/*
* @descriptor:主进程创建listenfd,子进程创建connfd,次用文件锁方式保证子进程中的accept并发安全
*/
void my_lock_init(char *filename)
{
char lock_file[1024];
strncpy(lock_file,filename,sizeof(lock_file));
//创建一个零时文件
Mktemp(lock_file);
fd = open(lock_file,O_CREAT | O_WRONLY,FILE_MODE);
unlink(lock_file);
bzero(lock_it,sizeof(struct flock));
bzero(unlock_it,sizeof(struct flock));
lock_it.l_type = F_WRLCK;
lock_it.l_wheel = SEEK_SET;
lock_it.l_start = 0;
lock_it.l_len = 0;
unlock_it.l_type = F_UNLCK;
unlock_it.l_wheel = SEEK_SET;
unlock_it.l_start = 0;
unlock_it.l_len = 0;
}
char *Mktemp(const char *base)
{
static char id[16] = "AAAAAAAAAAAAAAA";
char *p1,*p2,*st;
if ((st = malloc(strlen(base) + 1)) == NULL)
{
fprintf(stderr,"%s: memory allocation failure\n", program_name);
exit (EXIT_FAILURE);
}
st = strcpy(st,base);
if (*st == '\0')
{
free (st);
if ((st = strdup("TXXXXXXX")) == NULL)
{
fprintf(stderr,"%s: memory allocation failure\n", program_name);
exit (EXIT_FAILURE);
}
}
/* Replace all "X" with part of ID string */
for(p1 = st + strlen(st) - 1,p2 = &id[14];
p1 >= st && p2 >= id && *p1 == 'X';
p1--,p2--)
*p1 = *p2;
/* Update ID string to "count" one further */
for(p1 = &id[14];p1 >= id;)
if(*p1 == 'Z')
{
*p1 = 'A';
p1--;
} else {
*p1 += 1;
break;
}
/* Make sure the file name does not already exist */
#ifdef __GNO__
if (needsgno() == TRUE) {
#endif
if (stat(st,&tstat) == 0)
{
free (st);
st = Mktemp (base);
}
#ifdef __GNO__
} else { /* ORCA/Shell doesn't like stat one little bit */
FILE *fp;
if ((fp = fopen(st,"r")) != NULL)
{
fclose(fp);
free (st);
st = Mktemp (base);
} else if ((fp = fopen(st,"a")) == NULL) {
free(st);
st = Mktemp (base);
} else {
fclose(fp);
}
}
#endif /* __GNO__ */
return st;
}
