mirror of
https://github.com/aljazceru/lightning.git
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lightningd/subdaemon: routines to create daemons and get request/response.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
346
lightningd/subdaemon.c
Normal file
346
lightningd/subdaemon.c
Normal file
@@ -0,0 +1,346 @@
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#include <ccan/io/fdpass/fdpass.h>
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#include <ccan/io/io.h>
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#include <ccan/noerr/noerr.h>
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#include <ccan/tal/path/path.h>
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#include <daemon/log.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <lightningd/lightningd.h>
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#include <lightningd/subdaemon.h>
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#include <status.h>
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#include <stdarg.h>
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#include <sys/socket.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <wire/wire.h>
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#include <wire/wire_io.h>
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/* A single request/response for subdaemon. */
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struct subdaemon_req {
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struct subdaemon *sd;
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/* In sd->reqs */
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struct list_node list;
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/* Request message. */
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const u8 *msg_out;
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int fd_out;
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/* Response */
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u8 *req_in;
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int *fd_in;
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/* Callback when response comes in. */
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void (*req)(struct subdaemon *, const u8 *msg_in, void *req_data);
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void *req_data;
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};
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static bool move_fd(int from, int to)
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{
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if (dup2(from, to) == -1)
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return false;
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close(from);
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return true;
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}
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/* We use sockets, not pipes, because fds are bidir. */
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static int subdaemon(const char *dir, const char *name,
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int *statusfd, int *reqfd, va_list ap)
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{
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int childreq[2], childstatus[2], execfail[2];
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pid_t childpid;
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int err, fd;
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if (socketpair(AF_LOCAL, SOCK_STREAM, 0, childstatus) != 0)
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goto fail;
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if (reqfd) {
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if (socketpair(AF_LOCAL, SOCK_STREAM, 0, childreq) != 0)
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goto close_childstatus_fail;
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} else {
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childreq[0] = open("/dev/null", O_RDONLY);
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if (childreq[0] < 0)
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goto close_childstatus_fail;
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}
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if (pipe(execfail) != 0)
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goto close_reqfd_fail;
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if (fcntl(execfail[1], F_SETFD, fcntl(execfail[1], F_GETFD)
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| FD_CLOEXEC) < 0)
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goto close_execfail_fail;
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childpid = fork();
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if (childpid < 0)
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goto close_execfail_fail;
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if (childpid == 0) {
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int fdnum = 4;
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if (reqfd)
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close(childreq[0]);
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close(childstatus[0]);
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close(execfail[0]);
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// Status = STDOUT
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if (childstatus[1] != STDOUT_FILENO) {
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if (!move_fd(childstatus[1], STDOUT_FILENO))
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goto child_errno_fail;
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}
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// Req = STDIN.
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if (childreq[1] != STDIN_FILENO) {
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if (!move_fd(childreq[1], STDIN_FILENO))
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goto child_errno_fail;
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}
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/* Dup any extra fds up first. */
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while ((fd = va_arg(ap, int)) != -1) {
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/* If these were stdin or stdout, dup2 closed! */
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assert(fd != STDIN_FILENO);
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assert(fd != STDOUT_FILENO);
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if (!move_fd(fd, fdnum))
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goto child_errno_fail;
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fdnum++;
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}
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execl(path_join(NULL, dir, name), name, NULL);
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child_errno_fail:
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err = errno;
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/* Gcc's warn-unused-result fail. */
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if (write(execfail[1], &err, sizeof(err))) {
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;
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}
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exit(127);
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}
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if (reqfd)
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close(childreq[1]);
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close(childstatus[1]);
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close(execfail[1]);
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while ((fd = va_arg(ap, int)) != -1)
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close(fd);
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/* Child will close this without writing on successful exec. */
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if (read(execfail[0], &err, sizeof(err)) == sizeof(err)) {
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close(execfail[0]);
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waitpid(childpid, NULL, 0);
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errno = err;
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return -1;
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}
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close(execfail[0]);
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*statusfd = childstatus[0];
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if (reqfd)
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*reqfd = childreq[0];
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return childpid;
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close_execfail_fail:
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close_noerr(execfail[0]);
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close_noerr(execfail[1]);
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close_reqfd_fail:
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if (reqfd)
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close_noerr(childreq[1]);
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close_noerr(childreq[0]);
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close_childstatus_fail:
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close_noerr(childstatus[0]);
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close_noerr(childstatus[1]);
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fail:
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return -1;
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}
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static struct io_plan *status_read(struct io_conn *conn, struct subdaemon *sd);
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static struct io_plan *status_process(struct io_conn *conn, struct subdaemon *sd)
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{
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int type = fromwire_peektype(sd->status_in);
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const char *str;
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int str_len;
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if (type == -1) {
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log_unusual(sd->log, "ERROR: Invalid status output");
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return io_close(conn);
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}
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/* If it's a string. */
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str_len = tal_count(sd->status_in) - sizeof(be16);
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str = (const char *)sd->status_in + sizeof(be16);
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if (type == STATUS_TRACE)
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log_debug(sd->log, "TRACE: %.*s", str_len, str);
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else if (type & STATUS_FAIL)
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log_unusual(sd->log, "FAILURE %s: %.*s",
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sd->statusname(type), str_len, str);
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else {
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log_info(sd->log, "UPDATE %s", sd->statusname(type));
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tal_free(sd->last_status);
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/* Keep last status around. */
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sd->last_status = tal_steal(sd, sd->status_in);
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sd->status_in = NULL;
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}
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sd->status_in = tal_free(sd->status_in);
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return status_read(conn, sd);
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}
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static struct io_plan *status_read(struct io_conn *conn, struct subdaemon *sd)
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{
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return io_read_wire(conn, sd, &sd->status_in, status_process, sd);
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}
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static struct io_plan *req_next(struct io_conn *conn, struct subdaemon *sd);
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static void destroy_subdaemon(struct subdaemon *sd)
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{
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int status;
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switch (waitpid(sd->pid, &status, WNOHANG)) {
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case 0:
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log_debug(sd->log, "Status closed, but not exited. Killing");
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kill(sd->pid, SIGKILL);
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waitpid(sd->pid, &status, 0);
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break;
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case -1:
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log_unusual(sd->log, "Status closed, but waitpid %i says %s",
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sd->pid, strerror(errno));
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status = -1;
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break;
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}
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if (sd->finished)
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sd->finished(sd, status);
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}
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struct subdaemon *new_subdaemon(const tal_t *ctx,
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struct lightningd *ld,
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const char *name,
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const char *(*statusname)(int status),
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const char *(*reqname)(int req),
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void (*finished)(struct subdaemon *, int),
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...)
