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/*
* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
* Licensed under the GPL
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sched.h>
#include <limits.h>
#include <sys/signal.h>
#include <sys/wait.h>
#include "user.h"
#include "kern_util.h"
#include "os.h"
#include "um_malloc.h"
#include "kern_constants.h"
struct helper_data {
void (*pre_exec)(void*);
void *pre_data;
char **argv;
int fd;
char *buf;
};
static int helper_child(void *arg)
{
struct helper_data *data = arg;
char **argv = data->argv;
int errval;
if (data->pre_exec != NULL)
(*data->pre_exec)(data->pre_data);
errval = execvp_noalloc(data->buf, argv[0], argv);
printk("helper_child - execvp of '%s' failed - errno = %d\n", argv[0],
-errval);
write(data->fd, &errval, sizeof(errval));
kill(os_getpid(), SIGKILL);
return 0;
}
/* Returns either the pid of the child process we run or -E* on failure.
* XXX The alloc_stack here breaks if this is called in the tracing thread, so
* we need to receive a preallocated stack (a local buffer is ok). */
int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
{
struct helper_data data;
unsigned long stack, sp;
int pid, fds[2], ret, n;
stack = alloc_stack(0, __cant_sleep());
if (stack == 0)
return -ENOMEM;
ret = os_pipe(fds, 1, 0);
if (ret < 0) {
printk("run_helper : pipe failed, ret = %d\n", -ret);
goto out_free;
}
ret = os_set_exec_close(fds[1], 1);
if (ret < 0) {
printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n",
-ret);
goto out_close;
}
sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
data.pre_exec = pre_exec;
data.pre_data = pre_data;
data.argv = argv;
data.fd = fds[1];
data.buf = __cant_sleep() ? um_kmalloc_atomic(PATH_MAX) :
um_kmalloc(PATH_MAX);
pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
if (pid < 0) {
ret = -errno;
printk("run_helper : clone failed, errno = %d\n", errno);
goto out_free2;
}
close(fds[1]);
fds[1] = -1;
/*
* Read the errno value from the child, if the exec failed, or get 0 if
* the exec succeeded because the pipe fd was set as close-on-exec.
*/
n = read(fds[0], &ret, sizeof(ret));
if (n == 0) {
ret = pid;
} else {
if (n < 0) {
n = -errno;
printk("run_helper : read on pipe failed, ret = %d\n",
-n);
ret = n;
kill(pid, SIGKILL);
}
CATCH_EINTR(waitpid(pid, NULL, 0));
}
out_free2:
kfree(data.buf);
out_close:
if (fds[1] != -1)
close(fds[1]);
close(fds[0]);
out_free:
free_stack(stack, 0);
return ret;
}
int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
unsigned long *stack_out)
{
unsigned long stack, sp;
int pid, status, err;
stack = alloc_stack(0, __cant_sleep());
if (stack == 0)
return -ENOMEM;
sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
if (pid < 0) {
err = -errno;
printk("run_helper_thread : clone failed, errno = %d\n",
errno);
return err;
}
if (stack_out == NULL) {
CATCH_EINTR(pid = waitpid(pid, &status, 0));
if (pid < 0) {
err = -errno;
printk("run_helper_thread - wait failed, errno = %d\n",
errno);
pid = err;
}
if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
printk("run_helper_thread - thread returned status "
"0x%x\n", status);
free_stack(stack, 0);
} else
*stack_out = stack;
return pid;
}
int helper_wait(int pid)
{
int ret;
CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG));
if (ret < 0) {
ret = -errno;
printk("helper_wait : waitpid failed, errno = %d\n", errno);
}
return ret;
}
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