1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
* 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 <sys/socket.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 = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
if (ret < 0) {
ret = -errno;
printk("run_helper : pipe failed, errno = %d\n", errno);
goto out_free;
}
ret = os_set_exec_close(fds[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() ? kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
kmalloc(PATH_MAX, UM_GFP_KERNEL);
pid = clone(helper_child, (void *) sp, CLONE_VM, &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, __WCLONE));
}
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, 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, __WCLONE));
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 nohang, char *pname)
{
int ret, status;
int wflags = __WCLONE;
if (nohang)
wflags |= WNOHANG;
if (!pname)
pname = "helper_wait";
CATCH_EINTR(ret = waitpid(pid, &status, wflags));
if (ret < 0) {
printk(UM_KERN_ERR "%s : waitpid process %d failed, "
"errno = %d\n", pname, pid, errno);
return -errno;
} else if (nohang && ret == 0) {
printk(UM_KERN_ERR "%s : process %d has not exited\n",
pname, pid);
return -ECHILD;
} else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
printk(UM_KERN_ERR "%s : process %d didn't exit with "
"status 0\n", pname, pid);
return -ECHILD;
} else
return 0;
}
|
