1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2009 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * This software was developed at the University of Cambridge Computer 8 * Laboratory with support from a grant from Google, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #ifndef _SYS_PROCDESC_H_ 33 #define _SYS_PROCDESC_H_ 34 35 #ifdef _KERNEL 36 37 #include <sys/selinfo.h> /* struct selinfo */ 38 #include <sys/_lock.h> 39 #include <sys/_mutex.h> 40 41 /*- 42 * struct procdesc describes a process descriptor, and essentially consists 43 * of two pointers -- one to the file descriptor, and one to the process. 44 * When both become NULL, the process descriptor will be freed. An important 45 * invariant is that there is only ever one process descriptor for a process, 46 * so a single file pointer will suffice. 47 * 48 * Locking key: 49 * (c) - Constant after initial setup. 50 * (p) - Protected by the process descriptor mutex. 51 * (r) - Atomic reference count. 52 * (s) - Protected by selinfo. 53 * (t) - Protected by the proctree_lock 54 */ 55 struct proc; 56 struct sigio; 57 struct procdesc { 58 /* 59 * Basic process descriptor state: the process, a cache of its pid to 60 * satisfy queries after the process exits, and process descriptor 61 * refcount. 62 */ 63 struct proc *pd_proc; /* (t) Process. */ 64 pid_t pd_pid; /* (c) Cached pid. */ 65 u_int pd_refcount; /* (r) Reference count. */ 66 67 /* 68 * In-flight data and notification of events. 69 */ 70 int pd_flags; /* (p) PD_ flags. */ 71 u_short pd_xstat; /* (p) Exit status. */ 72 struct selinfo pd_selinfo; /* (p) Event notification. */ 73 struct mtx pd_lock; /* Protect data + events. */ 74 }; 75 76 /* 77 * Locking macros for the procdesc itself. 78 */ 79 #define PROCDESC_LOCK_DESTROY(pd) mtx_destroy(&(pd)->pd_lock) 80 #define PROCDESC_LOCK_INIT(pd) mtx_init(&(pd)->pd_lock, "procdesc", NULL, \ 81 MTX_DEF) 82 #define PROCDESC_LOCK(pd) mtx_lock(&(pd)->pd_lock) 83 #define PROCDESC_UNLOCK(pd) mtx_unlock(&(pd)->pd_lock) 84 85 /* 86 * Flags for the pd_flags field. 87 */ 88 #define PDF_CLOSED 0x00000001 /* Descriptor has closed. */ 89 #define PDF_SELECTED 0x00000002 /* Issue selwakeup(). */ 90 #define PDF_EXITED 0x00000004 /* Process exited. */ 91 #define PDF_DAEMON 0x00000008 /* Don't exit when procdesc closes. */ 92 93 /* 94 * In-kernel interfaces to process descriptors. 95 */ 96 int procdesc_exit(struct proc *); 97 int procdesc_find(struct thread *, int fd, cap_rights_t *, struct proc **); 98 int kern_pdgetpid(struct thread *, int fd, cap_rights_t *, pid_t *pidp); 99 void procdesc_new(struct proc *, int); 100 void procdesc_finit(struct procdesc *, struct file *); 101 pid_t procdesc_pid(struct file *); 102 void procdesc_reap(struct proc *); 103 104 int procdesc_falloc(struct thread *, struct file **, int *, int, 105 struct filecaps *); 106 107 #else /* !_KERNEL */ 108 109 #include <sys/_types.h> 110 111 #ifndef _PID_T_DECLARED 112 typedef __pid_t pid_t; 113 #define _PID_T_DECLARED 114 #endif 115 116 struct rusage; 117 118 /* 119 * Process descriptor system calls. 120 */ 121 __BEGIN_DECLS 122 pid_t pdfork(int *, int); 123 int pdkill(int, int); 124 int pdgetpid(int, pid_t *); 125 __END_DECLS 126 127 #endif /* _KERNEL */ 128 129 /* 130 * Flags which can be passed to pdfork(2). 131 */ 132 #define PD_DAEMON 0x00000001 /* Don't exit when procdesc closes. */ 133 #define PD_CLOEXEC 0x00000002 /* Close file descriptor on exec. */ 134 135 #define PD_ALLOWED_AT_FORK (PD_DAEMON | PD_CLOEXEC) 136 137 #endif /* !_SYS_PROCDESC_H_ */ 138