Avoid stpncpy
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
parent
f3868cb9d1
commit
5315e6e8d7
7 changed files with 8 additions and 297 deletions
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@ -45,7 +45,7 @@ GNULIB_MODULES='
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pathmax pipe2 pselect pthread_sigmask
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qcopy-acl readlink readlinkat regex
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sig2str sigdescr_np socklen stat-time std-gnu11 stdbool stdckdint stddef stdio
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stpcpy stpncpy strnlen strnlen strtoimax symlink sys_stat sys_time
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stpcpy strnlen strnlen strtoimax symlink sys_stat sys_time
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tempname time-h time_r time_rz timegm timer-time timespec-add timespec-sub
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update-copyright unlocked-io utimensat
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vla warnings year2038
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@ -62,8 +62,8 @@ AC_TYPE_SSIZE_T
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AC_TYPE_PID_T
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AC_HEADER_STDBOOL
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AC_CHECK_FUNCS([getpagesize stpcpy stpncpy])
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AC_CHECK_DECLS([stpcpy, stpncpy])
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AC_CHECK_FUNCS([getpagesize stpcpy])
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AC_CHECK_DECLS([stpcpy])
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AC_CHECK_FUNC([process_vm_readv],
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[AC_CHECK_FUNC([process_vm_writev],
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[AC_CHECK_DECL([process_vm_readv],
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77
exec/exec.c
77
exec/exec.c
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@ -66,74 +66,6 @@ rpl_stpcpy (char *dest, const char *src)
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#define stpcpy rpl_stpcpy
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#endif /* !defined HAVE_STPCPY || !defined HAVE_DECL_STPCPY */
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#if !defined HAVE_STPNCPY || !defined HAVE_DECL_STPNCPY
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/* Copy no more than N bytes of SRC to DST, returning a pointer past
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the last non-NUL byte written into DST. */
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static char *
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rpl_stpncpy (char *dest, const char *src, size_t n)
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{
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char c, *s;
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size_t n4;
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s = dest;
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if (n >= 4)
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{
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n4 = n >> 2;
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for (;;)
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{
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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if (--n4 == 0)
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goto last_chars;
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}
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n -= dest - s;
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goto zero_fill;
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}
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last_chars:
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n &= 3;
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if (n == 0)
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return dest;
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for (;;)
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{
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c = *src++;
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--n;
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*dest++ = c;
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if (c == '\0')
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break;
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if (n == 0)
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return dest;
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}
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zero_fill:
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while (n-- > 0)
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dest[n] = '\0';
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return dest - 1;
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}
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#define stpncpy rpl_stpncpy
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#endif /* !defined HAVE_STPNCPY || !defined HAVE_DECL_STPNCPY */
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/* Executable reading functions.
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@ -1005,13 +937,14 @@ exec_0 (char *name, struct exec_tracee *tracee,
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else
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{
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/* If name is not absolute, then make it relative to TRACEE's
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cwd. Use stpcpy, as sprintf is not reentrant. */
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cwd. Do not use sprintf at it is not reentrant and it
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mishandles results longer than INT_MAX. */
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if (name[0] && name[0] != '/')
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{
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/* Clear `buffer'. */
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/* Clear both buffers. */
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memset (buffer, 0, sizeof buffer);
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memset (buffer1, 0, sizeof buffer);
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memset (buffer1, 0, sizeof buffer1);
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/* Copy over /proc, the PID, and /cwd/. */
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rewrite = stpcpy (buffer, "/proc/");
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@ -1042,7 +975,7 @@ exec_0 (char *name, struct exec_tracee *tracee,
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rewrite = buffer1 + link_size;
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remaining = buffer1 + sizeof buffer1 - rewrite - 1;
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rewrite = stpncpy (rewrite, name, remaining);
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memcpy (rewrite, name, strnlen (name, remaining));
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/* Replace name with buffer1. */
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#ifndef REENTRANT
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@ -157,7 +157,6 @@
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# stddef \
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# stdio \
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# stpcpy \
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# stpncpy \
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# strnlen \
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# strtoimax \
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# symlink \
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@ -336,7 +335,6 @@ GL_COND_OBJ_SIGDESCR_NP_CONDITION = @GL_COND_OBJ_SIGDESCR_NP_CONDITION@
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GL_COND_OBJ_STDIO_READ_CONDITION = @GL_COND_OBJ_STDIO_READ_CONDITION@
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GL_COND_OBJ_STDIO_WRITE_CONDITION = @GL_COND_OBJ_STDIO_WRITE_CONDITION@
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GL_COND_OBJ_STPCPY_CONDITION = @GL_COND_OBJ_STPCPY_CONDITION@
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GL_COND_OBJ_STPNCPY_CONDITION = @GL_COND_OBJ_STPNCPY_CONDITION@
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GL_COND_OBJ_STRNLEN_CONDITION = @GL_COND_OBJ_STRNLEN_CONDITION@
