How to get file descriptor from abfd?
Paul Pluzhnikov
ppluzhnikov@google.com
Wed Jun 10 17:09:00 GMT 2009
On Wed, Jun 10, 2009 at 8:26 AM, Dave
Korn<dave.korn.cygwin@googlemail.com> wrote:
>> +. void (*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
>> +. int prot, int flags, file_ptr offset);
>
> The return type here should be void*, not plain void.
Thanks, fixed.
>> + void *ret = (void *)-1;
>
> Gnu coding standards request a space between the cast and the -1.
Fixed in all the places I could find.
>> + if ((abfd->flags & BFD_IN_MEMORY) != 0)
>> + abort ();
>> +#ifdef HAVE_MMAP
>> + else
>> + {
>> + FILE *f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
>
> Since abort() doesn't return, the else clause and extra level of nested
> braces is superfluous here.
The braces introduce a new scope for 'FILE *f'.
If I move the declaration to the top of function, then it fails to build
when !HAVE_MMAP:
cc1: warnings being treated as errors
../../src/bfd/cache.c: In function 'cache_bmmap':
../../src/bfd/cache.c:404: warning: unused variable 'f'
I left this "as is".
Corrected patch attached.
Thanks,
--
Paul Pluzhnikov
-------------- next part --------------
Index: bfd-in2.h
===================================================================
RCS file: /cvs/src/src/bfd/bfd-in2.h,v
retrieving revision 1.482
diff -u -p -u -r1.482 bfd-in2.h
--- bfd-in2.h 1 Jun 2009 13:11:51 -0000 1.482
+++ bfd-in2.h 10 Jun 2009 17:01:28 -0000
@@ -463,6 +463,7 @@ extern int bfd_seek (bfd *, file_ptr, in
extern file_ptr bfd_tell (bfd *);
extern int bfd_flush (bfd *);
extern int bfd_stat (bfd *, struct stat *);
+extern void *bfd_mmap (bfd *, void *, bfd_size_type, int, int, file_ptr);
/* Deprecated old routines. */
#if __GNUC__
Index: bfdio.c
===================================================================
RCS file: /cvs/src/src/bfd/bfdio.c,v
retrieving revision 1.21
diff -u -p -u -r1.21 bfdio.c
--- bfdio.c 24 May 2009 11:47:27 -0000 1.21
+++ bfdio.c 10 Jun 2009 17:01:28 -0000
@@ -158,6 +158,8 @@ DESCRIPTION
. int (*bclose) (struct bfd *abfd);
. int (*bflush) (struct bfd *abfd);
. int (*bstat) (struct bfd *abfd, struct stat *sb);
+. void* (*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
+. int prot, int flags, file_ptr offset);
.};
*/
@@ -511,3 +513,31 @@ bfd_get_size (bfd *abfd)
return buf.st_size;
}
+
+
+/*
+FUNCTION
+ bfd_mmap
+
+SYNOPSIS
+ void *bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
+ int prot, int flags, file_ptr offset);
+
+DESCRIPTION
+ Return mmap()ed region of the file, if possible and implemented.
+
+*/
+
+void *
+bfd_mmap (bfd *abfd, void *addr, bfd_size_type len,
+ int prot, int flags, file_ptr offset)
+{
+ void *ret = (void *)-1;
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ return ret;
+
+ if (abfd->iovec == NULL)
+ return ret;
+
+ return abfd->iovec->bmmap (abfd, addr, len, prot, flags, offset);
+}
Index: cache.c
===================================================================
RCS file: /cvs/src/src/bfd/cache.c,v
retrieving revision 1.34
diff -u -p -u -r1.34 cache.c
--- cache.c 30 Oct 2008 09:05:32 -0000 1.34
+++ cache.c 10 Jun 2009 17:01:28 -0000
@@ -46,6 +46,10 @@ SUBSECTION
#include "libbfd.h"
#include "libiberty.h"
+#ifdef HAVE_MMAP
+#include <sys/mman.h>
+#endif
+
/* In some cases we can optimize cache operation when reopening files.
For instance, a flush is entirely unnecessary if the file is already
closed, so a flush would use CACHE_NO_OPEN. Similarly, a seek using
@@ -388,10 +392,38 @@ cache_bstat (struct bfd *abfd, struct st
return sts;
}
+static void *
+cache_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED,
+ void *addr ATTRIBUTE_UNUSED,
+ bfd_size_type len ATTRIBUTE_UNUSED,
+ int prot ATTRIBUTE_UNUSED,
+ int flags ATTRIBUTE_UNUSED,
+ file_ptr offset ATTRIBUTE_UNUSED)
+{
+ void *ret = (void *) -1;
+
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+#ifdef HAVE_MMAP
+ else
+ {
+ FILE *f = bfd_cache_lookup (abfd, CACHE_NO_SEEK_ERROR);
+ if (f == NULL)
+ return ret;
+
+ ret = mmap (addr, len, prot, flags, fileno (f), offset);
+ if (ret == (void *) -1)
+ bfd_set_error (bfd_error_system_call);
+ }
+#endif
+
+ return ret;
+}
+
static const struct bfd_iovec cache_iovec =
{
&cache_bread, &cache_bwrite, &cache_btell, &cache_bseek,
- &cache_bclose, &cache_bflush, &cache_bstat
+ &cache_bclose, &cache_bflush, &cache_bstat, &cache_bmmap
};
/*
Index: libbfd.h
===================================================================
RCS file: /cvs/src/src/bfd/libbfd.h,v
retrieving revision 1.216
diff -u -p -u -r1.216 libbfd.h
--- libbfd.h 1 Jun 2009 13:11:52 -0000 1.216
+++ libbfd.h 10 Jun 2009 17:01:28 -0000
@@ -773,6 +773,9 @@ struct bfd_iovec
int (*bclose) (struct bfd *abfd);
int (*bflush) (struct bfd *abfd);
int (*bstat) (struct bfd *abfd, struct stat *sb);
+ /* Just like mmap: (void*)-1 on failure, mmapped address on success. */
+ void *(*bmmap) (struct bfd *abfd, void *addr, bfd_size_type len,
+ int prot, int flags, file_ptr offset);
};
/* Extracted from bfdwin.c. */
struct _bfd_window_internal {
Index: opncls.c
===================================================================
RCS file: /cvs/src/src/bfd/opncls.c,v
retrieving revision 1.53
diff -u -p -u -r1.53 opncls.c
--- opncls.c 23 Aug 2008 08:08:58 -0000 1.53
+++ opncls.c 10 Jun 2009 17:01:28 -0000
@@ -505,9 +505,20 @@ opncls_bstat (struct bfd *abfd, struct s
return (vec->stat) (abfd, vec->stream, sb);
}
+static void *
+opncls_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED,
+ void *addr ATTRIBUTE_UNUSED,
+ bfd_size_type len ATTRIBUTE_UNUSED,
+ int prot ATTRIBUTE_UNUSED,
+ int flags ATTRIBUTE_UNUSED,
+ file_ptr offset ATTRIBUTE_UNUSED)
+{
+ return (void *) -1;
+}
+
static const struct bfd_iovec opncls_iovec = {
&opncls_bread, &opncls_bwrite, &opncls_btell, &opncls_bseek,
- &opncls_bclose, &opncls_bflush, &opncls_bstat
+ &opncls_bclose, &opncls_bflush, &opncls_bstat, &opncls_bmmap
};
bfd *
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