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 265255 2014-05-03 04:44:03Z markj $ 27 */ 28 #include <sys/cdefs.h> 29 __RCSID("$NetBSD: proc_create.c,v 1.2 2015/09/24 14:12:48 christos Exp $"); 30 31 #include <sys/types.h> 32 #include <sys/sysctl.h> 33 #include <sys/wait.h> 34 35 #include <err.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <limits.h> 39 #include <stdlib.h> 40 #include <string.h> 41 #include <unistd.h> 42 43 #include "_libproc.h" 44 45 static int proc_init(pid_t, int, int, struct proc_handle *); 46 47 static int 48 proc_init(pid_t pid, int flags, int status, struct proc_handle *phdl) 49 { 50 int mib[4], error; 51 size_t len; 52 53 memset(phdl, 0, sizeof(*phdl)); 54 phdl->pid = pid; 55 phdl->flags = flags; 56 phdl->status = status; 57 58 mib[0] = CTL_KERN; 59 mib[1] = KERN_PROC_ARGS; 60 mib[2] = pid; 61 mib[3] = KERN_PROC_PATHNAME; 62 len = sizeof(phdl->execname); 63 if (sysctl(mib, 4, phdl->execname, &len, NULL, 0) != 0) { 64 error = errno; 65 DPRINTF("ERROR: cannot get pathname for child process %d", pid); 66 return (error); 67 } 68 if (len == 0) 69 phdl->execname[0] = '\0'; 70 71 return (0); 72 } 73 74 int 75 proc_attach(pid_t pid, int flags, struct proc_handle **pphdl) 76 { 77 struct proc_handle *phdl; 78 int error = 0; 79 int status; 80 81 if (pid == 0 || pid == getpid()) 82 return (EINVAL); 83 84 /* 85 * Allocate memory for the process handle, a structure containing 86 * all things related to the process. 87 */ 88 if ((phdl = malloc(sizeof(struct proc_handle))) == NULL) 89 return (ENOMEM); 90 91 elf_version(EV_CURRENT); 92 93 error = proc_init(pid, flags, PS_RUN, phdl); 94 if (error != 0) 95 goto out; 96 97 if (ptrace(PT_ATTACH, phdl->pid, 0, 0) != 0) { 98 error = errno; 99 DPRINTF("ERROR: cannot ptrace child process %d", pid); 100 goto out; 101 } 102 103 /* Wait for the child process to stop. */ 104 if (waitpid(pid, &status, WUNTRACED) == -1) { 105 error = errno; 106 DPRINTF("ERROR: child process %d didn't stop as expected", pid); 107 goto out; 108 } 109 110 /* Check for an unexpected status. */ 111 if (WIFSTOPPED(status) == 0) 112 DPRINTFX("ERROR: child process %d status 0x%x", pid, status); 113 else 114 phdl->status = PS_STOP; 115 116 out: 117 if (error) 118 proc_free(phdl); 119 else 120 *pphdl = phdl; 121 return (error); 122 } 123 124 int 125 proc_create(const char *file, char * const *argv, proc_child_func *pcf, 126 void *child_arg, struct proc_handle **pphdl) 127 { 128 struct proc_handle *phdl; 129 int error = 0; 130 int status; 131 pid_t pid; 132 133 /* 134 * Allocate memory for the process handle, a structure containing 135 * all things related to the process. 136 */ 137 if ((phdl = malloc(sizeof(struct proc_handle))) == NULL) 138 return (ENOMEM); 139 140 elf_version(EV_CURRENT); 141 142 /* Fork a new process. */ 143 if ((pid = vfork()) == -1) 144 error = errno; 145 else if (pid == 0) { 146 /* The child expects to be traced. */ 147 if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0) 148 _exit(1); 149 150 if (pcf != NULL) 151 (*pcf)(child_arg); 152 153 /* Execute the specified file: */ 154 execvp(file, argv); 155 156 /* Couldn't execute the file. */ 157 _exit(2); 158 } else { 159 /* The parent owns the process handle. */ 160 error = proc_init(pid, 0, PS_IDLE, phdl); 161 if (error != 0) 162 goto bad; 163 164 /* Wait for the child process to stop. */ 165 if (waitpid(pid, &status, WUNTRACED) == -1) { 166 error = errno; 167 DPRINTF("ERROR: child process %d didn't stop as expected", pid); 168 goto bad; 169 } 170 171 /* Check for an unexpected status. */ 172 if (WIFSTOPPED(status) == 0) { 173 error = errno; 174 DPRINTFX("ERROR: child process %d status 0x%x", pid, status); 175 goto bad; 176 } else 177 phdl->status = PS_STOP; 178 } 179 bad: 180 if (error) 181 proc_free(phdl); 182 else 183 *pphdl = phdl; 184 return (error); 185 } 186 187 void 188 proc_free(struct proc_handle *phdl) 189 { 190 free(phdl); 191 } 192