My IRC chatbot – SeeBorg.

My Music.

Links that I'd like to hoard.

Undocumented or rare but very useful.

• close(2) with enabled SO_LINGER results in block even if socket is nonblocking, blocks for 'linger_timeout' at most.
• To fix iosnoop dynamic variable drops, edit it and add this:

  #pragma D option dynvarsize=16m

  Tweak this value up until you stop getting dynamic variable drops.

• To avoid creating temporary files:

  diff -u <(sort /etc/passwd) <(shuf /etc/passwd | sort)

• To disable mobile time machine:

  sudo tmutil disablelocal

• To have a meaningful stack trace with optimized code:

  -fno-optimize-sibling-calls

• To flush caches on Linux (I don't need to do that very often nowadays):

  sudo sh -c "sync; echo 3 > /proc/sys/vm/drop_caches"

  OSX:

  purge

• Disable OSX UBC for a given file globally:

  fcntl(fd, F_GLOBAL_NOCACHE, 1);

int sendfile(int fd, int s, off_t offset, off_t *len, struct sf_hdtr* hdtr, int flags);

• Offset can't fall beyond EOF
• len can't be NULL
• on return, len is number of bytes successfully sent
• returns EAGAIN on non-blocking fd
• on EINTR, len of 0 does not mean everything was copied
• len 0 → till EOF
• FD must point to regular file
• s must be sock_stream socket

int sendfile(int fd, int s, off_t offset, size_t nbytes, struct sf_hdtr *hdtr, off_t *sbytes, int flags);

• offset can't fall beyond EOF
• nbytes 0 → till eof
• sbytes – total bytes sent
• flags sf_nodiskio – no blocking or return EBUSY
• fd must be file descriptor
• s must be sock_stream descriptor
• on EINTR, some data might be already sent

ssize_t sendfile(int out, int in, off_t *off, size_t len);

• in must be regular file
• out must be sock_stream socket
• off is pointer to offset
• on return, off points to byte following last byte that was read
• does not modify in_fd offset
• does modify out_fd offset
• on EINTR, no data was transferred

ssize_t sendfile(int out, int in, off_t *offset, size_t count);

• If offset is set to NULL, update in_fd's offset
• else write to offset
• in_fd must support mmap()
• in_fd can't be socket
• count can't be zero
• user should fall back to read()/write() if sendfile() fails with EINVAL or ENOSYS
• returns EAGAIN on non-blocking FD

(2 days, 16 hours ago) Никогда в жизни так много не кашлял.