wget: -O FILE is allowed to overwrite existing file (compat)
[oweals/busybox.git] / networking / ifupdown.c
index ede2f8997a46980e09a8959ab92dec3cac79500b..02e13ed2769df764ea97d31611a46853847f24b2 100644 (file)
@@ -1,7 +1,7 @@
 /* vi: set sw=4 ts=4: */
 /*
  *  ifupdown for busybox
- *  Copyright (c) 2002 Glenn McGrath <bug1@iinet.net.au>
+ *  Copyright (c) 2002 Glenn McGrath
  *  Copyright (c) 2003-2004 Erik Andersen <andersen@codepoet.org>
  *
  *  Based on ifupdown v 0.6.4 by Anthony Towns
  *  Changes to upstream version
  *  Remove checks for kernel version, assume kernel version 2.2.0 or better.
  *  Lines in the interfaces file cannot wrap.
- *  To adhere to the FHS, the default state file is /var/run/ifstate.
+ *  To adhere to the FHS, the default state file is /var/run/ifstate
+ *  (defined via CONFIG_IFUPDOWN_IFSTATE_PATH) and can be overridden by build
+ *  configuration.
  *
  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  */
 
-#include "busybox.h"
 #include <sys/utsname.h>
 #include <fnmatch.h>
 #include <getopt.h>
 
+#include "libbb.h"
+
 #define MAX_OPT_DEPTH 10
 #define EUNBALBRACK 10001
 #define EUNDEFVAR   10002
 #define EUNBALPER   10000
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
 #define MAX_INTERFACE_LENGTH 10
 #endif
 
-#define debug_noise(fmt, args...)
+#define debug_noise(args...) /*fprintf(stderr, args)*/
 
 /* Forward declaration */
 struct interface_defn_t;
 
-typedef int (execfn)(char *command);
+typedef int execfn(char *command);
 
-struct method_t
-{
-       char *name;
+struct method_t {
+       const char *name;
        int (*up)(struct interface_defn_t *ifd, execfn *e);
        int (*down)(struct interface_defn_t *ifd, execfn *e);
 };
 
-struct address_family_t
-{
-       char *name;
+struct address_family_t {
+       const char *name;
        int n_methods;
        const struct method_t *method;
 };
 
-struct mapping_defn_t
-{
+struct mapping_defn_t {
        struct mapping_defn_t *next;
 
        int max_matches;
@@ -65,14 +65,12 @@ struct mapping_defn_t
        char **mapping;
 };
 
-struct variable_t
-{
+struct variable_t {
        char *name;
        char *value;
 };
 
-struct interface_defn_t
-{
+struct interface_defn_t {
        const struct address_family_t *address_family;
        const struct method_t *method;
 
@@ -82,8 +80,7 @@ struct interface_defn_t
        struct variable_t *option;
 };
 
-struct interfaces_file_t
-{
+struct interfaces_file_t {
        llist_t *autointerfaces;
        llist_t *ifaces;
        struct mapping_defn_t *mappings;
@@ -103,62 +100,33 @@ enum {
 #define FORCE (option_mask32 & OPT_force)
 #define NO_MAPPINGS (option_mask32 & OPT_no_mappings)
 
-static char **__myenviron;
+static char **my_environ;
 
-static char *startup_PATH;
+static const char *startup_PATH;
 
 #if ENABLE_FEATURE_IFUPDOWN_IPV4 || ENABLE_FEATURE_IFUPDOWN_IPV6
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
-
-static unsigned int count_bits(unsigned int a)
-{
-       unsigned int result;
-       result = (a & 0x55) + ((a >> 1) & 0x55);
-       result = (result & 0x33) + ((result >> 2) & 0x33);
-       return ((result & 0x0F) + ((result >> 4) & 0x0F));
-}
-
-static int count_netmask_bits(char *dotted_quad)
+static void addstr(char **bufp, const char *str, size_t str_length)
 {
-       unsigned int result, a, b, c, d;
-       /* Found a netmask...  Check if it is dotted quad */
-       if (sscanf(dotted_quad, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
-               return -1;
-       result = count_bits(a);
-       result += count_bits(b);
-       result += count_bits(c);
-       result += count_bits(d);
-       return (int)result;
-}
-#endif
-
-static void addstr(char **buf, size_t *len, size_t *pos, const char *str, size_t str_length)
-{
-       if (*pos + str_length >= *len) {
-               char *newbuf;
-
-               newbuf = xrealloc(*buf, *len * 2 + str_length + 1);
-               *buf = newbuf;
-               *len = *len * 2 + str_length + 1;
-       }
-
-       while (str_length-- >= 1) {
-               (*buf)[(*pos)++] = *str;
-               str++;
-       }
-       (*buf)[*pos] = '\0';
+       /* xasprintf trick will be smaller, but we are often
+        * called with str_length == 1 - don't want to have
+        * THAT much of malloc/freeing! */
+       char *buf = *bufp;
+       int len = (buf ? strlen(buf) : 0);
+       str_length++;
+       buf = xrealloc(buf, len + str_length);
+       /* copies at most str_length-1 chars! */
+       safe_strncpy(buf + len, str, str_length);
+       *bufp = buf;
 }
 
 static int strncmpz(const char *l, const char *r, size_t llen)
 {
        int i = strncmp(l, r, llen);
 
