ifupdown: if $PATH is not set, do not set it to "" in children

Also random code shrink:

function                                             old     new   delta
set_environ                                          328     330      +2
static.label_buf                                       4       -      -4
startup_PATH                                           4       -      -4
my_environ                                             4       -      -4
ifupdown_main                                       2148    2134     -14
setlocalenv                                          117      90     -27
get_var                                              139     112     -27
------------------------------------------------------------------------------
(add/remove: 0/3 grow/shrink: 1/3 up/down: 2/-80)             Total: -78 bytes

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

1 files changed, 65 insertions, 59 deletions

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 6d608105e..7a9709e40 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -87,23 +87,29 @@ struct interfaces_file_t {
 	struct mapping_defn_t *mappings;
 };
 
+
 #define OPTION_STR "anvf" IF_FEATURE_IFUPDOWN_MAPPING("m") "i:"
 enum {
-	OPT_do_all = 0x1,
-	OPT_no_act = 0x2,
-	OPT_verbose = 0x4,
-	OPT_force = 0x8,
+	OPT_do_all      = 0x1,
+	OPT_no_act      = 0x2,
+	OPT_verbose     = 0x4,
+	OPT_force       = 0x8,
 	OPT_no_mappings = 0x10,
 };
-#define DO_ALL (option_mask32 & OPT_do_all)
-#define NO_ACT (option_mask32 & OPT_no_act)
-#define VERBOSE (option_mask32 & OPT_verbose)
-#define FORCE (option_mask32 & OPT_force)
+#define DO_ALL      (option_mask32 & OPT_do_all)
+#define NO_ACT      (option_mask32 & OPT_no_act)
+#define VERBOSE     (option_mask32 & OPT_verbose)
+#define FORCE       (option_mask32 & OPT_force)
 #define NO_MAPPINGS (option_mask32 & OPT_no_mappings)
 
-static char **my_environ;
 
-static const char *startup_PATH;
+struct globals {
+	char **my_environ;
+	const char *startup_PATH;
+};
+#define G (*(struct globals*)&bb_common_bufsiz1)
+#define INIT_G() do { } while (0)
+
 
 #if ENABLE_FEATURE_IFUPDOWN_IPV4 || ENABLE_FEATURE_IFUPDOWN_IPV6
 
@@ -126,7 +132,7 @@ static int strncmpz(const char *l, const char *r, size_t llen)
 	int i = strncmp(l, r, llen);
 
 	if (i == 0)
-		return -r[llen];
+		return - (unsigned char)r[llen];
 	return i;
 }
 
@@ -135,16 +141,17 @@ static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
 	int i;
 
 	if (strncmpz(id, "iface", idlen) == 0) {
-		static char *label_buf;
+		// ubuntu's ifup doesn't do this:
+		//static char *label_buf;
 		//char *result;
-
-		free(label_buf);
-		label_buf = xstrdup(ifd->iface);
-		// Remove virtual iface suffix - why?
-		// ubuntu's ifup doesn't do this
+		//free(label_buf);
+		//label_buf = xstrdup(ifd->iface);
+		// Remove virtual iface suffix
 		//result = strchrnul(label_buf, ':');
 		//*result = '\0';
-		return label_buf;
+		//return label_buf;
+
+		return ifd->iface;
 	}
 	if (strncmpz(id, "label", idlen) == 0) {
 		return ifd->iface;
@@ -547,7 +554,7 @@ static int FAST_FUNC dhcp_down(struct interface_defn_t *ifd, execfn *exec)
 
 	for (i = 0; i < ARRAY_SIZE(ext_dhcp_clients); i++) {
 		if (exists_execable(ext_dhcp_clients[i].name)) {
-			result += execute(ext_dhcp_clients[i].stopcmd, ifd, exec);
+			result = execute(ext_dhcp_clients[i].stopcmd, ifd, exec);
 			if (result)
 				break;
 		}
@@ -620,13 +627,13 @@ static int FAST_FUNC wvdial_down(struct interface_defn_t *ifd, execfn *exec)
 }
 
 static const struct method_t methods[] = {
-	{ "manual", manual_up_down, manual_up_down, },
-	{ "wvdial", wvdial_up, wvdial_down, },
-	{ "ppp", ppp_up, ppp_down, },
-	{ "static", static_up, static_down, },
-	{ "bootp", bootp_up, static_down, },
-	{ "dhcp", dhcp_up, dhcp_down, },
-	{ "loopback", loopback_up, loopback_down, },
+	{ "manual"  , manual_up_down, manual_up_down, },
+	{ "wvdial"  , wvdial_up     , wvdial_down   , },
+	{ "ppp"     , ppp_up        , ppp_down      , },
+	{ "static"  , static_up     , static_down   , },
+	{ "bootp"   , bootp_up      , static_down   , },
+	{ "dhcp"    , dhcp_up       , dhcp_down     , },
+	{ "loopback", loopback_up   , loopback_down , },
 };
 
 static const struct address_family_t addr_inet = {
@@ -896,43 +903,40 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
 static char *setlocalenv(const char *format, const char *name, const char *value)
 {
 	char *result;
-	char *here;
-	char *there;
+	char *dst;
+	char *src;
+	char c;
 
 	result = xasprintf(format, name, value);
 