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GL_COND_OBJ_STRTOIMAX_CONDITION = @GL_COND_OBJ_STRTOIMAX_CONDITION@
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GL_COND_OBJ_STRTOLL_CONDITION = @GL_COND_OBJ_STRTOLL_CONDITION@
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@ -3454,16 +3452,6 @@ endif
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endif
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## end gnulib module stpcpy
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## begin gnulib module stpncpy
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ifeq (,$(OMIT_GNULIB_MODULE_stpncpy))
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ifneq (,$(GL_COND_OBJ_STPNCPY_CONDITION))
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libgnu_a_SOURCES += stpncpy.c
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endif
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endif
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## end gnulib module stpncpy
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## begin gnulib module string
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ifeq (,$(OMIT_GNULIB_MODULE_string))
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@ -1,92 +0,0 @@
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/* Copyright (C) 1993, 1995-1997, 2002-2003, 2005-2007, 2009-2023 Free Software
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* Foundation, Inc.
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NOTE: The canonical source of this file is maintained with the GNU C Library.
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Bugs can be reported to bug-glibc@gnu.org.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* This is almost copied from strncpy.c, written by Torbjorn Granlund. */
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#include <config.h>
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/* Specification. */
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#include <string.h>
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#ifndef weak_alias
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# define __stpncpy stpncpy
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#endif
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/* Copy no more than N bytes of SRC to DST, returning a pointer past the
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last non-NUL byte written into DST. */
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char *
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(__stpncpy) (char *dest, const char *src, size_t n)
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{
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char c;
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char *s = dest;
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if (n >= 4)
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{
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size_t n4 = n >> 2;
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for (;;)
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{
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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if (--n4 == 0)
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goto last_chars;
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}
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n -= dest - s;
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goto zero_fill;
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}
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last_chars:
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n &= 3;
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if (n == 0)
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return dest;
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for (;;)
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{
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c = *src++;
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--n;
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*dest++ = c;
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if (c == '\0')
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break;
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if (n == 0)
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return dest;
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}
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zero_fill:
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while (n-- > 0)
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dest[n] = '\0';
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return dest - 1;
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}
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#ifdef weak_alias
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weak_alias (__stpncpy, stpncpy)
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#endif
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@ -181,7 +181,6 @@ AC_DEFUN([gl_EARLY],
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gl_STDIO_H_EARLY
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# Code from module stdlib:
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# Code from module stpcpy:
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# Code from module stpncpy:
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# Code from module string:
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# Code from module strnlen:
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# Code from module strtoimax:
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@ -567,13 +566,6 @@ AC_DEFUN([gl_INIT],
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gl_PREREQ_STPCPY
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])
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gl_STRING_MODULE_INDICATOR([stpcpy])
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gl_FUNC_STPNCPY
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gl_CONDITIONAL([GL_COND_OBJ_STPNCPY],
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[test $HAVE_STPNCPY = 0 || test $REPLACE_STPNCPY = 1])
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AM_COND_IF([GL_COND_OBJ_STPNCPY], [
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gl_PREREQ_STPNCPY
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])
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gl_STRING_MODULE_INDICATOR([stpncpy])
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gl_STRING_H
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gl_STRING_H_REQUIRE_DEFAULTS
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AC_PROG_MKDIR_P
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@ -1422,7 +1414,6 @@ AC_DEFUN([gl_FILE_LIST], [
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lib/stdio.in.h
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lib/stdlib.in.h
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lib/stpcpy.c
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lib/stpncpy.c
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lib/str-two-way.h
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lib/strftime.h
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lib/string.in.h
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@ -1569,7 +1560,6 @@ AC_DEFUN([gl_FILE_LIST], [
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m4/stdio_h.m4
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m4/stdlib_h.m4
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m4/stpcpy.m4
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m4/stpncpy.m4
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m4/string_h.m4
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m4/strnlen.m4
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m4/strtoimax.m4
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108
m4/stpncpy.m4
108
m4/stpncpy.m4
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@ -1,108 +0,0 @@
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# stpncpy.m4 serial 22
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dnl Copyright (C) 2002-2003, 2005-2007, 2009-2023 Free Software Foundation,
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dnl Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_FUNC_STPNCPY],
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[
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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dnl Persuade glibc <string.h> to declare stpncpy().
