Add support for fflush and close syscalls

arch/aarch64.c

@@ -99,4 +99,32 @@ int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode)
   return (int32_t)rtn;
 }
 
+int close(unsigned int fd){
+  long int rtn;
+  asm ( 
+    "mov x0, %1\n"
+    "mov x8, #57\n"
+    "svc #0\n"
+    "mov %0, x0\n"
+    : "=r"(rtn)
+    : "r" ((long)fd)
+    : "x0", "x8"
+  );
+  return (int)rtn;
+}
+
+int fsync(unsigned int fd){
+  long int rtn;
+  asm ( 
+    "mov x0, %1\n"
+    "mov x8, #82\n"
+    "svc #0\n"
+    "mov %0, x0\n"
+    : "=r"(rtn)
+    : "r" ((long)fd)
+    : "x0", "x8"
+  );
+  return (int)rtn;
+}
+
 #endif

arch/mips.c

@@ -71,20 +71,35 @@ int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode)
     : "r"(fd), "r"(filename), "r"(flags), "r"(mode)
     : "a0", "a1", "a2", "a3", "v0"
   );
-  /*
-  asm volatile (
-    "move $a0, %1\n"
-    "move $a1, %2\n"
-    "move $a2, %3\n"
-    "li $v0, 4005\n"
-    "syscall\n"
-    "move %0, $v0\n"
-    : "=r"(file)
-    : "r"(filename), "r"(flags), "r"(mode)
-    : "a0", "a1", "a2", "a3", "v0"
-  );
-  */
   return file;
 }
 
+int close(unsigned int fd){
+  int rtn = 0;
+  asm ( 
+    "move $a0, %1\n"
+    "li $v0, 4006\n"
+    "syscall\n"
+    "move %0, $v0\n"
+    : "=r"(rtn)
+    : "r" (fd)
+    : "a0", "v0"
+  );
+  return rtn;
+}
+
+int fsync(unsigned int fd){
+  int rtn = 0;
+  asm ( 
+    "move $a0, %1\n"
+    "li $v0, 4118\n"
+    "syscall\n"
+    "move %0, $v0\n"
+    : "=r"(rtn)
+    : "r" (fd)
+    : "a0", "v0"
+  );
+  return rtn;
+}
+
 #endif

arch/x86_64.c

@@ -55,7 +55,7 @@ uint32_t fork() {
 int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode) {
   int32_t file;
   asm volatile (
-      "mov %%r10, %5\n"
+      "mov %5, %%r10\n"
       "syscall\n"
       : "=a"(file)
       : "a"(SYS_OPENAT), "D"(fd), "S"(filename), "d"(flags), "r"((uint64_t)mode)  // RDI, RSI, RDX are used in x86-64 for write args
@@ -64,4 +64,28 @@ int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode)
   return file;
 }
 
+#define SYS_CLOSE 3
+int close(unsigned int fd) {
+  int rtn;
+  asm volatile(
+    "syscall"
+    : "=a"(rtn)
+    : "a"(SYS_CLOSE), "D"(fd)
+    : "rcx", "r11"
+  );
+  return rtn;
+}
+
+#define SYS_FSYNC 74
+int fsync(unsigned int fd) {
+  int rtn;
+  asm volatile(
+    "syscall"
+    : "=a"(rtn)
+    : "a"(SYS_FSYNC), "D"(fd)
+    : "rcx", "r11"
+  );
+  return rtn;
+}
+
 #endif /* ifdef __x86_64__ */

buildtest.c

@@ -28,9 +28,16 @@ int main() {
   // Test the read syscall
   #define INPUT_BUFFER_LEN 4096
   char input_buffer[INPUT_BUFFER_LEN] = {0};
+  int32_t fout = openc("outfile", O_RDWR | O_CREAT | O_TRUNC, 0664);
+
   write(STDOUT, "Enter some text:", 16);
   intptr_t n_read = read(STDIN, input_buffer, INPUT_BUFFER_LEN);
   write(STDOUT, input_buffer, n_read);
+  if(fout > 0) {
+    write(fout, input_buffer, n_read);
+    fsync(fout);
+    close(fout);
+  }
 
   // Test the open syscall
   int32_t file = open("/proc/version", O_RDONLY);

sys.h

@@ -13,11 +13,27 @@ intptr_t read(int32_t fd, const void* buf, intptr_t size);
 #define O_WRONLY       01
 #define O_RDWR         02
 #define AT_FDCWD      -100
+
+#if defined(__mips__)
+  // linux/arch/mips/include/uapi/asm/fcntl.h
+  #define O_APPEND	0x0008
+  #define O_CREAT		0x0100	/* not fcntl */
+  #define O_TRUNC		0x0200	/* not fcntl */
+  #define O_EXCL		0x0400	/* not fcntl */
+  #define O_NOCTTY	0x0800	/* not fcntl */
+#else
+  // linux/include/uapi/asm-generic/fcntl.h
+  #define O_CREAT        1<<6
+  #define O_EXCL         1<<7
+  #define O_NOCTTY       1<<8
+  #define O_TRUNC        1<<9
+  #define O_APPEND       1<<10
+#endif 
 int32_t openat(int32_t fd, const char* filename, uint32_t flags, uint32_t mode);
 #define open(...) openat(AT_FDCWD, __VA_ARGS__, 0)
-//inline int32_t openat(int32_t fd, const char* filename, uint32_t flags) {return openat(fd, filename, flags, 0);}
+#define openc(...) openat(AT_FDCWD, __VA_ARGS__)
-//inline int32_t open(const char* filename, uint32_t flags, uint32_t mode) {return openat(AT_FDCWD, filename, flags, mode);}
+int close(unsigned int fd);
-//inline int32_t open(const char* filename, uint32_t flags) {return openat(AT_FDCWD, filename, flags, 0);}
+int fsync(unsigned int fd);
 
 uint32_t fork();