dhcpcd: stdout output sometimes empty when redirected to a file

Running dhpcd --dumplease with input from stdin and redirecting stdout
to a file outputs nothing to the output. The reason is that printf /
fprintf is used to write the output but it is not explicitly flushed
when done, or before exiting, and stdout to files is fully buffered by
default while stdout to terminals is line buffered by default.

This adds calls to fflush() at the end of dhcp_print_option_encoding()
and script_dump(), plus one just before exiting dhcpcd.

Signed-off-by: Diego Santa Cruz <[email protected]>

src/dhcp-common.c

@@ -136,6 +136,7 @@ dhcp_print_option_encoding(const struct dhcp_opt *opt, int cols)
 	if (opt->type & OT_NOREQ)
 		printf(" norequest");
 	putchar('\n');
+	fflush(stdout);
 }
 
 struct dhcp_opt *

src/dhcpcd.c

@@ -2719,6 +2719,7 @@ main(int argc, char **argv, char **envp)
 	eloop_free(ctx.eloop);
 	logclose();
 	free(ctx.logfile);
+	fflush(stdout);
 	free(ctx.ctl_buf);
 #ifdef SETPROCTITLE_H
 	setproctitle_fini();

src/script.c

@@ -738,6 +738,7 @@ script_dump(const char *env, size_t len)
 			env += 4;
 		printf("%s\n", env);
 	}
+	fflush(stdout);
 	return 0;
 }