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/*~ Welcome, wonderful reader!
*
* This is the core of c-lightning: the main file of the master daemon
* `lightningd`. It's mainly cluttered with the miscellany of setup,
* and a few startup sanity checks.
*
* The role of this daemon is to start the subdaemons, shuffle peers
* between them, handle the JSON RPC requests, bitcoind, the database
* and centralize logging. In theory, it doesn't trust the other
* daemons, though we expect `hsmd` (which holds secret keys) to be
* responsive.
*
* Comments beginning with a ~ (like this one!) are part of our shared
* adventure through the source, so they're more meta than normal code
* comments, and meant to be read in a certain order.
*/
/*~ Notice how includes are in ASCII order: this is actually enforced by
* the build system under `make check-source`. It avoids merge conflicts
* and keeps things consistent. */
#include "gossip_control.h"
#include "hsm_control.h"
#include "lightningd.h"
#include "peer_control.h"
#include "subd.h"
/*~ This is Ian Lance Taylor's libbacktrace. It turns out that it's
* horrifically difficult to obtain a decent backtrace in C; the standard
* backtrace function is useless in most programs. */
#include <backtrace.h>
/*~ These headers are from CCAN: http://ccodearchive.net.
*
* It's another one of Rusty's projects, and we copy and paste it
* automatically into the source tree here, so you should never edit
* it. There's a Makefile target update-ccan to update it (and add modules
* if CCAN_NEW is specified).
*
* The most used of these are `ccan/tal` and `ccan/take`, which we'll describe
* in detail below.
*/
#include <ccan/array_size/array_size.h>
#include <ccan/cast/cast.h>
#include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
#include <ccan/daemonize/daemonize.h>
#include <ccan/err/err.h>
#include <ccan/io/fdpass/fdpass.h>
#include <ccan/io/io.h>
#include <ccan/noerr/noerr.h>
#include <ccan/pipecmd/pipecmd.h>
#include <ccan/read_write_all/read_write_all.h>
#include <ccan/take/take.h>
#include <ccan/tal/grab_file/grab_file.h>
#include <ccan/tal/path/path.h>
#include <ccan/tal/str/str.h>
/*~ This is common code: routines shared by one or more executables
* (separate daemons, or the lightning-cli program). */
#include <common/daemon.h>
#include <common/memleak.h>
#include <common/timeout.h>
#include <common/utils.h>
#include <common/version.h>
#include <errno.h>
#include <fcntl.h>
#include <lightningd/bitcoind.h>
#include <lightningd/chaintopology.h>
#include <lightningd/channel_control.h>
#include <lightningd/connect_control.h>
#include <lightningd/invoice.h>
#include <lightningd/jsonrpc.h>
#include <lightningd/log.h>
#include <lightningd/onchain_control.h>
#include <lightningd/options.h>
#include <onchaind/onchain_wire.h>
#include <signal.h>
#include <sys/types.h>
#include <unistd.h>
/*~ The core lightning object: it's passed everywhere, and is basically a
* global variable. This new_xxx pattern is something we'll see often:
* it allocates and initializes a new structure, using *tal*, the hierarchical
* allocator. */
static struct lightningd *new_lightningd(const tal_t *ctx)
{
/*~ tal: each allocation is a child of an existing object (or NULL,
* the top-level object). When an object is freed, all the objects
* `tallocated` off it are also freed. We use it in place of malloc
* and free. For the technically inclined: tal allocations usually
* build a tree, and tal_freeing any node in the tree will result in
* the entire subtree rooted at that node to be freed.
*
* It's incredibly useful for grouping object lifetimes, as we'll see.
* For example, a `struct bitcoin_tx` has a pointer to an array of
* `struct bitcoin_tx_input`; they are allocated off the `struct
* bitcoind_tx`, so freeing the `struct bitcoind_tx` frees them all.
