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 ac8c870f8..620f7c00f 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 0047a8445..efb5cfba7 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 93cbc961f..dd2a20689 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 8c4242e44..82891f121 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 cb937cac4..c0e9e812e 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 83b24f1d6..065b4baeb 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 17af41f9c..bdccad69d 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 797c83b4e..b22df9cb7 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 76a8cb7df..5a3bd606f 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 24b26545e..46510acc1 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 7b6d4f45f..2bc2f9210 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 f16fc792f..4e6ca2d9b 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 fe6bff4ba..264a98899 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)) {