[PATCH liburing v4 03/10] arch: syscall: Add `__sys_read()` syscall

[Ammar Faizi <ammarfaizi2@gnuweeb.org>]

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

A prep patch to support aarch64 nolibc. We will use this to get the
page size by reading /proc/self/auxv.

v2:
  - Fix return type, __sys_read() returns ssize_t, not int.

Reviewed-by: Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
 src/arch/generic/syscall.h | 7 +++++++
 src/arch/syscall-defs.h    | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/src/arch/generic/syscall.h b/src/arch/generic/syscall.h
index 71b2234..22252a1 100644
--- a/src/arch/generic/syscall.h
+++ b/src/arch/generic/syscall.h
@@ -50,6 +50,13 @@ static inline int __sys_open(const char *pathname, int flags, mode_t mode)
 	return (ret < 0) ? -errno : ret;
 }
 
+static inline ssize_t __sys_read(int fd, void *buffer, size_t size)
+{
+	ssize_t ret;
+	ret = read(fd, buffer, size);
+	return (ret < 0) ? -errno : ret;
+}
+
 static inline void *__sys_mmap(void *addr, size_t length, int prot, int flags,
 			       int fd, off_t offset)
 {
diff --git a/src/arch/syscall-defs.h b/src/arch/syscall-defs.h
index 9d4424d..bde69fa 100644
--- a/src/arch/syscall-defs.h
+++ b/src/arch/syscall-defs.h
@@ -17,6 +17,11 @@ static inline int __sys_open(const char *pathname, int flags, mode_t mode)
 #endif
 }
 
+static inline ssize_t __sys_read(int fd, void *buffer, size_t size)
+{
+	return (ssize_t) __do_syscall3(__NR_read, fd, buffer, size);
+}
+
 static inline void *__sys_mmap(void *addr, size_t length, int prot, int flags,
 			       int fd, off_t offset)
 {
-- 
Ammar Faizi