make a few struct bb_applet members conditional

rename sllep_and_die -> xfunc_die
make fflush_stdout_and_exit NOFORK-safe
fix some buglets found by randomconfig

libbb/copyfd.c

@@ -74,7 +74,7 @@ void complain_copyfd_and_die(off_t sz)
 	if (sz != -1)
 		bb_error_msg_and_die("short read");
 	/* if sz == -1, bb_copyfd_XX already complained */
-	sleep_and_die();
+	xfunc_die();
 }
 #endif
 
@@ -94,7 +94,7 @@ void bb_copyfd_exact_size(int fd1, int fd2, off_t size)
 	if (sz != -1)
 		bb_error_msg_and_die("short read");
 	/* if sz == -1, bb_copyfd_XX already complained */
-	sleep_and_die();
+	xfunc_die();
 }
 
 off_t bb_copyfd_eof(int fd1, int fd2)

libbb/error_msg_and_die.c

@@ -10,14 +10,25 @@
 #include "libbb.h"
 
 int die_sleep;
+#if ENABLE_FEATURE_EXEC_PREFER_APPLETS
 jmp_buf die_jmp;
+#endif
 
-void sleep_and_die(void)
+void xfunc_die(void)
 {
 	if (die_sleep) {
-		/* Special case: don't die, but jump */
-		if (die_sleep < 0)
-			longjmp(die_jmp, xfunc_error_retval);
+		if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && die_sleep < 0) {
+			/* Special case. We arrive here if NOFORK applet
+			 * calls xfunc, which then decides to die.
+			 * We don't die, but jump instead back to caller.
+			 * NOFORK applets still cannot carelessly call xfuncs:
+			 * p = xmalloc(10);
+			 * q = xmalloc(10); // BUG! if this dies, we leak p!
+			 */
+			/* -111 means "zero" (longjmp can't pass 0)
+			 * spawn_and_wait() catches -111. */
+			longjmp(die_jmp, xfunc_error_retval ? xfunc_error_retval : -111);
+		}
 		sleep(die_sleep);
 	}
 	exit(xfunc_error_retval);
@@ -30,5 +41,5 @@ void bb_error_msg_and_die(const char *s, ...)
 	va_start(p, s);
 	bb_verror_msg(s, p, NULL);
 	va_end(p);
-	sleep_and_die();
+	xfunc_die();
 }

libbb/fflush_stdout_and_exit.c

@@ -13,13 +13,17 @@
 
 #include "libbb.h"
 
-// TODO: make it safe to call from NOFORK applets
-// Currently, it can exit(0). Even if it is made to do longjmp trick
-// (see sleep_and_die internals), zero cannot be passed thru this way!
-
 void fflush_stdout_and_exit(int retval)
 {
 	if (fflush(stdout))
-		sleep_and_die();
+		xfunc_die();
+
+	if (ENABLE_FEATURE_EXEC_PREFER_APPLETS && die_sleep < 0) {
+		/* We are in NOFORK applet. Do not exit() directly,
+		 * but use xfunc_die() */
+		xfunc_error_retval = retval;
+		xfunc_die();
+	}
+
 	exit(retval);
 }

libbb/herror_msg_and_die.c

@@ -7,9 +7,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdarg.h>
-#include <stdlib.h>
-
 #include "libbb.h"
 
 void bb_herror_msg_and_die(const char *s, ...)
@@ -19,5 +16,5 @@ void bb_herror_msg_and_die(const char *s, ...)
 	va_start(p, s);
 	bb_vherror_msg(s, p);
 	va_end(p);
-	sleep_and_die();
+	xfunc_die();
 }

libbb/perror_msg_and_die.c

@@ -7,10 +7,6 @@
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-#include <stdio.h>
-#include <errno.h>
-#include <string.h>
-#include <stdlib.h>
 #include "libbb.h"
 
 void bb_perror_msg_and_die(const char *s, ...)
@@ -20,5 +16,5 @@ void bb_perror_msg_and_die(const char *s, ...)
 	va_start(p, s);
 	bb_vperror_msg(s, p);
 	va_end(p);
-	sleep_and_die();
+	xfunc_die();
 }

libbb/vfork_daemon_rexec.c

@@ -16,7 +16,7 @@
  */
 
 #include <paths.h>
-#include "busybox.h" /* for struct BB_applet */
+#include "busybox.h" /* for struct bb_applet */
 
 /* This does a fork/exec in one call, using vfork().  Returns PID of new child,
  * -1 for failure.  Runs argv[0], searching path if that has no / in it. */
@@ -104,8 +104,9 @@ int spawn_and_wait(char **argv)
 {
 	int rc;
 
-	if (ENABLE_FEATURE_EXEC_PREFER_APPLETS) {
-		const struct BB_applet *a = find_applet_by_name(argv[0]);
+#if ENABLE_FEATURE_EXEC_PREFER_APPLETS
+	{
+		const struct bb_applet *a = find_applet_by_name(argv[0]);
 		if (a && (a->nofork
 #ifndef BB_NOMMU
 			 || a->noexec /* NOEXEC cannot be used on NOMMU */
@@ -120,19 +121,27 @@ int spawn_and_wait(char **argv)
 #endif
 			{
 				int old_sleep = die_sleep;
+				int old_x = xfunc_error_retval;
 				die_sleep = -1; /* special flag */
-				/* sleep_and_die() checks for it */
+				/* xfunc_die() checks for it */
+
 				rc = setjmp(die_jmp);
 				if (!rc) {
-					const struct BB_applet *old_a = current_applet;
+					const struct bb_applet *old_a = current_applet;
 					current_applet = a;
 					applet_name = a->name;
 // what else should we save/restore?
 					rc = a->main(argc, argv);
 					current_applet = old_a;
 					applet_name = old_a->name;					
+				} else {
+					/* xfunc died in NOFORK applet */
+					if (rc == -111)
+						rc = 0;
 				}
+
 				die_sleep = old_sleep;
+				xfunc_error_retval = old_x;
 				return rc;
 			}
 #ifndef BB_NOMMU	/* MMU only */
@@ -145,9 +154,13 @@ int spawn_and_wait(char **argv)
 			run_current_applet_and_exit(argc, argv);
 #endif
 		}
+
 	}
 	rc = spawn(argv);
  w:
+#else /* !FEATURE_EXEC_PREFER_APPLETS */
+	rc = spawn(argv);
+#endif /* FEATURE_EXEC_PREFER_APPLETS */
 	return wait4pid(rc);
 }
 

libbb/xconnect.c

@@ -166,7 +166,7 @@ USE_FEATURE_IPV6(sa_family_t af,)
 	if (rc || !result) {
 		bb_error_msg("bad address '%s'", org_host);
 		if (ai_flags & DIE_ON_ERROR)
-			sleep_and_die();
+			xfunc_die();
 		goto ret;
 	}
 	r = xmalloc(offsetof(len_and_sockaddr, sa) + result->ai_addrlen);

libbb/xfuncs.c

@@ -476,7 +476,7 @@ void xprint_and_close_file(FILE *file)
 	fflush(stdout);
 	// copyfd outputs error messages for us.
 	if (bb_copyfd_eof(fileno(file), 1) == -1)
-		sleep_and_die();
+		xfunc_die();
 
 	fclose(file);
 }