*: introduce and use bb_unsetenv_and_free

function                                             old     new   delta
bb_unsetenv_and_free                                   -      17     +17
tcpudpsvd_main                                      1819    1810      -9
safe_setenv                                           58      47     -11
udhcp_run_script                                     630     616     -14
make_device                                         1683    1663     -20
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/4 up/down: 17/-54)            Total: -37 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

include/libbb.h

@@ -408,6 +408,7 @@ void xchdir(const char *path) FAST_FUNC;
 void xchroot(const char *path) FAST_FUNC;
 void xsetenv(const char *key, const char *value) FAST_FUNC;
 void bb_unsetenv(const char *key) FAST_FUNC;
+void bb_unsetenv_and_free(char *key) FAST_FUNC;
 void xunlink(const char *pathname) FAST_FUNC;
 void xstat(const char *pathname, struct stat *buf) FAST_FUNC;
 int xopen(const char *pathname, int flags) FAST_FUNC;

libbb/xfuncs_printf.c

@@ -323,6 +323,11 @@ void FAST_FUNC bb_unsetenv(const char *var)
 	free(tp);
 }
 
+void FAST_FUNC bb_unsetenv_and_free(char *var)
+{
+	bb_unsetenv(var);
+	free(var);
+}
 
 // Die with an error message if we can't set gid.  (Because resource limits may
 // limit this user to a given number of processes, and if that fills up the

miscutils/crond.c

@@ -264,8 +264,7 @@ static void safe_setenv(char **pvar_val, const char *var, const char *val)
 	char *var_val = *pvar_val;
 
 	if (var_val) {
-		bb_unsetenv(var_val);
-		free(var_val);
+		bb_unsetenv_and_free(var_val);
 	}
 	*pvar_val = xasprintf("%s=%s", var, val);
 	putenv(*pvar_val);

networking/tcpudp.c

@@ -85,8 +85,7 @@ static void undo_xsetenv(void)
 	char **pp = env_cur = &env_var[0];
 	while (*pp) {
 		char *var = *pp;
-		bb_unsetenv(var);
-		free(var);
+		bb_unsetenv_and_free(var);
 		*pp++ = NULL;
 	}
 }

networking/udhcp/dhcpc.c

@@ -327,8 +327,7 @@ static void udhcp_run_script(struct dhcp_packet *packet, const char *name)
 
 	for (curr = envp; *curr; curr++) {
 		log2(" %s", *curr);
-		bb_unsetenv(*curr);
-		free(*curr);
+		bb_unsetenv_and_free(*curr);
 	}
 	free(envp);
 }

util-linux/mdev.c

@@ -374,10 +374,8 @@ static void make_device(char *path, int delete)
 				putenv(s1);
 				if (system(command) == -1)
 					bb_perror_msg("can't run '%s'", command);
-				unsetenv("SUBSYSTEM");
-				free(s1);
-				unsetenv("MDEV");
-				free(s);
+				bb_unsetenv_and_free(s1);
+				bb_unsetenv_and_free(s);
 				free(command);
 			}