Create a much more careful ftruncate64 implementation, that should

address all the concern Miles had with the earlier versions...
 -Erik

2 files changed, 40 insertions, 1 deletions

diff --git a/libc/sysdeps/linux/common/Makefile b/libc/sysdeps/linux/common/Makefile
index 48214189e..af7f5bf01 100644
--- a/libc/sysdeps/linux/common/Makefile
+++ b/libc/sysdeps/linux/common/Makefile
@@ -32,7 +32,7 @@ endif
 CSRC=	waitpid.c kernel_version.c statfix.c getdnnm.c gethstnm.c \
 	mkfifo.c setegid.c wait.c getpagesize.c seteuid.c \
 	wait3.c setpgrp.c getdtablesize.c create_module.c ptrace.c \
-	cmsg_nxthdr.c open64.c statfix64.c longjmp.c \
+	cmsg_nxthdr.c open64.c statfix64.c longjmp.c ftruncate64.c \
 	getrlimit64.c setrlimit64.c
 ifneq ($(strip $(EXCLUDE_BRK)),true)
 CSRC+=sbrk.c
diff --git a/libc/sysdeps/linux/common/ftruncate64.c b/libc/sysdeps/linux/common/ftruncate64.c
new file mode 100644
index 000000000..0b87eb58a
--- /dev/null
+++ b/libc/sysdeps/linux/common/ftruncate64.c
@@ -0,0 +1,39 @@
+/*
+ * ftruncate64 syscall.  Copes with 64 bit and 32 bit machines
+ * and on 32 bit machines this sends things into the kernel as
+ * two 32-bit arguments (high and low 32 bits of length) that 
+ * are ordered based on endianess.  It turns out endian.h has
+ * just the macro we need to order things (__LONG_LONG_PAIR).
+ *
+ *  Copyright (C) 2002  Erik Andersen <andersen@codepoet.org>
+ *
+ * This file is subject to the terms and conditions of the GNU
+ * Lesser General Public License.  See the file COPYING.LIB in
+ * the main directory of this archive for more details.
+ */
+
+#include <features.h>
+#include <unistd.h>
+#include <errno.h>
+#include <endian.h>
+#include <stdint.h>
+#include <sys/syscall.h>
+
+#if defined __UCLIBC_HAVE_LFS__ && defined __NR_ftruncate64
+#if (__WORDSIZE == 64)
+/* For a 64 bit machine, life is simple... */
+_syscall2(int, ftruncate64, int, fd, __off64_t, length);
+#elif (__WORDSIZE == 32)
+#define __NR___ftruncate64 __NR_ftruncate64
+static inline _syscall3(int, __ftruncate64, int, fd, int, high_length, int, low_length);
+/* The exported ftruncate64 function.  */
+int ftruncate64 (int fd, __off64_t length)
+{
+    unsigned int low = length & 0xffffffff;
+    unsigned int high = length >> 32;
+    return __ftruncate64(fd, __LONG_LONG_PAIR (high, low));
+}
+#else
+#error Your machine is not 64 bit or 32 bit, I am dazed and confused.
+#endif
+#endif /* __UCLIBC_HAVE_LFS__ */