Function main

lightningd/lightningd.c:868–1292

}

int main(int argc, char *argv[])
{
	struct lightningd *ld;
	u32 min_blockheight, max_blockheight;
	int connectd_gossipd_fd;
	int stop_fd;
	struct timers *timers;
	const char *stop_response;
	struct htlc_in_map *unconnected_htlcs_in;
	struct ext_key *bip32_base;
	int sigchld_rfd;
	struct io_conn *sigchld_conn;
	int exit_code = 0;
	char **orig_argv;
	bool try_reexec;

	/*~ We fork out new processes very very often; every channel gets its
	 * own process, for example, and we have `hsmd` and `gossipd` and
	 * the plugins as well.
	 * Now, we also keep around several file descriptors (`fd`s), including
	 * file descriptors to communicate with `hsmd` which is a privileged
	 * process with access to private keys and is therefore very sensitive.
	 * Thus, we need to close all file descriptors other than what the
	 * forked-out new process should have ASAP.
	 *
	 * We do this by using the `ccan/closefrom` module, which implements
	 * an emulation for the `closefrom` syscall on BSD and Solaris.
	 * This emulation tries to use the fastest facility available on the
	 * system (`close_range` syscall on Linux 5.9+, snooping through
	 * `/proc/$PID/fd` on many OSs (but requires procps to be mounted),
	 * the actual `closefrom` call if available, etc.).
	 * As a fallback if none of those are available on the system, however,
	 * it just iterates over the theoretical range of possible file
	 * descriptors.
	 *
	 * On some systems, that theoretical range can be very high, up to
	 * `INT_MAX` in the worst case.
	 * If the `closefrom` emulation has to fall back to this loop, it
	 * can be very slow; fortunately, the emulation will also inform
	 * us of that via the `closefrom_may_be_slow` function, and also has
	 * `closefrom_limit` to limit the number of allowed file descriptors
	 * *IF AND ONLY IF* `closefrom_may_be_slow()` is true.
	 *
	 * On systems with a fast `closefrom` then `closefrom_limit` does
	 * nothing.
	 *
	 * Previously we always imposed a limit of 1024 file descriptors
	 * (because we used to always iterate up to limit instead of using
	 * some OS facility, because those were non-portable and needed
	 * code for each OS), until @whitslack went and made >1000 channels
	 * and hit the 1024 limit.
	 */
	closefrom_limit(4096);

	/*~ What happens in strange locales should stay there. */
	setup_locale();

	/*~ This sets up SIGCHLD to make sigchld_rfd readable. */