proc_create.c revision 216432 
1/*-
2 * Copyright (c) 2008 John Birrell (jb@freebsd.org)
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/lib/libproc/proc_create.c 216432 2010-12-14 15:14:08Z kevlo $
27 */
28
29#include "_libproc.h"
30#include <stdio.h>
31#include <err.h>
32#include <errno.h>
33#include <fcntl.h>
34#include <limits.h>
35#include <stdlib.h>
36#include <string.h>
37#include <unistd.h>
38#include <sys/wait.h>
39
40int
41proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
42{
43	struct proc_handle *phdl;
44	int error = 0;
45	int status;
46
47	if (pid == 0 || pid == getpid())
48		return (EINVAL);
49
50	/*
51	 * Allocate memory for the process handle, a structure containing
52	 * all things related to the process.
53	 */
54	if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
55		return (ENOMEM);
56
57	memset(phdl, 0, sizeof(struct proc_handle));
58	phdl->pid = pid;
59	phdl->flags = flags;
60	phdl->status = PS_RUN;
61	elf_version(EV_CURRENT);
62
63	if (ptrace(PT_ATTACH, phdl->pid, 0, 0) != 0) {
64		error = errno;
65		DPRINTF("ERROR: cannot ptrace child process %d", pid);
66		goto out;
67	}
68
69	/* Wait for the child process to stop. */
70	if (waitpid(pid, &status, WUNTRACED) == -1) {
71		error = errno;
72		DPRINTF("ERROR: child process %d didn't stop as expected", pid);
73		goto out;
74	}
75
76	/* Check for an unexpected status. */
77	if (WIFSTOPPED(status) == 0)
78		DPRINTF("ERROR: child process %d status 0x%x", pid, status);
79	else
80		phdl->status = PS_STOP;
81
82	if (error)
83		proc_free(phdl);
84	else
85		*pphdl = phdl;
86out:
87	proc_free(phdl);
88	return (error);
89}
90
91int
92proc_create(const char *file, char * const *argv, proc_child_func *pcf,
93    void *child_arg, struct proc_handle **pphdl)
94{
95	struct proc_handle *phdl;
96	int error = 0;
97	int status;
98	pid_t pid;
99
100	/*
101	 * Allocate memory for the process handle, a structure containing
102	 * all things related to the process.
103	 */
104	if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
105		return (ENOMEM);
106
107	elf_version(EV_CURRENT);
108
109	/* Fork a new process. */
110	if ((pid = vfork()) == -1)
111		error = errno;
112	else if (pid == 0) {
113		/* The child expects to be traced. */
114		if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0)
115			_exit(1);
116
117		if (pcf != NULL)
118			(*pcf)(child_arg);
119
120		/* Execute the specified file: */
121		execvp(file, argv);
122
123		/* Couldn't execute the file. */
124		_exit(2);
125	} else {
126		/* The parent owns the process handle. */
127		memset(phdl, 0, sizeof(struct proc_handle));
128		phdl->pid = pid;
129		phdl->status = PS_IDLE;
130
131		/* Wait for the child process to stop. */
132		if (waitpid(pid, &status, WUNTRACED) == -1) {
133			error = errno;
134                	DPRINTF("ERROR: child process %d didn't stop as expected", pid);
135			goto bad;
136		}
137
138		/* Check for an unexpected status. */
139		if (WIFSTOPPED(status) == 0) {
140			error = errno;
141                	DPRINTF("ERROR: child process %d status 0x%x", pid, status);
142			goto bad;
143		} else
144			phdl->status = PS_STOP;
145	}
146bad:
147	if (error)
148		proc_free(phdl);
149	else
150		*pphdl = phdl;
151	return (error);
152}
153
154void
155proc_free(struct proc_handle *phdl)
156{
157	free(phdl);
158}
159