serval-dna/nacl/nacl-20110221/curvecp/open_lock.c

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#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "open.h"
int open_lock(const char *fn)
{
#ifdef O_CLOEXEC
int fd = open(fn,O_RDWR | O_CLOEXEC);
if (fd == -1) return -1;
#else
int fd = open(fn,O_RDWR);
if (fd == -1) return -1;
fcntl(fd,F_SETFD,1);
#endif
if (lockf(fd,F_LOCK,0) == -1) { close(fd); return -1; }
return fd;
}