-       if (i == 0) {
+       if (i == 0)
                return -r[llen];
-       } else {
-               return i;
-       }
+       return i;
 }
 
 static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
@@ -168,58 +136,87 @@ static char *get_var(const char *id, size_t idlen, struct interface_defn_t *ifd)
        if (strncmpz(id, "iface", idlen) == 0) {
                char *result;
                static char label_buf[20];
-               strncpy(label_buf, ifd->iface, 19);
-               label_buf[19]=0;
+               safe_strncpy(label_buf, ifd->iface, sizeof(label_buf));
                result = strchr(label_buf, ':');
                if (result) {
-                       *result=0;
+                       *result = '\0';
                }
                return label_buf;
-       } else if (strncmpz(id, "label", idlen) == 0) {
+       }
+       if (strncmpz(id, "label", idlen) == 0) {
                return ifd->iface;
-       } else {
-               for (i = 0; i < ifd->n_options; i++) {
-                       if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
-                               return ifd->option[i].value;
-                       }
+       }
+       for (i = 0; i < ifd->n_options; i++) {
+               if (strncmpz(id, ifd->option[i].name, idlen) == 0) {
+                       return ifd->option[i].value;
                }
        }
-
        return NULL;
 }
 
-static char *parse(const char *command, struct interface_defn_t *ifd)
+#if ENABLE_FEATURE_IFUPDOWN_IP
+static int count_netmask_bits(const char *dotted_quad)
 {
+//     int result;
+//     unsigned a, b, c, d;
+//     /* Found a netmask...  Check if it is dotted quad */
+//     if (sscanf(dotted_quad, "%u.%u.%u.%u", &a, &b, &c, &d) != 4)
+//             return -1;
+//     if ((a|b|c|d) >> 8)
+//             return -1; /* one of numbers is >= 256 */
+//     d |= (a << 24) | (b << 16) | (c << 8); /* IP */
+//     d = ~d; /* 11110000 -> 00001111 */
+
+       /* Shorter version */
+       int result;
+       struct in_addr ip;
+       unsigned d;
+
+       if (inet_aton(dotted_quad, &ip) == 0)
+               return -1; /* malformed dotted IP */
+       d = ntohl(ip.s_addr); /* IP in host order */
+       d = ~d; /* 11110000 -> 00001111 */
+       if (d & (d+1)) /* check that it is in 00001111 form */
+               return -1; /* no it is not */
+       result = 32;
+       while (d) {
+               d >>= 1;
+               result--;
+       }
+       return result;
+}
+#endif
 
-       char *result = NULL;
-       size_t pos = 0, len = 0;
+static char *parse(const char *command, struct interface_defn_t *ifd)
+{
        size_t old_pos[MAX_OPT_DEPTH] = { 0 };
        int okay[MAX_OPT_DEPTH] = { 1 };
        int opt_depth = 1;
+       char *result = NULL;
 
        while (*command) {
                switch (*command) {
                default:
-                       addstr(&result, &len, &pos, command, 1);
+                       addstr(&result, command, 1);
                        command++;
                        break;
                case '\\':
                        if (command[1]) {
-                               addstr(&result, &len, &pos, command + 1, 1);
+                               addstr(&result, command + 1, 1);
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, command, 1);
+                               addstr(&result, command, 1);
                                command++;
                        }
                        break;
                case '[':
                        if (command[1] == '[' && opt_depth < MAX_OPT_DEPTH) {
-                               old_pos[opt_depth] = pos;
+                               old_pos[opt_depth] = result ? strlen(result) : 0;
                                okay[opt_depth] = 1;
                                opt_depth++;
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, "[", 1);
+                               addstr(&result, "[", 1);
                                command++;
                        }
                        break;
@@ -227,12 +224,11 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                        if (command[1] == ']' && opt_depth > 1) {
                                opt_depth--;
                                if (!okay[opt_depth]) {
-                                       pos = old_pos[opt_depth];
-                                       result[pos] = '\0';
+                                       result[old_pos[opt_depth]] = '\0';
                                }
                                command += 2;
                        } else {
-                               addstr(&result, &len, &pos, "]", 1);
+                               addstr(&result, "]", 1);
                                command++;
                        }
                        break;
@@ -252,20 +248,22 @@ static char *parse(const char *command, struct interface_defn_t *ifd)
                                varvalue = get_var(command, nextpercent - command, ifd);
 
