libbb: [x]fopen_for_{read,write} introduced and used.

 (by Valdimir)

function                                             old     new   delta
config_open2                                           -      41     +41
config_read                                          507     542     +35
find_pair                                            169     187     +18
fopen_for_write                                        -      14     +14
fopen_for_read                                         -      14     +14
find_main                                            406     418     +12
xfopen_for_write                                       -      10     +10
xfopen_for_read                                        -      10     +10
popstring                                            134     140      +6
parse_inittab                                        396     401      +5
next_token                                           923     928      +5
pack_gzip                                           1659    1661      +2
bb__parsespent                                       117     119      +2
fallbackSort                                        1719    1717      -2
evalvar                                             1376    1374      -2
qrealloc                                              36      33      -3
...
...
...
...
singlemount                                         4579    4569     -10
process_stdin                                        443     433     -10
patch_main                                          1111    1101     -10
ifupdown_main                                       2175    2165     -10
file_action_grep                                      90      80     -10
uuidcache_init                                       649     637     -12
hush_main                                            797     785     -12
read_config                                          230     217     -13
dpkg_main                                           3835    3820     -15
read_line_input                                     3134    3110     -24
sysctl_main                                          232     203     -29
config_open                                           40      10     -30
WARN_BAD_LINE                                         44       -     -44
login_main                                          1714    1575    -139
------------------------------------------------------------------------------
(add/remove: 5/1 grow/shrink: 8/74 up/down: 174/-737)        Total: -563 bytes

13 files changed, 27 insertions, 37 deletions

diff --git a/networking/arp.c b/networking/arp.c
index ac8c870..620f7c0 100644
--- a/networking/arp.c
+++ b/networking/arp.c
@@ -382,7 +382,7 @@ static int arp_show(char *name)
 		}
 		host = xstrdup(ap->sprint(&sa, 1));
 	}
-	fp = xfopen("/proc/net/arp", "r");
+	fp = xfopen_for_read("/proc/net/arp");
 	/* Bypass header -- read one line */
 	fgets(line, sizeof(line), fp);
 
diff --git a/networking/dnsd.c b/networking/dnsd.c
index 0047a84..efb5cfb 100644
--- a/networking/dnsd.c
+++ b/networking/dnsd.c
@@ -113,7 +113,7 @@ static void dnsentryinit(void)
 	parser = config_open(fileconf);
 	if (parser) {
 		char *token[2];
-		while (config_read(parser, token, 2, 0, "# \t", 0)) {
+		while (config_read(parser, token, 2, 2, "# \t", 0)) {
 			unsigned int a,b,c,d;
 			/*
 			 * Assumes all host names are lower case only
@@ -121,7 +121,8 @@ static void dnsentryinit(void)
 			 * Presently the dot is copied into name without
 			 * converting to a length/string substring for that label.
 			 */
-			if (!token[1] || sscanf(token[1], ".%u.%u.%u.%u"+1, &a, &b, &c, &d) != 4)
+//			if (!token[1] || sscanf(token[1], ".%u.%u.%u.%u"+1, &a, &b, &c, &d) != 4)
+			if (sscanf(token[1], ".%u.%u.%u.%u"+1, &a, &b, &c, &d) != 4)
 				continue;
 
 			m = xzalloc(sizeof(*m));
diff --git a/networking/hostname.c b/networking/hostname.c
index 93cbc96..dd2a206 100644
--- a/networking/hostname.c
+++ b/networking/hostname.c
@@ -16,28 +16,19 @@
 