*
* In this case, freeing `ctx` will free `ld`:
*/
struct lightningd *ld = tal(ctx, struct lightningd);
/*~ Style note: `ctx` is declared `const`, yet we can `tallocate` from
* it. Adding/removing children is not considered to change an
* object; nor, in fact, is freeing it with tal_free(). This allows
* us to use const more liberally: the style rule here is that you
* should use 'const' on pointers if you can. */
/*~ Note that we generally EXPLICITLY #if-wrap DEVELOPER code. This
* is a nod to keeping it minimal and explicit: we need this code for
* testing, but its existence means we're not actually testing the
* same exact code users will be running. */
#if DEVELOPER
ld->dev_debug_subdaemon = NULL;
ld->dev_disconnect_fd = -1;
ld->dev_subdaemon_fail = false;
ld->dev_allow_localhost = false;
/*~ Behaving differently depending on environment variables is a hack,
* *but* hacks are allowed for dev-mode stuff. In this case, there's
* a significant overhead to the memory leak detection stuff, and we
* can't use it under valgrind (an awesome runtime memory usage
* detector for C and C++ programs), so the test harness uses this var
* to disable it in that case. */
if (getenv("LIGHTNINGD_DEV_MEMLEAK"))
memleak_init();
#endif
/*~ These are CCAN lists: an embedded double-linked list. It's not
* really typesafe, but relies on convention to access the contents.
* It's inspired by the closely-related Linux kernel list.h.
*
* You declare them as a `struct list_head` (or use the LIST_HEAD()
* macro which doesn't work on dynamically-allocated objects like `ld`
* here). The item which will go into the list must declared a
* `struct list_node` for each list it can be in.
*
* The most common operations are list_head_init(), list_add(),
* list_del() and list_for_each().
*
* This method of manually declaring the list hooks avoids dynamic
* allocations to put things into a list. */
list_head_init(&ld->peers);
/*~ These are hash tables of incoming and outgoing HTLCs (contracts),
* defined as `struct htlc_in` and `struct htlc_out`in htlc_end.h.
* The hash tables are declared there using the very ugly
* HTABLE_DEFINE_TYPE macro. The key is the channel the HTLC is in
* and the 64-bit htlc-id which is unique for that channel and
* direction. That htlc-id is used in the inter-peer wire protocol,
* so it is the logical key.
*
* There aren't usually many HTLCs, so we could have just used a linked
* list attached to the channel structure itself, or even left them in
* the database rather than making an in-memory version. Obviously
* I was in a premature optimization mood when I wrote this: */
htlc_in_map_init(&ld->htlcs_in);
htlc_out_map_init(&ld->htlcs_out);
/*~ We have a two-level log-book infrastructure: we define a 20MB log
* book to hold all the entries (and trims as necessary), and multiple
* log objects which each can write into it, each with a unique
* prefix. */
ld->log_book = new_log_book(20*1024*1024, LOG_INFORM);
/*~ Note the tal context arg (by convention, the first argument to any
* allocation function): ld->log will be implicitly freed when ld
* is. */
ld->log = new_log(ld, ld->log_book, "lightningd(%u):", (int)getpid());
ld->logfile = NULL;
/*~ We explicitly set these to NULL: if they're still NULL after option
* parsing, we know they're to be set to the defaults. */
ld->alias = NULL;
ld->rgb = NULL;
list_head_init(&ld->connects);
list_head_init(&ld->waitsendpay_commands);
list_head_init(&ld->sendpay_commands);
list_head_init(&ld->close_commands);
list_head_init(&ld->ping_commands);
/*~ Tal also explicitly supports arrays: it stores the number of
* elements, which can be accessed with tal_count() (or tal_bytelen()
* for raw bytecount). It's common for simple arrays to use
* tal_resize() to expand, which does not work on NULL. So we start
* with an zero-length array. */
ld->proposed_wireaddr = tal_arr(ld, struct wireaddr_internal, 0);
ld->proposed_listen_announce = tal_arr(ld, enum addr_listen_announce, 0);
ld->portnum = DEFAULT_PORT;
ld->listen = true;
ld->autolisten = true;
ld->reconnect = true;
/*~ This is from ccan/timer: it is efficient for the case where timers
* are deleted before expiry (as is common with timeouts) using an
* ingenious bucket system which more precisely sorts timers as they
* approach expiry. It's a fascinating implementation you should read
* if you have a spare few hours. */
timers_init(&ld->timers, time_mono());
/*~ This is detailed in chaintopology.c */
ld->topology = new_topology(ld, ld->log);
ld->daemon = false;
ld->config_filename = NULL;
ld->pidfile = NULL;
ld->ini_autocleaninvoice_cycle = 0;
ld->ini_autocleaninvoice_expiredby = 86400;
ld->proxyaddr = NULL;
ld->use_proxy_always = false;
ld->pure_tor_setup = false;
ld->tor_service_password = NULL;
ld->max_funding_unconfirmed = 2016;
return ld;
}
/*~ We list our daemons here so on startup we can test they're the
* correct versions and that they exist. */
static const char *subdaemons[] = {
"lightning_channeld",
"lightning_closingd",
"lightning_connectd",
"lightning_gossipd",
"lightning_hsmd",
"lightning_onchaind",
"lightning_openingd"
};
/*~ Check we can run them, and check their versions */
void test_subdaemons(const struct lightningd *ld)
{
size_t i;
/*~ CCAN's ARRAY_SIZE() should always be used on defined arrays like
* the subdaemons array above. You can calculate the number of
* elements it has using `sizeof(subdaemons)/sizeof(subdaemons[0])`
* but if `subdaemons` were refactored into a pointer (eg. to make
* it a dynamic array) that would erroneously evaluate to `1`.
