Re: emacs & MAXPATHLEN

[Giuseppe Scrivano <gscrivano@gmail.com>]

This new patch should fix the problem both with get_current_dir_name and getcwd. I think a compilation error when getwd is used without a MAXPATHLEN is nice to have.
The buffer used with getcwd is duplicated ever time it is too small. configure.in was modified to check for the get_current_dir_name function too. I hope I am following GCS now.

Giuseppe Scivano


--- 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/buffer.c.old	2005-07-28 19:14:42.000000000 +0200
+++ src/buffer.c	2005-07-30 03:20:36.000000000 +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>
@@ -5114,7 +5110,7 @@
 void
 init_buffer ()
 {
-  char buf[MAXPATHLEN + 1];
+  char *buf;
   char *pwd;
   struct stat dotstat, pwdstat;
   Lisp_Object temp;
@@ -5140,20 +5136,64 @@
   /* 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
+    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));
+#ifdef MAXPATHLEN
+      && strlen (pwd) < MAXPATHLEN
+#endif
+      )
+    {
+      buf = xmalloc (strlen (pwd) + 1);
+      strcpy (buf, pwd);
+    }
+#ifdef HAVE_CURRENT_DIR_NAME
+  else
+    {
+      buf = get_current_dir_name ();
+      if(!buf)
+        fatal ("`get_current_dir_name' failed in init_buffer\n");
+    }
+#elif HAVE_GETCWD
+  else
+    {
+#ifdef MAXPATHLEN
+      buf = xmalloc (MAXPATHLEN + 1);
+      if(getcwd (buf, MAXPATHLEN + 1) == 0)
+        fatal ("`getwd' failed: %s\n", buf);   
+#else 
+      {
+        int buf_size = 2;
+        buf = xmalloc (buf_size);
+        for(;;)
+          {
+            if(getcwd (buf, buf_size) == 0)
+              {
+                if(errno == ERANGE)
+                  {
+                    buf_size *= 2;
+                    buf = xrealloc (buf, buf_size);
+                  }
+                else
+                  fatal ("`getcwd' failed: %s\n", strerror (errno));
+              }
+            else
+              break;
+          }
+
+      }     
+#endif
+    }
 #else
-  else if (getwd (buf) == 0)
-    fatal ("`getwd' failed: %s\n", buf);
+  else
+    {
+      buf = xmalloc (MAXPATHLEN + 1);
+      if(getwd (buf) == 0)
+        fatal ("`getwd' failed: %s\n", buf); 
+    }
 #endif
 
 #ifndef VMS
@@ -5189,6 +5229,12 @@
 
   temp = get_minibuffer (0);
   XBUFFER (temp)->directory = current_buffer->directory;
+
+#ifdef HAVE_CURRENT_DIR_NAME
+  free (buf);
+#else
+  xfree (buf);
+#endif
 }
 
 /* initialize the buffer routines */
--- src/xsmfns.c.old	2005-07-28 19:51:24.000000000 +0200
+++ src/xsmfns.c	2005-07-30 03:29:19.000000000 +0200
@@ -45,6 +45,8 @@
 #include <sys/param.h>
 #include <stdio.h>
 
+#include <errno.h>
+
 #include "systime.h"
 #include "sysselect.h"
 #include "lisp.h"
@@ -52,10 +54,6 @@
 #include "termopts.h"
 #include "xterm.h"
 
-#ifndef MAXPATHLEN
-#define MAXPATHLEN 1024
-#endif /* not MAXPATHLEN */
-
 
 /* The user login name.  */
 
@@ -205,7 +203,7 @@
   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 +257,42 @@
   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)
+#ifdef HAVE_GET_CURRENT_DIR_NAME
+  cwd = get_current_dir_name ();
+#elif HAVE_GETCWD
+  {
+    int cwd_size = 2;
+    cwd = xmalloc (cwd_size);
+    for(;;)
+      {
+        if(getcwd (cwd, cwd_size) == 0)
+          {
+            if(errno == ERANGE)
+              {
+                cwd_size *= 2;
+                cwd = xrealloc (cwd, cwd_size);
+              }
+            else
+              {
+                xfree (cwd);
+                cwd = NULL;
+              }
+          }
+        else
+          break;
+      }
+    
+  }  
 #else
-  if (getwd (cwd) != 0)
+  cwd = xmalloc (MAXPATHLEN + 1);
+  if(getwd (cwd) == 0)
+    {
+      xfree (cwd);
+      cwd = NULL;
+    }
 #endif
+
+  if(!cwd)
     {
       props[props_idx] = &prop_ptr[props_idx];
       props[props_idx]->name = SmCurrentDirectory;
@@ -281,6 +309,13 @@
 
   xfree (smid_opt);
 
+  if(cwd)
+#ifdef HAVE_CURRENT_DIR_NAME
+    free (cwd);
+#else
+    xfree (cwd);
+#endif
+
   /* See if we maybe shall interact with the user.  */
   if (interactStyle != SmInteractStyleAny
       || ! shutdown