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author | Jim Meyering <jim@meyering.net> | 2003-03-04 17:18:13 +0000 |
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committer | Jim Meyering <jim@meyering.net> | 2003-03-04 17:18:13 +0000 |
commit | 618481ca0cf615697373edea7da1c17cd67f01cc (patch) | |
tree | 14d48180e1a9b3d28084baed0c9a9294428a56d8 /m4/getcwd-robust.m4 | |
parent | 59ae46343b1fb621b47af2496deb132ab9458585 (diff) | |
download | coreutils-618481ca0cf615697373edea7da1c17cd67f01cc.tar.xz |
*** empty log message ***
Diffstat (limited to 'm4/getcwd-robust.m4')
-rw-r--r-- | m4/getcwd-robust.m4 | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/m4/getcwd-robust.m4 b/m4/getcwd-robust.m4 new file mode 100644 index 000000000..3e5f49d5f --- /dev/null +++ b/m4/getcwd-robust.m4 @@ -0,0 +1,112 @@ +#serial 1 +# Check whether getcwd can return a path longer than PATH_MAX. +# If not, arrange to compile the wrapper function. +# From Jim Meyering + +AC_DEFUN([GL_FUNC_GETCWD_ROBUST], +[ + AC_CACHE_CHECK([whether getcwd can return a path longer than PATH_MAX], + utils_cv_func_getcwd_robust, + [ + # Arrange for deletion of the temporary directory this test creates. + ac_clean_files="$ac_clean_files confdir3" + AC_RUN_IFELSE([AC_LANG_SOURCE([[ +#include <stdlib.h> +#include <unistd.h> +#include <string.h> +#include <limits.h> +#include <sys/stat.h> +#include <sys/types.h> + +#ifndef CHAR_BIT +# define CHAR_BIT 8 +#endif + +/* The extra casts work around common compiler bugs. */ +#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1)) +/* The outer cast is needed to work around a bug in Cray C 5.0.3.0. + It is necessary at least when t == time_t. */ +#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \ + ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0)) +#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t))) + +#ifndef INT_MAX +# define INT_MAX TYPE_MAXIMUM (int) +#endif + +#ifndef PATH_MAX +# define PATH_MAX 40000 +#endif + +/* The length of this name must be 8. */ +#define DIR_NAME "confdir3" + +int +main () +{ + /* The '9' comes from strlen (DIR_NAME) + 1. */ +#if INT_MAX - 9 <= PATH_MAX + /* FIXME: Assuming there's a system for which this is true -- Hurd?, + this should be done in a compile test. */ + exit (0); +#else + char buf[PATH_MAX + 20]; + char *cwd = getcwd (buf, PATH_MAX); + size_t cwd_len; + int fail = 0; + size_t n_chdirs = 0; + + if (cwd == NULL) + exit (1); + + cwd_len = strlen (cwd); + + while (1) + { + char *c; + size_t len; + + cwd_len += 1 + strlen (DIR_NAME); + if (mkdir (DIR_NAME, 0700) < 0 + || chdir (DIR_NAME) < 0 + || (c = getcwd (buf, PATH_MAX)) == NULL + || (len = strlen (c)) != cwd_len) + { + fail = 1; + break; + } + ++n_chdirs; + if (PATH_MAX < len) + break; + } + + /* Leaving behind such a deep directory is not polite. + So clean up here, right away, even though the driving + shell script would also clean up. */ + { + size_t i; + + /* Unlink first, in case the chdir failed. */ + unlink (DIR_NAME); + for (i = 0; i <= n_chdirs; i++) + { + if (chdir ("..") < 0) + break; + rmdir (DIR_NAME); + } + } + + exit (fail); +#endif +} + ]])], + [utils_cv_func_getcwd_robust=yes], + [utils_cv_func_getcwd_robust=no], + [utils_cv_func_getcwd_robust=no])]) + + if test $utils_cv_func_getcwd_robust = yes; then + AC_LIBOBJ(getcwd) + AC_DEFINE(getcwd, rpl_getcwd, + [Define to rpl_getcwd if the wrapper function should be used.]) + fi +]) |