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Avoid stpncpy

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It’s not worth the porting hassle, and as the glibc manual says,
“this function is generally a poor choice for processing strings”.
* admin/merge-gnulib (GNULIB_MODULES): Remove stpncpy.
* exec/configure.ac: Do not check for stpncpy.
* exec/exec.c (rpl_stpncpy, stpncpy): Remove this replacement.
(exec_0): Properly clear buffer1.  Use memcpy instead of
stpncpy to add the trailing name.  This code is clearly
still suboptimal but efficiency is not that important here
and I tried to minimize the change.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
This commit is contained in:
Paul Eggert
2023-08-12 12:50:15 -07:00
parent f3868cb9d1
commit 5315e6e8d7
7 changed files with 8 additions and 297 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
admin/merge-gnulib
View File

@@ -45,7 +45,7 @@ GNULIB_MODULES='
pathmax pipe2 pselect pthread_sigmask pathmax pipe2 pselect pthread_sigmask
qcopy-acl readlink readlinkat regex qcopy-acl readlink readlinkat regex
sig2str sigdescr_np socklen stat-time std-gnu11 stdbool stdckdint stddef stdio sig2str sigdescr_np socklen stat-time std-gnu11 stdbool stdckdint stddef stdio
stpcpy stpncpy strnlen strnlen strtoimax symlink sys_stat sys_time stpcpy strnlen strnlen strtoimax symlink sys_stat sys_time
tempname time-h time_r time_rz timegm timer-time timespec-add timespec-sub tempname time-h time_r time_rz timegm timer-time timespec-add timespec-sub
update-copyright unlocked-io utimensat update-copyright unlocked-io utimensat
vla warnings year2038 vla warnings year2038

4
exec/configure.ac
View File

@@ -62,8 +62,8 @@ AC_TYPE_SSIZE_T
AC_TYPE_PID_T AC_TYPE_PID_T
AC_HEADER_STDBOOL AC_HEADER_STDBOOL
AC_CHECK_FUNCS([getpagesize stpcpy stpncpy]) AC_CHECK_FUNCS([getpagesize stpcpy])
AC_CHECK_DECLS([stpcpy, stpncpy]) AC_CHECK_DECLS([stpcpy])
AC_CHECK_FUNC([process_vm_readv], AC_CHECK_FUNC([process_vm_readv],
[AC_CHECK_FUNC([process_vm_writev], [AC_CHECK_FUNC([process_vm_writev],
[AC_CHECK_DECL([process_vm_readv], [AC_CHECK_DECL([process_vm_readv],

77
exec/exec.c
View File

@@ -66,74 +66,6 @@ rpl_stpcpy (char *dest, const char *src)
#define stpcpy rpl_stpcpy #define stpcpy rpl_stpcpy
#endif /* !defined HAVE_STPCPY || !defined HAVE_DECL_STPCPY */ #endif /* !defined HAVE_STPCPY || !defined HAVE_DECL_STPCPY */
#if !defined HAVE_STPNCPY || !defined HAVE_DECL_STPNCPY
/* Copy no more than N bytes of SRC to DST, returning a pointer past
the last non-NUL byte written into DST. */
static char *
rpl_stpncpy (char *dest, const char *src, size_t n)
{
char c, *s;
size_t n4;
s = dest;
if (n >= 4)
{
n4 = n >> 2;
for (;;)
{
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
if (--n4 == 0)
goto last_chars;
}
n -= dest - s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return dest;
for (;;)
{
c = *src++;
--n;
*dest++ = c;
if (c == '\0')
break;
if (n == 0)
return dest;
}
zero_fill:
while (n-- > 0)
dest[n] = '\0';
return dest - 1;
}
#define stpncpy rpl_stpncpy
#endif /* !defined HAVE_STPNCPY || !defined HAVE_DECL_STPNCPY */
/* Executable reading functions. /* Executable reading functions.
@@ -1005,13 +937,14 @@ exec_0 (char *name, struct exec_tracee *tracee,
else else
{ {
/* If name is not absolute, then make it relative to TRACEE's /* If name is not absolute, then make it relative to TRACEE's
cwd. Use stpcpy, as sprintf is not reentrant. */ cwd. Do not use sprintf at it is not reentrant and it
mishandles results longer than INT_MAX. */
if (name[0] && name[0] != '/') if (name[0] && name[0] != '/')
{ {
/* Clear `buffer'. */ /* Clear both buffers. */
memset (buffer, 0, sizeof buffer); memset (buffer, 0, sizeof buffer);
memset (buffer1, 0, sizeof buffer); memset (buffer1, 0, sizeof buffer1);
/* Copy over /proc, the PID, and /cwd/. */ /* Copy over /proc, the PID, and /cwd/. */
rewrite = stpcpy (buffer, "/proc/"); rewrite = stpcpy (buffer, "/proc/");
@@ -1042,7 +975,7 @@ exec_0 (char *name, struct exec_tracee *tracee,
rewrite = buffer1 + link_size; rewrite = buffer1 + link_size;
remaining = buffer1 + sizeof buffer1 - rewrite - 1; remaining = buffer1 + sizeof buffer1 - rewrite - 1;
rewrite = stpncpy (rewrite, name, remaining); memcpy (rewrite, name, strnlen (name, remaining));
/* Replace name with buffer1. */ /* Replace name with buffer1. */
#ifndef REENTRANT #ifndef REENTRANT