 static void do_sethostname(char *s, int isfile)
 {
-	FILE *f;
-
 	if (!s)
 		return;
-	if (!isfile) {
-		if (sethostname(s, strlen(s)) < 0) {
-			if (errno == EPERM)
-				bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
-			bb_perror_msg_and_die("sethostname");
-		}
-	} else {
-		f = xfopen(s, "r");
-#define strbuf bb_common_bufsiz1
-		while (fgets(strbuf, sizeof(strbuf), f) != NULL) {
-			if (strbuf[0] == '#') {
-				continue;
-			}
-			chomp(strbuf);
-			do_sethostname(strbuf, 0);
+	if (isfile) {
+		parser_t *parser = config_open2(s, xfopen_for_read);
+		while (config_read(parser, &s, 1, 1, "# \t", 0)) {
+			do_sethostname(s, 0);
 		}
 		if (ENABLE_FEATURE_CLEAN_UP)
-			fclose(f);
+			config_close(parser);
+	} else if (sethostname(s, strlen(s)) < 0) {
+		if (errno == EPERM)
+			bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
+		bb_perror_msg_and_die("sethostname");
 	}
 }
 
@@ -98,5 +89,5 @@ int hostname_main(int argc, char **argv)
 	}
 	if (ENABLE_FEATURE_CLEAN_UP)
 		free(buf);
-	return 0;
+	return EXIT_SUCCESS;
 }
diff --git a/networking/httpd.c b/networking/httpd.c
index 8c4242e..82891f1 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -518,7 +518,7 @@ static void parse_conf(const char *path, int flag)
 		sprintf((char *)filename, "%s/%s", path, httpd_conf);
 	}
 
-	while ((f = fopen(filename, "r")) == NULL) {
+	while ((f = fopen_for_read(filename)) == NULL) {
 		if (flag == SUBDIR_PARSE || flag == FIND_FROM_HTTPD_ROOT) {
 			/* config file not found, no changes to config */
 			return;
diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index cb937ca..c0e9e81 100644
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -692,7 +692,7 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
 	enum { NONE, IFACE, MAPPING } currently_processing = NONE;
 
 	defn = xzalloc(sizeof(*defn));
-	f = xfopen(filename, "r");
+	f = xfopen_for_read(filename);
 
 	while ((buf = xmalloc_fgetline(f)) != NULL) {
 #if ENABLE_DESKTOP
@@ -1090,7 +1090,7 @@ static llist_t *find_iface_state(llist_t *state_list, const char *iface)
 static llist_t *read_iface_state(void)
 {
 	llist_t *state_list = NULL;
-	FILE *state_fp = fopen(CONFIG_IFUPDOWN_IFSTATE_PATH, "r");
+	FILE *state_fp = fopen_for_read(CONFIG_IFUPDOWN_IFSTATE_PATH);
 
 	if (state_fp) {
 		char *start, *end_ptr;
@@ -1256,7 +1256,7 @@ int ifupdown_main(int argc, char **argv)
 			}
 
 			/* Actually write the new state */
-			state_fp = xfopen(CONFIG_IFUPDOWN_IFSTATE_PATH, "w");
+			state_fp = xfopen_for_write(CONFIG_IFUPDOWN_IFSTATE_PATH);
 			state = state_list;
 			while (state) {
 				if (state->data) {
diff --git a/networking/interface.c b/networking/interface.c
index 83b24f1..065b4ba 100644
--- a/networking/interface.c
+++ b/networking/interface.c
@@ -990,7 +990,7 @@ static void ife_print(struct interface *ptr)
 #define IPV6_ADDR_MAPPED        0x1000U
 #define IPV6_ADDR_RESERVED      0x2000U	/* reserved address space */
 
-	f = fopen(_PATH_PROCNET_IFINET6, "r");
+	f = fopen_for_read(_PATH_PROCNET_IFINET6);
 	if (f != NULL) {
 		while (fscanf
 			   (f, "%4s%4s%4s%4s%4s%4s%4s%4s %08x %02x %02x %02x %20s\n",
diff --git a/networking/libiproute/iproute.c b/networking/libiproute/iproute.c
index 17af41f..bdccad6 100644
--- a/networking/libiproute/iproute.c
+++ b/networking/libiproute/iproute.c
@@ -64,7 +64,7 @@ static unsigned get_hz(void)
 	if (hz_internal)
 		return hz_internal;
 
