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/* ISC license. */
#include <errno.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/strerr2.h>
#include <skalibs/djbunix.h>
#define USAGE "s6lockd-helper lockfile"
#define dieusage() strerr_dieusage(100, USAGE)
int main (int argc, char const *const *argv)
{
int fd, r ;
char c ;
PROG = "s6lockd-helper" ;
if (argc < 3) dieusage() ;
fd = open_create(argv[2]) ;
if (fd < 0) strerr_diefu2sys(111, "open ", argv[1]) ;
r = fd_lock(fd, argv[1][0] == 'w', 0) ;
if (!r) errno = EBUSY ;
if (r < 1) strerr_diefu2sys(111, "lock ", argv[2]) ;
if (fd_write(1, "!", 1) <= 0)
strerr_diefu1sys(111, "write to stdout") ;
if (fd_read(0, &c, 1) < 0)
strerr_diefu1sys(111, "read from stdin") ;
return 0 ;
}
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