*
* ARRAY_SIZE will cause a compiler error if the argument is actually
* a pointer, not an array. */
for (i = 0; i < ARRAY_SIZE(subdaemons); i++) {
int outfd;
/*~ CCAN's path module uses tal, so wants a context to
* allocate from. We have a magic convenience context
* `tmpctx` for temporary allocations like this.
*
* Because all our daemons at their core are of form `while
* (!stopped) handle_events();` (an event loop pattern), we
* can free `tmpctx` in that top-level loop after each event
* is handled.
*/
const char *dpath = path_join(tmpctx, ld->daemon_dir, subdaemons[i]);
const char *verstring;
/*~ CCAN's pipecmd module is like popen for grownups: it
* takes pointers to fill in stdout, stdin and stderr file
* descriptors if desired, and the remainder of arguments
* are the command and its argument. */
pid_t pid = pipecmd(&outfd, NULL, &outfd,
dpath, "--version", NULL);
/*~ Our logging system: spam goes in at log_debug level, but
* logging is mainly added by developer necessity and removed
* by developer/user complaints . The only strong convention
* is that log_broken() is used for "should never happen".
*
* Note, however, that logging takes care to preserve the
* global `errno` which is set above. */
log_debug(ld->log, "testing %s", dpath);
/*~ ccan/err is a wrapper around BSD's err.h, which defines
* the convenience functions err() (error with message
* followed by a string based on errno) and errx() (same,
* but no errno string). */
if (pid == -1)
err(1, "Could not run %s", dpath);
/*~ CCAN's grab_file module contains a routine to read into a
* tallocated buffer until EOF */
verstring = grab_fd(tmpctx, outfd);
/*~ Like many CCAN modules, it set errno on failure, which
* err (ccan/err, but usually just the BSD <err.h>) prints */
if (!verstring)
err(1, "Could not get output from %s", dpath);
/*~ strstarts is from CCAN/str. */
if (!strstarts(verstring, version())
|| verstring[strlen(version())] != '\n')
errx(1, "%s: bad version '%s'",
subdaemons[i], verstring);
}
}
/* Check if all subdaemons exist in specified directory. */
static bool has_all_subdaemons(const char *daemon_dir)
{
size_t i;
bool missing_daemon = false;
for (i = 0; i < ARRAY_SIZE(subdaemons); ++i) {
if (!path_is_file(path_join(tmpctx, daemon_dir, subdaemons[i]))) {
missing_daemon = true;
break;
}
}
return !missing_daemon;
}
/* Returns the directory this executable is running from */
static const char *find_my_directory(const tal_t *ctx, const char *argv0)
{
/* find_my_abspath simply exits on failure, so never returns NULL. */
const char *me = find_my_abspath(NULL, argv0);
/*~ The caller just wants the directory we're in.
*
* Note the magic `take()` macro here: it annotates a pointer as "to
* be taken", and the recipient is expected to take ownership of the
* pointer. This improves efficiency because the recipient might
* choose to use or even keep it rather than make a copy (or it
* might just free it).
*
* Many CCAN and our own routines support this, but if you hand a
* `take()` to a routine which *doesn't* expect it, unfortunately you
* don't get a compile error (we have runtime detection for this
* case, however).
*/
return path_dirname(ctx, take(me));
}
/*~ This returns the PKGLIBEXEC path which is where binaries get installed.