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AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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dnl The stpncpy() declaration in lib/string.in.h uses 'restrict'.
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AC_REQUIRE([AC_C_RESTRICT])
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AC_REQUIRE([gl_STRING_H_DEFAULTS])
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dnl Both glibc and AIX (4.3.3, 5.1) have an stpncpy() function
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dnl declared in <string.h>. Its side effects are the same as those
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dnl of strncpy():
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dnl stpncpy (dest, src, n)
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dnl overwrites dest[0..n-1], min(strlen(src),n) bytes coming from src,
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dnl and the remaining bytes being NULs. However, the return value is
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dnl in glibc: dest + min(strlen(src),n)
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dnl in AIX: dest + max(0,n-1)
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dnl Only the glibc return value is useful in practice.
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AC_CHECK_DECLS_ONCE([stpncpy])
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gl_CHECK_FUNCS_ANDROID([stpncpy], [[#include <string.h>]])
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if test $ac_cv_func_stpncpy = yes; then
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AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [
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AC_RUN_IFELSE(
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[AC_LANG_SOURCE([[
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#include <stdlib.h>
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#include <string.h> /* for strcpy */
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/* The stpncpy prototype is missing in <string.h> on AIX 4. */
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#if !HAVE_DECL_STPNCPY
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extern
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# ifdef __cplusplus
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"C"
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# endif
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char *stpncpy (char *dest, const char *src, size_t n);
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#endif
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int main ()
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{
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int result = 0;
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const char *src = "Hello";
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char dest[10];
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/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */
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{
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strcpy (dest, "\377\377\377\377\377\377");
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if (stpncpy (dest, src, 2) != dest + 2)
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result |= 1;
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}
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/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */
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{
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strcpy (dest, "\377\377\377\377\377\377");
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if (stpncpy (dest, src, 5) != dest + 5)
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result |= 2;
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}
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/* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */
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{
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strcpy (dest, "\377\377\377\377\377\377");
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if (stpncpy (dest, src, 7) != dest + 5)
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result |= 4;
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}
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return result;
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}
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]])],
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[gl_cv_func_stpncpy=yes],
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[gl_cv_func_stpncpy=no],
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[dnl Guess yes on glibc systems and musl systems.
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AC_EGREP_CPP([Thanks for using GNU], [
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#include <features.h>
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#ifdef __GNU_LIBRARY__
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Thanks for using GNU
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#endif
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], [gl_cv_func_stpncpy="guessing yes"],
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[case "$host_os" in
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*-musl* | midipix*) gl_cv_func_stpncpy="guessing yes" ;;
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*) gl_cv_func_stpncpy="$gl_cross_guess_normal" ;;
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esac
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])
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])
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])
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case "$gl_cv_func_stpncpy" in
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*yes)
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AC_DEFINE([HAVE_STPNCPY], [1],
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[Define if you have the stpncpy() function and it works.])
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;;
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*)
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REPLACE_STPNCPY=1
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;;
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esac
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else
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HAVE_STPNCPY=0
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case "$gl_cv_onwards_func_stpncpy" in
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future*) REPLACE_STPNCPY=1 ;;
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esac
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fi
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])
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# Prerequisites of lib/stpncpy.c.
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AC_DEFUN([gl_PREREQ_STPNCPY], [
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:
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])
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Loading…
Add table
Reference in a new issue