freebsd-dev/lib/libproc/proc_create.c
Mark Johnston acc0eea6b0 Allow "a.out" as an alias for the executable if no other matching entries
are found. This improves compatibility with Solaris' libproc and fixes a
number of failing DTrace tests that rely on this feature.

MFC after:	3 weeks
2014-05-03 04:44:03 +00:00

190 lines
4.6 KiB
C

/*-
* 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <sys/sysctl.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 "_libproc.h"
static int proc_init(pid_t, int, int, struct proc_handle *);
static int
proc_init(pid_t pid, int flags, int status, struct proc_handle *phdl)
{
int mib[4], error;
size_t len;
memset(phdl, 0, sizeof(*phdl));
phdl->pid = pid;
phdl->flags = flags;
phdl->status = status;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PATHNAME;
mib[3] = pid;
len = sizeof(phdl->execname);
if (sysctl(mib, 4, phdl->execname, &len, NULL, 0) != 0) {
error = errno;
DPRINTF("ERROR: cannot get pathname for child process %d", pid);
return (error);
}
if (len == 0)
phdl->execname[0] = '\0';
return (0);
}
int
proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error = 0;
int status;
if (pid == 0 || pid == getpid())
return (EINVAL);
/*
* Allocate memory for the process handle, a structure containing
* all things related to the process.
*/
if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
return (ENOMEM);
elf_version(EV_CURRENT);
error = proc_init(pid, flags, PS_RUN, phdl);
if (error != 0)
goto out;
if (ptrace(PT_ATTACH, phdl->pid, 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) == 0)
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
else
phdl->status = PS_STOP;
out:
if (error)
proc_free(phdl);
else
*pphdl = phdl;
return (error);
}
int
proc_create(const char *file, char * const *argv, proc_child_func *pcf,
void *child_arg, struct proc_handle **pphdl)
{
struct proc_handle *phdl;
int error = 0;
int status;
pid_t pid;
/*
* Allocate memory for the process handle, a structure containing
* all things related to the process.
*/
if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
return (ENOMEM);
elf_version(EV_CURRENT);
/* Fork a new process. */
if ((pid = vfork()) == -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);
/* Execute the specified file: */
execvp(file, argv);
/* Couldn't execute the file. */
_exit(2);
} else {
/* The parent owns the process handle. */
error = proc_init(pid, 0, PS_IDLE, phdl);
if (error != 0)
goto bad;
/* 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) == 0) {
error = errno;
DPRINTFX("ERROR: child process %d status 0x%x", pid, status);
goto bad;
} else
phdl->status = PS_STOP;
}
bad:
if (error)
proc_free(phdl);
else
*pphdl = phdl;
return (error);
}
void
proc_free(struct proc_handle *phdl)
{
free(phdl);
}