(recheck): Factor out a block of duplicated code.

Set f->size to 0 upon encountering a new file so we read it from
the beginning rather than from then end of the first line or
block.  Otherwise, after a log rotation, tail would omit the first
line or block of the new file.  Reported by Ed Avis.

diff --git a/src/tail.c b/src/tail.c
index 11e78f2..c549105 100644 (file)
--- a/src/tail.c
+++ b/src/tail.c
@@ -629,6 +629,7 @@ recheck (struct File_spec *f)
   int fail = 0;
   int is_stdin = (STREQ (f->name, "-"));
   int was_missing = f->missing;
+  int new_file;
 
   fd = (is_stdin ? STDIN_FILENO : open (f->name, O_RDONLY));
 
@@ -663,6 +664,7 @@ cannot follow end of non-regular file"),
             pretty_name (f));
     }
 
+  new_file = 0;
   if (fail)
     {
       close_fd (fd, pretty_name (f));
@@ -671,6 +673,7 @@ cannot follow end of non-regular file"),
     }
   else if (f->ino != new_stats.st_ino || f->dev != new_stats.st_dev)
     {
+      new_file = 1;
       if (f->fd == -1)
        {
          error (0, 0,
@@ -688,33 +691,29 @@ cannot follow end of non-regular file"),
                 _("`%s' has been replaced;  following end of new file"),
                 pretty_name (f));
        }
-
-      f->fd = fd;
-      f->size = new_stats.st_size;
-      f->dev = new_stats.st_dev;
-      f->ino = new_stats.st_ino;
-      f->n_unchanged_stats = 0;
-      f->n_consecutive_size_changes = 0;
-      /* FIXME: check lseek return value  */
-      lseek (f->fd, new_stats.st_size, SEEK_SET);
     }
   else if (f->missing)
     {
+      new_file = 1;
       error (0, 0, _("`%s' has reappeared"), pretty_name (f));
       f->missing = 0;
+    }
+  else
+    {
+      close_fd (fd, pretty_name (f));
+    }
 
+  if (new_file)
+    {
+      /* Record new file info in f.  */
       f->fd = fd;
-      f->size = new_stats.st_size;
+      f->size = 0; /* Start at the beginning of the file...  */
       f->dev = new_stats.st_dev;
       f->ino = new_stats.st_ino;
       f->n_unchanged_stats = 0;
       f->n_consecutive_size_changes = 0;
       /* FIXME: check lseek return value  */
-      lseek (f->fd, new_stats.st_size, SEEK_SET);
-    }
-  else
-    {
-      close_fd (fd, pretty_name (f));
+      lseek (f->fd, f->size, SEEK_SET);
     }
 }