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Add an implementation of the gnu-ish asprintf() and vasprintf(). They are

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not based on gpl'ed code, just prototype and usage.  I'm not 100% certain
they behave the same while the system is in trouble (eg: malloc() failing)
but in those circumstances all bets would be off anyway.

These routines work like sprintf() and vsprintf(), except that instead of
using a fixed buffer, they allocate memory and return it to the user
and it's the user's responsibility to free() it.  They have allocate as
much memory as they need (and can get), so the size of strings it can deal
with is limited only by the amount of memory it can malloc() on your
behalf.

There are a few gpl'ed programs starting to use this interface, and it's
becoming more common with the scares about security risks with sprintf().
I dont like the look of the code that the various programs (including
cvs, gdb, libg++, etc) provide if configure can't find it on the system.

It should be possible to modify the stdio core code to provide this
interface more efficiently, I was more worried about having something
that worked and was secure.  :-)  (I noticed that there was once intended
to be a smprintf() routine when our stdio was written for 4.4BSD, but it
looks pretty stillborn, and it's intended interface is not clear).  Since
Linux and gnu libc have this interface, it seemed silly to bring yet
another one onto the scene.
This commit is contained in:
Peter Wemm 1996-05-27 10:49:43 +00:00
parent c12a60de93
commit 15aa00d597
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=15931
5 changed files with 221 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/stdio.h
View File

@ -283,6 +283,7 @@ __END_DECLS
*/
#if !defined (_ANSI_SOURCE) && !defined(_POSIX_SOURCE)
__BEGIN_DECLS
int asprintf __P((char **, const char *, ...));
char *fgetln __P((FILE *, size_t *));
int fpurge __P((FILE *));
int getw __P((FILE *));
@ -293,6 +294,7 @@ void setbuffer __P((FILE *, char *, int));
int setlinebuf __P((FILE *));
char *tempnam __P((const char *, const char *));
int snprintf __P((char *, size_t, const char *, ...));
int vasprintf __P((char **, const char *, _BSD_VA_LIST_));
int vsnprintf __P((char *, size_t, const char *, _BSD_VA_LIST_));
int vscanf __P((const char *, _BSD_VA_LIST_));
int vsscanf __P((const char *, const char *, _BSD_VA_LIST_));

10
lib/libc/stdio/Makefile.inc
View File

@ -3,16 +3,16 @@
# stdio sources
.PATH: ${.CURDIR}/stdio
SRCS+= clrerr.c fclose.c fdopen.c feof.c ferror.c fflush.c fgetc.c \
fgetln.c fgetpos.c fgets.c fileno.c findfp.c flags.c fopen.c \
SRCS+= asprintf.c clrerr.c fclose.c fdopen.c feof.c ferror.c fflush.c \
fgetc.c fgetln.c fgetpos.c fgets.c fileno.c findfp.c flags.c fopen.c \
fprintf.c fpurge.c fputc.c fputs.c fread.c freopen.c fscanf.c \
fseek.c fsetpos.c ftell.c funopen.c fvwrite.c fwalk.c fwrite.c \
getc.c getchar.c gets.c getw.c makebuf.c mktemp.c perror.c \
printf.c putc.c putchar.c puts.c putw.c refill.c remove.c rewind.c \
rget.c scanf.c setbuf.c setbuffer.c setvbuf.c snprintf.c sprintf.c \
sscanf.c stdio.c tempnam.c tmpfile.c tmpnam.c ungetc.c vfprintf.c \
vfscanf.c vprintf.c vscanf.c vsnprintf.c vsprintf.c vsscanf.c \
wbuf.c wsetup.c
sscanf.c stdio.c tempnam.c tmpfile.c tmpnam.c ungetc.c vasprintf.c \
vfprintf.c vfscanf.c vprintf.c vscanf.c vsnprintf.c vsprintf.c \
vsscanf.c wbuf.c wsetup.c
MAN3+= stdio/fclose.3 stdio/ferror.3 stdio/fflush.3 stdio/fgetln.3 \
stdio/fgets.3 stdio/fopen.3 stdio/fputs.3 stdio/fread.3 stdio/fseek.3 \

59
lib/libc/stdio/asprintf.c Normal file
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@ -0,0 +1,59 @@
/*-
* Copyright (c) 1996 Peter Wemm <peter@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_RCS) && !defined(lint)
static char rcsid[] = "$Id$";
#endif /* LIBC_RCS and not lint */
#include <stdio.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#if __STDC__
int
asprintf(char **str, char const *fmt, ...)
#else
int
asprintf(str, fmt, va_alist)
char **str;
char *fmt;
va_dcl
#endif
{
int ret;
va_list ap;
#if __STDC__
va_start(ap, fmt);
#else
va_start(ap);
#endif
ret = vasprintf(str, fmt, ap);
va_end(ap);
return (ret);
}