* Note the `TAKES` annotation which indicates that the `my_path` parameter
* can be take(); in which case, this function will handle freeing it.
*
* TAKES is only a convention unfortunately, and ignored by the compiler.
*/
static const char *find_my_pkglibexec_path(const tal_t *ctx,
const char *my_path TAKES)
{
const char *pkglibexecdir;
/*~`path_join` is declared in ccan/path/path.h as:
*
* char *path_join(const tal_t *ctx,
* const char *base TAKES, const char *a TAKES);
*
* So, as we promised with 'TAKES' in our own declaration, if the
* caller has called `take()` the `my_path` parameter, path_join()
* will free it. */
pkglibexecdir = path_join(ctx, my_path, BINTOPKGLIBEXECDIR);
/*~ Sometimes take() can be more efficient, since the routine can
* manipulate the string in place. This is the case here. */
return path_simplify(ctx, take(pkglibexecdir));
}
/* Determine the correct daemon dir. */
static const char *find_daemon_dir(const tal_t *ctx, const char *argv0)
{
const char *my_path = find_my_directory(ctx, argv0);
/* If we're running in-tree, all the subdaemons are with lightningd. */
if (has_all_subdaemons(my_path))
return my_path;
/* Otherwise we assume they're in the installed dir. */
return find_my_pkglibexec_path(ctx, take(my_path));
}
/*~ We like to free everything on exit, so valgrind doesn't complain. In some
* ways it would be neater not to do this, but it turns out some transient
* objects still need cleaning. */
static void shutdown_subdaemons(struct lightningd *ld)
{
struct peer *p;
/*~ tal supports *destructors* using `tal_add_destructor()`; the most
* common use is for an object to delete itself from a linked list
* when it's freed.
*
* As a result, freeing an object (which frees any tal objects
* allocated off it, and any allocated off them, etc) may cause
* callbacks; in this case, some objects freed here can cause database
* writes, which must be inside a transaction. */
db_begin_transaction(ld->wallet->db);
/* Let everyone shutdown cleanly. */
close(ld->hsm_fd);
/*~ The three "global" daemons, which we shutdown explicitly: we
* give them 10 seconds to exit gracefully before killing them. */
subd_shutdown(ld->connectd, 10);
subd_shutdown(ld->gossip, 10);
subd_shutdown(ld->hsm, 10);
/* Now we free all the HTLCs */
free_htlcs(ld, NULL);
/*~ For every peer, we free every channel. On allocation the peer was
* given a destructor (`destroy_peer`) which removes itself from the
* list. Thus we use list_top() not list_pop() here. */
while ((p = list_top(&ld->peers, struct peer, list)) != NULL) {
struct channel *c;
/*~ A peer can have multiple channels; we only allow one to be
* open at any time, but we remember old ones for 100 blocks,
* after all the outputs we care about are spent. */
while ((c = list_top(&p->channels, struct channel, list))
!= NULL) {
/* Removes itself from list as we free it */
tal_free(c);
}
/* A peer may have a channel in the process of opening. */
if (p->uncommitted_channel) {
struct uncommitted_channel *uc = p->uncommitted_channel;
/* Setting to NULL stops destroy_uncommitted_channel
* from trying to remove peer from db! */
p->uncommitted_channel = NULL;
tal_free(uc);
}
/* Removes itself from list as we free it */
tal_free(p);
}
/*~ Commit the transaction. Note that the db is actually
* single-threaded, so commits never fail and we don't need
* spin-and-retry logic everywhere. */
db_commit_transaction(ld->wallet->db);
}
/*~ Chainparams are the parameters for eg. testnet vs mainnet. This wrapper
* saves lots of struggles with our 80-column guideline! */
const struct chainparams *get_chainparams(const struct lightningd *ld)
{
/* "The lightningd is connected to the blockchain."
* "The blockchain is connected to the bitcoind API."
* "The bitcoind API is connected chain parameters."
* -- Worst childhood song ever. */
return ld->topology->bitcoind->chainparams;
}
/*~ Our wallet logic needs to know what outputs we might be interested in. We
* use BIP32 (a.k.a. "HD wallet") to generate keys from a single seed, so we
* keep the maximum-ever-used key index in the db, and add them all to the
* filter here. */
static void init_txfilter(struct wallet *w, struct txfilter *filter)
{
/*~ This is defined in libwally, so we didn't have to reimplement */
struct ext_key ext;
/*~ Note the use of ccan/short_types u64 rather than uint64_t.
