1 files changed, 57 insertions, 0 deletions
diff --git a/lib/pread.h b/lib/pread.h
new file mode 100644
index 0000000..3db90e3
--- /dev/null
+++ b/lib/pread.h
@@ -0,0 +1,57 @@
+/*
+ *	The PCI Library -- Portable interface to pread() and pwrite()
+ *
+ *	Copyright (c) 1997--2003 Martin Mares <mj@ucw.cz>
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+/*
+ *  We'd like to use pread/pwrite for configuration space accesses, but
+ *  unfortunately it isn't simple at all since all libc's until glibc 2.1
+ *  don't define it.
+ */
+
+#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
+/* glibc 2.1 or newer -> pread/pwrite supported automatically */
+
+#elif defined(i386) && defined(__GLIBC__)
+/* glibc 2.0 on i386 -> call syscalls directly */
+#include <asm/unistd.h>
+#include <syscall-list.h>
+#ifndef SYS_pread
+#define SYS_pread 180
+#endif
+static int pread(unsigned int fd, void *buf, size_t size, loff_t where)
+{ return syscall(SYS_pread, fd, buf, size, where); }
+#ifndef SYS_pwrite
+#define SYS_pwrite 181
+#endif
+static int pwrite(unsigned int fd, void *buf, size_t size, loff_t where)
+{ return syscall(SYS_pwrite, fd, buf, size, where); }
+
+#else
+/* In all other cases we use lseek/read/write instead to be safe */
+#define make_rw_glue(op) \
+	static int do_##op(struct pci_dev *d, int fd, void *buf, size_t size, int where)	\
+	{											\
+	  struct pci_access *a = d->access;							\
+	  int r;										\
+	  if (a->fd_pos != where && lseek(fd, where, SEEK_SET) < 0)				\
+	    return -1;										\
+	  r = op(fd, buf, size);								\
+	  if (r < 0)										\
+	    a->fd_pos = -1;									\
+	  else											\
+	    a->fd_pos = where + r;								\
+	  return r;										\
+	}
+make_rw_glue(read)
+make_rw_glue(write)
+#define PCI_HAVE_DO_READ
+#endif
+
+#ifndef PCI_HAVE_DO_READ
+#define do_read(d,f,b,l,p) pread(f,b,l,p)
+#define do_write(d,f,b,l,p) pwrite(f,b,l,p)
+#endif