2 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
10 #include <sys/socket.h>
12 #include "kern_constants.h"
13 #include "kern_util.h"
15 #include "um_malloc.h"
17 #include <linux/limits.h>
20 void (*pre_exec)(void*);
27 static int helper_child(void *arg)
29 struct helper_data *data = arg;
30 char **argv = data->argv;
33 if (data->pre_exec != NULL)
34 (*data->pre_exec)(data->pre_data);
35 err = execvp_noalloc(data->buf, argv[0], argv);
37 /* If the exec succeeds, we don't get here */
38 write(data->fd, &err, sizeof(err));
43 /* Returns either the pid of the child process we run or -E* on failure. */
44 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
46 struct helper_data data;
47 unsigned long stack, sp;
48 int pid, fds[2], ret, n;
50 stack = alloc_stack(0, __cant_sleep());
54 ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
57 printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n",
62 ret = os_set_exec_close(fds[1]);
64 printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, "
69 sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
70 data.pre_exec = pre_exec;
71 data.pre_data = pre_data;
74 data.buf = __cant_sleep() ? kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
75 kmalloc(PATH_MAX, UM_GFP_KERNEL);
76 pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
79 printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n",
88 * Read the errno value from the child, if the exec failed, or get 0 if
89 * the exec succeeded because the pipe fd was set as close-on-exec.
91 n = read(fds[0], &ret, sizeof(ret));
97 printk(UM_KERN_ERR "run_helper : read on pipe failed, "
101 CATCH_EINTR(waitpid(pid, NULL, __WCLONE));
111 free_stack(stack, 0);
115 int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
116 unsigned long *stack_out)
118 unsigned long stack, sp;
119 int pid, status, err;
121 stack = alloc_stack(0, __cant_sleep());
125 sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
126 pid = clone(proc, (void *) sp, flags, arg);
129 printk(UM_KERN_ERR "run_helper_thread : clone failed, "
130 "errno = %d\n", errno);
133 if (stack_out == NULL) {
134 CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE));
137 printk(UM_KERN_ERR "run_helper_thread - wait failed, "
138 "errno = %d\n", errno);
141 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
142 printk(UM_KERN_ERR "run_helper_thread - thread "
143 "returned status 0x%x\n", status);
144 free_stack(stack, 0);
150 int helper_wait(int pid)
153 int wflags = __WCLONE;
155 CATCH_EINTR(ret = waitpid(pid, &status, wflags));
157 printk(UM_KERN_ERR "helper_wait : waitpid process %d failed, "
158 "errno = %d\n", pid, errno);
160 } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
161 printk(UM_KERN_ERR "helper_wait : process %d exited with "
162 "status 0x%x\n", pid, status);