empty input for fakemail.c

[Dan Nicolaescu]

AFAICS this Coverity problem report can happen if the input file is
empty. What should be done in that case exit (1)?
Can someone familiar with this code take a look?


CID: 9
Checker: FORWARD_NULL (help)
File: emacs/lib-src/fakemail.c
Function: read_header
Description: Variable "the_header " tracked as NULL was dereferenced.

Event assign_zero: Variable "the_header " assigned value 0.
Also see events: [var_deref_op]

651        register header the_header = ((header) NULL);
652          register line_list *next_line = ((line_list *) NULL);
653          
654            init_linebuffer (&lb);
655            
656              do
657                  {
658                        long length;
659                              register char *line;
660                              
661                                    readline (&lb, stdin);
662                                          line = lb.buffer;
663                                                length = strlen
(line);

At conditional (1): "length == 0 " taking true path

664                  if (length == 0) break;
665                  
666                        if (has_keyword (line))
667                           {
668                               register header old = the_header;
669                                          the_header = new_header
();
670               if (old == ((header) NULL))
671                      {
672                                   the_header->next = the_header;
673
the_header->previous = the_header;
674                        }
675                               else
676                                         {
677
the_header->previous = old;
678                          the_header->next = old->next;
679                                                 old->next =
the_header;
680                 }
681                       next_line = & (the_header->text);
682                                 }
683                                 
684                                       if (next_line == ((line_list
*) NULL))
685             {
686                       /* Not a valid header */
687                            exit (EXIT_FAILURE);
688                                 }
689                                       *next_line = new_list ();
690                                             (*next_line)->string =
alloc_string (length);
691                strcpy (((*next_line)->string), line);
692                      next_line = & ((*next_line)->continuation);
693                            *next_line = NIL;
694                            
695                                } while (true);
696                                

Event var_deref_op: Variable "the_header " tracked as NULL was
dereferenced.
Also see events: [assign_zero]

697        return the_header->next;
698        }