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-rw-r--r--lib/pread.h57
1 files changed, 57 insertions, 0 deletions
diff --git a/lib/pread.h b/lib/pread.h
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+++ b/lib/pread.h
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+/*
+ * 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