Re: [PATCH v5 07/11] libio: Convert __vsprintf_internal to buffers

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

LGTM, with a small fix below.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

On 12/12/22 12:23, Florian Weimer via Libc-alpha wrote:
> ---
>  include/printf_buffer.h            |  2 +
>  libio/iovsprintf.c                 | 70 ++++++++----------------------
>  stdio-common/printf_buffer_flush.c |  4 ++
>  3 files changed, 24 insertions(+), 52 deletions(-)
> 
> diff --git a/include/printf_buffer.h b/include/printf_buffer.h
> index e89f984aca..92393399fb 100644
> --- a/include/printf_buffer.h
> +++ b/include/printf_buffer.h
> @@ -44,7 +44,9 @@
>  enum __printf_buffer_mode
>    {
>      __printf_buffer_mode_failed,
> +    __printf_buffer_mode_sprintf,
>      __printf_buffer_mode_snprintf,
> +    __printf_buffer_mode_sprintf_chk,
>      __printf_buffer_mode_to_file,
>      __printf_buffer_mode_strfmon,
>      __printf_buffer_mode_fp,         /* For __printf_fp_l_buffer.  */
> diff --git a/libio/iovsprintf.c b/libio/iovsprintf.c
> index 72c67bf27b..7305d8e247 100644
> --- a/libio/iovsprintf.c
> +++ b/libio/iovsprintf.c
> @@ -25,58 +25,18 @@
>     in files containing the exception.  */
>  
>  #include "libioP.h"
> -#include "strfile.h"
>  
> -static int __THROW
> -_IO_str_chk_overflow (FILE *fp, int c)
> -{
> -  /* If we get here, the user-supplied buffer would be overrun by
> -     further output.  */
> -  __chk_fail ();
> -}
> -
> -static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable =

Remove the _IO_str_chk_jumps entry from tst-relro-libc.out check.

> -{
> -  JUMP_INIT_DUMMY,
> -  JUMP_INIT(finish, _IO_str_finish),
> -  JUMP_INIT(overflow, _IO_str_chk_overflow),
> -  JUMP_INIT(underflow, _IO_str_underflow),
> -  JUMP_INIT(uflow, _IO_default_uflow),
> -  JUMP_INIT(pbackfail, _IO_str_pbackfail),
> -  JUMP_INIT(xsputn, _IO_default_xsputn),
> -  JUMP_INIT(xsgetn, _IO_default_xsgetn),
> -  JUMP_INIT(seekoff, _IO_str_seekoff),
> -  JUMP_INIT(seekpos, _IO_default_seekpos),
> -  JUMP_INIT(setbuf, _IO_default_setbuf),
> -  JUMP_INIT(sync, _IO_default_sync),
> -  JUMP_INIT(doallocate, _IO_default_doallocate),
> -  JUMP_INIT(read, _IO_default_read),
> -  JUMP_INIT(write, _IO_default_write),
> -  JUMP_INIT(seek, _IO_default_seek),
> -  JUMP_INIT(close, _IO_default_close),
> -  JUMP_INIT(stat, _IO_default_stat),
> -  JUMP_INIT(showmanyc, _IO_default_showmanyc),
> -  JUMP_INIT(imbue, _IO_default_imbue)
> -};
> -
> -/* This function is called by regular vsprintf with maxlen set to -1,
> -   and by vsprintf_chk with maxlen set to the size of the output
> -   string.  In the former case, _IO_str_chk_overflow will never be
> -   called; in the latter case it will crash the program if the buffer
> -   overflows.  */
> +#include <printf.h>
> +#include <stdint.h>
> +#include <printf_buffer.h>
>  
>  int
>  __vsprintf_internal (char *string, size_t maxlen,
>  		     const char *format, va_list args,
>  		     unsigned int mode_flags)
>  {
> -  _IO_strfile sf;
> -  int ret;
> +  struct __printf_buffer buf;
>  
> -#ifdef _IO_MTSAFE_IO
> -  sf._sbf._f._lock = NULL;
> -#endif
> -  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
>    /* When called from fortified sprintf/vsprintf, erase the destination
>       buffer and try to detect overflows.  When called from regular
>       sprintf/vsprintf, do not erase the destination buffer, because
> @@ -84,19 +44,25 @@ __vsprintf_internal (char *string, size_t maxlen,
>       by ISO C), nor try to detect overflows.  */
>    if ((mode_flags & PRINTF_CHK) != 0)
>      {
> -      _IO_JUMPS (&sf._sbf) = &_IO_str_chk_jumps;
>        string[0] = '\0';
> +      __printf_buffer_init (&buf, string, maxlen,
> +			    __printf_buffer_mode_sprintf_chk);
>      }
>    else
> -    _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
> -  _IO_str_init_static_internal (&sf, string,
> -				(maxlen == -1) ? -1 : maxlen - 1,
> -				string);
> +    {
> +      __printf_buffer_init (&buf, string, 0, __printf_buffer_mode_sprintf);
> +      buf.write_end = (char *) ~(uintptr_t) 0; /* End of address space.  */
> +    }
> +
> +  __printf_buffer (&buf, format, args, mode_flags);
>  
> -  ret = __vfprintf_internal (&sf._sbf._f, format, args, mode_flags);
> +  /* Write the NUL terminator if there is room.  Do not use the putc
> +     operation to avoid overflowing the character write count.  */
> +  if ((mode_flags & PRINTF_CHK) != 0 && buf.write_ptr == buf.write_end)
> +    __chk_fail ();
> +  *buf.write_ptr = '\0';
>  
> -  *sf._sbf._f._IO_write_ptr = '\0';
> -  return ret;
> +  return __printf_buffer_done (&buf);
>  }
>  
>  int

Ok.

> diff --git a/stdio-common/printf_buffer_flush.c b/stdio-common/printf_buffer_flush.c
> index bfd1f9d733..f44c8b887f 100644
> --- a/stdio-common/printf_buffer_flush.c
> +++ b/stdio-common/printf_buffer_flush.c
> @@ -38,10 +38,14 @@ __printf_buffer_do_flush (struct __printf_buffer *buf)
>    switch (buf->mode)
>      {
>      case __printf_buffer_mode_failed:
> +    case __printf_buffer_mode_sprintf:
>        return;
>      case __printf_buffer_mode_snprintf:
>        __printf_buffer_flush_snprintf ((struct __printf_buffer_snprintf *) buf);
>        return;
> +    case __printf_buffer_mode_sprintf_chk:
> +      __chk_fail ();
> +      break;
>      case __printf_buffer_mode_to_file:
>        __printf_buffer_flush_to_file ((struct __printf_buffer_to_file *) buf);
>        return;

Ok.