* Thank me later. */
u64 bip32_max_index;
bip32_max_index = db_get_intvar(w->db, "bip32_max_index", 0);
/*~ One of the C99 things I unequivocally approve: for-loop scope. */
for (u64 i = 0; i <= bip32_max_index; i++) {
if (bip32_key_from_parent(w->bip32_base, i, BIP32_FLAG_KEY_PUBLIC, &ext) != WALLY_OK) {
abort();
}
txfilter_add_derkey(filter, ext.pub_key);
}
}
/*~ The normal advice for daemons is to move into the root directory, so you
* don't prevent unmounting whatever filesystem you happen to start in.
*
* But we define every path relative to our (~/.lightning) data dir, so we
* make sure we stay there.
*/
static void daemonize_but_keep_dir(struct lightningd *ld)
{
/* daemonize moves us into /, but we want to be here */
const char *cwd = path_cwd(NULL);
/*~ SQLite3 does NOT like being open across fork(), a.k.a. daemonize() */
db_close_for_fork(ld->wallet->db);
if (!cwd)
fatal("Could not get current directory: %s", strerror(errno));
if (!daemonize())
fatal("Could not become a daemon: %s", strerror(errno));
/*~ Move back: important, since lightning dir may be relative! */
if (chdir(cwd) != 0)
fatal("Could not return to directory %s: %s",
cwd, strerror(errno));
db_reopen_after_fork(ld->wallet->db);
/*~ Why not allocate cwd off tmpctx? Probably because this code predates
* tmpctx. So we free manually here. */
tal_free(cwd);
}
/*~ It's pretty standard behaviour (especially for daemons) to create and
* file-lock a pidfile. This not only prevents accidentally running multiple
* daemons on the same database at once, but lets nosy sysadmins see what pid
* the currently-running daemon is supposed to be. */
static int pidfile_create(const struct lightningd *ld)
{
int pid_fd;
/* Create PID file */
pid_fd = open(ld->pidfile, O_WRONLY|O_CREAT, 0640);
if (pid_fd < 0)
err(1, "Failed to open PID file");
/* Lock PID file, so future lockf will fail. */
if (lockf(pid_fd, F_TLOCK, 0) < 0)
/* Problem locking file */
err(1, "lightningd already running? Error locking PID file");
/*~ As closing the file will remove the lock, we need to keep it open;
* the OS will close it implicitly when we exit for any reason. */
return pid_fd;
}
/*~ Writing the pid into the lockfile provides a useful clue to users as to
* what created it; however, we can't do that until we've got a stable process
* id, and if --daemon is specified, that's quite late. */
static void pidfile_write(const struct lightningd *ld, int pid_fd)
{
char *pid;
/*~ Note that tal_fmt() is what asprintf() dreams of being. */
pid = tal_fmt(tmpctx, "%d\n", getpid());
/*~ CCAN's write_all writes to a file descriptor, looping if necessary
* (which, on a file unlike a socket, is never, for historical UNIX
* reasons). It also isn't declared with GCC's warn_unused_result
* which write() is when FORTIFY_SOURCE is defined, so we're allowed
* to ignore the result without jumping through hoops. */
write_all(pid_fd, pid, strlen(pid));
}
/*~ ccan/io allows overriding the poll() function that is the very core
* of the event loop it runs for us. We override it so that we can do
* extra sanity checks, and it's also a good point to free the tmpctx. */
static int io_poll_lightningd(struct pollfd *fds, nfds_t nfds, int timeout)
{
/*~ In particular, we should *not* have left a database transaction
* open! */
db_assert_no_outstanding_statements();
/* The other checks and freeing tmpctx are common to all daemons. */
return daemon_poll(fds, nfds, timeout);
}
/*~ Ever had one of those functions which doesn't quite fit anywhere? Me too.
