12604: Remove calls to zpathmax(), minor fixes to zopenmax().

5 files changed, 56 insertions, 47 deletions

diff --git a/ChangeLog b/ChangeLog
index 435aaa21c..7dc510610 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2000-08-13  Bart Schaefer  <schaefer@zsh.org>
 
+	* 12604: Src/compat.c, Src/system.h, Src/Modules/files.c,
+	Src/Modules/parameter.c: Remove calls to zpathmax(); fix some
+	serious errors in zpathmax() but wrap it in #if 0 anyway; minor
+	fixes to comments and coding style for zopenmax().
+
 	* 12601: aczsh.m4, configure.in: configure --enable-cflags and the
 	like, i.e., with no =... part, should preserve the environment
 	values for CFLAGS etc. rather than erase them.
diff --git a/Src/Modules/files.c b/Src/Modules/files.c
index d01a59b03..54b399866 100644
--- a/Src/Modules/files.c
+++ b/Src/Modules/files.c
@@ -91,11 +91,6 @@ bin_mkdir(char *nam, char **args, char *ops, int func)
 
 	while(ptr > *args + (**args == '/') && *--ptr == '/')
 	    *ptr = 0;
-	if(zpathmax(unmeta(*args)) < 0) {
-	    zwarnnam(nam, "%s: %e", *args, errno);
-	    err = 1;
-	    continue;
-	}
 	if(ops['p']) {
 	    char *ptr = *args;
 
diff --git a/Src/Modules/parameter.c b/Src/Modules/parameter.c
index b2b3657c0..e8a0c09a0 100644
--- a/Src/Modules/parameter.c
+++ b/Src/Modules/parameter.c
@@ -1397,9 +1397,8 @@ scanpmjobdirs(HashTable ht, ScanFunc func, int flags)
 static void
 setpmnameddir(Param pm, char *value)
 {
-    errno = 0;
-    if (!value || *value != '/' || zpathmax(value) < 0)
-	zwarn((errno ? "%s: %e" : "invalid value: %s"), value, errno);
+    if (!value || *value != '/')
+	zwarn("invalid value: %s", value, 0);
     else
 	adduserdir(pm->nam, value, 0, 1);
     zsfree(value);
@@ -1443,9 +1442,8 @@ setpmnameddirs(Param pm, HashTable ht)
 	    v.arr = NULL;
 	    v.pm = (Param) hn;
 
-	    errno = 0;
-	    if (!(val = getstrvalue(&v)) || *val != '/' || zpathmax(val) < 0)
-		zwarn((errno ? "%s: %e" : "invalid value: %s"), val, errno);
+	    if (!(val = getstrvalue(&v)) || *val != '/')
+		zwarn("invalid value: %s", val, 0);
 	    else
 		adduserdir(hn->nam, val, 0, 1);
 	}
diff --git a/Src/compat.c b/Src/compat.c
index 88ceac2c8..8cfb8a3a5 100644
--- a/Src/compat.c
+++ b/Src/compat.c
@@ -105,7 +105,23 @@ strerror(int errnum)
 #endif
 
 
-#ifdef HAVE_PATHCONF
+#if 0
+/* pathconf(_PC_PATH_MAX) is not currently useful to zsh.  The value *
+ * returned varies depending on a number of factors, e.g. the amount *
+ * of memory available to the operating system at a given time; thus *
+ * it can't be used for buffer allocation, or even as an indication  *
+ * of whether an attempt to use or create a given pathname may fail  *
+ * at any future time.                                               *
+ *                                                                   *
+ * The call is also permitted to fail if the argument path is not an *
+ * existing directory, so even to make sense of that one must search *
+ * for a valid directory somewhere in the path and adjust.  Even if  *
+ * it succeeds, the return value is relative to the input directory, *
+ * and therefore potentially relative to the length of the shortest  *
+ * path either to that directory or to our working directory.        *
+ *                                                                   *
+ * Finally, see the note below for glibc; detection of pathconf() is *
+ * not by itself an indication that it works reliably.               */
 
 /* The documentation for pathconf() says something like:             *
  *     The limit is returned, if one exists.  If the system  does    *
@@ -114,34 +130,24 @@ strerror(int errnum)
  *     -1  is returned, and errno is set to reflect the nature of    *
  *     the error.                                                    *
  *                                                                   *
- * This is less useful than may be, as one must reset errno to 0 (or *
+ * System calls are not permitted to set errno to 0; but we must (or *
  * some other flag value) in order to determine that the resource is *
  * unlimited.  What use is leaving errno unchanged?  Instead, define *
  * a wrapper that resets errno to 0 and returns 0 for "the system    *
- * does not have a limit," so that -1 always means a real error.     *
- *                                                                   *
- * This is replaced by a macro from system.h if not HAVE_PATHCONF.   *
- *
- * Note that the length of a relative path is compared without first *
- * prepending the current directory, if pathconf() does not return   *
- * an error.  This is for consistency with the macro and with older  *
- * zsh behavior; it may be problematic in the ENOENT/ENOTDIR cases.  */
+ * does not have a limit," so that -1 always means a real error.     */
 
