[PATCH] Check 'fd' neither -1 nor 0, before close it

[Chen Gang]

'fd' may be 0 which does not need 'open' operation, so neither need
'close' operation on it when it is 0.

Also in c_common_read_pch(), when failure occurs, also need be sure the
'fd' is not '-1' for the next close operation.

It passes testsuite under Fedora x86_64-unknown-linux-gnu.


gcc/

        * c-family/c-pch.c (c_common_read_pch): Check 'fd' neither -1
        nor 0, before close it,

libcpp/

        * files.c (_cpp_compare_file_date, read_file, validate_pch
        open_file, _cpp_save_file_entries): Check 'fd' neither -1 nor 0,
        before close it.
---
 gcc/c-family/c-pch.c | 10 ++++++----
 libcpp/files.c       | 20 +++++++++++---------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/gcc/c-family/c-pch.c b/gcc/c-family/c-pch.c
index 93609b6..d001965 100644
--- a/gcc/c-family/c-pch.c
+++ b/gcc/c-family/c-pch.c
@@ -355,7 +355,8 @@ c_common_read_pch (cpp_reader *pfile, const char *name,
   if (f == NULL)
     {
       cpp_errno (pfile, CPP_DL_ERROR, "calling fdopen");
-      close (fd);
+      if (fd && fd != -1)
+       close (fd);
       goto end;
     }
 
@@ -376,14 +377,15 @@ c_common_read_pch (cpp_reader *pfile, const char *name,
   timevar_push (TV_PCH_CPP_RESTORE);
   if (cpp_read_state (pfile, name, f, smd) != 0)
     {
-      fclose (f);
+      if (fd)
+       fclose (f);
       timevar_pop (TV_PCH_CPP_RESTORE);
       goto end;
     }
   timevar_pop (TV_PCH_CPP_RESTORE);
 
-
-  fclose (f);
+  if (fd)
+    fclose (f);
 
   line_table->trace_includes = saved_trace_includes;
   linemap_add (line_table, LC_ENTER, 0, saved_loc.file, saved_loc.line);
diff --git a/libcpp/files.c b/libcpp/files.c
index 3984821..5c845da 100644
--- a/libcpp/files.c
+++ b/libcpp/files.c
@@ -243,7 +243,8 @@ open_file (_cpp_file *file)
          errno = ENOENT;
        }
 
-      close (file->fd);
+      if (file->fd)
+        close (file->fd);
       file->fd = -1;
     }
 #if defined(_WIN32) && !defined(__CYGWIN__)
@@ -753,7 +754,8 @@ read_file (cpp_reader *pfile, _cpp_file *file)
     }
 
   file->dont_read = !read_file_guts (pfile, file);
-  close (file->fd);
+  if (file->fd)
+    close (file->fd);
   file->fd = -1;
 
   return !file->dont_read;
@@ -1435,11 +1437,9 @@ _cpp_compare_file_date (cpp_reader *pfile, const char 
*fname,
   if (file->err_no)
     return -1;
 
-  if (file->fd != -1)
-    {
-      close (file->fd);
-      file->fd = -1;
-    }
+  if (file->fd && file->fd != -1)
+    close (file->fd);
+  file->fd = -1;
 
   return file->st.st_mtime > pfile->buffer->file->st.st_mtime;
 }
@@ -1694,7 +1694,8 @@ validate_pch (cpp_reader *pfile, _cpp_file *file, const 
char *pchname)
 
       if (!valid)
        {
-         close (file->fd);
+         if (file->fd)
+           close (file->fd);
          file->fd = -1;
        }
 
@@ -1849,7 +1850,8 @@ _cpp_save_file_entries (cpp_reader *pfile, FILE *fp)
            }
          ff = fdopen (f->fd, "rb");
          md5_stream (ff, result->entries[count].sum);
-         fclose (ff);
+         if (f->fd)
+           fclose (ff);
          f->fd = oldfd;
        }
       result->entries[count].size = f->st.st_size;
-- 
1.9.3