From: Paul Eggert Date: Sat, 12 Aug 2023 19:50:15 +0000 (-0700) Subject: Avoid stpncpy X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5315e6e8d7e7233d54cce2b4c1bc8cf3b7acf4dc;p=emacs.git 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. --- diff --git a/admin/merge-gnulib b/admin/merge-gnulib index f64c0670bcf..2a713beb01a 100755 --- a/admin/merge-gnulib +++ b/admin/merge-gnulib @@ -45,7 +45,7 @@ GNULIB_MODULES=' pathmax pipe2 pselect pthread_sigmask qcopy-acl readlink readlinkat regex 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 update-copyright unlocked-io utimensat vla warnings year2038 diff --git a/exec/configure.ac b/exec/configure.ac index e78d8ebea90..180c200d13d 100644 --- a/exec/configure.ac +++ b/exec/configure.ac @@ -62,8 +62,8 @@ AC_TYPE_SSIZE_T AC_TYPE_PID_T AC_HEADER_STDBOOL -AC_CHECK_FUNCS([getpagesize stpcpy stpncpy]) -AC_CHECK_DECLS([stpcpy, stpncpy]) +AC_CHECK_FUNCS([getpagesize stpcpy]) +AC_CHECK_DECLS([stpcpy]) AC_CHECK_FUNC([process_vm_readv], [AC_CHECK_FUNC([process_vm_writev], [AC_CHECK_DECL([process_vm_readv], diff --git a/exec/exec.c b/exec/exec.c index 935c94a59af..dae05755675 100644 --- a/exec/exec.c +++ b/exec/exec.c @@ -66,74 +66,6 @@ rpl_stpcpy (char *dest, const char *src) #define stpcpy rpl_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. @@ -1005,13 +937,14 @@ exec_0 (char *name, struct exec_tracee *tracee, else { /* 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] != '/') { - /* Clear `buffer'. */ + /* Clear both buffers. */ memset (buffer, 0, sizeof buffer); - memset (buffer1, 0, sizeof buffer); + memset (buffer1, 0, sizeof buffer1); /* Copy over /proc, the PID, and /cwd/. */ rewrite = stpcpy (buffer, "/proc/"); @@ -1042,7 +975,7 @@ exec_0 (char *name, struct exec_tracee *tracee, rewrite = buffer1 + link_size; remaining = buffer1 + sizeof buffer1 - rewrite - 1; - rewrite = stpncpy (rewrite, name, remaining); + memcpy (rewrite, name, strnlen (name, remaining)); /* Replace name with buffer1. */ #ifndef REENTRANT diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in index 78ecb544c6e..785bdc70c5c 100644 --- a/lib/gnulib.mk.in +++ b/lib/gnulib.mk.in @@ -157,7 +157,6 @@ # stddef \ # stdio \ # stpcpy \ -# stpncpy \ # strnlen \ # strtoimax \ # 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_WRITE_CONDITION = @GL_COND_OBJ_STDIO_WRITE_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_STRTOIMAX_CONDITION = @GL_COND_OBJ_STRTOIMAX_CONDITION@ GL_COND_OBJ_STRTOLL_CONDITION = @GL_COND_OBJ_STRTOLL_CONDITION@ @@ -3454,16 +3452,6 @@ endif endif ## 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 ifeq (,$(OMIT_GNULIB_MODULE_string)) diff --git a/lib/stpncpy.c b/lib/stpncpy.c deleted file mode 100644 index d1422a927df..00000000000 --- a/lib/stpncpy.c +++ /dev/null @@ -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 . */ - -/* This is almost copied from strncpy.c, written by Torbjorn Granlund. */ - -#include - -/* Specification. */ -#include - -#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 diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4 index 72adcf90d5e..3382e9bc241 100644 --- a/m4/gnulib-comp.m4 +++ b/m4/gnulib-comp.m4 @@ -181,7 +181,6 @@ AC_DEFUN([gl_EARLY], gl_STDIO_H_EARLY # Code from module stdlib: # Code from module stpcpy: - # Code from module stpncpy: # Code from module string: # Code from module strnlen: # Code from module strtoimax: @@ -567,13 +566,6 @@ AC_DEFUN([gl_INIT], gl_PREREQ_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_REQUIRE_DEFAULTS AC_PROG_MKDIR_P @@ -1422,7 +1414,6 @@ AC_DEFUN([gl_FILE_LIST], [ lib/stdio.in.h lib/stdlib.in.h lib/stpcpy.c - lib/stpncpy.c lib/str-two-way.h lib/strftime.h lib/string.in.h @@ -1569,7 +1560,6 @@ AC_DEFUN([gl_FILE_LIST], [ m4/stdio_h.m4 m4/stdlib_h.m4 m4/stpcpy.m4 - m4/stpncpy.m4 m4/string_h.m4 m4/strnlen.m4 m4/strtoimax.m4 diff --git a/m4/stpncpy.m4 b/m4/stpncpy.m4 deleted file mode 100644 index 073607004be..00000000000 --- a/m4/stpncpy.m4 +++ /dev/null @@ -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 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 . 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 ]]) - if test $ac_cv_func_stpncpy = yes; then - AC_CACHE_CHECK([for working stpncpy], [gl_cv_func_stpncpy], [ - AC_RUN_IFELSE( - [AC_LANG_SOURCE([[ -#include -#include /* for strcpy */ -/* The stpncpy prototype is missing in on AIX 4. */ -#if !HAVE_DECL_STPNCPY -extern -# ifdef __cplusplus -"C" -# endif -char *stpncpy (char *dest, const char *src, size_t n); -#endif -int main () -{ - int result = 0; - const char *src = "Hello"; - char dest[10]; - /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+1 here. */ - { - strcpy (dest, "\377\377\377\377\377\377"); - if (stpncpy (dest, src, 2) != dest + 2) - result |= 1; - } - /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+4 here. */ - { - strcpy (dest, "\377\377\377\377\377\377"); - if (stpncpy (dest, src, 5) != dest + 5) - result |= 2; - } - /* AIX 4.3.3 and AIX 5.1 stpncpy() returns dest+6 here. */ - { - strcpy (dest, "\377\377\377\377\377\377"); - if (stpncpy (dest, src, 7) != dest + 5) - result |= 4; - } - return result; -} -]])], - [gl_cv_func_stpncpy=yes], - [gl_cv_func_stpncpy=no], - [dnl Guess yes on glibc systems and musl systems. - AC_EGREP_CPP([Thanks for using GNU], [ -#include -#ifdef __GNU_LIBRARY__ - Thanks for using GNU -#endif -], [gl_cv_func_stpncpy="guessing yes"], - [case "$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], [ - : -])