                                if (varvalue) {
-                                       addstr(&result, &len, &pos, varvalue, strlen(varvalue));
+                                       addstr(&result, varvalue, strlen(varvalue));
                                } else {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
                                        /* Sigh...  Add a special case for 'ip' to convert from
                                         * dotted quad to bit count style netmasks.  */
-                                       if (strncmp(command, "bnmask", 6)==0) {
-                                               int res;
+                                       if (strncmp(command, "bnmask", 6) == 0) {
+                                               unsigned res;
                                                varvalue = get_var("netmask", 7, ifd);
-                                               if (varvalue && (res=count_netmask_bits(varvalue)) > 0) {
-                                                       char argument[255];
-                                                       sprintf(argument, "%d", res);
-                                                       addstr(&result, &len, &pos, argument, strlen(argument));
-                                                       command = nextpercent + 1;
-                                                       break;
+                                               if (varvalue) {
+                                                       res = count_netmask_bits(varvalue);
+                                                       if (res > 0) {
+                                                               const char *argument = utoa(res);
+                                                               addstr(&result, argument, strlen(argument));
+                                                               command = nextpercent + 1;
+                                                               break;
+                                                       }
                                                }
                                        }
 #endif
@@ -301,9 +299,11 @@ static int execute(const char *command, struct interface_defn_t *ifd, execfn *ex
 
        out = parse(command, ifd);
        if (!out) {
+               /* parse error? */
                return 0;
        }
-       ret = (*exec)(out);
+       /* out == "": parsed ok but not all needed variables known, skip */
+       ret = out[0] ? (*exec)(out) : 1;
 
        free(out);
        if (ret != 1) {
@@ -313,10 +313,10 @@ static int execute(const char *command, struct interface_defn_t *ifd, execfn *ex
 }
 #endif
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_IPV6
+#if ENABLE_FEATURE_IFUPDOWN_IPV6
 static int loopback_up6(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        int result;
        result = execute("ip addr add ::1 dev %iface%", ifd, exec);
        result += execute("ip link set %iface% up", ifd, exec);
@@ -328,7 +328,7 @@ static int loopback_up6(struct interface_defn_t *ifd, execfn *exec)
 
 static int loopback_down6(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        return execute("ip link set %iface% down", ifd, exec);
 #else
        return execute("ifconfig %iface% del ::1", ifd, exec);
@@ -338,36 +338,37 @@ static int loopback_down6(struct interface_defn_t *ifd, execfn *exec)
 static int static_up6(struct interface_defn_t *ifd, execfn *exec)
 {
        int result;
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
-       result = execute("ip addr add %address%/%netmask% dev %iface% [[label %label%]]", ifd, exec);
-       result += execute("ip link set [[mtu %mtu%]] [[address %hwaddress%]] %iface% up", ifd, exec);
-       result += execute("[[ ip route add ::/0 via %gateway% ]]", ifd, exec);
+#if ENABLE_FEATURE_IFUPDOWN_IP
+       result = execute("ip addr add %address%/%netmask% dev %iface%[[ label %label%]]", ifd, exec);
+       result += execute("ip link set[[ mtu %mtu%]][[ address %hwaddress%]] %iface% up", ifd, exec);
+       /* Was: "[[ ip ....%gateway% ]]". Removed extra spaces w/o checking */
+       result += execute("[[ip route add ::/0 via %gateway%]]", ifd, exec);
 #else
-       result = execute("ifconfig %iface% [[media %media%]] [[hw %hwaddress%]] [[mtu %mtu%]] up", ifd, exec);
+       result = execute("ifconfig %iface%[[ media %media%]][[ hw %hwaddress%]][[ mtu %mtu%]] up", ifd, exec);
        result += execute("ifconfig %iface% add %address%/%netmask%", ifd, exec);
-       result += execute("[[ route -A inet6 add ::/0 gw %gateway% ]]", ifd, exec);
+       result += execute("[[route -A inet6 add ::/0 gw %gateway%]]", ifd, exec);
 #endif
        return ((result == 3) ? 3 : 0);
 }
 
 static int static_down6(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        return execute("ip link set %iface% down", ifd, exec);
 #else
        return execute("ifconfig %iface% down", ifd, exec);
 #endif
 }
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
 static int v4tunnel_up(struct interface_defn_t *ifd, execfn *exec)
 {
        int result;
        result = execute("ip tunnel add %iface% mode sit remote "
-                       "%endpoint% [[local %local%]] [[ttl %ttl%]]", ifd, exec);
+                       "%endpoint%[[ local %local%]][[ ttl %ttl%]]", ifd, exec);
        result += execute("ip link set %iface% up", ifd, exec);
        result += execute("ip addr add %address%/%netmask% dev %iface%", ifd, exec);
-       result += execute("[[ ip route add ::/0 via %gateway% ]]", ifd, exec);
+       result += execute("[[ip route add ::/0 via %gateway%]]", ifd, exec);
        return ((result == 4) ? 4 : 0);
 }
 
@@ -378,7 +379,7 @@ static int v4tunnel_down(struct interface_defn_t * ifd, execfn * exec)
 #endif
 
 static const struct method_t methods6[] = {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        { "v4tunnel", v4tunnel_up, v4tunnel_down, },
 #endif
        { "static", static_up6, static_down6, },
@@ -387,15 +388,15 @@ static const struct method_t methods6[] = {
 
 static const struct address_family_t addr_inet6 = {
        "inet6",
-       sizeof(methods6) / sizeof(struct method_t),
+       ARRAY_SIZE(methods6),
        methods6
 };
-#endif /* CONFIG_FEATURE_IFUPDOWN_IPV6 */
+#endif /* FEATURE_IFUPDOWN_IPV6 */
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_IPV4
+#if ENABLE_FEATURE_IFUPDOWN_IPV4
 static int loopback_up(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        int result;
        result = execute("ip addr add 127.0.0.1/8 dev %iface%", ifd, exec);
        result += execute("ip link set %iface% up", ifd, exec);
@@ -407,7 +408,7 @@ static int loopback_up(struct interface_defn_t *ifd, execfn *exec)
 
