/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2008 John Birrell (jb@freebsd.org)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/sysctl.h>
#include <sys/user.h>
#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libelf.h>
#include <libprocstat.h>
#include "_libproc.h"
extern char * const *environ;
static int getelfclass(int);
static int proc_init(pid_t, int, int, struct proc_handle **);
static int
getelfclass(int fd)
{
GElf_Ehdr ehdr;
Elf *e;
int class;
class = ELFCLASSNONE;
if ((e = elf_begin(fd, ELF_C_READ, NULL)) == NULL)
goto out;
if (gelf_getehdr(e, &ehdr) == NULL)
goto out;
class = ehdr.e_ident[EI_CLASS];
out:
(void)elf_end(e);
return (class);
}
static int
proc_init(pid_t pid, int flags, int status, struct proc_handle **pphdl)
{
struct kinfo_proc *kp;
struct proc_handle *phdl;
int error, class, count, fd;
error = ENOMEM;
if ((phdl = malloc(sizeof(*phdl))) == NULL)
goto out;
memset(phdl, 0, sizeof(*phdl));
phdl->public.pid = pid;
phdl->flags = flags;
phdl->status = status;
phdl->procstat = procstat_open_sysctl();
if (phdl->procstat == NULL)
goto out;
/* Obtain a path to the executable. */
if ((kp = procstat_getprocs(phdl->procstat, KERN_PROC_PID, pid,
&count)) == NULL)
goto out;
error = procstat_getpathname(phdl->procstat, kp, phdl->execpath,
sizeof(phdl->execpath));
procstat_freeprocs(phdl->procstat, kp);
if (error != 0)
goto out;
/* Use it to determine the data model for the process. */
if ((fd = open(phdl->execpath, O_RDONLY)) < 0) {
error = errno;
goto out;
}
class = getelfclass(fd);
switch (class) {
case ELFCLASS64:
phdl->model = PR_MODEL_LP64;
break;
case ELFCLASS32:
phdl->model = PR_MODEL_ILP32;
break;
case ELFCLASSNONE:
default:
error = EINVAL;
break;
}
(void)close(fd);
out:
*pphdl = phdl;
return (error);
}
int
proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error, status;
if (pid == 0 || (pid == getpid() && (flags & PATTACH_RDONLY) == 0))
return (EINVAL);
if (elf_version(EV_CURRENT) == EV_NONE)
return (ENOENT);
/*
* Allocate memory for the process handle, a structure containing
* all things related to the process.
*/
error = proc_init(pid, flags, PS_RUN, &phdl);
if (error != 0)
goto out;
if ((flags & PATTACH_RDONLY) == 0) {
if (ptrace(PT_ATTACH, proc_getpid(phdl), 0, 0) != 0) {
error = errno;
DPRINTF("ERROR: cannot ptrace child process %d", pid);
goto out;
}
/* Wait for the child process to stop. */
if (waitpid(pid, &status, WUNTRACED) == -1) {
error = errno;
DPRINTF("ERROR: child process %d didn't stop as expected", pid);
goto out;
}
/* Check for an unexpected status. */
if (!WIFSTOPPED(status))
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
else
phdl->status = PS_STOP;
if ((flags & PATTACH_NOSTOP) != 0)
proc_continue(phdl);
}
out:
if (error != 0 && phdl != NULL) {
proc_free(phdl);
phdl = NULL;
}
*pphdl = phdl;
return (error);
}
int
proc_create(const char *file, char * const *argv, char * const *envp,
proc_child_func *pcf, void *child_arg, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error, status;
pid_t pid;
if (elf_version(EV_CURRENT) == EV_NONE)
return (ENOENT);
error = 0;
phdl = NULL;
if ((pid = fork()) == -1)
error = errno;
else if (pid == 0) {
/* The child expects to be traced. */
if (ptrace(PT_TRACE_ME, 0, 0, 0) != 0)
_exit(1);
if (pcf != NULL)
(*pcf)(child_arg);
if (envp != NULL)
environ = envp;
execvp(file, argv);
_exit(2);
/* NOTREACHED */
} else {
/* Wait for the child process to stop. */
if (waitpid(pid, &status, WUNTRACED) == -1) {
error = errno;
DPRINTF("ERROR: child process %d didn't stop as expected", pid);
goto bad;
}
/* Check for an unexpected status. */
if (!WIFSTOPPED(status)) {
error = ENOENT;
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
goto bad;
}
/* The parent owns the process handle. */
error = proc_init(pid, 0, PS_IDLE, &phdl);
if (error == 0)
phdl->status = PS_STOP;
bad:
if (error != 0 && phdl != NULL) {
proc_free(phdl);
phdl = NULL;
}
}
*pphdl = phdl;
return (error);
}
void
proc_free(struct proc_handle *phdl)
{
struct file_info *file;
size_t i;
for (i = 0; i < phdl->nmappings; i++) {
file = phdl->mappings[i].file;
if (file != NULL && --file->refs == 0) {
if (file->elf != NULL) {
(void)elf_end(file->elf);
(void)close(file->fd);
if (file->symtab.nsyms > 0)
free(file->symtab.index);
if (file->dynsymtab.nsyms > 0)
free(file->dynsymtab.index);
}
free(file);
}
}
if (phdl->maparrsz > 0)
free(phdl->mappings);
if (phdl->procstat != NULL)
procstat_close(phdl->procstat);
if (phdl->rdap != NULL)
rd_delete(phdl->rdap);
free(phdl);
}
