fixed fstat/stat/readlink syscall.

components/lwp/lwp_syscall.c

@@ -612,7 +612,7 @@ int sys_fstat(int file, struct stat *buf)
 {
 #ifdef ARCH_MM_MMU
  int ret = -1;
- struct stat statbuff;
+ struct stat statbuff = {0};
 
  if (!lwp_user_accessable((void *)buf, sizeof(struct stat)))
  {
@@ -2575,7 +2575,45 @@ int sys_log(const char* log, int size)
 int sys_stat(const char *file, struct stat *buf)
 {
  int ret = 0;
- ret = stat(file, buf);
+ int err;
+ size_t len;
+ size_t copy_len;
+ char *copy_path;
+ struct stat statbuff = {0};
+
+ if (!lwp_user_accessable((void *)buf, sizeof(struct stat)))
+ {
+ return -EFAULT;
+ }
+
+ len = lwp_user_strlen(file, &err);
+ if (err)
+ {
+ return -EFAULT;
+ }
+
+ copy_path = (char*)rt_malloc(len + 1);
+ if (!copy_path)
+ {
+ return -ENOMEM;
+ }
+
+ copy_len = lwp_get_from_user(copy_path, (void*)file, len);
+ if (copy_len == 0)
+ {
+ rt_free(copy_path);
+ return -EFAULT;
+ }
+ copy_path[copy_len] = '\0';
+
+ ret = stat(copy_path, &statbuff);
+ rt_free(copy_path);
+
+ if (ret == 0)
+ {
+ lwp_put_to_user(buf, &statbuff, sizeof statbuff);
+ }
+
  return (ret < 0 ? GET_ERRNO() : ret);
 }
 
@@ -4157,6 +4195,67 @@ int sys_getrandom(void *buf, size_t buflen, unsigned int flags)
 #endif
  return ret;
 }
+
+ssize_t sys_readlink(char* path, char *buf, size_t bufsz)
+{
+ size_t len, copy_len;
+ int err;
+ int fd = -1;
+ struct dfs_fd *d;
+ char *copy_path;
+
+ len = lwp_user_strlen(path, &err);
+ if (err)
+ {
+ return -EFAULT;
+ }
+
+ if (!lwp_user_accessable(buf, bufsz))
+ {
+ return -EINVAL;
+ }
+
+ copy_path = (char*)rt_malloc(len + 1);
+ if (!copy_path)
+ {
+ return -ENOMEM;
+ }
+
+ copy_len = lwp_get_from_user(copy_path, path, len);
+ copy_path[copy_len] = '\0';
+
+ /* musl __procfdname */
+ err = sscanf(copy_path, "/proc/self/fd/%d", &fd);
+ rt_free(copy_path);
+
+ if (err != 1)
+ {
+ LOG_E("readlink: path not is /proc/self/fd/* , call by musl __procfdname()?");
+ return -EINVAL;
+ }
+
+ d = fd_get(fd);
+ if (!d)
+ {
+ return -EBADF;
+ }
+
+ if (!d->vnode)
+ {
+ return -EBADF;
+ }
+
+ copy_len = strlen(d->vnode->fullpath);
+ if (copy_len > bufsz)
+ {
+ copy_len = bufsz;
+ }
+
+ bufsz = lwp_put_to_user(buf, d->vnode->fullpath, copy_len);
+
+ return bufsz;
+}
+
 int sys_setaffinity(pid_t pid, size_t size, void *set)
 {
  if (!lwp_user_accessable(set, sizeof(cpu_set_t)))
@@ -4672,7 +4771,7 @@ const static void* func_table[] =
  SYSCALL_SIGN(sys_setrlimit),
  SYSCALL_SIGN(sys_setsid),
  SYSCALL_SIGN(sys_getrandom),
- SYSCALL_SIGN(sys_notimpl), // SYSCALL_SIGN(sys_readlink) /* 145 */
+ SYSCALL_SIGN(sys_readlink), // SYSCALL_SIGN(sys_readlink) /* 145 */
  SYSCALL_USPACE(SYSCALL_SIGN(sys_mremap)),
  SYSCALL_USPACE(SYSCALL_SIGN(sys_madvise)),
  SYSCALL_SIGN(sys_sched_setparam),