1 files changed, 118 insertions, 0 deletions
diff --git a/StdLib/PosixLib/Gen/access.c b/StdLib/PosixLib/Gen/access.c
new file mode 100644
index 0000000000..3031e4f942
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+++ b/StdLib/PosixLib/Gen/access.c
@@ -0,0 +1,118 @@
+/** @file
+  Implementation of the Posix access() function.
+
+  Copyright (c) 2011, Intel Corporation. All rights reserved.<BR>
+  This program and the accompanying materials are licensed and made available under
+  the terms and conditions of the BSD License that accompanies this distribution.
+  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+**/
+#include  <LibConfig.h>
+#include  <sys/EfiCdefs.h>
+
+#include  <ctype.h>
+#include  <errno.h>
+#include  <sys/stat.h>
+#include  <string.h>
+#include  <unistd.h>
+#include  <sys/syslimits.h>
+
+/** Save some typing later on. */
+#define GOOD_MODE   (F_OK | X_OK | W_OK | R_OK)
+
+/** Determine accessibility of a file.
+    The access() function checks the file, named by the pathname pointed to by
+    the Path argument, for accessibility according to the bit pattern contained
+    in Mode.
+
+    The value of Mode is either the bitwise-inclusive OR of the access
+    permissions to be checked (R_OK, W_OK, X_OK) or the existence test (F_OK).
+
+    If Path ends in '/' or '\\', the target must be a directory, otherwise it doesn't matter.
+    A file is executable if it is NOT a directory and it ends in ".efi".
+
+    @param[in]    Path    Path or name of the file to be checked.
+    @param[in]    Mode    Access permissions to check for.
+
+    @retval   0   Successful completion.
+    @retval  -1   File is not accessible with the given Mode.  The error condition
+                  is indicated by errno.  Values of errno specific to the access
+                  function include: EACCES, ENOENT, ENOTDIR, ENAMETOOLONG
+**/
+int
+access(
+  const char *Path,
+  int         Mode
+  )
+{
+  struct stat     FileStat;
+  int             retval      = -1;
+  size_t          PLength;
+  uint32_t        WantDir;
+  uint32_t        DirMatch;
+
+  if((Path == NULL) || ((Mode & ~GOOD_MODE) != 0)) {
+    errno = EINVAL;
+  }
+  else {
+    PLength = strlen(Path);
+    if(PLength > PATH_MAX) {
+      errno = ENAMETOOLONG;
+    }
+    else {
+      retval = stat(Path, &FileStat);
+      if(retval == 0) {
+        /* Path exists.  FileStat now holds valid information. */
+        WantDir   = isDirSep(Path[PLength - 1]);   // Does Path end in '/' or '\\' ?
+        DirMatch = (! WantDir && (! S_ISDIR(FileStat.st_mode)));
+
+        /* Test each permission individually.  */
+        do {
+          if(Mode == F_OK) {  /* Existence test. */
+            if(DirMatch) {    /* This is a directory or file as desired. */
+              retval = 0;
+            }
+            else {
+              /* Indicate why we failed the test. */
+              errno = (WantDir) ? ENOTDIR : EISDIR;
+            }
+            break;  /* F_OK does not combine with any other tests. */
+          }
+          if(Mode & R_OK) {
+            if((FileStat.st_mode & READ_PERMS) == 0) {
+              /* No read permissions.
+                 For UEFI, everything should have READ permissions.
+              */
+              errno = EDOOFUS;  /* Programming Error. */
+              break;
+            }
+          }
+          if(Mode & W_OK) {
+            if((FileStat.st_mode & WRITE_PERMS) == 0) {
+              /* No write permissions. */
+              errno = EACCES;  /* Writing is not OK. */
+              break;
+            }
+          }
+          if(Mode & X_OK) {
+            /* In EDK II, executable files end in ".efi" */
+            if(strcmp(&Path[PLength-4], ".efi") != 0) {
+              /* File is not an executable. */
+              errno = EACCES;
+              break;
+            }
+          }
+          retval = 0;
+        } while(FALSE);
+      }
+      else {
+        /* File or path does not exist. */
+        errno = ENOENT;
+      }
+    }
+  }
+  return retval;
+}