fusl/src/stdio/__fopen_rb_ca.c

#include "stdio_impl.h"
#include <fcntl.h>
#include <string.h>

FILE* __fopen_rb_ca(const char* filename,
                    FILE* f,
                    unsigned char* buf,
                    size_t len) {
  memset(f, 0, sizeof *f);

  f->fd = sys_open(filename, O_RDONLY | O_CLOEXEC);
  if (f->fd < 0)
    return 0;
  __syscall(SYS_fcntl, f->fd, F_SETFD, FD_CLOEXEC);

  f->flags = F_NOWR | F_PERM;
  f->buf = buf + UNGET;
  f->buf_size = len - UNGET;
  f->read = __stdio_read;
  f->seek = __stdio_seek;
  f->close = __stdio_close;
  f->lock = -1;

  return f;
}