/*
   Copyright (c) 1995-1998 by Cisco systems, Inc.

   Permission to use, copy, modify, and distribute this software for
   any purpose and without fee is hereby granted, provided that this
   copyright and permission notice appear on all copies of the
   software and supporting documentation, the name of Cisco Systems,
   Inc. not be used in advertising or publicity pertaining to
   distribution of the program without specific prior permission, and
   notice be given in supporting documentation that modification,
   copying and distribution is by permission of Cisco Systems, Inc.

   Cisco Systems, Inc. makes no representations about the suitability
   of this software for any purpose.  THIS SOFTWARE IS PROVIDED ``AS
   IS'' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
   WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   FITNESS FOR A PARTICULAR PURPOSE.
*/


#include "tac_plus.h"

#include <stdlib.h>	/* malloc() can be found in <stdlib.h> OR <malloc.h> */
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
#include <string.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>	/* for "struct flock" */
#endif
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYSLOG_H
#include <syslog.h>
#endif
#ifdef HAVE_SYS_SYSLOG_H
#include <sys/syslog.h>
#endif

#include "utils.h"
#include "report.h"
#include "main.h"


void *tac_malloc TAC_ARGS((int size));

void *
tac_malloc(size)
int size;
{
    char *p;

    /* some mallocs don't like requests for zero length */
    if (size == 0) {
	size++;
    }

    p = (char *) malloc(size);

    if (p == NULL) {
	report(LOG_ERR, "malloc %d failure", size);
	tac_exit(1);
    }
    return (p);
}

void *tac_realloc TAC_ARGS((void *ptr, int size));

void *
tac_realloc(ptr, size)
void *ptr;
int size;
{
    char *p;

    if (ptr == NULL) {
	/* realloc(0, size) is not portable */
	p = tac_malloc(size);
    } else {
	p = (char *)realloc(ptr, size);
    }

    if (p == NULL) {
	report(LOG_ERR, "realloc %d failure", size);
	tac_exit(1);
    }
    return (p);
}

void tac_exit TAC_ARGS((int status)) G_GNUC_NORETURN;

void
tac_exit(status)
int status;
{
    if (debug & DEBUG_FORK_FLAG)
	report(LOG_DEBUG, "exit status=%d", status);
    exit(status);
}

char *tac_strdup TAC_ARGS((const char *p));

char *
tac_strdup(p)
const char *p;
{
    char *n = strdup(p);

    if (n == NULL) {
	report(LOG_ERR, "strdup allocation failure");
	tac_exit(1);
    }
    return (n);
}

char *tac_make_string TAC_ARGS((u_char *p, int len));

char *
tac_make_string(p, len)
u_char *p;
int len;
{
    char *string;
    int new_len = len;

    /*
     * Add space for a null terminator if needed. Also, no telling
     * what various mallocs will do when asked for a length of zero.
     */
    if (len == 0 || p[len - 1])
	new_len++;

    string = (char *) tac_malloc(new_len);

    bzero(string, new_len);
    bcopy(p, string, len);
    return (string);
}

/* return a pointer to the end of substring in string, or NULL. Substring
   must begin at start of string.
*/

const char *tac_find_substring TAC_ARGS((const char *substring, const char *string));

const char *
tac_find_substring(substring, string)
const char *substring;
const char *string;
{
    int len;

    if (!(substring && string)) {
	return(NULL);
    }

    len = strlen(substring);

    if (len > (int) strlen(string)) {
	return(NULL);
    }

    if (strncmp(substring, string, len)) {
	/* no match */
	return(NULL);
    }
    return(string + len);
}

#ifdef NEED_BZERO
int
bzero(p, len)
    register char *p;
    int len;
{
    register int n;

    if (len <= 0) {
	return;
    }
    for (n=0; n < len; n++) {
	p[n] = 0;
    }
}

int
bcopy(s1, s2, len)
    register char *s1, *s2;
    int len;
{
    register int n;

    if ((n = len) <= 0)
	return;
    do
	*s2++ = *s1++;
    while (--n);
}

int
bcmp(s1,s2,n)
    char *s1,*s2;
    int n;
{
    while (n-- > 0) {
	if (*s1++ != *s2++) {
	    return(1);
	}
    }
    return 0;
}
#endif /* NEED_BZERO */

/* Lock a file descriptor using fcntl. Returns 1 on successfully
   acquiring the lock. The lock disappears when we close the file.