* Implementing a generic notifier framework is overkill in a static codebase
* like this, and it's always better to have compile-time calls than runtime,
* as it makes the code more explicit. But pasting in direct calls is also an
* abstraction violation, so we use this middleman function. */
void notify_new_block(struct lightningd *ld, u32 block_height)
{
/* Inform our subcomponents individually. */
htlcs_notify_new_block(ld, block_height);
channel_notify_new_block(ld, block_height);
}
int main(int argc, char *argv[])
{
struct lightningd *ld;
u32 min_blockheight, max_blockheight;
int connectd_gossipd_fd, pid_fd;
/*~ What happens in strange locales should stay there. */
setup_locale();
/*~ Every daemon calls this in some form: the hooks are for dumping
* backtraces when we crash (if supported on this platform). */
daemon_setup(argv[0], log_backtrace_print, log_backtrace_exit);
/*~ There's always a battle between what a constructor like this
* should do, and what should be added later by the caller. In
* general, because we use valgrind heavily for testing, we prefer not
* to initialize unused fields which we expect the caller to set:
* valgrind will warn us if we make decisions based on uninitialized
* variables. */
ld = new_lightningd(NULL);
/* Figure out where our daemons are first. */
ld->daemon_dir = find_daemon_dir(ld, argv[0]);
if (!ld->daemon_dir)
errx(1, "Could not find daemons");
/*~ The ccan/opt code requires registration then parsing; we
* mimic this API here, even though they're on separate lines.*/
register_opts(ld);
/*~ Handle options and config; move to .lightningd (--lightning-dir) */
handle_opts(ld, argc, argv);
/*~ Make sure we can reach the subdaemons, and versions match. */
test_subdaemons(ld);
/*~ Our "wallet" code really wraps the db, which is more than a simple
* bitcoin wallet (though it's that too). It also stores channel
* states, invoices, payments, blocks and bitcoin transactions. */
ld->wallet = wallet_new(ld, ld->log, &ld->timers);
/*~ We keep a filter of scriptpubkeys we're interested in. */
ld->owned_txfilter = txfilter_new(ld);
/*~ This is the ccan/io central poll override from above. */
io_poll_override(io_poll_lightningd);
/*~ Set up the HSM daemon, which knows our node secret key, so tells
* us who we are.
*
* HSM stands for Hardware Security Module, which is the industry
* standard of key storage; ours is in software for now, so the name
* doesn't really make sense, but we can't call it the Badly-named
* Daemon Software Module. */
hsm_init(ld);
/*~ Our default color and alias are derived from our node id, so we
* can only set those now (if not set by config options). */
setup_color_and_alias(ld);
/*~ Set up connect daemon: this manages receiving and making
* TCP connections. It needs to talk to the gossip daemon
* which knows (via node_announcement messages) the public
* addresses of nodes, so connectd_init hands it one end of a
* socket pair, and gives us the other */
connectd_gossipd_fd = connectd_init(ld);
/*~ The gossip daemon looks after the routing gossip;
* channel_announcement, channel_update, node_announcement and gossip
* queries. */
gossip_init(ld, connectd_gossipd_fd);
/*~ We do every database operation within a transaction; usually this
* is covered by the infrastructure (eg. opening a transaction before
* handling a message or expiring a timer), but for startup we do this
* explicitly. */
db_begin_transaction(ld->wallet->db);
/*~ Our default names, eg. for the database file, are not dependent on
* the network. Instead, the db knows what chain it belongs to, and we
* simple barf here if it's wrong. */
if (!wallet_network_check(ld->wallet, get_chainparams(ld)))
errx(1, "Wallet network check failed.");
/*~ Initialize the transaction filter with our pubkeys. */
init_txfilter(ld->wallet, ld->owned_txfilter);
/*~ Set up invoice autoclean. */
wallet_invoice_autoclean(ld->wallet,
ld->ini_autocleaninvoice_cycle,
ld->ini_autocleaninvoice_expiredby);
/*~ Pull peers, channels and HTLCs from db. */
load_channels_from_wallet(ld);
/*~ Get the blockheight we are currently at, UINT32_MAX is used to signal
* an uninitialized wallet and that we should start off of bitcoind's
* current height */
wallet_blocks_heights(ld->wallet, UINT32_MAX,
&min_blockheight, &max_blockheight);
/*~ If we were asked to rescan from an absolute height (--rescan < 0)
