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 * $FreeBSD$
27 */
28
29 #include <sys/types.h>
30 #include <sys/sysctl.h>
31 #include <sys/wait.h>
32
33 #include <err.h>
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <limits.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <unistd.h>
40
41 #include "_libproc.h"
42
43 static int proc_init(pid_t, int, int, struct proc_handle *);
44
45 static int
proc_init(pid_t pid,int flags,int status,struct proc_handle * phdl)46 proc_init(pid_t pid, int flags, int status, struct proc_handle *phdl)
47 {
48 int mib[4], error;
49 size_t len;
50
51 memset(phdl, 0, sizeof(*phdl));
52 phdl->pid = pid;
53 phdl->flags = flags;
54 phdl->status = status;
55
56 mib[0] = CTL_KERN;
57 mib[1] = KERN_PROC;
58 mib[2] = KERN_PROC_PATHNAME;
59 mib[3] = pid;
60 len = sizeof(phdl->execname);
61 if (sysctl(mib, 4, phdl->execname, &len, NULL, 0) != 0) {
62 error = errno;
63 DPRINTF("ERROR: cannot get pathname for child process %d", pid);
64 return (error);
65 }
66 if (len == 0)
67 phdl->execname[0] = '\0';
68
69 return (0);
70 }
71
72 int
proc_attach(pid_t pid,int flags,struct proc_handle ** pphdl)73 proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
74 {
75 struct proc_handle *phdl;
76 int error = 0;
77 int status;
78
79 if (pid == 0 || pid == getpid())
80 return (EINVAL);
81
82 /*
83 * Allocate memory for the process handle, a structure containing
84 * all things related to the process.
85 */
86 if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
87 return (ENOMEM);
88
89 elf_version(EV_CURRENT);
90
91 error = proc_init(pid, flags, PS_RUN, phdl);
92 if (error != 0)
93 goto out;
94
95 if (ptrace(PT_ATTACH, phdl->pid, 0, 0) != 0) {
96 error = errno;
97 DPRINTF("ERROR: cannot ptrace child process %d", pid);
98 goto out;
99 }
100
101 /* Wait for the child process to stop. */
102 if (waitpid(pid, &status, WUNTRACED) == -1) {
103 error = errno;
104 DPRINTF("ERROR: child process %d didn't stop as expected", pid);
105 goto out;
106 }
107
108 /* Check for an unexpected status. */
109 if (WIFSTOPPED(status) == 0)
110 DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
111 else
112 phdl->status = PS_STOP;
113
114 out:
115 if (error)
116 proc_free(phdl);
117 else
118 *pphdl = phdl;
119 return (error);
120 }
121
122 int
proc_create(const char * file,char * const * argv,proc_child_func * pcf,void * child_arg,struct proc_handle ** pphdl)123 proc_create(const char *file, char * const *argv, proc_child_func *pcf,
124 void *child_arg, struct proc_handle **pphdl)
125 {
126 struct proc_handle *phdl;
127 int error = 0;
128 int status;
129 pid_t pid;
130
131 /*
132 * Allocate memory for the process handle, a structure containing
133 * all things related to the process.
134 */
135 if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
136 return (ENOMEM);
137
138 elf_version(EV_CURRENT);
139
140 /* Fork a new process. */
141 if ((pid = vfork()) == -1)
142 error = errno;
143 else if (pid == 0) {
144 /* The child expects to be traced. */
145 if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0)
146 _exit(1);
147
148 if (pcf != NULL)
149 (*pcf)(child_arg);
150
151 /* Execute the specified file: */
152 execvp(file, argv);
153
154 /* Couldn't execute the file. */
155 _exit(2);
156 } else {
157 /* The parent owns the process handle. */
158 error = proc_init(pid, 0, PS_IDLE, phdl);
159 if (error != 0)
160 goto bad;
161
162 /* Wait for the child process to stop. */
163 if (waitpid(pid, &status, WUNTRACED) == -1) {
164 error = errno;
165 DPRINTF("ERROR: child process %d didn't stop as expected", pid);
166 goto bad;
167 }
168
169 /* Check for an unexpected status. */
170 if (WIFSTOPPED(status) == 0) {
171 error = errno;
172 DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
173 goto bad;
174 } else
175 phdl->status = PS_STOP;
176 }
177 bad:
178 if (error)
179 proc_free(phdl);
180 else
181 *pphdl = phdl;
182 return (error);
183 }
184
185 void
proc_free(struct proc_handle * phdl)186 proc_free(struct proc_handle *phdl)
187 {
188 free(phdl);
189 }
190