checkentry.c

来自「Linux下server与client的通信实现。Server支持多线程。附有m」· C语言 代码 · 共 106 行

#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <firewall.h>
#include <server.h>


struct ConfigEntry *convertLine (struct ConfigLine *line, int *errno) {
  
  int portno;
  struct ElementList *uids, *programs, *IPAddresses, *ports;
  struct ConfigEntry *entry;
  char *endptr; /* for strtol */


  uids = line->uids;
  programs = line->programs;
  IPAddresses = line->IPAddresses;
  ports = line->ports;

  if (uids->next || programs->next || IPAddresses->next || ports->next) {
    *errno = ILLEGAL_PROGRAM;
    return NULL;
  }

  if (strcmp (ports->element, "*") == 0) {
    portno = 0;
  }
  else {
    portno = strtol (ports->element, &endptr, 10);
    if ((portno == 0 ) || (endptr == NULL) || (*endptr != '\0')) {
      *errno = ILLEGAL_PORT;
      return NULL;
    }
  }

  entry  = malloc (sizeof (struct ConfigEntry));
  if (!entry) {
    fprintf (stderr, "Out of memory!\n");
    exit (1);
  }

  entry->uid = uids->element;
  entry->program = programs->element;
  entry->IPAddress = IPAddresses->element;
  entry->port = portno;
  
  return entry;
}

/* only called from checkEntry. Frees temporarily used structures. configLine and entry share substructures, so they are freed only once */

void freeStructures (struct ConfigLine *configLine, struct ConfigEntry *entry) {
  if (configLine) {
    freeElementList (configLine->uids);
    freeElementList (configLine->programs);
    freeElementList (configLine->IPAddresses);
    freeElementList (configLine->ports);
    free (configLine);
  }
  
  free (entry); /* components have already been freed before */
}
    

char checkEntry (char *line, struct FirewallConfig *firewallTable, int *errno) {

  struct ConfigLine *configLine;
  struct ConfigEntry *entry;
  int result;

  *errno = 0;
   configLine = parseLine (line, errno);
  if (!configLine) {
    /* error has happend */
    return 0;
  }

  entry = convertLine (configLine, errno);
  if (!entry) {
    freeStructures (configLine, entry);
    return ENTRY_NOT_FOUND;
  }
  while (firewallTable) {
    result = compareEntry (entry, firewallTable->entry);
    if (result == 0) {
      freeStructures (configLine, entry);
      return ENTRY_FOUND;
    }
    if (result < 0) {
      firewallTable = firewallTable->left;
    }
    else {
      firewallTable = firewallTable->right;
    }
  }

  /* not found */
  freeStructures(configLine, entry);
  return ENTRY_NOT_FOUND;
  

}