hw.clau...@gmail.com writes:
> From: Claudio Fontana <claudio.font...@huawei.com>
>
> if the memmem function is missing, provide a trivial replacement.
>
> Signed-off-by: Claudio Fontana <claudio.font...@huawei.com>
> Reviewed-by: Eric Blake <ebl...@redhat.com>
> Acked-by: Luiz Capitulino <lcapitul...@redhat.com>
> ---
> configure | 15 +++++++++++++
> include/qemu/osdep.h | 4 ++++
> util/Makefile.objs | 1 +
> util/memmem.c | 63
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 83 insertions(+)
> create mode 100644 util/memmem.c
>
> diff --git a/configure b/configure
> index 409edf9..9e04269 100755
> --- a/configure
> +++ b/configure
> @@ -3091,6 +3091,17 @@ if compile_prog "" "" ; then
> fi
>
> ##########################################
> +# memmem probe
> +cat > $TMPC <<EOF
> +#include <string.h>
> +int main(int argc, char *argv[]) { return memmem(argv[0], 0, argv[0], 0) !=
> argv[0]; }
> +EOF
> +memmem=no
> +if compile_prog "" "" ; then
> + memmem=yes
> +fi
> +
> +##########################################
> # fdt probe
> # fdt support is mandatory for at least some target architectures,
> # so insist on it if we're building those system emulators.
> @@ -4473,6 +4484,7 @@ echo "RDMA support $rdma"
> echo "TCG interpreter $tcg_interpreter"
> echo "fdt support $fdt"
> echo "preadv support $preadv"
> +echo "memmem support $memmem"
> echo "fdatasync $fdatasync"
> echo "madvise $madvise"
> echo "posix_madvise $posix_madvise"
> @@ -4822,6 +4834,9 @@ fi
> if test "$preadv" = "yes" ; then
> echo "CONFIG_PREADV=y" >> $config_host_mak
> fi
> +if test "$memmem" = "yes" ; then
> + echo "CONFIG_MEMMEM=y" >> $config_host_mak
> +fi
> if test "$fdt" = "yes" ; then
> echo "CONFIG_FDT=y" >> $config_host_mak
> fi
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index 3247364..abc5486 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -201,6 +201,10 @@ ssize_t writev(int fd, const struct iovec *iov, int
> iov_cnt);
> #include <sys/uio.h>
> #endif
>
> +#ifndef CONFIG_MEMMEM
> +void *memmem(const void *hay, size_t hay_len, const void *s, size_t s_len);
> +#endif /* !CONFIG_MEMMEM */
> +
> #ifdef _WIN32
> static inline void qemu_timersub(const struct timeval *val1,
> const struct timeval *val2,
> diff --git a/util/Makefile.objs b/util/Makefile.objs
> index ceaba30..628242f 100644
> --- a/util/Makefile.objs
> +++ b/util/Makefile.objs
> @@ -1,6 +1,7 @@
> util-obj-y = osdep.o cutils.o unicode.o qemu-timer-common.o
> util-obj-$(CONFIG_WIN32) += oslib-win32.o qemu-thread-win32.o
> event_notifier-win32.o
> util-obj-$(CONFIG_POSIX) += oslib-posix.o qemu-thread-posix.o
> event_notifier-posix.o qemu-openpty.o
> +util-obj-$(call lnot,$(CONFIG_MEMMEM)) += memmem.o
> util-obj-y += envlist.o path.o module.o
> util-obj-$(call lnot,$(CONFIG_INT128)) += host-utils.o
> util-obj-y += bitmap.o bitops.o hbitmap.o
> diff --git a/util/memmem.c b/util/memmem.c
> new file mode 100644
> index 0000000..16ac611
> --- /dev/null
> +++ b/util/memmem.c
> @@ -0,0 +1,63 @@
> +/*
> + * memmem replacement function
> + *
> + * Copyright (C) 2015 Huawei Technologies Duesseldorf GmbH
> + * Written by Claudio Fontana <claudio.font...@huawei.com>
> + *
> + * 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 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.
> + */
> +
> +#include <qemu-common.h>
#include "qemu-common.h", please, like everywhere else.
> +
> +/*
> + * Search for the first occurrence of a binary string ("needle")
> + * in a memory region ("haystack").
> + *
> + * If needle length is 0, it returns the pointer to the haystack.
> + * Otherwise it returns the pointer to the first character of the first
> + * occurrence of the needle in the haystack, or NULL if none are found.
> + *
> + */
> +void *
> +memmem(const void *haystack, size_t hay_len, const void *needle, size_t
> s_len)
I prefer function comments to follow a strict pattern:
/*
* Headline explaining the function's purpose[*]
* Zero or more paragraphs explaining preconditions, side effects,
* return values, error conditions.
*/
[*] If you can't come up with a headline fitting into a single line,
chances are the function does too many things.
Calling the size of @needle @s_len is odd.
What about:
/*
* Return the first occurrence of @needle in @haystack, or else NULL.
* @needle consists of @needle_sz bytes.
* @haystack consists of @haystack_sz bytes.
* Note: returns @haystack when @needle_sz is zero, because an empty
* needle matches anywhere.
*/
void *
memmem(const void *haystack, size_t haystack_sz,
const void *needle, size_t needle_sz)
> +{
> + const unsigned char *hay = (const unsigned char *)haystack;
> + const unsigned char *s = (const unsigned char *)needle;
Superfluous casts.
> + const unsigned char *last = hay + (hay_len - s_len);
> +
> + if (s_len == 0) {
> + return (void *)hay;
> + }
> +
> + if (hay_len < s_len) {
> + return NULL;
> + }
> +
> + if (s_len == 1) {
> + return memchr(hay, s[0], hay_len);
> + }
Why special-case length 1?
> +
> + for (; hay <= last; hay++) {
> + if (hay[0] == s[0] && memcmp(hay, s, s_len) == 0) {
Why not just memcmp()?
> + return (void *)hay;
> + }
> + }
> +
> + return NULL;
> +}