   Note that if the locked file is on an NFS-mounted partition, you
   are at the mercy of SUN's lockd, which is probably a bad idea
*/

int tac_lockfd TAC_ARGS((char *filename, int lockfd));

int
tac_lockfd (filename, lockfd)
char *filename;
int lockfd;
{
    int tries;
    struct flock flock;
    int status;

    flock.l_type   = F_WRLCK;
    flock.l_whence = SEEK_SET; /* relative to bof */
    flock.l_start  = 0L; /* from offset zero */
    flock.l_len    = 0L; /* lock to eof */

    if (debug & DEBUG_LOCK_FLAG) {
	syslog(LOG_ERR, "Attempting to lock %s fd %d", filename, lockfd);
    }

    for (tries = 0; tries < 10; tries++) {
	errno = 0;
	status = fcntl(lockfd, F_SETLK, &flock);
	if (status == -1) {
	    if (errno == EACCES || errno == EAGAIN) {
		sleep(1);
		continue;
	    } else {
		syslog(LOG_ERR, "fcntl lock error status %d on %s %d %s",
		       status, filename, lockfd, sys_errlist[errno]);
		return(0);
	    }
	}
	/* successful lock */
	break;
    }

    if (errno != 0) {
	syslog(LOG_ERR, "Cannot lock %s fd %d in %d tries %s",
	       filename, lockfd, tries+1, sys_errlist[errno]);

	/* who is hogging this lock */
	flock.l_type   = F_WRLCK;
	flock.l_whence = SEEK_SET; /* relative to bof */
	flock.l_start  = 0L; /* from offset zero */
	flock.l_len    = 0L; /* lock to eof */
#ifdef HAS_FLOCK_SYSID
	flock.l_sysid  = 0L;
#endif
	flock.l_pid    = 0;

	status = fcntl(lockfd, F_GETLK, &flock);
	if ((status == -1) || (flock.l_type == F_UNLCK)) {
	    syslog(LOG_ERR, "Cannot determine %s lockholder status=%d type=%d",
		   filename, status, flock.l_type);
	    return(0);
	}

	if (debug & DEBUG_LOCK_FLAG) {
	    syslog(LOG_ERR, "Lock on %s is being held by sys=%u pid=%d",
		   filename,
#ifdef HAS_FLOCK_SYSID
		   flock.l_sysid,
#else
		   0,
#endif
		   flock.l_pid);
	}
	return(0);
    }

    if (debug & DEBUG_LOCK_FLAG) {
	syslog(LOG_ERR, "Successfully locked %s fd %d after %d tries",
	       filename, lockfd, tries+1);
    }
    return(1);
}

/* Unlock a file descriptor using fcntl. Returns 1 on successfully
   releasing a lock. The lock dies when we close the file.

   Note that if the locked file is on an NFS-mounted partition, you
   are at the mercy of SUN's lockd, which is probably a bad idea
*/

#if 0 /* unused */
static int
tac_unlockfd (filename,lockfd)
char *filename;
int lockfd;
{
    struct flock flock;
    int status;

    flock.l_type   = F_WRLCK;
    flock.l_whence = SEEK_SET; /* relative to bof */
    flock.l_start  = 0L; /* from offset zero */
    flock.l_len    = 0L; /* lock to eof */

    if (debug & DEBUG_LOCK_FLAG) {
	syslog(LOG_ERR, "Attempting to unlock %s fd %d", filename, lockfd);
    }

    status = fcntl(lockfd, F_UNLCK, &flock);
    if (status == -1) {
	syslog(LOG_ERR, "fcntl unlock error status %d on %s %d %s",
	       status, filename, lockfd, sys_errlist[errno]);
	return(1);
    }

    if (debug & DEBUG_LOCK_FLAG) {
	syslog(LOG_ERR, "Successfully unlocked %s fd %d",
	       filename, lockfd);
    }
    return(0);
}
#endif /* unused */

