src/basic/pidref.h

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 #pragma once
   3
   4 #include "macro.h"
   5
   6 /* An embeddable structure carrying a reference to a process. Supposed to be used when tracking processes continuously. */
   7 typedef struct PidRef {
   8         pid_t pid; /* always valid */
   9         int fd;    /* only valid if pidfd are available in the kernel, and we manage to get an fd */
  10 } PidRef;
  11
  12 #define PIDREF_NULL (PidRef) { .fd = -EBADF }
  13
  14 static inline bool pidref_is_set(const PidRef *pidref) {
  15         return pidref && pidref->pid > 0;
  16 }
  17
  18 static inline bool pidref_equal(const PidRef *a, const PidRef *b) {
  19
  20         if (pidref_is_set(a)) {
  21                 if (!pidref_is_set(b))
  22                         return false;
  23
  24                 return a->pid == b->pid;
  25         }
  26
  27         return !pidref_is_set(b);
  28 }
  29
  30 int pidref_set_pid(PidRef *pidref, pid_t pid);
  31 int pidref_set_pidstr(PidRef *pidref, const char *pid);
  32 int pidref_set_pidfd(PidRef *pidref, int fd);
  33 int pidref_set_pidfd_take(PidRef *pidref, int fd); /* takes ownership of the passed pidfd on success*/
  34 int pidref_set_pidfd_consume(PidRef *pidref, int fd); /* takes ownership of the passed pidfd in both success and failure */
  35
  36 void pidref_done(PidRef *pidref);
  37
  38 int pidref_kill(PidRef *pidref, int sig);
  39 int pidref_kill_and_sigcont(PidRef *pidref, int sig);
  40 int pidref_sigqueue(PidRef *pidfref, int sig, int value);
  41
  42 #define TAKE_PIDREF(p) TAKE_GENERIC((p), PidRef, PIDREF_NULL)