine. But curious I am curious what the interface would look like >>> to fit TOMOYO's >>> needs. >> >> Stream (like "FILE *") with restart from the beginning (like rewind(fp)) >> support. >> That is, the caller can read/write at least one byte at a time, and written >> data >> is processed upon encountering '\n'. >> > > that can be emulated within the current sycall, where the lsm maintains a > buffer.
That cannot be emulated, for there is no event that is automatically triggered when the process terminates (i.e. implicit close() upon exit()) in order to release the buffer the LSM maintains. > Are you asking to also read data back out as well, that could be added, but > doing > a syscall per byte here or through the fs is going to have fairly high > overhead. At least one byte means arbitrary bytes; that is, the caller does not need to read or write the whole policy at one syscall. > > Without understanding the requirement it would seem to me, that it would be > better to emulate that file buffer manipulation in userspace similar say C++ > stringstreams, and then write the syscall when done. The size of the whole policy in byte varies a lot.
