Re: emacs & MAXPATHLEN

[Giuseppe Scrivano <gscrivano@gmail.com>]

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

> 1. I'd rather put this in sysdep.c and avoid the hassle of
> two new files.
Done.

> 2. It could be called get_current_dir_name,
> and defined only when the system does not define it.
> That would simplify things.
Done.

> 3. I'd rather not include this:
>
> +#ifdef MAXPATHLEN
> +      buf = (char *) malloc (MAXPATHLEN + 1);
> +      if (!buf)
> +        return NULL;
> +      if (getcwd (buf, MAXPATHLEN + 1) == NULL)
> +        return NULL;
> +#else 
Done.

Giuseppe Scrivano

This is the new patch, please let me know if you have other comments or suggestions:

--- 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/sysdep.c.old	2005-07-27 13:54:24.000000000 +0200
+++ src/sysdep.c	2005-08-01 15:28:44.000000000 +0200
@@ -258,6 +258,81 @@
 
 SIGMASKTYPE sigprocmask_set;
 
+
+#ifndef HAVE_CURRENT_DIR_NAME
+
+/* Return the current working directory.  Returns NULL on errors. 
+   Any other returned value must be freed with free. This is used
+   only when get_current_dir_name s not yet defined on the system.  */
+char*
+get_current_dir_name ()
+{
+  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_GETCWD
+  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;
+}
+#endif
+
 \f
 /* Specify a different file descriptor for further input operations.  */
 
--- src/buffer.c.old	2005-07-28 19:14:42.000000000 +0200
+++ src/buffer.c	2005-08-01 15:13:38.000000000 +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>
@@ -53,6 +49,8 @@
 #include "keymap.h"
 #include "frame.h"
 
+extern char * get_current_dir_name ();
+
 struct buffer *current_buffer;		/* the current buffer */
 
 /* First buffer in chain of all buffers (in reverse order of creation).
@@ -5114,7 +5112,6 @@
 void
 init_buffer ()
 {
-  char buf[MAXPATHLEN + 1];
   char *pwd;
   struct stat dotstat, pwdstat;
   Lisp_Object temp;
@@ -5137,37 +5134,23 @@
   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_current_dir_name ();
+ 
+  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 +5172,8 @@
 
   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	2005-08-01 15:13:46.000000000 +0200
@@ -52,10 +52,7 @@
 #include "termopts.h"
 #include "xterm.h"
 
-#ifndef MAXPATHLEN
-#define MAXPATHLEN 1024
-#endif /* not MAXPATHLEN */
-
+extern char * get_current_dir_name ();
 
 /* The user login name.  */
 
@@ -205,7 +202,7 @@
   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 +256,9 @@
   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_current_dir_name ();
+
+  if (cwd)
     {
       props[props_idx] = &prop_ptr[props_idx];
       props[props_idx]->name = SmCurrentDirectory;
@@ -281,6 +275,9 @@
 
   xfree (smid_opt);
 
+  if (cwd)
+    free (cwd);
+
   /* See if we maybe shall interact with the user.  */
   if (interactStyle != SmInteractStyleAny
       || ! shutdown