* cygcheck.cc (dirname): New static function.

	(find_app_on_path): Use SYMLINK_MAX.  Resolve symlink relative
	to link's location.  Adjust to the fact that cygpath already
	normalizes its return value.
	* path.cc (rel_vconcat): Add cwd parameter, and use it instead
	of calling GetCurrentDirectory() if possible.  Rename throughout.
	(vcygpath): Rename from cygpath and accept cwd and va_list.  Pass
	cwd on to rel_vconcat().
	(cygpath_rel): New front end for vcygpath.
	(cygpath): Ditto.
	* path.h (cygpath_rel): Declare.
	(SYMLINK_MAX): Define to 4095.

4 files changed, 100 insertions, 31 deletions

diff --git a/winsup/utils/ChangeLog b/winsup/utils/ChangeLog
index 18f70518a..288beafd0 100644
--- a/winsup/utils/ChangeLog
+++ b/winsup/utils/ChangeLog
@@ -1,3 +1,18 @@
+2008-03-11  Brian Dessent  <brian@dessent.net>
+
+	* cygcheck.cc (dirname): New static function.
+	(find_app_on_path): Use SYMLINK_MAX.  Resolve symlink relative
+	to link's location.  Adjust to the fact that cygpath already
+	normalizes its return value.
+	* path.cc (rel_vconcat): Add cwd parameter, and use it instead
+	of calling GetCurrentDirectory() if possible.  Rename throughout.
+	(vcygpath): Rename from cygpath and accept cwd and va_list.  Pass
+	cwd on to rel_vconcat().
+	(cygpath_rel): New front end for vcygpath.
+	(cygpath): Ditto.
+	* path.h (cygpath_rel): Declare.
+	(SYMLINK_MAX): Define to 4095.
+
 2008-03-09  Brian Dessent  <brian@dessent.net>
 
 	* Makefile.in (install): Don't install the testsuite.
diff --git a/winsup/utils/cygcheck.cc b/winsup/utils/cygcheck.cc
index 5e9713e03..e23a6858e 100644
--- a/winsup/utils/cygcheck.cc
+++ b/winsup/utils/cygcheck.cc
@@ -807,6 +807,28 @@ ls (char *f)
     display_error ("ls: CloseHandle()");
 }
 
+/* Remove filename from 's' and return directory name without trailing
+   backslash, or NULL if 's' doesn't seem to have a dirname.  */
+static char *
+dirname (const char *s)
+{
+  static char buf[MAX_PATH];
+
+  if (!s)
+    return NULL;
+
+  strncpy (buf, s, MAX_PATH);
+  buf[MAX_PATH - 1] = '\0';   // in case strlen(s) > MAX_PATH
+  char *lastsep = strrchr (buf, '\\');
+  if (!lastsep)
+    return NULL;          // no backslash -> no dirname
+  else if (lastsep - buf <= 2 && buf[1] == ':')
+    lastsep[1] = '\0';    // can't remove backslash of "x:\"
+  else
+    *lastsep = '\0';
+  return buf;
+}
+
 // Find a real application on the path (possibly following symlinks)
 static const char *
 find_app_on_path (const char *app, bool showall = false)
@@ -821,26 +843,25 @@ find_app_on_path (const char *app, bool showall = false)
 
   if (is_symlink (fh))
     {
-      static char tmp[4000] = "";
-      char *ptr;
-      if (!readlink (fh, tmp, 3999))
+      static char tmp[SYMLINK_MAX];
+      if (!readlink (fh, tmp, SYMLINK_MAX))
 	display_error("readlink failed");
-      ptr = cygpath (tmp, NULL);
-      for (char *p = ptr; (p = strchr (p, '/')); p++)
-	*p = '\\';
+      
+      /* Resolve the linkname relative to the directory of the link.  */
+      char *ptr = cygpath_rel (dirname (papp), tmp, NULL);
       printf (" -> %s\n", ptr);
       if (!strchr (ptr, '\\'))
 	{
 	  char *lastsep;
-	  strncpy (tmp, cygpath (papp, NULL), 3999);
-	  for (char *p = tmp; (p = strchr (p, '/')); p++)
-	    *p = '\\';
+	  strncpy (tmp, cygpath (papp, NULL), SYMLINK_MAX - 1);
 	  lastsep = strrchr (tmp, '\\');
-	  strncpy (lastsep+1, ptr, 3999-(lastsep-tmp));
+	  strncpy (lastsep+1, ptr, SYMLINK_MAX - 1 - (lastsep-tmp));
 	  ptr = tmp;
 	}
       if (!CloseHandle (fh))
 	display_error ("find_app_on_path: CloseHandle()");
+      /* FIXME: We leak the ptr returned by cygpath() here which is a
+         malloc()d string.  */
       return find_app_on_path (ptr, showall);
     }
 
diff --git a/winsup/utils/path.cc b/winsup/utils/path.cc
index 569196344..4a29d14e9 100644
--- a/winsup/utils/path.cc
+++ b/winsup/utils/path.cc
@@ -486,26 +486,35 @@ unconvert_slashes (char* name)
     *name++ = '\\';
 }
 