 static int loopback_down(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        int result;
        result = execute("ip addr flush dev %iface%", ifd, exec);
        result += execute("ip link set %iface% down", ifd, exec);
@@ -420,36 +421,39 @@ static int loopback_down(struct interface_defn_t *ifd, execfn *exec)
 static int static_up(struct interface_defn_t *ifd, execfn *exec)
 {
        int result;
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
-       result = execute("ip addr add %address%/%bnmask% [[broadcast %broadcast%]] "
-                       "dev %iface% [[peer %pointopoint%]] [[label %label%]]", ifd, exec);
-       result += execute("ip link set [[mtu %mtu%]] [[address %hwaddress%]] %iface% up", ifd, exec);
-       result += execute("[[ ip route add default via %gateway% dev %iface% ]]", ifd, exec);
+#if ENABLE_FEATURE_IFUPDOWN_IP
+       result = execute("ip addr add %address%/%bnmask%[[ broadcast %broadcast%]] "
+                       "dev %iface%[[ peer %pointopoint%]][[ label %label%]]", ifd, exec);
+       result += execute("ip link set[[ mtu %mtu%]][[ address %hwaddress%]] %iface% up", ifd, exec);
+       result += execute("[[ip route add default via %gateway% dev %iface%]]", ifd, exec);
        return ((result == 3) ? 3 : 0);
 #else
-       result = execute("ifconfig %iface% %address% netmask %netmask% "
-                       "[[broadcast %broadcast%]] [[pointopoint %pointopoint%]] "
-                       "[[media %media%]] [[mtu %mtu%]] [[hw %hwaddress%]] up",
-                       ifd, exec);
-       result += execute("[[ route add default gw %gateway% %iface% ]]", ifd, exec);
-       return ((result == 2) ? 2 : 0);
+       /* ifconfig said to set iface up before it processes hw %hwaddress%,
+        * which then of course fails. Thus we run two separate ifconfig */
+       result = execute("ifconfig %iface%[[ hw %hwaddress%]][[ media %media%]][[ mtu %mtu%]] up",
+                               ifd, exec);
+       result += execute("ifconfig %iface% %address% netmask %netmask%"
+                               "[[ broadcast %broadcast%]][[ pointopoint %pointopoint%]] ",
+                               ifd, exec);
+       result += execute("[[route add default gw %gateway% %iface%]]", ifd, exec);
+       return ((result == 3) ? 3 : 0);
 #endif
 }
 
 static int static_down(struct interface_defn_t *ifd, execfn *exec)
 {
        int result;
-#ifdef CONFIG_FEATURE_IFUPDOWN_IP
+#if ENABLE_FEATURE_IFUPDOWN_IP
        result = execute("ip addr flush dev %iface%", ifd, exec);
        result += execute("ip link set %iface% down", ifd, exec);
 #else
-       result = execute("[[ route del default gw %gateway% %iface% ]]", ifd, exec);
+       result = execute("[[route del default gw %gateway% %iface%]]", ifd, exec);
        result += execute("ifconfig %iface% down", ifd, exec);
 #endif
        return ((result == 2) ? 2 : 0);
 }
 
-#ifndef CONFIG_APP_UDHCPC
+#if ENABLE_FEATURE_IFUPDOWN_EXTERNAL_DHCP
 struct dhcp_client_t
 {
        const char *name;
@@ -458,55 +462,69 @@ struct dhcp_client_t
 };
 
 static const struct dhcp_client_t ext_dhcp_clients[] = {
-       { "udhcpc",
-               "udhcpc -R -n -p /var/run/udhcpc.%iface%.pid -i %iface% [[-H %hostname%]] [[-c %clientid%]] [[-s %script%]]",
-               "kill -TERM `cat /var/run/udhcpc.%iface%.pid` 2>/dev/null",
-       },
-       { "pump",
-               "pump -i %iface% [[-h %hostname%]] [[-l %leasehours%]]",
-               "pump -i %iface% -k",
+       { "dhcpcd",
+               "dhcpcd[[ -h %hostname%]][[ -i %vendor%]][[ -I %clientid%]][[ -l %leasetime%]] %iface%",
+               "dhcpcd -k %iface%",
        },
        { "dhclient",
                "dhclient -pf /var/run/dhclient.%iface%.pid %iface%",
                "kill -9 `cat /var/run/dhclient.%iface%.pid` 2>/dev/null",
        },
-       { "dhcpcd",
-               "dhcpcd [[-h %hostname%]] [[-i %vendor%]] [[-I %clientid%]] [[-l %leasetime%]] %iface%",
-               "dhcpcd -k %iface%",
+       { "pump",
+               "pump -i %iface%[[ -h %hostname%]][[ -l %leasehours%]]",
+               "pump -i %iface% -k",
+       },
+       { "udhcpc",
+               "udhcpc -R -n -p /var/run/udhcpc.%iface%.pid -i %iface%[[ -H %hostname%]][[ -c %clientid%]][[ -s %script%]]",
+               "kill `cat /var/run/udhcpc.%iface%.pid` 2>/dev/null",
        },
 };
-#endif
+#endif /* ENABLE_FEATURE_IFUPDOWN_EXTERNAL_DHCPC */
 
