Implement syscall readlinkat

Author: mylai-mtk

fesvr/syscall.cc

@@ -161,6 +161,7 @@ syscall_t::syscall_t(htif_t* htif)
   table[64] = &syscall_t::sys_write;
   table[67] = &syscall_t::sys_pread;
   table[68] = &syscall_t::sys_pwrite;
+  table[78] = &syscall_t::sys_readlinkat;
   table[79] = &syscall_t::sys_fstatat;
   table[80] = &syscall_t::sys_fstat;
   table[93] = &syscall_t::sys_exit;
@@ -512,3 +513,16 @@ void syscall_t::set_chroot(const char* where)
 
   chroot = buf2;
 }
+
+reg_t syscall_t::sys_readlinkat(reg_t dirfd, reg_t ppathname, reg_t ppathname_size,
+                                reg_t pbuf, reg_t bufsiz, reg_t a5, reg_t a6)
+{
+  std::vector<char> pathname(ppathname_size);
+  memif->read(ppathname, ppathname_size, pathname.data());
+
+  std::vector<char> buf(bufsiz);
+  ssize_t ret = sysret_errno(AT_SYSCALL(readlinkat, dirfd, pathname.data(), buf.data(), bufsiz));
+  if (ret > 0)
+    memif->write(pbuf, ret, buf.data());
+  return ret;
+}

fesvr/syscall.h

@@ -70,6 +70,7 @@ class syscall_t : public device_t
   reg_t sys_getcwd(reg_t, reg_t, reg_t, reg_t, reg_t, reg_t, reg_t);
   reg_t sys_getmainvars(reg_t, reg_t, reg_t, reg_t, reg_t, reg_t, reg_t);
   reg_t sys_chdir(reg_t, reg_t, reg_t, reg_t, reg_t, reg_t, reg_t);
+  reg_t sys_readlinkat(reg_t, reg_t, reg_t, reg_t, reg_t, reg_t, reg_t);
 };
 
 #endif