Re: emacs & MAXPATHLEN

[Giuseppe Scrivano <gscrivano@gmail.com>]

"Richard M. Stallman" <rms@gnu.org> writes:

> Could you make a single subroutine and call it from both
> buffer.c and xsmfns.c?


I created two new files: cwd.h and cwd.c with the routine. This new patch uses them. Now src/Makefile.in is modified too:

--- configure.in.old	2005-07-29 18:14:02.000000000 +0200
+++ configure.in	2005-07-29 18:19:26.000000000 +0200
@@ -2414,7 +2414,7 @@
 AC_CHECK_HEADERS(maillock.h)
 
 AC_CHECK_FUNCS(gethostname getdomainname dup2 \
-rename closedir mkdir rmdir sysinfo getrusage \
+rename closedir mkdir rmdir sysinfo getrusage get_current_dir_name \
 random lrand48 bcopy bcmp logb frexp fmod rint cbrt ftime res_init setsid \
 strerror fpathconf select mktime euidaccess getpagesize tzset setlocale \
 utimes setrlimit setpgid getcwd getwd shutdown getaddrinfo \
--- src/Makefile.in.old	2005-07-30 18:28:12.000000000 +0200
+++ src/Makefile.in	2005-07-30 18:15:26.000000000 +0200
@@ -587,7 +587,7 @@
 	alloc.o data.o doc.o editfns.o callint.o \
 	eval.o floatfns.o fns.o print.o lread.o \
 	abbrev.o syntax.o UNEXEC bytecode.o \
-	process.o callproc.o \
+	process.o cwd.o callproc.o \
 	region-cache.o sound.o atimer.o \
 	doprnt.o strftime.o intervals.o textprop.o composite.o md5.o \
 	$(MSDOS_OBJ) $(MAC_OBJ) $(CYGWIN_OBJ)
@@ -1078,6 +1078,7 @@
 cm.o: cm.c cm.h termhooks.h $(config_h)
 cmds.o: cmds.c syntax.h buffer.h charset.h commands.h window.h $(config_h) \
 	msdos.h dispextern.h keyboard.h keymap.h
+cwd.o: cwd.c cwd.h $(config_h)
 pre-crt0.o: pre-crt0.c
 ecrt0.o: ecrt0.c $(config_h)
 	CRT0_COMPILE ${srcdir}/ecrt0.c
--- src/cwd.h.old	1970-01-01 01:00:00.000000000 +0100
+++ src/cwd.h	2005-07-30 18:06:43.000000000 +0200
@@ -0,0 +1,24 @@
+/* Header file for the curret working directory routine.
+   Copyright (C) 1985, 1986, 1993, 1994, 1995, 1997, 1998, 1999, 2000, 2001,
+     2003, 2004, 2005  Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+
+
+extern char * get_cwd ();
--- src/cwd.c.old	1970-01-01 01:00:00.000000000 +0100
+++ src/cwd.c	2005-07-30 19:04:03.000000000 +0200
@@ -0,0 +1,125 @@
+/* Get current working directory routine for GNU Emacs.
+   Copyright (C) 1985, 86, 87, 88, 89, 93, 94, 95, 97, 98, 99,
+     2000, 01, 02, 03, 04, 2005 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <errno.h>
+#include <stdio.h>
+
+#include "lisp.h"
+
+#ifndef USE_CRT_DLL
+extern int errno;
+#endif
+
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+/* Return the current working directory.  Returns NULL on errors. 
+   Any other returned value must be freed with free.  */
+char*
+get_cwd ()
+{
+  char *buf;
+  char *pwd;
+  struct stat dotstat, pwdstat;
+  /* If PWD is accurate, use it instead of calling getwd.  PWD is
+     sometimes a nicer name, and using it may avoid a fatal error if a
+     parent directory is searchable but not readable.  */
+    if ((pwd = getenv ("PWD")) != 0
+      && (IS_DIRECTORY_SEP (*pwd) || (*pwd && IS_DEVICE_SEP (pwd[1])))
+      && stat (pwd, &pwdstat) == 0
+      && stat (".", &dotstat) == 0
+      && dotstat.st_ino == pwdstat.st_ino
+      && dotstat.st_dev == pwdstat.st_dev
+#ifdef MAXPATHLEN
+      && strlen (pwd) < MAXPATHLEN
+#endif
+      )
+    {
+      buf = (char *) malloc (strlen (pwd) + 1);
+      if (!buf)
+        return NULL;
+      strcpy (buf, pwd);
+    }
+#ifdef HAVE_CURRENT_DIR_NAME
+  else
+    {
+      buf = get_current_dir_name ();
+      if (!buf)
+        return NULL;
+    }
+#elif HAVE_GETCWD
+  else
+    {
+#ifdef MAXPATHLEN
+      buf = (char *) malloc (MAXPATHLEN + 1);
+      if (!buf)
+        return NULL;
+      if (getcwd (buf, MAXPATHLEN + 1) == NULL)
+        return NULL;
+#else 
+      {
+        size_t buf_size = 1024;
+        buf = (char *) malloc (buf_size); 
+        if (!buf)
+          return NULL;
+        for (;;)
+          {
+            if (getcwd (buf, buf_size) == buf)
+              break;
+            if (errno != ERANGE)
+              {
+                int tmp_errno = errno;
+                free (buf);
+                errno = tmp_errno;
+                return NULL;
+              }
+            buf_size *= 2;
+            buf = (char *) realloc (buf, buf_size);
+            if (!buf)
+              return NULL;
+          }
+      }     
+#endif
+    }
+#else
+  else
+    {
+      buf = (char *) malloc (MAXPATHLEN + 1);
+      if (!buf)
+        return NULL;
+      if (getwd (buf) == NULL)
+        {
+          int tmp_errno = errno;
+          free (buf);
+          errno = tmp_errno;
+          return NULL;
+        }
+    }
+#endif
+  return buf;
+}
--- src/buffer.c.old	2005-07-28 19:14:42.000000000 +0200
+++ src/buffer.c	2005-07-30 18:42:20.000000000 +0200
@@ -31,10 +31,6 @@
 extern int errno;
 #endif
 
