backend: Remove setting custom envrionment variables

Fixes #41

FAQ.md

@@ -69,14 +69,6 @@ and buffer handling are different.
 
 ------
 
-**Q4: How to get Windows IP address in WSL2 quickly?**
-
-**A4:** Run `wslbridge2.exe` command as usual. IPv4 address of Windows 10 side
-is set to `WSL_HOST_IP` and of WSL2 side is set to `WSL_GUEST_IP` environment
-variable. e.g. for GUI programs, use `export DISPLAY=$WSL_HOST_IP:0`.
-
-------
-
 **Q5: What are the error code starting with 0x8?**
 
 **A5:** Generally the [system error codes][3] are translated into error

src/nix-sock.c

@@ -160,60 +160,3 @@ int nix_vsock_listen(unsigned int *port)
     *port = addr.svm_port;
     return sock;
 }
-
-// Set custom environment variables with IP values for WSL2.
-void nix_set_env(void)
-{
-    const int sock = socket(AF_INET, SOCK_DGRAM, 0);
-    if (sock < 0)
-    {
-        perror("socket(AF_INET)");
-        return;
-    }
-
-    struct ifreq ifr;
-    memset(&ifr, 0, sizeof ifr);
-    strncpy(ifr.ifr_name, "eth0", IFNAMSIZ);
-    const int ioctlRet = ioctl(sock, SIOCGIFADDR, &ifr);
-    close(sock);
-    if (ioctlRet != 0)
-    {
-        perror("ioctl(SIOCGIFADDR)");
-        return;
-    }
-
-    // Do not override environment if the name already exists.
-    struct sockaddr_in *addr_in = (struct sockaddr_in *)&ifr.ifr_addr;
-    setenv("WSL_GUEST_IP", inet_ntoa(addr_in->sin_addr), false);
-
-    unsigned long int dest, gateway;
-    char iface[IF_NAMESIZE];
-    char buf[4096];
-
-    memset(iface, 0, sizeof iface);
-    memset(buf, 0, sizeof buf);
-
-    // Read route file to get IP address of default gateway or host.
-    FILE *rfd = fopen("/proc/net/route", "r");
-    if (rfd == NULL)
-    {
-        perror("fopen(route)");
-        return;
-    }
-
-    while (fgets(buf, sizeof buf, rfd))
-    {
-        if (sscanf(buf, "%s %lx %lx", iface, &dest, &gateway) == 3)
-        {
-            if (dest == 0) // Default destination.
-            {
-                struct in_addr addr;
-                addr.s_addr = gateway;
-                setenv("WSL_HOST_IP", inet_ntoa(addr), false);
-                break;
-            }
-        }
-    }
-
-    fclose(rfd);
-}

src/nix-sock.h

@@ -35,9 +35,6 @@ int nix_vsock_connect(const unsigned int port);
 // Create and listen to a vsocket and return it.
 int nix_vsock_listen(unsigned int *port);
 
-// Set custom environment variables with IP values for WSL2.
-void nix_set_env(void);
-
 #ifdef __cplusplus
 }
 #endif

src/wslbridge2-backend.cpp

@@ -337,13 +337,6 @@ int main(int argc, char *argv[])
         for (char *const &setting : childParams.env)
             putenv(setting);
 
-        /*
-         * wsltty#225: Set WSL_GUEST_IP environment variable in WSL2 only.
-         * As WSL1 gets same IP address as Windows and NIC may not be eth0.
-         */
-        if (vmMode)
-            nix_set_env();
-
         /* Changed directory should affect in child process */
         if (!childParams.cwd.empty())
         {