networking/interface.c: get rid of global data

These were data/bss:

static.proc_read                                       1       -      -1
int_list                                               4       -      -4
int_last                                               4       -      -4

We never call display_interfaces() twice, thus code to not scan /proc twice
never triggers.

function                                             old     new   delta
do_if_print                                            -    1998   +1998
display_interfaces                                   145     249    +104
static.proc_read                                       1       -      -1
add_interface                                        104     103      -1
int_list                                               4       -      -4
int_last                                               4       -      -4
if_readlist_proc                                     560     542     -18
if_readconf                                          141       -    -141
do_if_fetch                                          643       -    -643
ife_print                                           1296       -   -1296
------------------------------------------------------------------------------
(add/remove: 1/6 grow/shrink: 1/2 up/down: 2102/-2108)         Total: -6 bytes
   text	   data	    bss	    dec	    hex	filename
 933084	    473	   6844	 940401	  e5971	busybox_old
 933087	    473	   6836	 940396	  e596c	busybox_unstripped

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

1 files changed, 36 insertions, 85 deletions

diff --git a/networking/interface.c b/networking/interface.c
index ff99c2981..e5e55d8d4 100644
--- a/networking/interface.c
+++ b/networking/interface.c
@@ -341,8 +341,9 @@ struct interface {
 #endif
 };
 
-
-static struct interface *int_list, *int_last;
+struct iface_list {
+        struct interface *int_list, *int_last;
+};
 
 
 #if 0
@@ -373,11 +374,11 @@ static int nstrcmp(const char *a, const char *b)
 }
 #endif
 
-static struct interface *add_interface(char *name)
+static struct interface *add_interface(struct iface_list *ilist, char *name)
 {
         struct interface *ife, **nextp, *new;
 
-        for (ife = int_last; ife; ife = ife->prev) {
+        for (ife = ilist->int_last; ife; ife = ife->prev) {
                 int n = /*n*/strcmp(ife->name, name);
 
                 if (n == 0)
@@ -388,13 +389,14 @@ static struct interface *add_interface(char *name)
 
         new = xzalloc(sizeof(*new));
         strncpy_IFNAMSIZ(new->name, name);
-        nextp = ife ? &ife->next : &int_list;
+
+        nextp = ife ? &ife->next : &ilist->int_list;
         new->prev = ife;
         new->next = *nextp;
         if (new->next)
                 new->next->prev = new;
         else
-                int_last = new;
+                ilist->int_last = new;
         *nextp = new;
         return new;
 }
@@ -500,12 +502,12 @@ static int procnetdev_version(char *buf)
         return 0;
 }
 
-static int if_readconf(void)
+static void if_readconf(struct iface_list *ilist)
 {
         int numreqs = 30;
         struct ifconf ifc;
         struct ifreq *ifr;
-        int n, err;
+        int n;
         int skfd;
 
         ifc.ifc_buf = NULL;
@@ -518,10 +520,7 @@ static int if_readconf(void)
                 ifc.ifc_len = sizeof(struct ifreq) * numreqs;
                 ifc.ifc_buf = xrealloc(ifc.ifc_buf, ifc.ifc_len);
 
-                err = ioctl_or_warn(skfd, SIOCGIFCONF, &ifc);
-                if (err < 0) {
-                        goto out;
-                }
+                xioctl(skfd, SIOCGIFCONF, &ifc);
                 if (ifc.ifc_len == (int)(sizeof(struct ifreq) * numreqs)) {
                         /* assume it overflowed and try again */
                         numreqs += 10;
@@ -532,71 +531,54 @@ static int if_readconf(void)
 
         ifr = ifc.ifc_req;
         for (n = 0; n < ifc.ifc_len; n += sizeof(struct ifreq)) {
-                add_interface(ifr->ifr_name);
+                add_interface(ilist, ifr->ifr_name);
                 ifr++;
         }
-        err = 0;
 