12
lib/gnulib.mk.in
View File

@@ -157,7 +157,6 @@
# stddef \ # stddef \
# stdio \ # stdio \
# stpcpy \ # stpcpy \
# stpncpy \
# strnlen \ # strnlen \
# strtoimax \ # strtoimax \
# symlink \ # symlink \
@@ -336,7 +335,6 @@ GL_COND_OBJ_SIGDESCR_NP_CONDITION = @GL_COND_OBJ_SIGDESCR_NP_CONDITION@
GL_COND_OBJ_STDIO_READ_CONDITION = @GL_COND_OBJ_STDIO_READ_CONDITION@ GL_COND_OBJ_STDIO_READ_CONDITION = @GL_COND_OBJ_STDIO_READ_CONDITION@
GL_COND_OBJ_STDIO_WRITE_CONDITION = @GL_COND_OBJ_STDIO_WRITE_CONDITION@ GL_COND_OBJ_STDIO_WRITE_CONDITION = @GL_COND_OBJ_STDIO_WRITE_CONDITION@
GL_COND_OBJ_STPCPY_CONDITION = @GL_COND_OBJ_STPCPY_CONDITION@ GL_COND_OBJ_STPCPY_CONDITION = @GL_COND_OBJ_STPCPY_CONDITION@
GL_COND_OBJ_STPNCPY_CONDITION = @GL_COND_OBJ_STPNCPY_CONDITION@
GL_COND_OBJ_STRNLEN_CONDITION = @GL_COND_OBJ_STRNLEN_CONDITION@ GL_COND_OBJ_STRNLEN_CONDITION = @GL_COND_OBJ_STRNLEN_CONDITION@
GL_COND_OBJ_STRTOIMAX_CONDITION = @GL_COND_OBJ_STRTOIMAX_CONDITION@ GL_COND_OBJ_STRTOIMAX_CONDITION = @GL_COND_OBJ_STRTOIMAX_CONDITION@
GL_COND_OBJ_STRTOLL_CONDITION = @GL_COND_OBJ_STRTOLL_CONDITION@ GL_COND_OBJ_STRTOLL_CONDITION = @GL_COND_OBJ_STRTOLL_CONDITION@
@@ -3454,16 +3452,6 @@ endif
endif endif
## end gnulib module stpcpy ## end gnulib module stpcpy
## begin gnulib module stpncpy
ifeq (,$(OMIT_GNULIB_MODULE_stpncpy))
ifneq (,$(GL_COND_OBJ_STPNCPY_CONDITION))
libgnu_a_SOURCES += stpncpy.c
endif
endif
## end gnulib module stpncpy
## begin gnulib module string ## begin gnulib module string
ifeq (,$(OMIT_GNULIB_MODULE_string)) ifeq (,$(OMIT_GNULIB_MODULE_string))

92
lib/stpncpy.c
View File

@@ -1,92 +0,0 @@
/* Copyright (C) 1993, 1995-1997, 2002-2003, 2005-2007, 2009-2023 Free Software
* Foundation, Inc.
NOTE: The canonical source of this file is maintained with the GNU C Library.
Bugs can be reported to bug-glibc@gnu.org.
This file 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.
This file 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 this program. If not, see <https://www.gnu.org/licenses/>. */
/* This is almost copied from strncpy.c, written by Torbjorn Granlund. */
#include <config.h>
/* Specification. */
#include <string.h>
#ifndef weak_alias
# define __stpncpy stpncpy
#endif
/* Copy no more than N bytes of SRC to DST, returning a pointer past the
last non-NUL byte written into DST. */
char *
(__stpncpy) (char *dest, const char *src, size_t n)
{
char c;
char *s = dest;
if (n >= 4)
{
size_t n4 = n >> 2;
for (;;)
{
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
c = *src++;
*dest++ = c;
if (c == '\0')
break;
if (--n4 == 0)
goto last_chars;
}
n -= dest - s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return dest;
for (;;)
{
c = *src++;
--n;
*dest++ = c;
if (c == '\0')
break;
if (n == 0)
return dest;
}
zero_fill:
while (n-- > 0)
dest[n] = '\0';
return dest - 1;
}
#ifdef weak_alias
weak_alias (__stpncpy, stpncpy)
#endif

