[binutils-gdb] Don't optimise bfd_seek to same position

[binutils-gdb] Don't optimise bfd_seek to same position

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=014a602b86f08de96fc80ef3f96a87db6cccad56

commit 014a602b86f08de96fc80ef3f96a87db6cccad56
Author: Alan Modra <amodra@gmail.com>
Date:   Wed May 24 12:47:09 2023 +0930

    Don't optimise bfd_seek to same position
    
    It's not worth avoiding an fseek to the same position, and can cause
    problems if the linker's output file (which is opened "w+") is read,
    because that can result in writing, reading, then writing again.
    
    POSIX.1-2017 (IEEE Std 1003.1) says of fopen:
    "When a file is opened with update mode ('+' as the second or third
    character in the mode argument), both input and output may be
    performed on the associated stream. However, the application shall
    ensure that output is not directly followed by input without an
    intervening call to fflush() or to a file positioning function
    (fseek(), fsetpos(), or rewind()), and input is not directly followed
    by output without an intervening call to a file positioning function,
    unless the input operation encounters end-of-file."
    
            * bfdio.c (bfd_seek): Always call iovec->bseek.

Diff:
---
 bfd/bfdio.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/bfd/bfdio.c b/bfd/bfdio.c
index 75a3309c582..22c39a7b0cc 100644
--- a/bfd/bfdio.c
+++ b/bfd/bfdio.c
@@ -456,10 +456,6 @@ bfd_seek (bfd *abfd, file_ptr position, int direction)
   if (direction != SEEK_CUR)
     position += offset;
 
-  if ((direction == SEEK_CUR && position == 0)
-      || (direction == SEEK_SET && (ufile_ptr) position == abfd->where))
-    return 0;
-
   result = abfd->iovec->bseek (abfd, position, direction);
   if (result != 0)
     {