/* Management of bidirectional lists.
*/

#ifdef TAC_LIST_PARANOIA

static void tac_list_check_magic TAC_ARGS((const struct tac_list *list));

static void
tac_list_check_magic(list)
const struct tac_list *list;
{
   if (list->_magic != TAC_LIST_MAGIC)
	report(LOG_ERR, "MAGIC fail for tac_list");
}

static void tac_list_node_check_magic TAC_ARGS((const struct tac_list_node *node));

static void
tac_list_node_check_magic(node)
const struct tac_list_node *node;
{
   if (node->_magic != TAC_LIST_NODE_MAGIC)
	report(LOG_ERR, "MAGIC fail for tac_list_node");
}
#else /* TAC_LIST_PARANOIA */

#define tac_list_check_magic(list)
#define tac_list_node_check_magic(node)

#endif /* TAC_LIST_PARANOIA */


void tac_list_init TAC_ARGS((struct tac_list *list));

void
tac_list_init(list)
struct tac_list *list;
{
#ifdef TAC_LIST_PARANOIA
    list->_magic = TAC_LIST_MAGIC;
#endif
    list->_head = NULL;
    list->_tail = NULL;

    tac_list_check_magic(list);
}

void tac_list_node_init TAC_ARGS((struct tac_list_node *node));

void
tac_list_node_init(node)
struct tac_list_node *node;
{
#ifdef TAC_LIST_PARANOIA
    node->_magic = TAC_LIST_NODE_MAGIC;
#endif
    node->_list = NULL;

    tac_list_node_check_magic(node);
}

struct tac_list *tac_list_node_get_list TAC_ARGS((struct tac_list_node *node));

struct tac_list *
tac_list_node_get_list(node)
struct tac_list_node *node;
{
    tac_list_node_check_magic(node);

    return (node->_list);
}

struct tac_list_node *tac_list_first_node TAC_ARGS((struct tac_list *list));

struct tac_list_node *
tac_list_first_node(list)
struct tac_list *list;
{
    tac_list_check_magic(list);

    return (list->_head);
}

#if 0 /* unused */
struct tac_list_node *tac_list_last_node TAC_ARGS((struct tac_list *list));

struct tac_list_node *
tac_list_last_node(list)
struct tac_list *list;
{
    tac_list_check_magic(list);

    return (list->_tail);
}
#endif /* unused */

void tac_list_addhead TAC_ARGS((struct tac_list *list, struct tac_list_node *node));

void
tac_list_addhead(list, node)
struct tac_list *list;
struct tac_list_node *node;
{
    tac_list_check_magic(list);
    tac_list_node_check_magic(node);

    if ((node->_next = list->_head))
	node->_next->_prev = node;
    list->_head = node;
    node->_prev = NULL;
    if (!list->_tail)
	list->_tail = node;
    node->_list = list;
}

void tac_list_addtail TAC_ARGS((struct tac_list *list, struct tac_list_node *node));

void
tac_list_addtail(list, node)
struct tac_list *list;
struct tac_list_node *node;
{
    tac_list_check_magic(list);
    tac_list_node_check_magic(node);

    if ((node->_prev = list->_tail))
	node->_prev->_next = node;
    list->_tail = node;
    node->_next = NULL;
    if (!list->_head)
	list->_head = node;
    node->_list = list;
}

struct tac_list_node *tac_list_node_next TAC_ARGS((struct tac_list_node *node));

struct tac_list_node *
tac_list_node_next(node)
struct tac_list_node *node;
{
    tac_list_node_check_magic(node);

    return (node->_next);
}
    
#if 0 /* unused */
struct tac_list_node *tac_list_node_prev TAC_ARGS((struct tac_list_node *node));

struct tac_list_node *
tac_list_node_prev(node)
struct tac_list_node *node;
{
    tac_list_node_check_magic(node);

    return (node->_prev);
}
#endif /* unused */

void tac_list_node_remove TAC_ARGS((struct tac_list_node *node));

void
tac_list_node_remove(node)
struct tac_list_node *node;
{
    tac_list_node_check_magic(node);
    tac_list_check_magic(node->_list);

    if (node->_next)
	node->_next->_prev = node->_prev;
    else
	node->_list->_tail = node->_prev;

    if (node->_prev)
	node->_prev->_next = node->_next;
    else
	node->_list->_head = node->_next;

    node->_list = NULL;
}