 /**/
 mod_export long
 zpathmax(char *dir)
 {
+#ifdef HAVE_PATHCONF
     long pathmax;
 
     errno = 0;
     if ((pathmax = pathconf(dir, _PC_PATH_MAX)) >= 0) {
-	/* This code is redundant if pathconf works correctly, but   *
-	 * some versions of glibc pathconf return a hardwired value. */
-	if (strlen(dir) < pathmax)
-	    return pathmax;
-	else
-	    errno = ENAMETOOLONG;
-    } else if (errno == ENOENT || errno == ENOTDIR) {
+	/* Some versions of glibc pathconf return a hardwired value! */
+	return pathmax;
+    } else if (errno == EINVAL || errno == ENOENT || errno == ENOTDIR) {
 	/* Work backward to find a directory, until we run out of path. */
 	char *tail = strrchr(dir, '/');
 	while (tail > dir && tail[-1] == '/')
@@ -158,8 +164,9 @@ zpathmax(char *dir)
 		pathmax = pathconf(".", _PC_PATH_MAX);
 	}
 	if (pathmax > 0) {
-	    if (strlen(dir) < pathmax)
-		return pathmax;
+	    long taillen = (tail ? strlen(tail) : (strlen(dir) + 1));
+	    if (taillen < pathmax)
+		return pathmax - taillen;
 	    else
 		errno = ENAMETOOLONG;
 	}
@@ -168,12 +175,20 @@ zpathmax(char *dir)
 	return -1;
     else
 	return 0; /* pathmax should be considered unlimited */
-}
+#else
+    long dirlen = strlen(dir);
+
+    /* The following is wrong if dir is not an absolute path. */
+    return ((long) ((dirlen >= PATH_MAX) ?
+		    ((errno = ENAMETOOLONG), -1) :
+		    ((errno = 0), PATH_MAX - dirlen)));
 #endif
+}
+#endif // 0
 
 #ifdef HAVE_SYSCONF
-/* This is replaced by a macro from system.h if not HAVE_PATHCONF.   *
- * 0 is returned if _SC_OPEN_MAX is unavailable                      *
+/* This is replaced by a macro from system.h if not HAVE_SYSCONF.    *
+ * 0 is returned by sysconf if _SC_OPEN_MAX is unavailable;          *
  * -1 is returned on error                                           *
  *                                                                   *
  * Neither of these should happen, but resort to OPEN_MAX rather     *
@@ -183,10 +198,9 @@ zpathmax(char *dir)
 mod_export long
 zopenmax(void)
 {
-    long openmax;
-    
-    openmax = sysconf(_SC_OPEN_MAX);
-    if(openmax < 1)
+    long openmax = sysconf(_SC_OPEN_MAX);
+
+    if (openmax < 1)
 	return OPEN_MAX;
     else
 	return openmax;
diff --git a/Src/system.h b/Src/system.h
index 2ed75b621..3d23f5761 100644
--- a/Src/system.h
+++ b/Src/system.h
@@ -200,18 +200,15 @@ struct timezone {
 # ifdef MAXPATHLEN
 #  define PATH_MAX MAXPATHLEN
 # else
-   /* so we will just pick something */
-#  define PATH_MAX 1024
+#  ifdef _POSIX_PATH_MAX
+#   define PATH_MAX _POSIX_PATH_MAX
+#  else
+    /* so we will just pick something */
+#   define PATH_MAX 1024
+#  endif
 # endif
 #endif
-#ifndef HAVE_PATHCONF
-# define zpathmax(X) ((long)((strlen(X) >= PATH_MAX) ? \
-			     ((errno = ENAMETOOLONG), -1) : \
-			     ((errno = 0), PATH_MAX)))
-#endif
 
-/* we should be getting this value from sysconf(_SC_OPEN_MAX) */
-/* but this is too much trouble                               */
 #ifndef OPEN_MAX
 # ifdef NOFILE
 #  define OPEN_MAX NOFILE
@@ -221,7 +218,7 @@ struct timezone {
 # endif
 #endif
 #ifndef HAVE_SYSCONF
-# define zopenmax() (long) OPEN_MAX
+# define zopenmax() ((long) OPEN_MAX)
 #endif
 
 #ifdef HAVE_FCNTL_H