-	fp = fopen("/proc/net/psched", "r");
+	fp = fopen_for_read("/proc/net/psched");
 	if (fp) {
 		unsigned nom, denom;
 
diff --git a/networking/libiproute/rt_names.c b/networking/libiproute/rt_names.c
index 797c83b..b22df9c 100644
--- a/networking/libiproute/rt_names.c
+++ b/networking/libiproute/rt_names.c
@@ -18,7 +18,7 @@ static void rtnl_tab_initialize(const char *file, const char **tab, int size)
 	char buf[512];
 	FILE *fp;
 
-	fp = fopen(file, "r");
+	fp = fopen_for_read(file);
 	if (!fp)
 		return;
 	while (fgets(buf, sizeof(buf), fp)) {
diff --git a/networking/nameif.c b/networking/nameif.c
index 76a8cb7..5a3bd60 100644
--- a/networking/nameif.c
+++ b/networking/nameif.c
@@ -170,7 +170,7 @@ int nameif_main(int argc, char **argv)
 	}
 
 	ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);
-	ifh = xfopen("/proc/net/dev", "r");
+	ifh = xfopen_for_read("/proc/net/dev");
 
 	linenum = 0;
 	while (clist) {
diff --git a/networking/netstat.c b/networking/netstat.c
index 24b2654..46510ac 100644
--- a/networking/netstat.c
+++ b/networking/netstat.c
@@ -466,7 +466,7 @@ static void do_info(const char *file, const char *name, int (*proc)(int, char *)
 	FILE *procinfo;
 	char *buffer;
 
-	procinfo = fopen(file, "r");
+	procinfo = fopen_for_read(file);
 	if (procinfo == NULL) {
 		if (errno != ENOENT) {
 			bb_simple_perror_msg(file);
diff --git a/networking/route.c b/networking/route.c
index 7b6d4f4..2bc2f92 100644
--- a/networking/route.c
+++ b/networking/route.c
@@ -484,7 +484,7 @@ void FAST_FUNC bb_displayroutes(int noresolve, int netstatfmt)
 	struct sockaddr_in s_addr;
 	struct in_addr mask;
 
-	FILE *fp = xfopen("/proc/net/route", "r");
+	FILE *fp = xfopen_for_read("/proc/net/route");
 
 	printf("Kernel IP routing table\n"
 	       "Destination     Gateway         Genmask         Flags %s Iface\n",
@@ -552,7 +552,7 @@ static void INET6_displayroutes(void)
 	int iflags, metric, refcnt, use, prefix_len, slen;
 	struct sockaddr_in6 snaddr6;
 
-	FILE *fp = xfopen("/proc/net/ipv6_route", "r");
+	FILE *fp = xfopen_for_read("/proc/net/ipv6_route");
 
 	printf("Kernel IPv6 routing table\n%-44s%-40s"
 			  "Flags Metric Ref    Use Iface\n",
diff --git a/networking/traceroute.c b/networking/traceroute.c
index f16fc79..4e6ca2d 100644
--- a/networking/traceroute.c
+++ b/networking/traceroute.c
@@ -508,7 +508,7 @@ findsaddr(const struct sockaddr_in *to, struct sockaddr_in *from)
 	struct IFADDRLIST *al;
 	char buf[256], tdevice[256], device[256];
 
-	f = xfopen("/proc/net/route", "r");
+	f = xfopen_for_read("/proc/net/route");
 
 	/* Find the appropriate interface */
 	n = 0;
diff --git a/networking/udhcp/files.c b/networking/udhcp/files.c
index fe6bff4..264a988 100644
--- a/networking/udhcp/files.c
+++ b/networking/udhcp/files.c
@@ -321,9 +321,7 @@ void read_config(const char *file)
 	if (!parser)
 		return;
 
-	while (config_read(parser, token, 2, 0, "# \t", PARSE_LAST_IS_GREEDY)) {
-		if (!token[1])
-			continue;
+	while (config_read(parser, token, 2, 2, "# \t", PARSE_LAST_IS_GREEDY)) {
 		for (k = keywords, i = 0; i < ARRAY_SIZE(keywords); k++, i++) {
 			if (!strcasecmp(token[0], k->keyword)) {
 				if (!k->handler(token[1], k->var)) {