10
m4/gnulib-comp.m4
View File

@@ -181,7 +181,6 @@ AC_DEFUN([gl_EARLY],
gl_STDIO_H_EARLY gl_STDIO_H_EARLY
# Code from module stdlib: # Code from module stdlib:
# Code from module stpcpy: # Code from module stpcpy:
# Code from module stpncpy:
# Code from module string: # Code from module string:
# Code from module strnlen: # Code from module strnlen:
# Code from module strtoimax: # Code from module strtoimax:
@@ -567,13 +566,6 @@ AC_DEFUN([gl_INIT],
gl_PREREQ_STPCPY gl_PREREQ_STPCPY
]) ])
gl_STRING_MODULE_INDICATOR([stpcpy]) gl_STRING_MODULE_INDICATOR([stpcpy])
gl_FUNC_STPNCPY
gl_CONDITIONAL([GL_COND_OBJ_STPNCPY],
[test $HAVE_STPNCPY = 0 || test $REPLACE_STPNCPY = 1])
AM_COND_IF([GL_COND_OBJ_STPNCPY], [
gl_PREREQ_STPNCPY
])
gl_STRING_MODULE_INDICATOR([stpncpy])
gl_STRING_H gl_STRING_H
gl_STRING_H_REQUIRE_DEFAULTS gl_STRING_H_REQUIRE_DEFAULTS
AC_PROG_MKDIR_P AC_PROG_MKDIR_P
@@ -1422,7 +1414,6 @@ AC_DEFUN([gl_FILE_LIST], [
lib/stdio.in.h lib/stdio.in.h
lib/stdlib.in.h lib/stdlib.in.h
lib/stpcpy.c lib/stpcpy.c
lib/stpncpy.c
lib/str-two-way.h lib/str-two-way.h
lib/strftime.h lib/strftime.h
lib/string.in.h lib/string.in.h
@@ -1569,7 +1560,6 @@ AC_DEFUN([gl_FILE_LIST], [
m4/stdio_h.m4 m4/stdio_h.m4
m4/stdlib_h.m4 m4/stdlib_h.m4
m4/stpcpy.m4 m4/stpcpy.m4
m4/stpncpy.m4
m4/string_h.m4 m4/string_h.m4
m4/strnlen.m4 m4/strnlen.m4
m4/strtoimax.m4 m4/strtoimax.m4

108
m4/stpncpy.m4
View File

@@ -1,108 +0,0 @@
# stpncpy.m4 serial 22
dnl Copyright (C) 2002-2003, 2005-2007, 2009-2023 Free Software Foundation,
dnl Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_FUNC_STPNCPY],
[
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
dnl Persuade glibc <string.h> to declare stpncpy().
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
dnl The stpncpy() declaration in lib/string.in.h uses 'restrict'.
AC_REQUIRE([AC_C_RESTRICT])
AC_REQUIRE([gl_STRING_H_DEFAULTS])
dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function
dnl declared in <string.h>. Its side effects are the same as those
dnl of strncpy():
dnl stpncpy (dest, src, n)
dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src,
dnl and the remaining bytes being NULs. However, the return value is
dnl in glibc: dest + min(strlen(src),n)
dnl in AIX: dest + max(0,n-1)
dnl Only the glibc return value is useful in practice.
AC_CHECK_DECLS_ONCE([stpncpy])
gl_CHECK_FUNCS_ANDROID([stpncpy], [[#include <string.h>]])
if test $ac_cv_func_stpncpy = yes; then
AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [
AC_RUN_IFELSE(
[AC_LANG_SOURCE([[
#include <stdlib.h>
#include <string.h> /* for strcpy */
/* The stpncpy prototype is missing in <string.h> on AIX 4. */
#if !HAVE_DECL_STPNCPY
extern
# ifdef __cplusplus
"C"
# endif
char *stpncpy (char *dest, const char *src, size_t n);
#endif
int main ()
{
int result = 0;
const char *src = "Hello";
char dest[10];
/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */
{
strcpy (dest, "\377\377\377\377\377\377");
if (stpncpy (dest, src, 2) != dest + 2)
result |= 1;
}
/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */
{
strcpy (dest, "\377\377\377\377\377\377");
if (stpncpy (dest, src, 5) != dest + 5)
result |= 2;
}
/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */
{
strcpy (dest, "\377\377\377\377\377\377");
if (stpncpy (dest, src, 7) != dest + 5)
result |= 4;
}
return result;
}
]])],
[gl_cv_func_stpncpy=yes],
[gl_cv_func_stpncpy=no],
[dnl Guess yes on glibc systems and musl systems.
AC_EGREP_CPP([Thanks for using GNU], [
#include <features.h>
#ifdef __GNU_LIBRARY__
Thanks for using GNU
#endif
], [gl_cv_func_stpncpy="guessing yes"],
[case "$host_os" in
*-musl* | midipix*) gl_cv_func_stpncpy="guessing yes" ;;
*) gl_cv_func_stpncpy="$gl_cross_guess_normal" ;;
esac
])
])
])
case "$gl_cv_func_stpncpy" in
*yes)
AC_DEFINE([HAVE_STPNCPY], [1],
[Define if you have the stpncpy() function and it works.])
;;
*)
REPLACE_STPNCPY=1
;;
esac
else
HAVE_STPNCPY=0
case "$gl_cv_onwards_func_stpncpy" in
future*) REPLACE_STPNCPY=1 ;;
esac
fi
])
# Prerequisites of lib/stpncpy.c.
AC_DEFUN([gl_PREREQ_STPNCPY], [
:
])