* then just go there. Otherwise compute the diff to our current height,
* lowerbounded by 0. */
if (ld->config.rescan < 0)
max_blockheight = -ld->config.rescan;
else if (max_blockheight < (u32)ld->config.rescan)
max_blockheight = 0;
else if (max_blockheight != UINT32_MAX)
max_blockheight -= ld->config.rescan;
/*~ That's all of the wallet db operations for now. */
db_commit_transaction(ld->wallet->db);
/*~ Initialize block topology. This does its own io_loop to
* talk to bitcoind, so does its own db transactions. */
setup_topology(ld->topology, &ld->timers,
min_blockheight, max_blockheight);
/*~ Now create the PID file: this errors out if there's already a
* daemon running, so we call before trying to create an RPC socket. */
pid_fd = pidfile_create(ld);
/*~ Create RPC socket: now lightning-cli can send us JSON RPC commands
* over a UNIX domain socket specified by `ld->rpc_filename`. */
setup_jsonrpc(ld, ld->rpc_filename);
/*~ We defer --daemon until we've completed most initialization: that
* way we'll exit with an error rather than silently exiting 0, then
* realizing we can't start and forcing the confused user to read the
* logs. */
if (ld->daemon)
daemonize_but_keep_dir(ld);
/*~ We have to do this after daemonize, since that changes our pid! */
pidfile_write(ld, pid_fd);
/*~ Activate connect daemon. Needs to be after the initialization of
* chaintopology, otherwise peers may connect and ask for
* uninitialized data. */
connectd_activate(ld);
/*~ "onchaind" is a dumb daemon which tries to get our funds back: it
* doesn't handle reorganizations, but it's idempotent, so we can
* simply just restart it if the chain moves. Similarly, we replay it
* chain events from the database on restart, beginning with the
* "funding transaction spent" event which creates it. */
onchaind_replay_channels(ld);
/*~ Mark ourselves live.
*
* Note the use of type_to_string() here: it's a typesafe formatter,
* often handed 'tmpctx' like here to allocate a throwaway string for
* formatting. json_escape() avoids printing weird characters in our
* log. And tal_hex() is a helper from utils which returns a hex string;
* it's assumed that the argument was allocated with tal or tal_arr
* so it can use tal_bytelen() to get the length. */
log_info(ld->log, "Server started with public key %s, alias %s (color #%s) and lightningd %s",
type_to_string(tmpctx, struct pubkey, &ld->id),
json_escape(tmpctx, (const char *)ld->alias)->s,
tal_hex(tmpctx, ld->rgb), version());
/*~ This is where we ask connectd to reconnect to any peers who have
* live channels with us, and makes sure we're watching the funding
* tx. */
activate_peers(ld);
/*~ Now that all the notifications for transactions are in place, we
* can start the poll loop which queries bitcoind for new blocks. */
begin_topology(ld->topology);
/*~ Setting this (global) activates the crash log: we don't usually need
* a backtrace if we fail during startup. */
crashlog = ld->log;
/*~ The root of every backtrace (almost). This is our main event
* loop. */
for (;;) {
/* ~ccan/io's io_loop() continuously calls
* io_poll_lightningd() for all file descriptors registered
* with it, then calls their callbacks or closes them if they
* fail, as appropriate.
*
* It will only exit if there's an expired timer, *or* someone
* calls io_break, or if there are no more file descriptors
* (which never happens in our code). */
struct timer *expired;
void *v = io_loop(&ld->timers, &expired);
/*~ We use io_break(ld) to shut down. */
if (v == ld)
break;
/*~ Notice that timers are called here in the event loop like
* anything else, so there are no weird concurrency issues. */
if (expired) {
db_begin_transaction(ld->wallet->db);
timer_expired(ld, expired);
db_commit_transaction(ld->wallet->db);
}
}
shutdown_subdaemons(ld);
/* Clean up the JSON-RPC. This needs to happen in a DB transaction since
* it might actually be touching the DB in some destructors, e.g.,
* unreserving UTXOs (see #1737) */
db_begin_transaction(ld->wallet->db);
tal_free(ld->rpc_listener);
db_commit_transaction(ld->wallet->db);
remove(ld->pidfile);
/* FIXME: pay can have children off tmpctx which unlink from
* ld->payments, so clean that up. */
clean_tmpctx();
tal_free(ld);
opt_free_table();
#if DEVELOPER
memleak_cleanup();
#endif
daemon_shutdown();
/*~ Farewell. Next stop: hsmd/hsmd.c. */
return 0;
}