dhcpcd: Close fork_fd on hangup

Closing it early results in zero length reads in some situations.
Logging that we forked via the launcher process also make more sense
and allows us to use log* functions.

While here, handle error condtions better by forcing a return
rather than handling an invalid state.

Fixes #260.

diff --git a/src/dhcpcd.c b/src/dhcpcd.c
index 71e7d807d01bddca8b83dd05396986bce6749439..46c64b42f0601e220594406840a7754bfc41bfef 100644 (file)
--- a/src/dhcpcd.c
+++ b/src/dhcpcd.c
@@ -365,7 +365,6 @@ dhcpcd_daemonise(struct dhcpcd_ctx *ctx)
        return;
 #else
        int i;
-       unsigned int logopts = loggetopts();
 
        if (ctx->options & DHCPCD_DAEMONISE &&
            !(ctx->options & (DHCPCD_DAEMONISED | DHCPCD_NOWAITIP)))
@@ -385,11 +384,6 @@ dhcpcd_daemonise(struct dhcpcd_ctx *ctx)
            !(ctx->options & DHCPCD_DAEMONISE))
                return;
 
-       /* Don't use loginfo because this makes no sense in a log. */
-       if (!(logopts & LOGERR_QUIET) && ctx->stderr_valid)
-               (void)fprintf(stderr,
-                   "forked to background, child pid %d\n", getpid());
-
 #ifdef PRIVSEP
        ps_daemonised(ctx);
 #else
@@ -400,9 +394,8 @@ dhcpcd_daemonise(struct dhcpcd_ctx *ctx)
        if (write(ctx->fork_fd, &i, sizeof(i)) == -1)
                logerr("write");
        ctx->options |= DHCPCD_DAEMONISED;
-       eloop_event_delete(ctx->eloop, ctx->fork_fd);
-       close(ctx->fork_fd);
-       ctx->fork_fd = -1;
+       // dhcpcd_fork_cb will close the socket
+       shutdown(ctx->fork_fd, SHUT_RDWR);
 #endif
 }
 
@@ -1822,31 +1815,6 @@ dhcpcd_readdump(struct dhcpcd_ctx *ctx)
            dhcpcd_readdump0, ctx);
 }
 
-static void
-dhcpcd_fork_cb(void *arg, unsigned short events)
-{
-       struct dhcpcd_ctx *ctx = arg;
-       int exit_code;
-       ssize_t len;
-
-       if (!(events & ELE_READ))
-               logerrx("%s: unexpected event 0x%04x", __func__, events);
-
-       len = read(ctx->fork_fd, &exit_code, sizeof(exit_code));
-       if (len == -1) {
-               logerr(__func__);
-               exit_code = EXIT_FAILURE;
-       } else if ((size_t)len < sizeof(exit_code)) {
-               logerrx("%s: truncated read %zd (expected %zu)",
-                   __func__, len, sizeof(exit_code));
-               exit_code = EXIT_FAILURE;
-       }
-       if (ctx->options & DHCPCD_FORKED)
-               eloop_exit(ctx->eloop, exit_code);
-       else
-               dhcpcd_signal_cb(exit_code, ctx);
-}
-
 static void
 dhcpcd_stderr_cb(void *arg, unsigned short events)
 {
@@ -1871,6 +1839,51 @@ dhcpcd_stderr_cb(void *arg, unsigned short events)
        fprintf(stderr, "%s", log);
 }
 
+static void
+dhcpcd_fork_cb(void *arg, unsigned short events)
+{
+       struct dhcpcd_ctx *ctx = arg;
+       int exit_code;
+       ssize_t len;
+
+       if (!(events & ELE_READ))
+               logerrx("%s: unexpected event 0x%04x", __func__, events);
+
+       len = read(ctx->fork_fd, &exit_code, sizeof(exit_code));
+       if (len == -1) {
+               logerr(__func__);
+               eloop_exit(ctx->eloop, EXIT_FAILURE);
+               return;
+       }
+       if (len == 0) {
+               if (ctx->options & DHCPCD_FORKED) {
+                       logerrx("%s: dhcpcd manager hungup", __func__);
+                       eloop_exit(ctx->eloop, EXIT_FAILURE);
+               } else {
+                       // Launcher exited
+                       eloop_event_delete(ctx->eloop, ctx->fork_fd);
+                       close(ctx->fork_fd);
+                       ctx->fork_fd = -1;
+               }
+               return;
+       }
+       if ((size_t)len < sizeof(exit_code)) {
+               logerrx("%s: truncated read %zd (expected %zu)",
+                   __func__, len, sizeof(exit_code));
+               eloop_exit(ctx->eloop, EXIT_FAILURE);
+               return;
+       }
+
+       if (ctx->options & DHCPCD_FORKED) {
+               if (exit_code == EXIT_SUCCESS)
+                       logdebugx("forked to background");
+               else
+                       logerrx("exited with code %d", exit_code);
+               eloop_exit(ctx->eloop, exit_code);
+       } else
+               dhcpcd_signal_cb(exit_code, ctx);
+}
+
 static void
 dhcpcd_pidfile_timeout(void *arg)
 {