accept connections and for-exec to appropriate image

Signed-off-by: Mattias Andrée <maandree@member.fsf.org>

2 files changed, 68 insertions, 6 deletions

diff --git a/src/README b/src/README
index 541907e..e36126f 100644
--- a/src/README
+++ b/src/README
@@ -4,7 +4,11 @@ satr.c   The satr program, ask satd to run jobs early.
 satrm.c  The satrm program, ask satd to remove jobs from the queue.
 
 satd.c             The initialisation part of satd.
-satd-diminished.c  The rest of satd, std.c exec:s to this.
+satd-diminished.c  The rest of satd, satd.c exec:s to this.
+satd-add.c         The part of satd responding to sat, satd-diminished.c fork–exec:s to this.
+satd-rm.c          The part of satd responding to satrm, satd-diminished.c fork–exec:s to this.
+satd-list.c        The part of satd responding to satlist, satd-diminished.c fork–exec:s to this.
+satd-run.c         The part of satd responding to satr, satd-diminished.c fork–exec:s to this.
 
 parse_time.[ch]    Use by sat.c to parse the time argument.
                    Only rudimentary parsing is done.
diff --git a/src/satd-diminished.c b/src/satd-diminished.c
index 48ada56..d887e27 100644
--- a/src/satd-diminished.c
+++ b/src/satd-diminished.c
@@ -20,6 +20,9 @@
  * DEALINGS IN THE SOFTWARE.
  */
 #include <unistd.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <sys/socket.h>
 
 
@@ -70,17 +73,72 @@
 int
 main(int argc, char *argv[])
 {
-	int fd;
+	int fd = -1, rc = 0;
+	pid_t pid;
+	char type;
+	const char *image;
 
-	fd = accept(SOCK_FILENO. NULL, NULL);
-	shutdown(fd, SHUT_RDWR);
-	close(fd);
+accept_again:
+	fd = accept(SOCK_FILENO, NULL, NULL);
+	if (fd == -1) {
+		switch (errno) {
+		case ECONNABORTED:
+		case EINTR:
+			goto accept_again;
+		default:
+			/* Including EMFILE, ENFILE, and ENOMEM
+			 * because of potential resource leak. */
+			goto fail;
+		}
+	}
+fork_again:
+	if (recv(fd, &type, (size_t)1, 0) <= 0) {
+		perror(argv[0]);
+		goto connection_done;
+	}
+	switch ((pid = fork())) {
+	case -1:
+		if (errno != EAGAIN)
+			goto fail;
+		(void) sleep(1); /* Possibly shorter because of SIGCHLD. */
+		goto fork_again;
+	case 0:
+		switch (type) {
+		case SAT_QUEUE:   image = LIBEXEC "/" PACKAGE "/satd-add";   break;
+		case SAT_REMOVE:  image = LIBEXEC "/" PACKAGE "/satd-rm";    break;
+		case SAT_PRINT:   image = LIBEXEC "/" PACKAGE "/satd-list";  break;
+		case SAT_RUN:     image = LIBEXEC "/" PACKAGE "/satd-run";   break;
+		default:
+			fprintf(stderr, "%s: invalid command received.\n", argv[0]);
+			exit(1);
+		}
+		if (dup2(fd, SOCK_FILENO) != -1)
+			close(fd), fd = SOCK_FILENO, execv(image, argv);
+		perror(argv[0]);
+		close(fd);
+		exit(1);
+	default:
+		break;
+	}
+connection_done:
+	close(fd), fd = -1;
+	goto accept_again;
 
+done:
 	unlink(argv[1]);
-	unlink(argv[2]); /* Only on success! */
+	if (!rc)
+		unlink(argv[2]);
 	close(SOCK_FILENO);
 	close(STATE_FILENO);
 	return 0;
+
+fail:
+	perror(argv[0]);
+	if (fd >= 0)
+		close(fd);
+	rc = 1;
+	goto done;
+
 	(void) argc;
 }