Adjust to recent Gnulib changes

The latest Gnulib merge brought in free-posix, which causes 'free'
to preserve errno.  This lets us simplify some Emacs code that
calls 'free'.
* admin/merge-gnulib (GNULIB_MODULES): Add free-posix.
This module is pulled in by canonicalize-lgpl anyway,
so we might as well rely on it.
* lib-src/emacsclient.c (get_current_dir_name):
Sync better with src/sysdep.c.
* lib-src/etags.c (process_file_name, etags_mktmp):
* lib-src/update-game-score.c (unlock_file):
* src/fileio.c (file_accessible_directory_p):
* src/sysdep.c (get_current_dir_name_or_unreachable):
Simplify by assuming that 'free' preserves errno.
* src/alloc.c (malloc_unblock_input):
Preserve errno, so that xfree preserves errno.
* src/sysdep.c (get_current_dir_name_or_unreachable):
Simplify by using strdup instead of malloc+memcpy.
No need for realloc (and the old code leaked memory anyway on
failure); just use free+malloc.

admin/merge-gnulib

@@ -34,7 +34,8 @@ GNULIB_MODULES='
   d-type diffseq double-slash-root dtoastr dtotimespec dup2
   environ execinfo explicit_bzero faccessat
   fchmodat fcntl fcntl-h fdopendir
-  filemode filename filevercmp flexmember fpieee fstatat fsusage fsync futimens
+  filemode filename filevercmp flexmember fpieee
+  free-posix fstatat fsusage fsync futimens
   getloadavg getopt-gnu getrandom gettime gettimeofday gitlog-to-changelog
   ieee754-h ignore-value intprops largefile libgmp lstat
   manywarnings memmem-simple mempcpy memrchr minmax mkostemp mktime nstrftime

lib-src/emacsclient.c

@@ -251,7 +251,6 @@ get_current_dir_name (void)
   bufsize_max = min (bufsize_max, PATH_MAX);
 #endif
 
-  char *buf;
   struct stat dotstat, pwdstat;
   size_t pwdlen;
   /* If PWD is accurate, use it instead of calling getcwd.  PWD is
@@ -265,37 +264,23 @@ get_current_dir_name (void)
       && stat (".", &dotstat) == 0
       && dotstat.st_ino == pwdstat.st_ino
       && dotstat.st_dev == pwdstat.st_dev)
-    {
-      buf = xmalloc (strlen (pwd) + 1);
-      strcpy (buf, pwd);
-    }
+    return strdup (pwd);
   else
     {
-      size_t buf_size = 1024;
+      ptrdiff_t buf_size = min (bufsize_max, 1024);
       for (;;)
-        {
-	  int tmp_errno;
-	  buf = malloc (buf_size);
-	  if (! buf)
-	    break;
-          if (getcwd (buf, buf_size) == buf)
-            break;
-	  tmp_errno = errno;
+	{
+	  char *buf = malloc (buf_size);
+	  if (!buf)
+	    return NULL;
+	  if (getcwd (buf, buf_size) == buf)
+	    return buf;
 	  free (buf);
-	  if (tmp_errno != ERANGE)
-            {
-              errno = tmp_errno;
-              return NULL;
-            }
-          buf_size *= 2;
-	  if (! buf_size)
-	    {
-	      errno = ENOMEM;
-	      return NULL;
-	    }
-        }
+	  if (errno != ERANGE || buf_size == bufsize_max)
+	    return NULL;
+	  buf_size = buf_size <= bufsize_max / 2 ? 2 * buf_size : bufsize_max;
+	}
     }
-  return buf;
 }
 #endif
 

lib-src/etags.c

@@ -1643,19 +1643,10 @@ process_file_name (char *file, language *lang)
 	  char *cmd = concat (cmd1, "' > ", tmp_name);
 #endif
 	  free (cmd1);
-	  int tmp_errno;
-	  if (system (cmd) == -1)
-	    {
-	      inf = NULL;
-	      tmp_errno = EINVAL;
-	    }
-	  else
-	    {
-	      inf = fopen (tmp_name, "r" FOPEN_BINARY);
-	      tmp_errno = errno;
-	    }
+	  inf = (system (cmd) == -1
+		 ? NULL
+		 : fopen (tmp_name, "r" FOPEN_BINARY));
 	  free (cmd);
-	  errno = tmp_errno;
 	}
 
       if (!inf)
@@ -7068,9 +7059,7 @@ etags_mktmp (void)
   int fd = mkostemp (templt, O_CLOEXEC);
   if (fd < 0 || close (fd) != 0)
     {
-      int temp_errno = errno;
       free (templt);
-      errno = temp_errno;
       templt = NULL;
     }
 #if defined (DOS_NT)

lib-src/update-game-score.c

@@ -499,9 +499,9 @@ unlock_file (const char *filename, void *state)
   char *lockpath = (char *) state;
   int saved_errno = errno;
   int ret = unlink (lockpath);
-  int unlink_errno = errno;
+  if (0 <= ret)
+    errno = saved_errno;
   free (lockpath);
-  errno = ret < 0 ? unlink_errno : saved_errno;
   return ret;
 }
 

src/alloc.c

@@ -732,7 +732,11 @@ static void
 malloc_unblock_input (void)
 {
   if (block_input_in_memory_allocators)
-    unblock_input ();
+    {
+      int err = errno;
+      unblock_input ();
+      errno = err;
+    }
 }
 # define MALLOC_BLOCK_INPUT malloc_block_input ()
 # define MALLOC_UNBLOCK_INPUT malloc_unblock_input ()

src/fileio.c

@@ -3050,7 +3050,6 @@ file_accessible_directory_p (Lisp_Object file)
   ptrdiff_t len = SBYTES (file);
   char const *dir;
   bool ok;
-  int saved_errno;
   USE_SAFE_ALLOCA;
 
   /* Normally a file "FOO" is an accessible directory if "FOO/." exists.
@@ -3075,9 +3074,7 @@ file_accessible_directory_p (Lisp_Object file)
     }
 
   ok = file_access_p (dir, F_OK);
-  saved_errno = errno;
   SAFE_FREE ();
-  errno = saved_errno;
   return ok;
 #endif	/* !DOS_NT */
 }

src/sysdep.c

@@ -314,33 +314,21 @@ get_current_dir_name_or_unreachable (void)
       && emacs_fstatat (AT_FDCWD, ".", &dotstat, 0) == 0
       && dotstat.st_ino == pwdstat.st_ino
       && dotstat.st_dev == pwdstat.st_dev)
-    {
-      char *buf = malloc (pwdlen + 1);
-      if (!buf)
-        return NULL;
-      return memcpy (buf, pwd, pwdlen + 1);
-    }
+    return strdup (pwd);
   else
     {
       ptrdiff_t buf_size = min (bufsize_max, 1024);
-      char *buf = malloc (buf_size);
-      if (!buf)
-        return NULL;
       for (;;)
         {
+	  char *buf = malloc (buf_size);
+	  if (!buf)
+	    return NULL;
           if (getcwd (buf, buf_size) == buf)
 	    return buf;
-	  int getcwd_errno = errno;
-	  if (getcwd_errno != ERANGE || buf_size == bufsize_max)
-            {
-              free (buf);
-	      errno = getcwd_errno;
-              return NULL;
-            }
+	  free (buf);
+	  if (errno != ERANGE || buf_size == bufsize_max)
+	    return NULL;
 	  buf_size = buf_size <= bufsize_max / 2 ? 2 * buf_size : bufsize_max;
-          buf = realloc (buf, buf_size);
-          if (!buf)
-            return NULL;
         }
     }
 }