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{
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va_list ap;
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struct subdaemon *sd = tal(ctx, struct subdaemon);
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int req_fd, status_fd;
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va_start(ap, finished);
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sd->pid = subdaemon(ld->daemon_dir, name, &status_fd,
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reqname ? &req_fd : NULL, ap);
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va_end(ap);
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if (sd->pid == (pid_t)-1) {
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log_unusual(ld->log, "subdaemon %s failed: %s",
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name, strerror(errno));
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return tal_free(sd);
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}
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sd->ld = ld;
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sd->log = new_log(sd, ld->dstate.log_book, "%s(%u):", name, sd->pid);
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sd->name = name;
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sd->finished = finished;
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sd->statusname = statusname;
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sd->last_status = NULL;
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list_head_init(&sd->reqs);
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tal_add_destructor(sd, destroy_subdaemon);
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/* Status conn actually owns daemon: we die when it does. */
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sd->status_conn = io_new_conn(ctx, status_fd, status_read, sd);
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tal_steal(sd->status_conn, sd);
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sd->reqname = reqname;
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if (reqname)
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sd->req_conn = io_new_conn(sd, req_fd, req_next, sd);
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else
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sd->req_conn = NULL;
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log_info(sd->log, "pid %u, statusfd %i, reqfd %i",
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sd->pid, status_fd, req_fd);
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return sd;
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}
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static struct io_plan *req_finished_reply(struct io_conn *conn,
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struct subdaemon_req *sr)
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{
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struct subdaemon *sd = sr->sd;
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sr->req(sd, sr->req_in, sr->req_data);
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tal_free(sr);
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return req_next(conn, sd);
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}
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static struct io_plan *req_process_replymsg(struct io_conn *conn,
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struct subdaemon_req *sr)
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{
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int type = fromwire_peektype(sr->req_in);
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if (type == -1) {
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log_unusual(sr->sd->log, "ERROR: Invalid request output");
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return io_close(conn);
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}
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log_debug(sr->sd->log, "Received req response %s len %zu",
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sr->sd->reqname(type), tal_count(sr->req_in));
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/* If we're supposed to recv an fd, do it now. */
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if (sr->fd_in)
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return io_recv_fd(conn, sr->fd_in, req_finished_reply, sr);
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return req_finished_reply(conn, sr);
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}
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static struct io_plan *req_read_reply(struct io_conn *conn,
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struct subdaemon_req *sr)
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{
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/* No callback? Don't expect reply. */
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if (!sr->req) {
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struct subdaemon *sd = sr->sd;
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tal_free(sr);
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return req_next(conn, sd);
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}
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return io_read_wire(conn, sr, &sr->req_in, req_process_replymsg, sr);
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}
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static struct io_plan *req_close_fd_out(struct io_conn *conn,
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struct subdaemon_req *sr)
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{
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close(sr->fd_out);
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return req_read_reply(conn, sr);
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}
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static struct io_plan *req_sent_msg(struct io_conn *conn,
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struct subdaemon_req *sr)
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{
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/* If we're supposed to pass an fd, do it now. */
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if (sr->fd_out >= 0)
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return io_send_fd(conn, sr->fd_out, req_close_fd_out, sr);
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return req_read_reply(conn, sr);
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}
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static struct io_plan *req_next(struct io_conn *conn, struct subdaemon *sd)
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{
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struct subdaemon_req *sr;
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sr = list_pop(&sd->reqs, struct subdaemon_req, list);
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if (!sr)
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return io_wait(conn, sd, req_next, sd);
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log_debug(sd->log, "Sending req %s len %zu",
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sd->reqname(fromwire_peektype(sr->msg_out)),
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tal_count(sr->msg_out));
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return io_write_wire(conn, sr->msg_out, req_sent_msg, sr);
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}
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void subdaemon_req_(struct subdaemon *sd,
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const u8 *msg_out, int fd_out, int *fd_in,
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void (*reqcb)(struct subdaemon *, const u8 *, void *),
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void *reqcb_data)
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{
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struct subdaemon_req *sr = tal(sd, struct subdaemon_req);
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assert(sd->req_conn);
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sr->sd = sd;
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if (msg_out)
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sr->msg_out = tal_dup_arr(sr, u8, msg_out, tal_count(msg_out), 0);
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else
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sr->msg_out = NULL;
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sr->fd_out = fd_out;
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sr->fd_in = fd_in;
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sr->req = reqcb;
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sr->req_data = reqcb_data;
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list_add_tail(&sd->reqs, &sr->list);
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io_wake(sd);
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}
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