- out:
         close(skfd);
         free(ifc.ifc_buf);
-        return err;
 }
 
-static int if_readlist_proc(char *target)
+static int if_readlist_proc(struct iface_list *ilist, char *ifname)
 {
-        static smallint proc_read;
-
         FILE *fh;
         char buf[512];
         struct interface *ife;
-        int err, procnetdev_vsn;
-
-        if (proc_read)
-                return 0;
-        if (!target)
-                proc_read = 1;
+        int procnetdev_vsn;
+        int ret;
 
         fh = fopen_or_warn(_PATH_PROCNET_DEV, "r");
         if (!fh) {
-                return if_readconf();
+                return 0; /* "not found" */
         }
         fgets(buf, sizeof buf, fh);     /* eat line */
         fgets(buf, sizeof buf, fh);
 
         procnetdev_vsn = procnetdev_version(buf);
 
-        err = 0;
+        ret = 0;
         while (fgets(buf, sizeof buf, fh)) {
                 char *s, name[IFNAMSIZ];
 
                 s = get_name(name, buf);
-                ife = add_interface(name);
+                ife = add_interface(ilist, name);
                 get_dev_fields(s, ife, procnetdev_vsn);
                 ife->statistics_valid = 1;
-                if (target && strcmp(target, name) == 0)
+                if (ifname && strcmp(ifname, name) == 0) {
+                        ret = 1; /* found */
                         break;
+                }
         }
-
-#if 0 /* we trust kernel to not be buggy, /proc/net/dev reads never fail */
-        if (ferror(fh)) {
-                bb_perror_msg(_PATH_PROCNET_DEV);
-                err = -1;
-                proc_read = 0;
-        }
-#endif
-
         fclose(fh);
-        return err;
+        return ret;
 }
 
-static int if_readlist(void)
+static void if_readlist(struct iface_list *ilist, char *ifname)
 {
-        int err = if_readlist_proc(NULL);
+        int found = if_readlist_proc(ilist, ifname);
         /* Needed in order to get ethN:M aliases */
-        if (!err)
-                err = if_readconf();
-        return err;
+        if (!found)
+                if_readconf(ilist);
 }
 
 /* Fetch the interface configuration from the kernel. */
@@ -1096,50 +1078,21 @@ static int do_if_print(struct interface *ife, int show_downed_too)
         return res;
 }
 
-static struct interface *lookup_interface(char *name)
-{
-        struct interface *ife = NULL;
-
-        if (if_readlist_proc(name) < 0)
-                return NULL;
-        ife = add_interface(name);
-        return ife;
-}
-
-#ifdef UNUSED
-static int for_all_interfaces(int (*doit) (struct interface *, void *),
-                                                        void *cookie)
-{
-        struct interface *ife;
-
-        if (!int_list) {
-                int err = if_readlist();
-                if (err < 0)
-                        return err;
-        }
-        for (ife = int_list; ife; ife = ife->next) {
-                int err = doit(ife, cookie);
-                if (err)
-                        return err;
-        }
-        return 0;
-}
-#endif
-
 int FAST_FUNC display_interfaces(char *ifname)
 {
         struct interface *ife;
         int res;
+        struct iface_list ilist;
+
+        ilist.int_list = NULL;
+        ilist.int_last = NULL;
+        if_readlist(&ilist, ifname != IFNAME_SHOW_DOWNED_TOO ? ifname : NULL);
 
         if (!ifname || ifname == IFNAME_SHOW_DOWNED_TOO) {
-                /*res = for_all_interfaces(do_if_print, &interface_opt_a);*/
-                if (!int_list) {
-                        res = if_readlist();
-                        if (res < 0)
-                                goto ret;
-                }
-                for (ife = int_list; ife; ife = ife->next) {
+                for (ife = ilist.int_list; ife; ife = ife->next) {
+
                         BUILD_BUG_ON((int)(intptr_t)IFNAME_SHOW_DOWNED_TOO != 1);
+
                         res = do_if_print(ife, (int)(intptr_t)ifname);
                         if (res < 0)
                                 goto ret;
@@ -1147,10 +1100,8 @@ int FAST_FUNC display_interfaces(char *ifname)
                 return 0;
         }
 
-        ife = lookup_interface(ifname);
-        res = do_if_fetch(ife);
-        if (res >= 0)
-                ife_print(ife);
+        ife = add_interface(&ilist, ifname);
+        res = do_if_print(ife, /*show_downed_too:*/ 1);
  ret:
         return (res < 0); /* status < 0 == 1 -- error */
 }