libCom/RTEMS: ensure lookup of localhost on RTEMS

create /etc/hosts if it doesn't already exist

src/libCom/RTEMS/rtems_init.c

@@ -18,8 +18,10 @@
 #include <time.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <unistd.h>
 #include <sys/termios.h>
 #include <sys/types.h>
+#include <sys/stat.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -335,6 +337,46 @@ initialize_remote_filesystem(char **argv, int hasLocalFilesystem)
 #endif
 }
 
+static
+char rtems_etc_hosts[] = "127.0.0.1       localhost\n";
+
+/* If it doesn't already exist, create /etc/hosts with an entry for 'localhost' */
+static
+void fixup_hosts(void)
+{
+    FILE *fp;
+    int ret;
+    struct stat STAT;
+
+    ret=stat("/etc/hosts", &STAT);
+    if(ret==0)
+    {
+        return; /* already exists, assume file */
+    } else if(errno!=ENOENT) {
+        perror("error: fixup_hosts stat /etc/hosts");
+        return;
+    }
+
+    ret = mkdir("/etc", 0775);
+    if(ret!=0 && errno!=EEXIST)
+    {
+        perror("error: fixup_hosts create /etc");
+        return;
+    }
+
+    if((fp=fopen("/etc/hosts", "w"))==NULL)
+    {
+        perror("error: fixup_hosts create /etc/hosts");
+    }
+
+    if(fwrite(rtems_etc_hosts, 1, sizeof(rtems_etc_hosts)-1, fp)!=sizeof(rtems_etc_hosts)-1)
+    {
+        perror("error: failed to write /etc/hosts");
+    }
+
+    fclose(fp);
+}
+
 /*
  * Get to the startup script directory
  * The TFTP filesystem requires a trailing '/' on chdir arguments.
@@ -546,6 +588,7 @@ Init (rtems_task_argument ignored)
     printf("\n***** Initializing network *****\n");
     rtems_bsdnet_initialize_network();
     initialize_remote_filesystem(argv, initialize_local_filesystem(argv));
+    fixup_hosts();
 
     /*
      * More environment: iocsh prompt and hostname