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 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 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 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 186 proc_free(struct proc_handle *phdl) 187 { 188 free(phdl); 189 } 190