-#ifndef MAXPATHLEN
-/* in 4.1 [probably SunOS? -stef] , param.h fails to define this. */
-#define MAXPATHLEN 1024
-#endif /* not MAXPATHLEN */
 
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
@@ -52,6 +48,7 @@
 #include "keyboard.h"
 #include "keymap.h"
 #include "frame.h"
+#include "cwd.h"
 
 struct buffer *current_buffer;		/* the current buffer */
 
@@ -5114,7 +5111,6 @@
 void
 init_buffer ()
 {
-  char buf[MAXPATHLEN + 1];
   char *pwd;
   struct stat dotstat, pwdstat;
   Lisp_Object temp;
@@ -5137,37 +5133,23 @@
   if (NILP (buffer_defaults.enable_multibyte_characters))
     Fset_buffer_multibyte (Qnil);
 
-  /* If PWD is accurate, use it instead of calling getwd.  PWD is
-     sometimes a nicer name, and using it may avoid a fatal error if a
-     parent directory is searchable but not readable.  */
-  if ((pwd = getenv ("PWD")) != 0
-      && (IS_DIRECTORY_SEP (*pwd) || (*pwd && IS_DEVICE_SEP (pwd[1])))
-      && stat (pwd, &pwdstat) == 0
-      && stat (".", &dotstat) == 0
-      && dotstat.st_ino == pwdstat.st_ino
-      && dotstat.st_dev == pwdstat.st_dev
-      && strlen (pwd) < MAXPATHLEN)
-    strcpy (buf, pwd);
-#ifdef HAVE_GETCWD
-  else if (getcwd (buf, MAXPATHLEN+1) == 0)
-    fatal ("`getcwd' failed: %s\n", strerror (errno));
-#else
-  else if (getwd (buf) == 0)
-    fatal ("`getwd' failed: %s\n", buf);
-#endif
+  pwd = get_cwd ();
+ 
+  if(!pwd)
+    fatal ("`get_cwd' failed: %s\n", strerror (errno)); 
 
 #ifndef VMS
   /* Maybe this should really use some standard subroutine
      whose definition is filename syntax dependent.  */
-  rc = strlen (buf);
-  if (!(IS_DIRECTORY_SEP (buf[rc - 1])))
+  rc = strlen (pwd);
+  if (!(IS_DIRECTORY_SEP (pwd[rc - 1])))
     {
-      buf[rc] = DIRECTORY_SEP;
-      buf[rc + 1] = '\0';
+      pwd[rc] = DIRECTORY_SEP;
+      pwd[rc + 1] = '\0';
     }
 #endif /* not VMS */
 
-  current_buffer->directory = make_unibyte_string (buf, strlen (buf));
+  current_buffer->directory = make_unibyte_string (pwd, strlen (pwd));
   if (! NILP (buffer_defaults.enable_multibyte_characters))
     /* At this momemnt, we still don't know how to decode the
        direcotry name.  So, we keep the bytes in multibyte form so
@@ -5189,6 +5171,8 @@
 
   temp = get_minibuffer (0);
   XBUFFER (temp)->directory = current_buffer->directory;
+
+  free (pwd);
 }
 
 /* initialize the buffer routines */
--- src/xsmfns.c.old	2005-07-28 19:51:24.000000000 +0200
+++ src/xsmfns.c	2005-07-30 19:11:29.000000000 +0200
@@ -51,11 +51,7 @@
 #include "termhooks.h"
 #include "termopts.h"
 #include "xterm.h"
-
-#ifndef MAXPATHLEN
-#define MAXPATHLEN 1024
-#endif /* not MAXPATHLEN */
-
+#include "cwd.h"
 
 /* The user login name.  */
 
@@ -205,7 +201,7 @@
   int val_idx = 0;
   int props_idx = 0;
 
-  char cwd[MAXPATHLEN+1];
+  char *cwd = NULL;
   char *smid_opt;
 
   /* How to start a new instance of Emacs.  */
@@ -259,12 +255,9 @@
   props[props_idx]->vals[0].value = SDATA (Vuser_login_name);
   ++props_idx;
 
-  /* The current directory property, not mandatory.  */
-#ifdef HAVE_GETCWD
-  if (getcwd (cwd, MAXPATHLEN+1) != 0)
-#else
-  if (getwd (cwd) != 0)
-#endif
+  cwd = get_cwd ();
+
+  if (cwd)
     {
       props[props_idx] = &prop_ptr[props_idx];
       props[props_idx]->name = SmCurrentDirectory;
@@ -281,6 +274,9 @@
 
   xfree (smid_opt);
 
+  if (cwd)
+    free (cwd);
+
   /* See if we maybe shall interact with the user.  */
   if (interactStyle != SmInteractStyleAny
       || ! shutdown