+/* This is a helper function for when vcygpath is passed what appears
+   to be a relative POSIX path.  We take a Win32 CWD (either as specified
+   in 'cwd' or as retrieved with GetCurrentDirectory() if 'cwd' is NULL)
+   and find the mount table entry with the longest match.  We replace the
+   matching portion with the corresponding POSIX prefix, and to that append
+   's' and anything in 'v'.  The returned result is a mostly-POSIX
+   absolute path -- 'mostly' because the portions of CWD that didn't
+   match the mount prefix will still have '\\' separators.  */
 static char *
-rel_vconcat (const char *s, va_list v)
+rel_vconcat (const char *cwd, const char *s, va_list v)
 {
-  char path[MAX_PATH + 1];
-  if (!GetCurrentDirectory (MAX_PATH, path))
-    return NULL;
+  char pathbuf[MAX_PATH];
+  if (!cwd || *cwd == '\0')
+    {
+      if (!GetCurrentDirectory (MAX_PATH, pathbuf))
+        return NULL;
+      cwd = pathbuf;
+    }
 
   int max_len = -1;
   struct mnt *m, *match = NULL;
 
-  if (s[0] == '.' && isslash (s[1]))
-    s += 2;
-
-  for (m = mount_table; m->posix ; m++)
+  for (m = mount_table; m->posix; m++)
     {
       if (m->flags & MOUNT_CYGDRIVE)
 	continue;
 
       int n = strlen (m->native);
-      if (n < max_len || !path_prefix_p (m->native, path, n))
+      if (n < max_len || !path_prefix_p (m->native, cwd, n))
 	continue;
       max_len = n;
       match = m;
@@ -514,34 +523,36 @@ rel_vconcat (const char *s, va_list v)
   char *temppath;
   if (!match)
     // No prefix matched - best effort to return meaningful value.
-    temppath = concat (path, "/", s, NULL);
+    temppath = concat (cwd, "/", s, NULL);
   else if (strcmp (match->posix, "/") != 0)
     // Matched on non-root.  Copy matching prefix + remaining 'path'.
-    temppath = concat (match->posix, path + max_len, "/", s, NULL);
-  else if (path[max_len] == '\0')
+    temppath = concat (match->posix, cwd + max_len, "/", s, NULL);
+  else if (cwd[max_len] == '\0')
     // Matched on root and there's no remaining 'path'.
     temppath = concat ("/", s, NULL);
-  else if (isslash (path[max_len]))
+  else if (isslash (cwd[max_len]))
     // Matched on root but remaining 'path' starts with a slash anyway.
-    temppath = concat (path + max_len, "/", s, NULL);
+    temppath = concat (cwd + max_len, "/", s, NULL);
   else
-    temppath = concat ("/", path + max_len, "/", s, NULL);
+    temppath = concat ("/", cwd + max_len, "/", s, NULL);
 
   char *res = vconcat (temppath, v);
   free (temppath);
   return res;
 }
 
-char *
-cygpath (const char *s, ...)
+/* Convert a POSIX path in 's' to an absolute Win32 path, and append
+   anything in 'v' to the end, returning the result.  If 's' is a
+   relative path then 'cwd' is used as the working directory to make
+   it absolute.  Pass NULL in 'cwd' to use GetCurrentDirectory.  */
+static char *
+vcygpath (const char *cwd, const char *s, va_list v)
 {
-  va_list v;
   int max_len = -1;
   struct mnt *m, *match = NULL;
 
   if (!mount_table[0].posix)
     read_mounts ();
-  va_start (v, s);
   char *path;
   if (s[0] == '.' && isslash (s[1]))
     s += 2;
@@ -549,7 +560,7 @@ cygpath (const char *s, ...)
   if (s[0] == '/' || s[1] == ':')	/* FIXME: too crude? */
     path = vconcat (s, v);
   else
-    path = rel_vconcat (s, v);
+    path = rel_vconcat (cwd, s, v);
 
   if (!path)
     return NULL;
@@ -557,7 +568,7 @@ cygpath (const char *s, ...)
   if (strncmp (path, "/./", 3) == 0)
     memmove (path + 1, path + 3, strlen (path + 3) + 1);
 
-  for (m = mount_table; m->posix ; m++)
+  for (m = mount_table; m->posix; m++)
     {
       if (m->flags & MOUNT_CYGDRIVE)
 	continue;
@@ -586,6 +597,26 @@ cygpath (const char *s, ...)
   return native;
 }
 
+char *
+cygpath_rel (const char *cwd, const char *s, ...)
+{
+  va_list v;
+
+  va_start (v, s);
+
+  return vcygpath (cwd, s, v);
+}
+
+char *
+cygpath (const char *s, ...)
+{
+  va_list v;
+  
+  va_start (v, s);
+  
+  return vcygpath (NULL, s, v);
+}
+
 static mnt *m = NULL;
 
 extern "C" FILE *
diff --git a/winsup/utils/path.h b/winsup/utils/path.h
index 134235e38..48739df74 100644
--- a/winsup/utils/path.h
+++ b/winsup/utils/path.h
@@ -9,9 +9,11 @@ Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
 details. */
 
 char *cygpath (const char *s, ...);
+char *cygpath_rel (const char *cwd, const char *s, ...);
 bool is_exe (HANDLE);
 bool is_symlink (HANDLE);
 bool readlink (HANDLE, char *, int);
 int get_word (HANDLE, int);
 int get_dword (HANDLE, int);
 
+#define SYMLINK_MAX 4095  /* PATH_MAX - 1 */