From 85d9370c2f7cdcbe59c5cf7604d309116359a6b2 Mon Sep 17 00:00:00 2001
From: Andrew Schwartzmeyer <andschwa@microsoft.com>
Date: Wed, 13 Jul 2016 15:55:15 -0700
Subject: [PATCH] Clean up FollowSymlink

---
 src/libpsl-native/src/followsymlink.cpp | 150 ++++++++----------------
 1 file changed, 47 insertions(+), 103 deletions(-)

diff --git a/src/libpsl-native/src/followsymlink.cpp b/src/libpsl-native/src/followsymlink.cpp
index 6a77bcc52..46576256e 100644
--- a/src/libpsl-native/src/followsymlink.cpp
+++ b/src/libpsl-native/src/followsymlink.cpp
@@ -37,124 +37,68 @@
 
 char* FollowSymLink(const char* fileName)
 {
-    errno = 0;  
+    errno = 0;
 
-    // if filename is null, return null value
     if (!fileName)
     {
         errno = ERROR_INVALID_PARAMETER;
         return NULL;
     }
 
-    //if lstat in IsSymLink returns -1, path does not exist
-    if (IsSymLink(fileName) == -1)
+    // return null for non symlinks
+    if (!IsSymLink(fileName))
     {
         return NULL;
     }
 
-    /*If the path is a symlink, the function return the absolute filepath if valid. if not valid, return null*/     
-    if (IsSymLink(fileName))
+    // attempt to resolve with the absolute file path
+    char buffer[PATH_MAX];
+    char* realPath = realpath(fileName, buffer);
+
+    if (realPath)
     {
-        //Attempt to resolve with the absolute filepath
-        char actualpath[PATH_MAX+1];
-        char* realPath = realpath(fileName, actualpath);
-    
-        //if realPath is null, go onto the readlink implementation
-        if (realPath == NULL)
-        {       
-            char buffer[PATH_MAX];
-            ssize_t sz = readlink(fileName, buffer, PATH_MAX);
-    
-            if  (sz == -1)
-            {
-                switch(errno)
-                {
-                    case EACCES:
-                        errno = ERROR_ACCESS_DENIED;
-                        break;
-                    case EFAULT:
-                        errno = ERROR_INVALID_ADDRESS;   /*If the path is a symlink, the function return the absolute filepath if valid. if not valid, return null*/     
-                        break;
-                    case EINVAL:
-                        errno = ERROR_INVALID_NAME;
-                    case EIO:
-                        errno = ERROR_GEN_FAILURE;
-                        break;
-                    case ELOOP:
-                        errno = ERROR_STOPPED_ON_SYMLINK;
-                        break;
-                    case ENAMETOOLONG:
-                        errno = ERROR_BAD_PATH_NAME;
-                        break;
-                    case ENOENT:
-                        errno = ERROR_FILE_NOT_FOUND;
-                        break;
-                    case ENOMEM:
-                        errno = ERROR_OUTOFMEMORY;
-                        break;
-                    case ENOTDIR:
-                        errno = ERROR_BAD_PATH_NAME;
-                        break;
-                    default:
-                        errno = ERROR_INVALID_FUNCTION;
-                }
+        return strndup(realPath, strlen(realPath) + 1);
+    }
 
-                return NULL;
-           }
-
-            buffer[sz] = '\0';
-            return strndup(buffer, sz + 1);
-        }
-        else
+    // if the path wasn't resolved, use readlink
+    ssize_t sz = readlink(fileName, buffer, PATH_MAX);
+    if  (sz == -1)
+    {
+        switch(errno)
         {
-            return strndup(realPath, strlen(realPath) + 1 );
+        case EACCES:
+            errno = ERROR_ACCESS_DENIED;
+            break;
+        case EFAULT:
+            errno = ERROR_INVALID_ADDRESS;
+            break;
+        case EINVAL:
+            errno = ERROR_INVALID_NAME;
+        case EIO:
+            errno = ERROR_GEN_FAILURE;
+            break;
+        case ELOOP:
+            errno = ERROR_STOPPED_ON_SYMLINK;
+            break;
+        case ENAMETOOLONG:
+            errno = ERROR_BAD_PATH_NAME;
+            break;
+        case ENOENT:
+            errno = ERROR_FILE_NOT_FOUND;
+            break;
+        case ENOMEM:
+            errno = ERROR_OUTOFMEMORY;
+            break;
+        case ENOTDIR:
+            errno = ERROR_BAD_PATH_NAME;
+            break;
+        default:
+            errno = ERROR_INVALID_FUNCTION;
         }
+
+        return NULL;
     }
-    
-    else
-    {
-          char buffer[PATH_MAX];
-            ssize_t sz = readlink(fileName, buffer, PATH_MAX);
-    
-            if  (sz == -1)
-            {
-                switch(errno)
-                {
-                    case EACCES:
-                        errno = ERROR_ACCESS_DENIED;
-                        break;
-                    case EFAULT:
-                        errno = ERROR_INVALID_ADDRESS;   /*If the path is a symlink, the function return the absolute filepath if valid. if not valid, return null*/     
-                        break;
-                    case EINVAL:
-                        errno = ERROR_INVALID_NAME;
-                    case EIO:
-                        errno = ERROR_GEN_FAILURE;
-                        break;
-                    case ELOOP:
-                        errno = ERROR_STOPPED_ON_SYMLINK;
-                        break;
-                    case ENAMETOOLONG:
-                        errno = ERROR_BAD_PATH_NAME;
-                        break;
-                    case ENOENT:
-                        errno = ERROR_FILE_NOT_FOUND;
-                        break;
-                    case ENOMEM:
-                        errno = ERROR_OUTOFMEMORY;
-                        break;
-                    case ENOTDIR:
-                        errno = ERROR_BAD_PATH_NAME;
-                        break;
-                    default:
-                        errno = ERROR_INVALID_FUNCTION;
-                }
 
-                return NULL;
-           }
-
-            buffer[sz] = '\0';
-            return strndup(buffer, sz + 1);
-
-    }
+    buffer[sz] = '\0';
+    return strndup(buffer, sz + 1);
 }