 static int dhcp_up(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_APP_UDHCPC
-       return execute("udhcpc -R -n -p /var/run/udhcpc.%iface%.pid "
-                       "-i %iface% [[-H %hostname%]] [[-c %clientid%]] [[-s %script%]]",
-                       ifd, exec);
-#else
-       int i, nclients = sizeof(ext_dhcp_clients) / sizeof(ext_dhcp_clients[0]);
-       for (i = 0; i < nclients; i++) {
+#if ENABLE_FEATURE_IFUPDOWN_EXTERNAL_DHCP
+       int i;
+#if ENABLE_FEATURE_IFUPDOWN_IP
+       /* ip doesn't up iface when it configures it (unlike ifconfig) */
+       if (!execute("ip link set %iface% up", ifd, exec))
+               return 0;
+#endif
+       for (i = 0; i < ARRAY_SIZE(ext_dhcp_clients); i++) {
                if (exists_execable(ext_dhcp_clients[i].name))
                        return execute(ext_dhcp_clients[i].startcmd, ifd, exec);
        }
        bb_error_msg("no dhcp clients found");
        return 0;
+#elif ENABLE_APP_UDHCPC
+#if ENABLE_FEATURE_IFUPDOWN_IP
+       /* ip doesn't up iface when it configures it (unlike ifconfig) */
+       if (!execute("ip link set %iface% up", ifd, exec))
+               return 0;
+#endif
+       return execute("udhcpc -R -n -p /var/run/udhcpc.%iface%.pid "
+                       "-i %iface%[[ -H %hostname%]][[ -c %clientid%]][[ -s %script%]]",
+                       ifd, exec);
+#else
+       return 0; /* no dhcp support */
 #endif
 }
 
 static int dhcp_down(struct interface_defn_t *ifd, execfn *exec)
 {
-#ifdef CONFIG_APP_UDHCPC
-       return execute("kill -TERM "
-                      "`cat /var/run/udhcpc.%iface%.pid` 2>/dev/null", ifd, exec);
-#else
-       int i, nclients = sizeof(ext_dhcp_clients) / sizeof(ext_dhcp_clients[0]);
-       for (i = 0; i < nclients; i++) {
+#if ENABLE_FEATURE_IFUPDOWN_EXTERNAL_DHCP
+       int i;
+       for (i = 0; i < ARRAY_SIZE(ext_dhcp_clients); i++) {
                if (exists_execable(ext_dhcp_clients[i].name))
                        return execute(ext_dhcp_clients[i].stopcmd, ifd, exec);
        }
        bb_error_msg("no dhcp clients found, using static interface shutdown");
        return static_down(ifd, exec);
+#elif ENABLE_APP_UDHCPC
+       return execute("kill "
+                      "`cat /var/run/udhcpc.%iface%.pid` 2>/dev/null", ifd, exec);
+#else
+       return 0; /* no dhcp support */
 #endif
 }
 
@@ -517,30 +535,30 @@ static int manual_up_down(struct interface_defn_t *ifd, execfn *exec)
 
 static int bootp_up(struct interface_defn_t *ifd, execfn *exec)
 {
-       return execute("bootpc [[--bootfile %bootfile%]] --dev %iface% "
-                       "[[--server %server%]] [[--hwaddr %hwaddr%]] "
-                       "--returniffail --serverbcast", ifd, exec);
+       return execute("bootpc[[ --bootfile %bootfile%]] --dev %iface%"
+                       "[[ --server %server%]][[ --hwaddr %hwaddr%]]"
+                       " --returniffail --serverbcast", ifd, exec);
 }
 
 static int ppp_up(struct interface_defn_t *ifd, execfn *exec)
 {
-       return execute("pon [[%provider%]]", ifd, exec);
+       return execute("pon[[ %provider%]]", ifd, exec);
 }
 
 static int ppp_down(struct interface_defn_t *ifd, execfn *exec)
 {
-       return execute("poff [[%provider%]]", ifd, exec);
+       return execute("poff[[ %provider%]]", ifd, exec);
 }
 
 static int wvdial_up(struct interface_defn_t *ifd, execfn *exec)
 {
-       return execute("/sbin/start-stop-daemon --start -x /usr/bin/wvdial "
-               "-p /var/run/wvdial.%iface% -b -m -- [[ %provider% ]]", ifd, exec);
+       return execute("start-stop-daemon --start -x wvdial "
+               "-p /var/run/wvdial.%iface% -b -m --[[ %provider%]]", ifd, exec);
 }
 
 static int wvdial_down(struct interface_defn_t *ifd, execfn *exec)
 {
-       return execute("/sbin/start-stop-daemon --stop -x /usr/bin/wvdial "
+       return execute("start-stop-daemon --stop -x wvdial "
                        "-p /var/run/wvdial.%iface% -s 2", ifd, exec);
 }
 
