From 772a6b7e3fa813310c645f81e83842f598bbc2e7 Mon Sep 17 00:00:00 2001 From: Bruno Haible Date: Sat, 31 Jul 2010 15:20:35 +0200 Subject: [PATCH 1/1] linkat: Work around AIX 7.1 bug. --- ChangeLog | 11 ++++++++ doc/posix-functions/linkat.texi | 4 +++ lib/linkat.c | 28 +++++++++++++++++++-- m4/linkat.m4 | 56 +++++++++++++++++++++++++++++++++++++++-- 4 files changed, 95 insertions(+), 4 deletions(-) diff --git a/ChangeLog b/ChangeLog index e90bfe899..032df8ef2 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,16 @@ 2010-07-31 Bruno Haible + linkat: Work around AIX 7.1 bug. + * m4/linkat.m4 (gl_FUNC_LINKAT): Require AC_CANONICAL_HOST. Test + whether linkat handles trailing slash correctly. If not, replace linkat + and define LINKAT_TRAILING_SLASH_BUG. + * lib/linkat.c (rpl_linkat): If LINKAT_TRAILING_SLASH_BUG is defined, + check whether (fd1,file1) points to a directory if file1 or file2 ends + in a slash. Code taken from lib/link.c. + * doc/posix-functions/linkat.texi: Mention trailing slash bug. + +2010-07-31 Bruno Haible + Correctly determine whether pow is available in libc on AIX 7 with xlc. * m4/mathfunc.m4 (gl_MATHFUNC): Actually use the 'funcptr' variable. This disables an xlc optimization that was causing wrong test results. diff --git a/doc/posix-functions/linkat.texi b/doc/posix-functions/linkat.texi index 1fe5434e9..1d9cc89a6 100644 --- a/doc/posix-functions/linkat.texi +++ b/doc/posix-functions/linkat.texi @@ -13,6 +13,10 @@ This function is missing on some platforms: glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 10, Cygwin 1.5.x, mingw, Interix 3.5, BeOS. But the replacement function is not safe to be used in libraries and is not multithread-safe. +@item +This function fails to reject trailing slashes on non-directories on +some platforms: +AIX 7.1. @end itemize Portability problems not fixed by Gnulib: diff --git a/lib/linkat.c b/lib/linkat.c index 30a61e938..73b1e3ed6 100644 --- a/lib/linkat.c +++ b/lib/linkat.c @@ -262,14 +262,38 @@ linkat_follow (int fd1, char const *file1, int fd2, char const *file2) int rpl_linkat (int fd1, char const *file1, int fd2, char const *file2, int flag) { - if (!flag) - return linkat (fd1, file1, fd2, file2, flag); if (flag & ~AT_SYMLINK_FOLLOW) { errno = EINVAL; return -1; } +#if LINKAT_TRAILING_SLASH_BUG + /* Reject trailing slashes on non-directories. */ + { + size_t len1 = strlen (file1); + size_t len2 = strlen (file2); + if ((len1 && file1[len1 - 1] == '/') + || (len2 && file2[len2 - 1] == '/')) + { + /* Let linkat() decide whether hard-linking directories is legal. + If fstatat() fails, then linkat() should fail for the same reason; + if fstatat() succeeds, require a directory. */ + struct stat st; + if (fstatat (fd1, file1, &st, flag ? 0 : AT_SYMLINK_NOFOLLOW)) + return -1; + if (!S_ISDIR (st.st_mode)) + { + errno = ENOTDIR; + return -1; + } + } + } +#endif + + if (!flag) + return linkat (fd1, file1, fd2, file2, flag); + /* Cache the information on whether the system call really works. */ { static int have_follow_really; /* 0 = unknown, 1 = yes, -1 = no */ diff --git a/m4/linkat.m4 b/m4/linkat.m4 index 630ce8906..c0b2729be 100644 --- a/m4/linkat.m4 +++ b/m4/linkat.m4 @@ -1,4 +1,4 @@ -# serial 2 +# serial 3 # See if we need to provide linkat replacement. dnl Copyright (C) 2009-2010 Free Software Foundation, Inc. @@ -15,6 +15,7 @@ AC_DEFUN([gl_FUNC_LINKAT], AC_REQUIRE([gl_FUNC_LINK_FOLLOWS_SYMLINK]) AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CHECK_FUNCS_ONCE([linkat symlink]) AC_CHECK_HEADERS_ONCE([sys/param.h]) if test $ac_cv_func_linkat = no; then @@ -39,9 +40,60 @@ choke me [gl_cv_func_linkat_follow=yes], [gl_cv_func_linkat_follow="need runtime check"]) rm -rf conftest.f1 conftest.f2]) - if test "$gl_cv_func_linkat_follow" != yes; then + AC_CACHE_CHECK([whether linkat handles trailing slash correctly], + [gl_cv_func_linkat_slash], + [rm -rf conftest.a conftest.b conftest.c conftest.d + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include + #include + #include + #include + ]], + [[int fd; + int err; + int ret; + /* Create a regular file. */ + fd = open ("conftest.a", O_CREAT | O_EXCL | O_WRONLY, 0600); + if (fd < 0) + return 1; + if (write (fd, "hello", 5) < 5) + return 2; + if (close (fd) < 0) + return 3; + /* Test whether hard links are supported on the current + device. */ + if (linkat (AT_FDCWD, "conftest.a", AT_FDCWD, "conftest.b", + AT_SYMLINK_FOLLOW) < 0) + return 0; + /* Test whether a trailing "/" is treated like "/.". */ + if (linkat (AT_FDCWD, "conftest.a/", AT_FDCWD, "conftest.c", + AT_SYMLINK_FOLLOW) == 0) + return 4; + if (linkat (AT_FDCWD, "conftest.a", AT_FDCWD, "conftest.d/", + AT_SYMLINK_FOLLOW) == 0) + return 5; + return 0; + ]])], + [gl_cv_func_linkat_slash=yes], + [gl_cv_func_linkat_slash=no], + [# Guess yes on glibc systems, no otherwise. + case "$host_os" in + *-gnu*) gl_cv_func_linkat_slash="guessing yes";; + *) gl_cv_func_linkat_slash="guessing no";; + esac + ]) + rm -rf conftest.a conftest.b conftest.c conftest.d]) + case "$gl_cv_func_linkat_slash" in + *yes) gl_linkat_slash_bug=0 ;; + *) gl_linkat_slash_bug=1 ;; + esac + if test "$gl_cv_func_linkat_follow" != yes \ + || test $gl_linkat_slash_bug = 1; then REPLACE_LINKAT=1 AC_LIBOBJ([linkat]) + AC_DEFINE_UNQUOTED([LINKAT_TRAILING_SLASH_BUG], [$gl_linkat_slash_bug], + [Define to 1 if linkat fails to recognize a trailing slash.]) fi fi ]) -- 2.11.0