brctl: make "show" command retrieve data from /sys

ioctl interface is obsolete and has no 32/64 compat shim,
making "brctl show" fail for 32-bit userspace and 64-bit kernel.

function                                             old     new   delta
show_bridge                                            -     310    +310
read_file                                              -      64     +64
if_indextoname                                       117       -    -117
brctl_main                                          1183     885    -298
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 0/1 up/down: 374/-415)          Total: -41 bytes

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

1 files changed, 114 insertions, 49 deletions

diff --git a/networking/brctl.c b/networking/brctl.c
index ba4a714f8..706ecfc07 100644
--- a/networking/brctl.c
+++ b/networking/brctl.c
@@ -67,6 +67,7 @@
 //usage:        )
 
 #include "libbb.h"
+#include "common_bufsiz.h"
 #include <linux/sockios.h>
 #include <net/if.h>
 
@@ -198,6 +199,69 @@ static void arm_ioctl(unsigned long *args,
 }
 #endif
 
+#define filedata bb_common_bufsiz1
+static int read_file(const char *name)
+{
+        int n = open_read_close(name, filedata, COMMON_BUFSIZE - 1);
+        if (n < 0) {
+                filedata[0] = '\0';
+        } else {
+                filedata[n] = '\0';
+                if (n != 0 && filedata[n - 1] == '\n')
+                        filedata[--n] = '\0';
+        }
+        return n;
+}
+
+/* NB: we are in /sys/class/net
+ */
+static int show_bridge(const char *name, int need_hdr)
+{
+// Output:
+//bridge name   bridge id               STP enabled     interfaces
+//br0           8000.000000000000       no              eth0
+        char pathbuf[IFNAMSIZ + sizeof("/bridge/bridge_id") + 32];
+        int tabs;
+        DIR *ifaces;
+        struct dirent *ent;
+        char *sfx;
+
+        sfx = pathbuf + sprintf(pathbuf, "%s/bridge/", name);
+        strcpy(sfx, "bridge_id");
+        if (read_file(pathbuf) < 0)
+                return -1; /* this iface is not a bridge */
+
+        if (need_hdr)
+                puts("bridge name\tbridge id\t\tSTP enabled\tinterfaces");
+        printf("%s\t\t", name);
+        printf("%s\t", filedata);
+
+        strcpy(sfx, "stp_state");
+        read_file(pathbuf);
+        if (LONE_CHAR(filedata, '0'))
+                strcpy(filedata, "no");
+        else
+        if (LONE_CHAR(filedata, '1'))
+                strcpy(filedata, "yes");
+        printf(filedata);
+
+        strcpy(sfx, "brif");
+        tabs = 0;
+        ifaces = opendir(pathbuf);
+        if (ifaces) {
+                while ((ent = readdir(ifaces)) != NULL) {
+                        if (tabs)
+                                printf("\t\t\t\t\t");
+                        else
+                                tabs = 1;
+                        printf("\t\t%s\n", ent->d_name);
+                }
+                closedir(ifaces);
+        }
+        if (!tabs)  /* bridge has no interfaces */
+                bb_putchar('\n');
+        return 0;
+}
 
 int brctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int brctl_main(int argc UNUSED_PARAM, char **argv)
@@ -226,6 +290,13 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
         char *br, *brif;
 
         argv++;
+        if (!*argv) {
+                /* bare "brctl" shows --help */
+                bb_show_usage();
+        }
+
+        xchdir("/sys/class/net");
+
         while (*argv) {
 #if ENABLE_FEATURE_BRCTL_FANCY
                 int ifidx[MAX_PORTS];
@@ -237,68 +308,50 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                 if (key == -1) /* no match found in keywords array, bail out. */
                         bb_error_msg_and_die(bb_msg_invalid_arg_to, *argv, applet_name);
                 argv++;
-                fd = xsocket(AF_INET, SOCK_STREAM, 0);
 
