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No thanks. The idiom you think you are replacing is very rare, and rare
as it is, it is even more rare for it to have a flaw.
>memdup(3) has strdup(3) semantics but without strings.
>
>Canonical code for duplicating buffer looks like:
>
> rpl = malloc(src, len);
> if (!rpl)
> ...
> memcpy(rpl, src, len);
>
>Mistakes happen and two lengths in snippet above will be different.
>To prevent this memdup(3) was created:
>
> rpl = memdup(src, len);
> if (!rpl)
> ...
> ...
>
>Index: memdup.c
>===================================================================
>RCS file: memdup.c
>diff -N memdup.c
>--- /dev/null 1 Jan 1970 00:00:00 -0000
>+++ memdup.c 14 Jul 2008 12:27:18 -0000
>@@ -0,0 +1,31 @@
>+/*
>+ * $OpenBSD$
>+ *
>+ * Copyright (c) 2008 Alexey Dobriyan <adobriyan@xxxxxxxxx>
>+ *
>+ * Permission to use, copy, modify, and distribute this software for any
>+ * purpose with or without fee is hereby granted, provided that the above
>+ * copyright notice and this permission notice appear in all copies.
>+ *
>+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
>+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
>+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
>+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
>+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
>+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
>+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
>+ */
>+#include <sys/types.h>
>+#include <stdlib.h>
>+#include <string.h>
>+
>+void *
>+memdup(const void *src, size_t len)
>+{
>+ void *dst;
>+
>+ dst = malloc(len);
>+ if (dst)
>+ memcpy(dst, src, len);
>+ return dst;
>+}
>Index: memdup.3
>===================================================================
>RCS file: memdup.3
>diff -N memdup.3
>--- /dev/null 1 Jan 1970 00:00:00 -0000
>+++ memdup.3 14 Jul 2008 12:27:18 -0000
>@@ -0,0 +1,66 @@
>+.\" $OpenBSD$
>+./"
>+./"Copyright (c) 2008 Alexey Dobriyan <adobriyan@xxxxxxxxx>
>+./"
>+./"Permission to use, copy, modify, and distribute this software for any
>+./"purpose with or without fee is hereby granted, provided that the above
>+./"copyright notice and this permission notice appear in all copies.
>+./"
>+./"THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
>+./"WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
>+./"MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
>+./"ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
>+./"WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
>+./"ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
>+./"OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
>+./"
>+.Dd $Mdocdate: Jul 14 2008 $
>+.Dt STRDUP 3
>+.Os
>+.Sh NAME
>+.Nm memdup
>+.Nd save a copy of a buffer
>+.Sh SYNOPSIS
>+.Fd #include <string.h>
>+.Ft void *
>+.Fn memdup "const void *src, size_t len"
>+.Sh DESCRIPTION
>+The
>+.Fn memdup
>+function allocates sufficient memory for a copy of the buffer
>+.Fa src ,
>+does the copy, and returns a pointer to it.
>+The pointer may subsequently be used as an argument to the function
>+.Xr free 3 .
>+.Pp
>+If insufficient memory is available,
>+.Dv NULL
>+is returned.
>+.Sh EXAMPLES
>+The following will point
>+.Va p
>+to an allocated area of memory containing the replica of buffer
>+.Va src
>+which has length
>+.Va len :
>+.Bd -literal -offset indent
>+void *p;
>+
>+p = memdup(src, len);
>+if (!p) {
>+ fprintf(stderr, "Out of memory.\en");
>+ exit(1);
>+}
>+.Ed
>+.Sh ERRORS
>+The
>+.Fn memdup
>+function may fail and set the external variable
>+.Va errno
>+for any of the errors specified for the library function
>+.Xr malloc 3 .
>+.Sh SEE ALSO
>+.Xr free 3 ,
>+.Xr malloc 3 ,
>+.Xr memcpy 3 ,
>+.Xr strdup 3
>Index: Makefile.inc
>===================================================================
>RCS file: /cvs/src/lib/libc/string/Makefile.inc,v
>retrieving revision 1.20
>diff -u -r1.20 Makefile.inc
>--- Makefile.inc 25 Oct 2007 22:41:02 -0000 1.20
>+++ Makefile.inc 14 Jul 2008 12:31:27 -0000
>@@ -3,7 +3,8 @@
> # string sources
> .PATH: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/string ${LIBCSRCDIR}/string
>
>-SRCS+= bm.c memccpy.c memrchr.c strcasecmp.c strcasestr.c strcoll.c
>strdup.c \
>+SRCS+= bm.c memccpy.c memdup.c memrchr.c strcasecmp.c strcasestr.c
>strcoll.c \
>+ strdup.c \
> strerror.c strerror_r.c strlcat.c strmode.c strsignal.c strtok.c \
> strxfrm.c \
> wcscat.c wcschr.c wcscmp.c wcscpy.c wcscspn.c wcslcat.c wcslcpy.c \
>@@ -139,7 +140,7 @@
> ${LIBCSRCDIR}/string/rindex.c
>
> MAN+= bm.3 bcmp.3 bcopy.3 bstring.3 bzero.3 ffs.3 memccpy.3 memchr.3 \
>- memcmp.3 memcpy.3 memmove.3 memset.3 strcasecmp.3 strcat.3 \
>+ memcmp.3 memcpy.3 memdup.3 memmove.3 memset.3 strcasecmp.3 strcat.3 \
> strchr.3 strcmp.3 strcoll.3 strcpy.3 strcspn.3 strerror.3 \
> string.3 strlen.3 strmode.3 strdup.3 strpbrk.3 strrchr.3 strsep.3 \
> strsignal.3 strspn.3 strstr.3 strtok.3 strxfrm.3 swab.3 strlcpy.3 \
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