proc_create.c revision 224632 
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 224632 2011-08-03 09:55:59Z avg $
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
82out:
83	if (error)
84		proc_free(phdl);
85	else
86		*pphdl = phdl;
87	return (error);
88}
89
90int
91proc_create(const char *file, char * const *argv, proc_child_func *pcf,
92    void *child_arg, struct proc_handle **pphdl)
93{
94	struct proc_handle *phdl;
95	int error = 0;
96	int status;
97	pid_t pid;
98
99	/*
100	 * Allocate memory for the process handle, a structure containing
101	 * all things related to the process.
102	 */
103	if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
104		return (ENOMEM);
105
106	elf_version(EV_CURRENT);
107
108	/* Fork a new process. */
109	if ((pid = vfork()) == -1)
110		error = errno;
111	else if (pid == 0) {
112		/* The child expects to be traced. */
113		if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0)
114			_exit(1);
115
116		if (pcf != NULL)
117			(*pcf)(child_arg);
118
119		/* Execute the specified file: */
120		execvp(file, argv);
121
122		/* Couldn't execute the file. */
123		_exit(2);
124	} else {
125		/* The parent owns the process handle. */
126		memset(phdl, 0, sizeof(struct proc_handle));
127		phdl->pid = pid;
128		phdl->status = PS_IDLE;
129
130		/* Wait for the child process to stop. */
131		if (waitpid(pid, &status, WUNTRACED) == -1) {
132			error = errno;
133                	DPRINTF("ERROR: child process %d didn't stop as expected", pid);
134			goto bad;
135		}
136
137		/* Check for an unexpected status. */
138		if (WIFSTOPPED(status) == 0) {
139			error = errno;
140                	DPRINTF("ERROR: child process %d status 0x%x", pid, status);
141			goto bad;
142		} else
143			phdl->status = PS_STOP;
144	}
145bad:
146	if (error)
147		proc_free(phdl);
148	else
149		*pphdl = phdl;
150	return (error);
151}
152
153void
154proc_free(struct proc_handle *phdl)
155{
156	free(phdl);
157}
158