@@ -556,18 +574,18 @@ static const struct method_t methods[] = {
 
 static const struct address_family_t addr_inet = {
        "inet",
-       sizeof(methods) / sizeof(struct method_t),
+       ARRAY_SIZE(methods),
        methods
 };
 
-#endif /* ifdef CONFIG_FEATURE_IFUPDOWN_IPV4 */
+#endif /* if ENABLE_FEATURE_IFUPDOWN_IPV4 */
 
 static char *next_word(char **buf)
 {
        unsigned short length;
        char *word;
 
-       if ((buf == NULL) || (*buf == NULL) || (**buf == '\0')) {
+       if (!buf || !*buf || !**buf) {
                return NULL;
        }
 
@@ -598,6 +616,9 @@ static const struct address_family_t *get_address_family(const struct address_fa
 {
        int i;
 
+       if (!name)
+               return NULL;
+
        for (i = 0; af[i]; i++) {
                if (strcmp(af[i]->name, name) == 0) {
                        return af[i];
@@ -610,6 +631,9 @@ static const struct method_t *get_method(const struct address_family_t *af, char
 {
        int i;
 
+       if (!name)
+               return NULL;
+
        for (i = 0; i < af->n_methods; i++) {
                if (strcmp(af->method[i].name, name) == 0) {
                        return &af->method[i];
@@ -620,6 +644,9 @@ static const struct method_t *get_method(const struct address_family_t *af, char
 
 static const llist_t *find_list_string(const llist_t *list, const char *string)
 {
+       if (string == NULL)
+               return NULL;
+
        while (list) {
                if (strcmp(list->data, string) == 0) {
                        return list;
@@ -631,7 +658,7 @@ static const llist_t *find_list_string(const llist_t *list, const char *string)
 
 static struct interfaces_file_t *read_interfaces(const char *filename)
 {
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
        struct mapping_defn_t *currmap = NULL;
 #endif
        struct interface_defn_t *currif = NULL;
@@ -656,7 +683,7 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                }
 
                if (strcmp(firstword, "mapping") == 0) {
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
                        currmap = xzalloc(sizeof(struct mapping_defn_t));
 
                        while ((firstword = next_word(&buf_ptr)) != NULL) {
@@ -684,10 +711,10 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                        currently_processing = MAPPING;
                } else if (strcmp(firstword, "iface") == 0) {
                        static const struct address_family_t *const addr_fams[] = {
-#ifdef CONFIG_FEATURE_IFUPDOWN_IPV4
+#if ENABLE_FEATURE_IFUPDOWN_IPV4
                                &addr_inet,
 #endif
-#ifdef CONFIG_FEATURE_IFUPDOWN_IPV6
+#if ENABLE_FEATURE_IFUPDOWN_IPV6
                                &addr_inet6,
 #endif
                                NULL
@@ -800,7 +827,7 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                                currif->n_options++;
                                break;
                        case MAPPING:
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
                                if (strcmp(firstword, "script") == 0) {
                                        if (currmap->script != NULL) {
                                                bb_error_msg("duplicate script in mapping \"%s\"", buf);
@@ -830,14 +857,15 @@ static struct interfaces_file_t *read_interfaces(const char *filename)
                free(buf);
        }
        if (ferror(f) != 0) {
-               bb_perror_msg_and_die("%s", filename);
+               /* ferror does NOT set errno! */
+               bb_error_msg_and_die("%s: I/O error", filename);
        }
        fclose(f);
 
        return defn;
 }
 
-static char *setlocalenv(char *format, const char *name, const char *value)
+static char *setlocalenv(const char *format, const char *name, const char *value)
 {
        char *result;
        char *here;
@@ -868,21 +896,22 @@ static void set_environ(struct interface_defn_t *iface, const char *mode)
        const int n_env_entries = iface->n_options + 5;
        char **ppch;
 
-       if (__myenviron != NULL) {
-               for (ppch = __myenviron; *ppch; ppch++) {
+       if (my_environ != NULL) {
+               for (ppch = my_environ; *ppch; ppch++) {
                        free(*ppch);
                        *ppch = NULL;
                }
-               free(__myenviron);
+               free(my_environ);
        }
-       __myenviron = xzalloc(sizeof(char *) * (n_env_entries + 1 /* for final NULL */ ));
-       environend = __myenviron;
+       my_environ = xzalloc(sizeof(char *) * (n_env_entries + 1 /* for final NULL */ ));
+       environend = my_environ;
 
        for (i = 0; i < iface->n_options; i++) {
                if (strcmp(iface->option[i].name, "up") == 0
-                               || strcmp(iface->option[i].name, "down") == 0
-                               || strcmp(iface->option[i].name, "pre-up") == 0
-                               || strcmp(iface->option[i].name, "post-down") == 0) {
+                || strcmp(iface->option[i].name, "down") == 0
+                || strcmp(iface->option[i].name, "pre-up") == 0
+                || strcmp(iface->option[i].name, "post-down") == 0
+               ) {
                        continue;
                }
                *(environend++) = setlocalenv("IF_%s=%s", iface->option[i].name, iface->option[i].value);
@@ -905,11 +934,12 @@ static int doit(char *str)
                int status;
 
