pidfile.hpp

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#ifndef _POWERDXX_SYS_PIDFILE_HPP_
#define _POWERDXX_SYS_PIDFILE_HPP_
 
#include "error.hpp"    /* sys::sc_error */
 
#include <libutil.h>    /* pidfile_*() */
 
namespace sys {
 
namespace pid {
 
struct error {};
 
class Pidfile final {
    private:
    pid_t otherpid;
 
    pidfh * pfh;
 
    public:
    Pidfile(char const * const pfname, mode_t const mode) :
        otherpid{0}, pfh{pidfile_open(pfname, mode, &this->otherpid)} {
        if (this->pfh == nullptr) {
            switch (errno) {
            case EEXIST:
                throw this->otherpid;
            default:
                throw sc_error<error>{errno};
            }
        }
    }
 
    ~Pidfile() {
        pidfile_remove(this->pfh);
    }
 
    pid_t other() { return this->otherpid; }
 
    void write() {
        if (pidfile_write(this->pfh) == -1) {
            throw sc_error<error>{errno};
        }
    }
};
 
} /* namespace pid */
 
} /* namespace sys */
 
#endif /* _POWERDXX_SYS_PIDFILE_HPP_ */