80
lib/libc/stdio/printf.3
View File

@ -43,10 +43,12 @@
.Nm fprintf ,
.Nm sprintf ,
.Nm snprintf ,
.Nm asprintf ,
.Nm vprintf ,
.Nm vfprintf,
.Nm vsprintf ,
.Nm vsnprintf
.Nm vsnprintf ,
.Nm vasprintf
.Nd formatted output conversion
.Sh SYNOPSIS
.Fd #include <stdio.h>
@ -58,8 +60,8 @@
.Fn sprintf "char *str" "const char *format" ...
.Ft int
.Fn snprintf "char *str" "size_t size" "const char *format" ...
.\" .Ft int
.\" .Fn smprintf "const char *format" ...
.Ft int
.Fn asprintf "char **ret" "const char *format" ...
.Fd #include <stdarg.h>
.Ft int
.Fn vprintf "const char *format" "va_list ap"
@ -69,8 +71,8 @@
.Fn vsprintf "char *str" "char *format" "va_list ap"
.Ft int
.Fn vsnprintf "char *str" "size_t size" "const char *format" "va_list ap"
.\" .Ft int
.\" .Fn vsmprintf "const char *format" "va_list ap"
.Ft int
.Fn vasprintf "char **ret" "const char *format" "va_list ap"
.Sh DESCRIPTION
The
.Fn printf
@ -94,45 +96,47 @@ write output to the given output
and
.Fn vsnprintf
write to the character string
.Fa str .
.\" .IR str ;
.\" and
.\" .I smprintf
.\" and
.\" .I vsmprintf
.\" dynamically allocate a new string with
.\" .IR malloc .
.Fa str ;
and
.Fn asprintf
and
.Fn vasprintf
dynamically allocate a new string with
.Xr malloc 3
/
.Xr realloc 3 .
.Pp
These functions write the output under the control of a
.Fa format
string that specifies how subsequent arguments
(or arguments accessed via the variable-length argument facilities of
.Xr stdarg 3 )
are converted for output.
.\" Except for
.\" .I smprintf
.\" and
.\" .IR vsmprintf ,
.\" all of these functions return
.Pp
These functions return
the number of characters printed
(not including the trailing
.Ql \e0
used to end output to strings).
.\" .I Smprintf
.\" and
.\" .I vsmprintf
.\" return a pointer to a string of an appropriate length;
.\" this pointer should be passed to
.\" .I free
.\" to release the associated storage
.\" when it is no longer needed.
.\" If sufficient space is not avaliable,
.\" .I smprintf
.\" and
.\" .I vsmprintf
.\" will return
.\" .SM
.\" .BR
.Pp
.Fn Asprintf
and
.Fn vasprintf
return a pointer to a buffer sufficiently large to hold the
string in the
.Fa ret
argument;
This pointer should be passed to
.Xr free 3
to release the allocated storage when it is no longer needed.
If sufficient space cannot be allocated,
.Fn asprintf
and
.Fn vasprintf
will return -1 and set
.Fa ret
to be a NULL pointer.
.Pp
.Fn Snprintf
and
.Fn vsnprintf
@ -147,6 +151,7 @@ if the return value is greater than or equal to the
.Fa size
argument, the string was too short
and some of the printed characters were discarded.
.Pp
.Fn Sprintf
and
.Fn vsprintf
@ -600,6 +605,15 @@ The functions
and
.Fn vsnprintf
are new to this release.
.Pp
The functions
.Fn asprintf
and
.Fn vasprintf
first appeared in the GNU C library. This implementation is thought
to be compatable but is not derived from the GNU code. This implementation
was written by Peter Wemm <peter@FreeBSD.org> and first appeared in
FreeBSD-2.2.
.Sh BUGS
The conversion formats
.Cm \&%D ,

108
lib/libc/stdio/vasprintf.c Normal file
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@ -0,0 +1,108 @@
/*-
* Copyright (c) 1996 Peter Wemm <peter@freebsd.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_RCS) && !defined(lint)
static char rcsid[] = "$Id$";
#endif /* LIBC_RCS and not lint */
#include <stdio.h>
#include <stdlib.h>
#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#define CHUNK_SPARE 128 /* how much spare to allocate to avoid realloc calls */
struct bufcookie {
char *base; /* start of buffer */
int size;
int left;
};
static int
writehook(cookie, buf, len)
void *cookie;
char *buf;
int len;
{
struct bufcookie *h = (struct bufcookie *)cookie;
if (len == 0)
return 0;
if (len > h->left) {
/* grow malloc region */
h->left = h->left + len + CHUNK_SPARE;
h->size = h->size + len + CHUNK_SPARE;
h->base = realloc(h->base, h->size);
if (h->base == NULL)
return (-1);
}
/* "write" it */
(void)memcpy(h->base + h->size - h->left, buf, len);
h->left -= len;
return (0);
}
int
vasprintf(str, fmt, ap)
char **str;
const char *fmt;
va_list ap;
{
int ret;
FILE *f;
struct bufcookie h;
h.base = malloc(CHUNK_SPARE);
if (h.base == NULL)
return (-1);
h.size = CHUNK_SPARE;
h.left = CHUNK_SPARE;
f = funopen(&h, NULL, writehook, NULL, NULL);
if (f == NULL) {
free(h.base);
return (-1);
}
ret = vfprintf(f, fmt, ap);
fclose(f);
if (ret < 0) {
free(h.base);
return (-1);
}
if (h.base == NULL) /* failed to realloc in writehook */
return (-1);
h.base[h.size - h.left] = '\0';
*str = realloc(h.base, h.size - h.left + 1);
if (*str == NULL) /* failed to realloc it to actual size */
return -1;
return (ret);
}