-	for (here = there = result; *there != '=' && *there; there++) {
-		if (*there == '-')
-			*there = '_';
-		if (isalpha(*there))
-			*there = toupper(*there);
-
-		if (isalnum(*there) || *there == '_') {
-			*here = *there;
-			here++;
-		}
+	for (dst = src = result; (c = *src) != '=' && c; src++) {
+		if (c == '-')
+			c = '_';
+		if (c >= 'a' && c <= 'z')
+			c -= ('a' - 'A');
+		if (isalnum(c) || c == '_')
+			*dst++ = c;
 	}
-	memmove(here, there, strlen(there) + 1);
+	overlapping_strcpy(dst, src);
 
 	return result;
 }
 
 static void set_environ(struct interface_defn_t *iface, const char *mode)
 {
-	char **environend;
 	int i;
-	const int n_env_entries = iface->n_options + 5;
-	char **ppch;
+	char **pp;
 
-	if (my_environ != NULL) {
-		for (ppch = my_environ; *ppch; ppch++) {
-			free(*ppch);
-			*ppch = NULL;
+	if (G.my_environ != NULL) {
+		for (pp = G.my_environ; *pp; pp++) {
+			free(*pp);
 		}
-		free(my_environ);
+		free(G.my_environ);
 	}
-	my_environ = xzalloc(sizeof(char *) * (n_env_entries + 1 /* for final NULL */ ));
-	environend = my_environ;
+
+	/* note: last element will stay NULL: */
+	G.my_environ = xzalloc(sizeof(char *) * (iface->n_options + 6));
+	pp = G.my_environ;
 
 	for (i = 0; i < iface->n_options; i++) {
 		if (strcmp(iface->option[i].name, "up") == 0
@@ -942,14 +946,15 @@ static void set_environ(struct interface_defn_t *iface, const char *mode)
 		) {
 			continue;
 		}
-		*(environend++) = setlocalenv("IF_%s=%s", iface->option[i].name, iface->option[i].value);
+		*pp++ = setlocalenv("IF_%s=%s", iface->option[i].name, iface->option[i].value);
 	}
 
-	*(environend++) = setlocalenv("%s=%s", "IFACE", iface->iface);
-	*(environend++) = setlocalenv("%s=%s", "ADDRFAM", iface->address_family->name);
-	*(environend++) = setlocalenv("%s=%s", "METHOD", iface->method->name);
-	*(environend++) = setlocalenv("%s=%s", "MODE", mode);
-	*(environend++) = setlocalenv("%s=%s", "PATH", startup_PATH);
+	*pp++ = setlocalenv("%s=%s", "IFACE", iface->iface);
+	*pp++ = setlocalenv("%s=%s", "ADDRFAM", iface->address_family->name);
+	*pp++ = setlocalenv("%s=%s", "METHOD", iface->method->name);
+	*pp++ = setlocalenv("%s=%s", "MODE", mode);
+	if (G.startup_PATH)
+		*pp++ = setlocalenv("%s=%s", "PATH", G.startup_PATH);
 }
 
 static int doit(char *str)
@@ -967,7 +972,7 @@ static int doit(char *str)
 		case -1: /* failure */
 			return 0;
 		case 0: /* child */
-			execle(DEFAULT_SHELL, DEFAULT_SHELL, "-c", str, (char *) NULL, my_environ);
+			execle(DEFAULT_SHELL, DEFAULT_SHELL, "-c", str, (char *) NULL, G.my_environ);
 			_exit(127);
 		}
 		safe_waitpid(child, &status, 0);
@@ -1142,6 +1147,10 @@ int ifupdown_main(int argc, char **argv)
 	const char *interfaces = "/etc/network/interfaces";
 	bool any_failures = 0;
 
+	INIT_G();
+
+	G.startup_PATH = getenv("PATH");
+
 	cmds = iface_down;
 	if (applet_name[2] == 'u') {
 		/* ifup command */
@@ -1159,9 +1168,6 @@ int ifupdown_main(int argc, char **argv)
 	defn = read_interfaces(interfaces);
 	debug_noise("\ndone reading %s\n\n", interfaces);
 
-	startup_PATH = getenv("PATH");
-	if (!startup_PATH) startup_PATH = "";
-
 	/* Create a list of interfaces to work on */
 	if (DO_ALL) {
 		target_list = defn->autointerfaces;