[PATCH 08/13] tools/nolibc: sys_lseek: riscv: use __NR_llseek for rv32

[Zhangjin Wu]

riscv uses the generic include/uapi/asm-generic/unistd.h, it has code
like this:

  #if __BITS_PER_LONG == 64 && !defined(__SYSCALL_COMPAT)
  #define __NR_lseek __NR3264_lseek
  #else
  #define __NR_llseek __NR3264_lseek
  #endif

There is no __NR_lseek for rv32, use __NR_llseek instead.

This code is based on sysdeps/unix/sysv/linux/lseek.c of glibc.

Signed-off-by: Zhangjin Wu <falcon at tinylab.org>
Signed-off-by: Willy Tarreau <w at 1wt.eu>
---
 tools/include/nolibc/std.h |  1 +
 tools/include/nolibc/sys.h | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/tools/include/nolibc/std.h b/tools/include/nolibc/std.h
index 933bc0be7e1c..83c0b0cb9564 100644
--- a/tools/include/nolibc/std.h
+++ b/tools/include/nolibc/std.h
@@ -32,5 +32,6 @@ typedef   signed long         off_t;
 typedef   signed long     blksize_t;
 typedef   signed long      blkcnt_t;
 typedef   signed long        time_t;
+typedef     long long        loff_t;
 
 #endif /* _NOLIBC_STD_H */
diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index d5792a5de70b..0ff77c0a06d7 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -671,7 +671,25 @@ int link(const char *old, const char *new)
 static __attribute__((unused))
 off_t sys_lseek(int fd, off_t offset, int whence)
 {
+#ifdef __NR_lseek
 	return my_syscall3(__NR_lseek, fd, offset, whence);
+#elif defined(__NR_llseek)
+	loff_t result;
+	off_t retval;
+	int ret;
+
+	ret = my_syscall5(__NR_llseek, fd, (long) (((uint64_t) (offset)) >> 32), (long) offset, &result, whence);
+	if (ret)
+		return ret;
+
+	retval = (off_t) result;
+	if (retval != result)
+		return -EOVERFLOW;
+
+	return retval;
+#else
+#error Neither __NR_lseek nor __NR_llseek defined, cannot implement sys_lseek()
+#endif
 }
 
 static __attribute__((unused))
-- 
2.25.1