                fflush(NULL);
-               switch (child = fork()) {
-               case -1:                /* failure */
+               child = fork();
+               switch (child) {
+               case -1: /* failure */
                        return 0;
-               case 0:         /* child */
-                       execle(DEFAULT_SHELL, DEFAULT_SHELL, "-c", str, NULL, __myenviron);
+               case 0: /* child */
+                       execle(DEFAULT_SHELL, DEFAULT_SHELL, "-c", str, NULL, my_environ);
                        exit(127);
                }
                waitpid(child, &status, 0);
@@ -933,19 +963,18 @@ static int execute_all(struct interface_defn_t *ifd, const char *opt)
        }
 
        buf = xasprintf("run-parts /etc/network/if-%s.d", opt);
-       if (doit(buf) != 1) {
-               return 0;
-       }
-       return 1;
+       /* heh, we don't bother free'ing it */
+       return doit(buf);
 }
 
-static int check(char *str) {
+static int check(char *str)
+{
        return str != NULL;
 }
 
 static int iface_up(struct interface_defn_t *iface)
 {
-       if (!iface->method->up(iface,check)) return -1;
+       if (!iface->method->up(iface, check)) return -1;
        set_environ(iface, "start");
        if (!execute_all(iface, "pre-up")) return 0;
        if (!iface->method->up(iface, doit)) return 0;
@@ -963,7 +992,7 @@ static int iface_down(struct interface_defn_t *iface)
        return 1;
 }
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
 static int popen2(FILE **in, FILE **out, char *command, ...)
 {
        va_list ap;
@@ -1005,7 +1034,7 @@ static int popen2(FILE **in, FILE **out, char *command, ...)
                close(infd[1]);
                close(outfd[0]);
                close(outfd[1]);
-               execvp(command, argv);
+               BB_EXECVP(command, argv);
                exit(127);
        default:                        /* parent */
                *in = fdopen(infd[1], "w");
@@ -1043,7 +1072,7 @@ static char *run_mapping(char *physical, struct mapping_defn_t * map)
                /* If the mapping script exited successfully, try to
                 * grab a line of output and use that as the name of the
                 * logical interface. */
-               char *new_logical = (char *)xmalloc(MAX_INTERFACE_LENGTH);
+               char *new_logical = xmalloc(MAX_INTERFACE_LENGTH);
 
                if (fgets(new_logical, MAX_INTERFACE_LENGTH, out)) {
                        /* If we are able to read a line of output from the script,
@@ -1067,7 +1096,7 @@ static char *run_mapping(char *physical, struct mapping_defn_t * map)
 
        return logical;
 }
-#endif /* CONFIG_FEATURE_IFUPDOWN_MAPPING */
+#endif /* FEATURE_IFUPDOWN_MAPPING */
 
 static llist_t *find_iface_state(llist_t *state_list, const char *iface)
 {
@@ -1075,8 +1104,8 @@ static llist_t *find_iface_state(llist_t *state_list, const char *iface)
        llist_t *search = state_list;
 
        while (search) {
-               if ((strncmp(search->data, iface, iface_len) == 0) &&
-                               (search->data[iface_len] == '=')) {
+               if ((strncmp(search->data, iface, iface_len) == 0)
+                && (search->data[iface_len] == '=')) {
                        return search;
                }
                search = search->link;
@@ -1084,37 +1113,54 @@ static llist_t *find_iface_state(llist_t *state_list, const char *iface)
        return NULL;
 }
 
-int ifupdown_main(int argc, char **argv)
+/* read the previous state from the state file */
+static llist_t *read_iface_state(void)
 {
-       static const char statefile[] = "/var/run/ifstate";
+       llist_t *state_list = NULL;
+       FILE *state_fp = fopen(CONFIG_IFUPDOWN_IFSTATE_PATH, "r");
+
+       if (state_fp) {
+               char *start, *end_ptr;
+               while ((start = xmalloc_fgets(state_fp)) != NULL) {
+                       /* We should only need to check for a single character */
+                       end_ptr = start + strcspn(start, " \t\n");
+                       *end_ptr = '\0';
+                       llist_add_to(&state_list, start);
+               }
+               fclose(state_fp);
+       }
+       return state_list;
+}
 
+
+int ifupdown_main(int argc, char **argv);
+int ifupdown_main(int argc, char **argv)
+{
        int (*cmds)(struct interface_defn_t *) = NULL;
        struct interfaces_file_t *defn;
-       llist_t *state_list = NULL;
        llist_t *target_list = NULL;
        const char *interfaces = "/etc/network/interfaces";
-       int any_failures = 0;
+       bool any_failures = 0;
 
+       cmds = iface_down;
        if (applet_name[2] == 'u') {
                /* ifup command */
                cmds = iface_up;
-       } else {
-               /* ifdown command */
-               cmds = iface_down;
        }
 
-       getopt32(argc, argv, OPTION_STR, &interfaces);
+       getopt32(argv, OPTION_STR, &interfaces);
        if (argc - optind > 0) {
                if (DO_ALL) bb_show_usage();
-       } else
+       } else {
                if (!DO_ALL) bb_show_usage();
+       }
 
        debug_noise("reading %s file:\n", interfaces);
        defn = read_interfaces(interfaces);
        debug_noise("\ndone reading %s\n\n", interfaces);
 
        if (!defn) {
-               exit(EXIT_FAILURE);
+               return EXIT_FAILURE;
        }
 
        startup_PATH = getenv("PATH");
@@ -1122,22 +1168,11 @@ int ifupdown_main(int argc, char **argv)
 
