--- a/upmpd/upmpdutils.cxx
+++ b/upmpd/upmpdutils.cxx
@@ -25,6 +25,7 @@
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <sys/file.h>
#include <math.h>
#include <pwd.h>
#include <regex.h>
@@ -366,3 +367,113 @@
regfree(&expr);
return out;
}
+
+// We do not want to mess with the pidfile content in the destructor:
+// the lock might still be in use in a child process. In fact as much
+// as we'd like to reset the pid inside the file when we're done, it
+// would be very difficult to do it right and it's probably best left
+// alone.
+Pidfile::~Pidfile()
+{
+ if (m_fd >= 0)
+ ::close(m_fd);
+ m_fd = -1;
+}
+
+pid_t Pidfile::read_pid()
+{
+ int fd = ::open(m_path.c_str(), O_RDONLY);
+ if (fd == -1)
+ return (pid_t)-1;
+
+ char buf[16];
+ int i = read(fd, buf, sizeof(buf) - 1);
+ ::close(fd);
+ if (i <= 0)
+ return (pid_t)-1;
+ buf[i] = '\0';
+ char *endptr;
+ pid_t pid = strtol(buf, &endptr, 10);
+ if (endptr != &buf[i])
+ return (pid_t)-1;
+ return pid;
+}
+
+int Pidfile::flopen()
+{
+ const char *path = m_path.c_str();
+ if ((m_fd = ::open(path, O_RDWR|O_CREAT, 0644)) == -1) {
+ m_reason = "Open failed: [" + m_path + "]: " + strerror(errno);
+ return -1;
+ }
+
+#ifdef sun
+ struct flock lockdata;
+ lockdata.l_start = 0;
+ lockdata.l_len = 0;
+ lockdata.l_type = F_WRLCK;
+ lockdata.l_whence = SEEK_SET;
+ if (fcntl(m_fd, F_SETLK, &lockdata) != 0) {
+ int serrno = errno;
+ (void)::close(m_fd);
+ errno = serrno;
+ m_reason = "fcntl lock failed";
+ return -1;
+ }
+#else
+ int operation = LOCK_EX | LOCK_NB;
+ if (flock(m_fd, operation) == -1) {
+ int serrno = errno;
+ (void)::close(m_fd);
+ errno = serrno;
+ m_reason = "flock failed";
+ return -1;
+ }
+#endif // ! sun
+
+ if (ftruncate(m_fd, 0) != 0) {
+ /* can't happen [tm] */
+ int serrno = errno;
+ (void)::close(m_fd);
+ errno = serrno;
+ m_reason = "ftruncate failed";
+ return -1;
+ }
+ return 0;
+}
+
+pid_t Pidfile::open()
+{
+ if (flopen() < 0) {
+ return read_pid();
+ }
+ return (pid_t)0;
+}
+
+int Pidfile::write_pid()
+{
+ /* truncate to allow multiple calls */
+ if (ftruncate(m_fd, 0) == -1) {
+ m_reason = "ftruncate failed";
+ return -1;
+ }
+ char pidstr[20];
+ sprintf(pidstr, "%u", int(getpid()));
+ lseek(m_fd, 0, 0);
+ if (::write(m_fd, pidstr, strlen(pidstr)) != (ssize_t)strlen(pidstr)) {
+ m_reason = "write failed";
+ return -1;
+ }
+ return 0;
+}
+
+int Pidfile::close()
+{
+ return ::close(m_fd);
+}
+
+int Pidfile::remove()
+{
+ return unlink(m_path.c_str());
+}
+