[08/11] stdio-common: Introduce the __printf_buffer function

  It can be used to write to a __print_buffer (incrementally).
---
 include/printf_buffer.h          |   5 ++
 stdio-common/Makefile            |   5 ++
 stdio-common/printf_buffer.c     |  30 +++++++
 stdio-common/tst-printf_buffer.c | 138 +++++++++++++++++++++++++++++++
 4 files changed, 178 insertions(+)
 create mode 100644 stdio-common/printf_buffer.c
 create mode 100644 stdio-common/tst-printf_buffer.c
  

On 09/02/24 12:25, Florian Weimer wrote:
> It can be used to write to a __print_buffer (incrementally).

LGTM, thanks.

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

> ---
>  include/printf_buffer.h          |   5 ++
>  stdio-common/Makefile            |   5 ++
>  stdio-common/printf_buffer.c     |  30 +++++++
>  stdio-common/tst-printf_buffer.c | 138 +++++++++++++++++++++++++++++++
>  4 files changed, 178 insertions(+)
>  create mode 100644 stdio-common/printf_buffer.c
>  create mode 100644 stdio-common/tst-printf_buffer.c
> 
> diff --git a/include/printf_buffer.h b/include/printf_buffer.h
> index cee5afb581..a5483e8a97 100644
> --- a/include/printf_buffer.h
> +++ b/include/printf_buffer.h
> @@ -206,6 +206,11 @@ bool __printf_buffer_flush (struct __printf_buffer *buf) attribute_hidden;
>  void __vprintf_buffer (struct __printf_buffer *buf, const char *format,
>                         va_list ap, unsigned int mode_flags) attribute_hidden;
>  
> +/* Write the argument list to BUF according to FORMAT.
> +   Unconditionally enables fortification (special procesing for %n).  */
> +void __printf_buffer (struct __printf_buffer *buf, const char *format, ...)
> +  __attribute__ ((__format__ (__printf__, 2, 3))) attribute_hidden;
> +
>  /* Wide version of struct __printf_buffer follows.  */
>  
>  enum __wprintf_buffer_mode

Ok.

> diff --git a/stdio-common/Makefile b/stdio-common/Makefile
> index 6447b6b444..d610ed67e6 100644
> --- a/stdio-common/Makefile
> +++ b/stdio-common/Makefile
> @@ -64,6 +64,7 @@ routines := \
>    perror \
>    printf \
>    printf-prs \
> +  printf_buffer \
>    printf_buffer_as_file \
>    printf_buffer_done \
>    printf_buffer_flush \
> @@ -290,6 +291,10 @@ test-srcs = \
>    tst-unbputc \
>    # test-srcs
>  
> +# Test for the internal, non-exported __printf_buffer function.
> +tests-internal += tst-printf_buffer
> +tests-static += tst-printf_buffer
> +

Maybe put in a newline to be future-proof.

>  ifeq ($(run-built-tests),yes)
>  tests-special += \
>    $(objpfx)tst-printf-bz18872-mem.out \
> diff --git a/stdio-common/printf_buffer.c b/stdio-common/printf_buffer.c
> new file mode 100644
> index 0000000000..fabb3b5bb4
> --- /dev/null
> +++ b/stdio-common/printf_buffer.c
> @@ -0,0 +1,30 @@
> +/* Write a format string to a buffer.
> +   Copyright (C) 2024 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <printf_buffer.h>
> +#include <libioP.h>
> +#include <stdarg.h>
> +
> +void
> +__printf_buffer (struct __printf_buffer *buf, const char *format, ...)
> +{
> +  va_list arg;
> +  va_start (arg, format);
> +  __vprintf_buffer (buf, format, arg, PRINTF_FORTIFY);
> +  va_end (arg);
> +}
> diff --git a/stdio-common/tst-printf_buffer.c b/stdio-common/tst-printf_buffer.c
> new file mode 100644
> index 0000000000..d12da8c939
> --- /dev/null
> +++ b/stdio-common/tst-printf_buffer.c
> @@ -0,0 +1,138 @@
> +/* Basic test for the __printf_buffer function (via asprintf).
> +   Copyright (C) 2024 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <printf_buffer.h>
> +#include <array_length.h>
> +#include <string.h>
> +#include <support/check.h>
> +
> +static int
> +do_test (void)
> +{
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "%s", "");
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_VERIFY (buf.base.write_ptr == buf.base.write_base);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "abc");
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_VERIFY (buf.base.write_ptr == buf.base.write_base + 3);
> +    TEST_COMPARE_BLOB (buf.direct, 3, "abc", 3);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "abc[%d]DEF", 17);
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_VERIFY (buf.base.write_ptr == buf.base.write_base + 10);
> +    TEST_COMPARE_BLOB (buf.direct, 10, "abc[17]DEF", 10);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  /* Test concatenation.  */
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "abc");
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_VERIFY (buf.base.write_ptr == buf.base.write_base + 3);
> +    TEST_COMPARE_BLOB (buf.direct, 3, "abc", 3);
> +    __printf_buffer (&buf.base, "[%d]DEF", 17);
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_VERIFY (buf.base.write_ptr == buf.base.write_base + 10);
> +    TEST_COMPARE_BLOB (buf.direct, 10, "abc[17]DEF", 10);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    char large_string[500];
> +    memset (large_string, 'X', array_length (large_string));
> +    large_string[array_length (large_string) -1] = '\0';
> +    int n;
> +
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "%s", large_string);
> +    TEST_VERIFY (buf.base.write_base != buf.direct);
> +    TEST_COMPARE_BLOB (buf.base.write_base,
> +                       buf.base.write_ptr - buf.base.write_base,
> +                       large_string, strlen (large_string));
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "abc");
> +    __printf_buffer (&buf.base, "%n", &n);
> +    /* %n counts from the start of the buffer, not from within the
> +        printf call.  */
> +    TEST_COMPARE (n, 3);
> +    __printf_buffer (&buf.base, "%s", large_string);
> +    TEST_VERIFY (buf.base.write_base != buf.direct);
> +    TEST_COMPARE_BLOB (buf.base.write_base, 3, "abc", 3);
> +    TEST_COMPARE_BLOB (buf.base.write_base + 3,
> +                       buf.base.write_ptr - buf.base.write_base - 3,
> +                       large_string, strlen (large_string));
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    __printf_buffer (&buf.base, "%n", &n);
> +    TEST_COMPARE (n, 3 + strlen (large_string));
> +    TEST_COMPARE_BLOB (buf.base.write_base, 3, "abc", 3);
> +    TEST_COMPARE_BLOB (buf.base.write_base + 3,
> +                       buf.base.write_ptr - buf.base.write_base - 3,
> +                       large_string, strlen (large_string));
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +
> +  /* Test %n with concatenation.  */
> +  {
> +    struct __printf_buffer_asprintf buf;
> +    __printf_buffer_asprintf_init (&buf);
> +    __printf_buffer (&buf.base, "abc");
> +    int n = -1;
> +    __printf_buffer (&buf.base, "D%nEF", &n);
> +    TEST_COMPARE (n, 4);        /* %n counts from the start of the buffer.  */
> +    TEST_VERIFY (buf.base.write_base == buf.direct);
> +    TEST_COMPARE_BLOB (buf.base.write_base,
> +                       buf.base.write_ptr - buf.base.write_base, "abcDEF", 6);
> +    TEST_VERIFY (!__printf_buffer_has_failed (&buf.base));
> +    TEST_COMPARE (__printf_buffer_asprintf_free (&buf), -1);
> +  }
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>