        /* Create a list of interfaces to work on */
        if (DO_ALL) {
-               if (cmds == iface_up) {
-                       target_list = defn->autointerfaces;
-               } else {
-                       /* iface_down */
-                       const llist_t *list = state_list;
-                       while (list) {
-                               llist_add_to_end(&target_list, xstrdup(list->data));
-                               list = list->link;
-                       }
-                       target_list = defn->autointerfaces;
-               }
+               target_list = defn->autointerfaces;
        } else {
                llist_add_to_end(&target_list, argv[optind]);
        }
 
-
        /* Update the interfaces */
        while (target_list) {
                llist_t *iface_list;
@@ -1145,8 +1180,8 @@ int ifupdown_main(int argc, char **argv)
                char *iface;
                char *liface;
                char *pch;
-               int okay = 0;
-               int cmds_ret;
+               bool okay = 0;
+               unsigned cmds_ret;
 
                iface = xstrdup(target_list->data);
                target_list = target_list->link;
@@ -1160,6 +1195,7 @@ int ifupdown_main(int argc, char **argv)
                }
 
                if (!FORCE) {
+                       llist_t *state_list = read_iface_state();
                        const llist_t *iface_state = find_iface_state(state_list, iface);
 
                        if (cmds == iface_up) {
@@ -1170,14 +1206,15 @@ int ifupdown_main(int argc, char **argv)
                                }
                        } else {
                                /* ifdown */
-                               if (iface_state) {
+                               if (!iface_state) {
                                        bb_error_msg("interface %s not configured", iface);
                                        continue;
                                }
                        }
+                       llist_free(state_list, free);
                }
 
-#ifdef CONFIG_FEATURE_IFUPDOWN_MAPPING
+#if ENABLE_FEATURE_IFUPDOWN_MAPPING
                if ((cmds == iface_up) && !NO_MAPPINGS) {
                        struct mapping_defn_t *currmap;
 
@@ -1196,7 +1233,6 @@ int ifupdown_main(int argc, char **argv)
                }
 #endif
 
-
                iface_list = defn->ifaces;
                while (iface_list) {
                        currif = (struct interface_defn_t *) iface_list->data;
@@ -1213,9 +1249,9 @@ int ifupdown_main(int argc, char **argv)
                                if (cmds_ret == -1) {
                                        bb_error_msg("don't seem to have all the variables for %s/%s",
                                                        liface, currif->address_family->name);
-                                       any_failures += 1;
+                                       any_failures = 1;
                                } else if (cmds_ret == 0) {
-                                       any_failures += 1;
+                                       any_failures = 1;
                                }
 
                                currif->iface = oldiface;
@@ -1223,17 +1259,21 @@ int ifupdown_main(int argc, char **argv)
                        iface_list = iface_list->link;
                }
                if (VERBOSE) {
-                       puts("");
+                       bb_putchar('\n');
                }
 
                if (!okay && !FORCE) {
                        bb_error_msg("ignoring unknown interface %s", liface);
-                       any_failures += 1;
-               } else {
+                       any_failures = 1;
+               } else if (!NO_ACT) {
+                       /* update the state file */
+                       FILE *state_fp;
+                       llist_t *state;
+                       llist_t *state_list = read_iface_state();
                        llist_t *iface_state = find_iface_state(state_list, iface);
 
                        if (cmds == iface_up) {
-                               char *newiface = xasprintf("%s=%s", iface, liface);
+                               char * const newiface = xasprintf("%s=%s", iface, liface);
                                if (iface_state == NULL) {
                                        llist_add_to_end(&state_list, newiface);
                                } else {
@@ -1241,28 +1281,24 @@ int ifupdown_main(int argc, char **argv)
                                        iface_state->data = newiface;
                                }
                        } else {
-                               /* Remove an interface from the linked list */
+                               /* Remove an interface from state_list */
+                               llist_unlink(&state_list, iface_state);
                                free(llist_pop(&iface_state));
                        }
-               }
-       }
-
-       /* Actually write the new state */
-       if (!NO_ACT) {
-               FILE *state_fp = NULL;
 
-               state_fp = xfopen(statefile, "w");
-               while (state_list) {
-                       if (state_list->data) {
-                               fputs(state_list->data, state_fp);
-                               fputc('\n', state_fp);
+                       /* Actually write the new state */
+                       state_fp = xfopen(CONFIG_IFUPDOWN_IFSTATE_PATH, "w");
+                       state = state_list;
+                       while (state) {
+                               if (state->data) {
+                                       fprintf(state_fp, "%s\n", state->data);
+                               }
+                               state = state->link;
                        }
-                       state_list = state_list->link;
+                       fclose(state_fp);
+                       llist_free(state_list, free);
                }
-               fclose(state_fp);
        }
 
-       if (any_failures)
-               return 1;
-       return 0;
+       return any_failures;
 }