X-Git-Url: https://git.dogcows.com/gitweb?a=blobdiff_plain;f=src%2Fmisc.c;h=734dc4eded7adcac4f7a29d84111a0d49306cfb4;hb=2a61a3701f1fa04e83a2a39013ab56530a44b777;hp=adc9298689caaef63a4777787e41b8049f44e544;hpb=50a57a014748f196dede7e677b509f6a7ec4f486;p=chaz%2Ftar

diff --git a/src/misc.c b/src/misc.c
index adc9298..734dc4e 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -37,8 +37,7 @@
 void
 assign_string (char **string, const char *value)
 {
-  if (*string)
-    free (*string);
+  free (*string);
   *string = value ? xstrdup (value) : 0;
 }
 
@@ -106,7 +105,7 @@ quote_copy_string (const char *string)
    completes the unquoting anyway.
 
    This is used for reading the saved directory file in incremental
-   dumps.  It is used for decoding old `N' records (demangling names).
+   dumps.  It is used for decoding old 'N' records (demangling names).
    But also, it is used for decoding file arguments, would they come
    from the shell or a -T file, and for decoding the --exclude
    argument.  */
@@ -617,6 +616,57 @@ deref_stat (char const *name, struct stat *buf)
   return fstatat (chdir_fd, name, buf, fstatat_flags);
 }
 
+/* Read from FD into the buffer BUF with COUNT bytes.  Attempt to fill
+   BUF.  Wait until input is available; this matters because files are
+   opened O_NONBLOCK for security reasons, and on some file systems
+   this can cause read to fail with errno == EAGAIN.  Return the
+   actual number of bytes read, zero for EOF, or
+   SAFE_READ_ERROR upon error.  */
+size_t
+blocking_read (int fd, void *buf, size_t count)
+{
+  size_t bytes = safe_read (fd, buf, count);
+
+#if defined F_SETFL && O_NONBLOCK
+  if (bytes == SAFE_READ_ERROR && errno == EAGAIN)
+    {
+      int flags = fcntl (fd, F_GETFL);
+      if (0 <= flags && flags & O_NONBLOCK
+	  && fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
+	bytes = safe_read (fd, buf, count);
+    }
+#endif
+
+  return bytes;
+}
+
+/* Write to FD from the buffer BUF with COUNT bytes.  Do a full write.
+   Wait until an output buffer is available; this matters because
+   files are opened O_NONBLOCK for security reasons, and on some file
+   systems this can cause write to fail with errno == EAGAIN.  Return
+   the actual number of bytes written, setting errno if that is less
+   than COUNT.  */
+size_t
+blocking_write (int fd, void const *buf, size_t count)
+{
+  size_t bytes = full_write (fd, buf, count);
+
+#if defined F_SETFL && O_NONBLOCK
+  if (bytes < count && errno == EAGAIN)
+    {
+      int flags = fcntl (fd, F_GETFL);
+      if (0 <= flags && flags & O_NONBLOCK
+	  && fcntl (fd, F_SETFL, flags & ~O_NONBLOCK) != -1)
+	{
+	  char const *buffer = buf;
+	  bytes += full_write (fd, buffer + bytes, count - bytes);
+	}
+    }
+#endif
+
+  return bytes;
+}
+
 /* Set FD's (i.e., assuming the working directory is PARENTFD, FILE's)
    access time to ATIME.  */
 int
@@ -663,7 +713,7 @@ static int wdcache[CHDIR_CACHE_SIZE];
 static size_t wdcache_count;
 
 int
-chdir_count ()
+chdir_count (void)
 {
   if (wd_count == 0)
     return wd_count;
@@ -764,11 +814,11 @@ chdir_do (int i)
 	  int prev = wdcache[0];
 	  for (ci = 1; prev != i; ci++)
 	    {
-	      int curr = wdcache[ci];
+	      int cur = wdcache[ci];
 	      wdcache[ci] = prev;
-	      if (curr == i)
+	      if (cur == i)
 		break;
-	      prev = curr;
+	      prev = cur;
 	    }
 	  wdcache[0] = i;
 	}
@@ -912,7 +962,7 @@ page_aligned_alloc (void **ptr, size_t size)
 
 struct namebuf
 {
-  char *buffer;		/* directory, `/', and directory member */
+  char *buffer;		/* directory, '/', and directory member */
   size_t buffer_size;	/* allocated size of name_buffer */
   size_t dir_length;	/* length of directory part in buffer */
 };