add syscall fsync

kernel/include/sysnum.h

@@ -81,6 +81,7 @@
 #define SYS_umask       166
 #define SYS_readlinkat  78
 #define SYS_sync        81
+#define SYS_fsync        82
 #define SYS_ftruncate   46
 
 #endif
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kernel/syscall.c

@@ -174,6 +174,7 @@ extern uint64 sys_gettid();
 extern uint64 sys_umask();
 extern uint64 sys_readlinkat();
 extern uint64 sys_sync();
+extern uint64 sys_fsync();
 extern uint64 sys_ftruncate();
 
 static uint64 (*syscalls[])(void) = {
@@ -253,6 +254,7 @@ static uint64 (*syscalls[])(void) = {
   [SYS_umask]       sys_umask,
   [SYS_readlinkat]  sys_readlinkat,
   [SYS_sync]        sys_sync,
+  [SYS_fsync]        sys_fsync,
   [SYS_ftruncate]   sys_ftruncate,
 };
 
@@ -332,6 +334,7 @@ static char *sysnames[] = {
   [SYS_umask]       "umask",
   [SYS_readlinkat]  "readlinkat",
   [SYS_sync]        "sync",
+  [SYS_fsync]       "fsync",
   [SYS_ftruncate]   "ftruncate",
 };
 

kernel/sysfile.c

@@ -1342,7 +1342,25 @@ sys_sync(void)
   return 0;
 }
 
+uint64
+sys_fsync(void)
+{
+  return 0;
+}
+
+uint64
 sys_ftruncate(void)
 {
+  struct file *fp;
+  int len, fd;
+  if (argfd(0,&fd,&fp) < 0 && fd != AT_FDCWD)
+    return -24;  // 打开文件太多
+
+  if (argint(1, &len) < 0)
+  {
+    return -1;
+  }
   
+
+  return 0;  
 }
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