#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#define HEADER_LINES 5

/* Directories whose immediate sub-directories are the repositories we
 * trust */
char *cvsroot_containers[] = { "/cvsroot", "/webcvs", NULL };

int check_line (int, char *);
extern char *index (const char *s, int c);


int
main (int argc, char *argv[])
{
  int i;
  char *line = malloc (BUFSIZ + 1);

  /* Read the pserver header */
  for (i = 1; i <= HEADER_LINES; i++)
    {
      fgets (line, BUFSIZ, stdin);
      if (!check_line (i, line))
	return 1;
    }


  /* Accept the request */
  printf ("I LOVE YOU\n");
  fflush (stdout);


  /* The rest of the stream can be parsed by 'cvs server' */
  {
    char *const exec_args[] = { "cvs", "server", NULL };
    execv ("/usr/bin/cvs", exec_args);
  }

  /* If we're here, there was an error in execv(3) */
  printf ("error 0 Server error: %s. "
	  "Please contact the system administrators.\n", strerror (errno));
  return 1;
}


#define CVSROOT_LINE 2

/* We check the destination CVSROOT to avoid people trying to run
 * uncontrolled CVSROOT */
int
check_line (int num_line, char *line)
{
  /* 2nd line indicates the target repository */
  /* Perl: chomp($line) =~ (^$cvsroot_container/[^/]+/?); */
  char *buf = malloc (BUFSIZ + 1);
  if (num_line == CVSROOT_LINE)
    {
      char *path;
      int i = 0;
      int error = 1;
      char *found = NULL;

      /* Remove trailing new line */
      strcpy (buf, line);
      buf[strlen (buf) - 1] = '\0';

      while ((path = cvsroot_containers[i++]) != NULL)
	if (strncmp (buf, path, strlen(path)) == 0)
	  found = path;

      if (found == NULL)
	  error = 1;
      else
	{
	  /* Reject empty sub-directories and sub-sub-directories */
	  char *subdir = buf + strlen(found);
	  if (*subdir != '/' || *(subdir+1) == '\0')
	    error = 1;
	  else
	    {
	      char *slash_pos = strchr(subdir+1, '/');
	      if (slash_pos != NULL)
		error = 1;
	      else
		error = 0;
	    }
	}

      if (error)
	{
	  printf ("error 0 Invalid path: %s\n", buf);
	  return 0;
	}
    }
  return 1;
}