*: introduce and use xvfork()

function                                             old     new   delta
time_main                                           1052    1285    +233
crontab_main                                         623     856    +233
ifupdown_main                                       2202    2403    +201
xvfork                                                 -      20     +20
passwd_main                                         1049    1053      +4
grave                                               1068    1066      -2
script_main                                          935     921     -14
vfork_or_die                                          20       -     -20
vfork_compressor                                     206     175     -31
open_as_user                                         109       -    -109
popen2                                               218       -    -218
edit_file                                            910     690    -220
run_command                                          268       -    -268
------------------------------------------------------------------------------
(add/remove: 1/4 grow/shrink: 4/4 up/down: 691/-882)         Total: -191 bytes

1 files changed, 2 insertions, 6 deletions

diff --git a/miscutils/crontab.c b/miscutils/crontab.c
index dc3179dac..4bba9fb44 100644
--- a/miscutils/crontab.c
+++ b/miscutils/crontab.c
@@ -38,10 +38,8 @@ static void change_user(const struct passwd *pas)
 static void edit_file(const struct passwd *pas, const char *file)
 {
         const char *ptr;
-        int pid = vfork();
+        int pid = xvfork();
 
-        if (pid < 0) /* failure */
-                bb_perror_msg_and_die("vfork");
         if (pid) { /* parent */
                 wait4pid(pid);
                 return;
@@ -65,9 +63,7 @@ static int open_as_user(const struct passwd *pas, const char *file)
         pid_t pid;
         char c;
 
-        pid = vfork();
-        if (pid < 0) /* ERROR */
-                bb_perror_msg_and_die("vfork");
+        pid = xvfork();
         if (pid) { /* PARENT */
                 if (wait4pid(pid) == 0) {
                         /* exitcode 0: child says it can read */