 #if ENABLE_FEATURE_BRCTL_SHOW
                 if (key == ARG_show) { /* show */
-                        char buf[IFNAMSIZ];
-                        int bridx[MAX_PORTS];
-                        int i, num;
-                        arm_ioctl(args, BRCTL_GET_BRIDGES,
-                                                (unsigned long) bridx, MAX_PORTS);
-                        num = xioctl(fd, SIOCGIFBR, args);
-                        puts("bridge name\tbridge id\t\tSTP enabled\tinterfaces");
-                        for (i = 0; i < num; i++) {
-                                int j, tabs;
-                                struct __bridge_info bi;
-                                unsigned char *x;
-
-                                if (!if_indextoname(bridx[i], buf))
-                                        bb_perror_msg_and_die("can't get bridge name for index %d", i);
-                                strncpy_IFNAMSIZ(ifr.ifr_name, buf);
-
-                                arm_ioctl(args, BRCTL_GET_BRIDGE_INFO,
-                                                        (unsigned long) &bi, 0);
-                                xioctl(fd, SIOCDEVPRIVATE, &ifr);
-                                printf("%s\t\t", buf);
-
-                                /* print bridge id */
-                                x = (unsigned char *) &bi.bridge_id;
-                                for (j = 0; j < 8; j++) {
-                                        printf("%02x", x[j]);
-                                        if (j == 1)
-                                                bb_putchar('.');
-                                }
-                                printf(bi.stp_enabled ? "\tyes" : "\tno");
+                        DIR *net;
+                        struct dirent *ent;
+                        int need_hdr = 1;
+                        int exitcode = EXIT_SUCCESS;
+
+                        if (*argv) {
+                                /* "brctl show BR1 BR2 BR3" */
+                                do {
+                                        if (show_bridge(*argv, need_hdr) >= 0) {
+                                                need_hdr = 0;
+                                        } else {
+                                                bb_error_msg("bridge %s does not exist", *argv);
+//TODO: if device exists, but is not a BR, brctl from bridge-utils 1.6 says this instead:
+// "device eth0 is not a bridge"
+                                                exitcode = EXIT_FAILURE;
+                                        }
+                                } while (*++argv != NULL);
+                                return exitcode;
+                        }
 
-                                /* print interface list */
-                                arm_ioctl(args, BRCTL_GET_PORT_LIST,
-                                                        (unsigned long) ifidx, MAX_PORTS);
-                                xioctl(fd, SIOCDEVPRIVATE, &ifr);
-                                tabs = 0;
-                                for (j = 0; j < MAX_PORTS; j++) {
-                                        if (!ifidx[j])
-                                                continue;
-                                        if (!if_indextoname(ifidx[j], buf))
-                                                bb_perror_msg_and_die("can't get interface name for index %d", j);
-                                        if (tabs)
-                                                printf("\t\t\t\t\t");
-                                        else
-                                                tabs = 1;
-                                        printf("\t\t%s\n", buf);
-                                }
-                                if (!tabs)  /* bridge has no interfaces */
-                                        bb_putchar('\n');
+                        /* "brctl show" (if no ifaces, shows nothing, not even header) */
+                        net = xopendir(".");
+                        while ((ent = readdir(net)) != NULL) {
+                                if (DOT_OR_DOTDOT(ent->d_name))
+                                        continue; /* . or .. */
+                                if (show_bridge(ent->d_name, need_hdr) >= 0)
+                                        need_hdr = 0;
                         }
-                        goto done;
+                        closedir(net);
+                        return exitcode;
                 }
 #endif
 
                 if (!*argv) /* all but 'show' need at least one argument */
                         bb_show_usage();
 
+                fd = xsocket(AF_INET, SOCK_STREAM, 0);
                 br = *argv++;
 
+//brctl from bridge-utils 1.6 also still uses ioctl
+//for SIOCBRADDBR / SIOCBRDELBR, not /sys accesses
                 if (key == ARG_addbr || key == ARG_delbr) { /* addbr or delbr */
                         ioctl_or_perror_and_die(fd,
                                         key == ARG_addbr ? SIOCBRADDBR : SIOCBRDELBR,
@@ -329,6 +382,8 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                         int onoff = index_in_strings(no_yes, *argv);
                         if (onoff < 0)
                                 bb_error_msg_and_die(bb_msg_invalid_arg_to, *argv, applet_name);
+//TODO: replace with:
+//write "0\n" or "1\n" to /sys/class/net/BR/bridge/stp_state
                         onoff = (unsigned)onoff / 4;
                         arm_ioctl(args, BRCTL_SET_BRIDGE_STP_STATE, onoff, 0);
                         goto fire;
@@ -340,6 +395,11 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                                 BRCTL_SET_BRIDGE_HELLO_TIME,    /* ARG_sethello  */
                                 BRCTL_SET_BRIDGE_MAX_AGE        /* ARG_setmaxage */
                         };
+//TODO: replace with:
+//setageing BR N: write "N*100\n" to /sys/class/net/BR/bridge/ageing_time
+//setfd BR N: write "N*100\n" to /sys/class/net/BR/bridge/forward_delay
+//sethello BR N: write "N*100\n" to /sys/class/net/BR/bridge/hello_time
+//setmaxage BR N: write "N*100\n" to /sys/class/net/BR/bridge/max_age
                         arm_ioctl(args, ops[key - ARG_setageing], str_to_jiffies(*argv), 0);
                         goto fire;
                 }
@@ -355,6 +415,11 @@ int brctl_main(int argc UNUSED_PARAM, char **argv)
                         int port = -1;
                         unsigned arg1, arg2;
 
+//TODO: replace with:
+//setbridgeprio BR N: write "N\n" to /sys/class/net/BR/bridge/priority
+//setpathcost BR PORT N: ??
+//setportprio BR PORT N: ??
+
                         if (key != ARG_setbridgeprio) {
                                 /* get portnum */
                                 unsigned i;