[Mesa-dev] [PATCH] util: implement strndup for WIN32

[Eirik Byrkjeflot Anonsen]

Samuel Iglesias Gonsalvez <siglesias at igalia.com> writes:

> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92124
> Cc: Jose Fonseca <jfonseca at vmware.com>
> ---
>
> I tested it on MSVC but not MinGW. I hope I did not something wrong.
>
>  src/mesa/main/shader_query.cpp |  1 +
>  src/util/Makefile.sources      |  1 +
>  src/util/strndup.c             | 47 ++++++++++++++++++++++++++++++++++++++++++
>  src/util/strndup.h             | 28 +++++++++++++++++++++++++
>  4 files changed, 77 insertions(+)
>  create mode 100644 src/util/strndup.c
>  create mode 100644 src/util/strndup.h
>
> diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
> index e020dce..0cada50 100644
> --- a/src/mesa/main/shader_query.cpp
> +++ b/src/mesa/main/shader_query.cpp
> @@ -37,6 +37,7 @@
>  #include "../glsl/program.h"
>  #include "uniforms.h"
>  #include "main/enums.h"
> +#include "util/strndup.h"
>  
>  extern "C" {
>  #include "shaderapi.h"
> diff --git a/src/util/Makefile.sources b/src/util/Makefile.sources
> index afdd0cb..10f2c02 100644
> --- a/src/util/Makefile.sources
> +++ b/src/util/Makefile.sources
> @@ -17,6 +17,7 @@ MESA_UTIL_FILES :=	\
>  	set.c \
>  	set.h \
>  	simple_list.h \
> +	strndup.c \
>  	strtod.c \
>  	strtod.h \
>  	texcompress_rgtc_tmp.h \
> diff --git a/src/util/strndup.c b/src/util/strndup.c
> new file mode 100644
> index 0000000..6e5bb22
> --- /dev/null
> +++ b/src/util/strndup.c
> @@ -0,0 +1,47 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#if defined(_WIN32)
> +#include <stdlib.h>
> +#include "strndup.h"
> +
> +char *
> +strndup(const char *str, size_t max)
> +{
> +   size_t n;
> +   char *ptr;
> +
> +   if (str == NULL)
> +      return NULL;
> +
> +   n = strlen(str);
> +   if (n > max)
> +      n = max;
> +
> +   ptr = (char *) malloc((n + 1) * sizeof(char));

In C++, I'm pretty sure sizeof(char) is always 1 (a 'char' is defined to
be of 'byte' size, and sizeof() returns size in 'bytes'. On the other
hand, the size of a 'byte' is not specified by C++.) But it could be
that C is of a different opinion.

However, there is a possibility for the calculation of the size to
overflow, which would most likely end up allocating a small buffer and
then overflow that buffer in the following memcpy. Of course, if
sizeof(char) is 1, that would probably never do anything worse than
crashing :)

eirik

> +   memcpy(ptr, str, n);
> +   ptr[n] = '\0';
> +   return ptr;
> +}
> +
> +#endif
> diff --git a/src/util/strndup.h b/src/util/strndup.h
> new file mode 100644
> index 0000000..dc8cdd2
> --- /dev/null
> +++ b/src/util/strndup.h
> @@ -0,0 +1,28 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#if defined(_WIN32)
> +
> +extern char *strndup(const char *str, size_t max);
> +
> +#endif
> -- 
> 2.1.4
>
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