From: Eric Blake Date: Wed, 23 Sep 2009 20:51:29 +0000 (-0600) Subject: same-inode: make SAME_INODE tri-state, to port to mingw X-Git-Tag: v0.1~5422 X-Git-Url: http://erislabs.net/gitweb/?p=gnulib.git;a=commitdiff_plain;h=b5eb8386645bf1bcfafa63c729ff9a86454def87 same-inode: make SAME_INODE tri-state, to port to mingw Mingw has the annoying habit (already documented in doc/posix-functions/*stat) that st_ino is always 0. This means that naive uses of SAME_INODE(a,b) would succeed, even on distinct files. Here's an analysis of all gnulib modules that used the macro before this commit: chdir-safer is safe - SAME_INODE protected by HAVE_READLINK cycle-check - mingw has no dir hard links and no symlinks, so no directory cycles can occur, and we should ignore -1 fts - SAME_INODE protected by FTS_DEBUG hash-triple - using -1 gives more hash collisions, but the results are still correct openat-proc - SAME_INODE protected by stat("/proc/self") same - no dir cycles, so files are only same with identical name link-follow.m4 - configure test already correct on mingw test-canonicalize* - test already passes on mingw test-[l]stat - test already passes on mingw * NEWS: Mention this change. * lib/same-inode.h (same-inode.h): Recognize mingw limitation of st_ino always being 0. * lib/cycle-check.h (CYCLE_CHECK_REFLECT_CHDIR_UP): Update caller. * lib/cycle-check.c (cycle_check): Likewise. * lib/same.c (same_name): Likewise. Signed-off-by: Eric Blake --- diff --git a/ChangeLog b/ChangeLog index 2baa04495..bed42c53f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2009-09-23 Eric Blake + same-inode: make SAME_INODE tri-state, to port to mingw + * NEWS: Mention this change. + * lib/same-inode.h (same-inode.h): Recognize mingw limitation of + st_ino always being 0. + * lib/cycle-check.h (CYCLE_CHECK_REFLECT_CHDIR_UP): Update caller. + * lib/cycle-check.c (cycle_check): Likewise. + * lib/same.c (same_name): Likewise. + lstat: avoid mingw compilation error * m4/lstat.m4 (gl_FUNC_LSTAT): Avoid duplicate calls to AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, and deal with missing diff --git a/NEWS b/NEWS index 62c631f1e..87fc884f3 100644 --- a/NEWS +++ b/NEWS @@ -6,6 +6,9 @@ User visible incompatible changes Date Modules Changes +2009-09-23 same-inode The macro SAME_INODE is now tri-state, adding -1 + for unknown. + 2009-09-16 canonicalize-lgpl The include file is changed from "canonicalize.h" to . diff --git a/lib/cycle-check.c b/lib/cycle-check.c index e120460e6..a5b6df1e5 100644 --- a/lib/cycle-check.c +++ b/lib/cycle-check.c @@ -1,6 +1,7 @@ /* help detect directory cycles efficiently - Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc. + Copyright (C) 2003, 2004, 2005, 2006, 2009 Free Software + Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -62,7 +63,7 @@ cycle_check (struct cycle_check_state *state, struct stat const *sb) /* If the current directory ever happens to be the same as the one we last recorded for the cycle detection, then it's obviously part of a cycle. */ - if (state->chdir_counter && SAME_INODE (*sb, state->dev_ino)) + if (state->chdir_counter && SAME_INODE (*sb, state->dev_ino) == 1) return true; /* If the number of `descending' chdir calls is a power of two, diff --git a/lib/cycle-check.h b/lib/cycle-check.h index ee3bf214b..ea9b9c4f0 100644 --- a/lib/cycle-check.h +++ b/lib/cycle-check.h @@ -1,6 +1,6 @@ /* help detect directory cycles efficiently - Copyright (C) 2003, 2004, 2006 Free Software Foundation, Inc. + Copyright (C) 2003, 2004, 2006, 2009 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -41,7 +41,7 @@ bool cycle_check (struct cycle_check_state *state, struct stat const *sb); /* You must call cycle_check at least once before using this macro. */ \ if ((State)->chdir_counter == 0) \ abort (); \ - if (SAME_INODE ((State)->dev_ino, SB_subdir)) \ + if (SAME_INODE ((State)->dev_ino, SB_subdir) == 1) \ { \ (State)->dev_ino.st_dev = (SB_dir).st_dev; \ (State)->dev_ino.st_ino = (SB_dir).st_ino; \ diff --git a/lib/same-inode.h b/lib/same-inode.h index 063271174..4b89dd1a6 100644 --- a/lib/same-inode.h +++ b/lib/same-inode.h @@ -1,6 +1,6 @@ /* Determine whether two stat buffers refer to the same file. - Copyright (C) 2006 Free Software Foundation, Inc. + Copyright (C) 2006, 2009 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -18,8 +18,18 @@ #ifndef SAME_INODE_H # define SAME_INODE_H 1 +/* Perform a tri-state query on whether STAT_BUF_1 and STAT_BUF_2 + represent the same file. Return 1 for equal, 0 for distinct, and + -1 for indeterminate (the latter is generally possible only on + mingw). Algorithms that use this macro must be prepared to handle + the indeterminate case without wrong results. For example, if an + optimization is possible if two files are the same but unsafe if + distinct, use SAME_INODE()==1; whereas for an optimization that is + possible only for distinct files, use !SAME_INODE(). */ + # define SAME_INODE(Stat_buf_1, Stat_buf_2) \ - ((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \ - && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev) + (((Stat_buf_1).st_ino == (Stat_buf_2).st_ino \ + && (Stat_buf_1).st_dev == (Stat_buf_2).st_dev) \ + ? 1 - 2 * !(Stat_buf_1).st_ino : 0) #endif diff --git a/lib/same.c b/lib/same.c index af3a95efb..5251fb88f 100644 --- a/lib/same.c +++ b/lib/same.c @@ -1,7 +1,7 @@ /* Determine whether two file names refer to the same file. - Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006 Free - Software Foundation, Inc. + Copyright (C) 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, + 2009 Free Software Foundation, Inc. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -97,6 +97,9 @@ same_name (const char *source, const char *dest) } same = SAME_INODE (source_dir_stats, dest_dir_stats); + if (same < 0) + same = (identical_basenames + && strcmp (source_basename, dest_basename) == 0); #if ! _POSIX_NO_TRUNC && HAVE_PATHCONF && defined _PC_NAME_MAX if (same && ! identical_basenames)