From 26088bf37ef85681cf2158fdff82233b1b0c9bfd Mon Sep 17 00:00:00 2001
From: johannst <johannes.stoelp@gmail.com>
Date: Sat, 17 Apr 2021 23:41:17 +0200
Subject: added close,access,write,pread,mmap,munmap syscalls + syscall ret
 handler

---
 lib/src/syscalls.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 44 insertions(+), 4 deletions(-)

(limited to 'lib/src')

diff --git a/lib/src/syscalls.c b/lib/src/syscalls.c
index d6ac1a5..074fced 100644
--- a/lib/src/syscalls.c
+++ b/lib/src/syscalls.c
@@ -4,16 +4,56 @@
 #include <syscall.h>
 #include <syscalls.h>
 
+// Storage for `dynld_errno`.
+int dynld_errno;
+
+// Convert return value to errno/ret.
+static long syscall_ret(unsigned long ret) {
+    if (ret > (unsigned long)-4096ul) {
+        dynld_errno = -ret;
+        return -1;
+    }
+    return ret;
+}
+
 int open(const char* path, int flags) {
-    return syscall2(__NR_open, path, flags);
+    long ret = syscall2(__NR_open, path, flags);
+    return syscall_ret(ret);
+}
+
+int close(int fd) {
+    long ret = syscall1(__NR_close, fd);
+    return syscall_ret(ret);
+}
+
+int access(const char* path, int mode) {
+    long ret = syscall2(__NR_access, path, mode);
+    return syscall_ret(ret);
+}
+
+ssize_t write(int fd, const void* buf, size_t count) {
+    long ret = syscall3(__NR_write, fd, buf, count);
+    return syscall_ret(ret);
 }
 
 ssize_t read(int fd, void* buf, size_t count) {
-    return syscall3(__NR_read, fd, buf, count);
+    long ret = syscall3(__NR_read, fd, buf, count);
+    return syscall_ret(ret);
+}
+
+ssize_t pread(int fd, void* buf, size_t count, off_t offset) {
+    long ret = syscall4(__NR_read, fd, buf, count, offset);
+    return syscall_ret(ret);
+}
+
+void* mmap(void* addr, size_t length, int prot, int flags, int fd, off_t offset) {
+    long ret = syscall6(__NR_mmap, addr, length, prot, flags, fd, offset);
+    return (void*)syscall_ret(ret);
 }
 
-off_t lseek(int fd, off_t offset, int whence) {
-    return syscall3(__NR_lseek, fd, offset, whence);
+int munmap(void* addr, size_t length) {
+    long ret = syscall2(__NR_munmap, addr, length);
+    return syscall_ret(ret);
 }
 
 void _exit(int status) {
-- 
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