Commit | Line | Data |
---|---|---|
ff5c6ff5 | 1 | /* |
1aa351a3 | 2 | * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
1da177e4 LT |
6 | #include <stdlib.h> |
7 | #include <unistd.h> | |
8 | #include <errno.h> | |
9 | #include <sched.h> | |
b6d8adf4 | 10 | #include <linux/limits.h> |
512b6fb1 | 11 | #include <sys/socket.h> |
1aa351a3 JD |
12 | #include <sys/wait.h> |
13 | #include "kern_constants.h" | |
1da177e4 | 14 | #include "kern_util.h" |
1da177e4 | 15 | #include "os.h" |
5d48545e | 16 | #include "um_malloc.h" |
1aa351a3 | 17 | #include "user.h" |
1da177e4 LT |
18 | |
19 | struct helper_data { | |
20 | void (*pre_exec)(void*); | |
21 | void *pre_data; | |
22 | char **argv; | |
23 | int fd; | |
5d48545e | 24 | char *buf; |
1da177e4 LT |
25 | }; |
26 | ||
1da177e4 LT |
27 | static int helper_child(void *arg) |
28 | { | |
29 | struct helper_data *data = arg; | |
30 | char **argv = data->argv; | |
1aa351a3 | 31 | int err; |
1da177e4 | 32 | |
8b028bcd | 33 | if (data->pre_exec != NULL) |
1da177e4 | 34 | (*data->pre_exec)(data->pre_data); |
1aa351a3 JD |
35 | err = execvp_noalloc(data->buf, argv[0], argv); |
36 | ||
37 | /* If the exec succeeds, we don't get here */ | |
38 | write(data->fd, &err, sizeof(err)); | |
39 | ||
8b028bcd | 40 | return 0; |
1da177e4 LT |
41 | } |
42 | ||
1aa351a3 | 43 | /* Returns either the pid of the child process we run or -E* on failure. */ |
c4399016 | 44 | int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv) |
1da177e4 LT |
45 | { |
46 | struct helper_data data; | |
47 | unsigned long stack, sp; | |
48 | int pid, fds[2], ret, n; | |
49 | ||
c4399016 | 50 | stack = alloc_stack(0, __cant_sleep()); |
8b028bcd | 51 | if (stack == 0) |
6b7aaad9 | 52 | return -ENOMEM; |
1da177e4 | 53 | |
512b6fb1 | 54 | ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds); |
8b028bcd | 55 | if (ret < 0) { |
512b6fb1 | 56 | ret = -errno; |
1aa351a3 JD |
57 | printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n", |
58 | errno); | |
1da177e4 LT |
59 | goto out_free; |
60 | } | |
61 | ||
512b6fb1 | 62 | ret = os_set_exec_close(fds[1]); |
8b028bcd | 63 | if (ret < 0) { |
1aa351a3 JD |
64 | printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, " |
65 | "ret = %d\n", -ret); | |
1da177e4 LT |
66 | goto out_close; |
67 | } | |
68 | ||
1ffb9164 | 69 | sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *); |
1da177e4 LT |
70 | data.pre_exec = pre_exec; |
71 | data.pre_data = pre_data; | |
72 | data.argv = argv; | |
73 | data.fd = fds[1]; | |
43f5b308 JD |
74 | data.buf = __cant_sleep() ? uml_kmalloc(PATH_MAX, UM_GFP_ATOMIC) : |
75 | uml_kmalloc(PATH_MAX, UM_GFP_KERNEL); | |
4dbed85a | 76 | pid = clone(helper_child, (void *) sp, CLONE_VM, &data); |
8b028bcd | 77 | if (pid < 0) { |
1da177e4 | 78 | ret = -errno; |
1aa351a3 JD |
79 | printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n", |
80 | errno); | |
5d48545e | 81 | goto out_free2; |
1da177e4 LT |
82 | } |
83 | ||
ff5c6ff5 | 84 | close(fds[1]); |
1da177e4 LT |
85 | fds[1] = -1; |
86 | ||
ef0470c0 JD |
87 | /* |
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. | |
90 | */ | |
a61f334f | 91 | n = read(fds[0], &ret, sizeof(ret)); |
8b028bcd | 92 | if (n == 0) { |
1da177e4 | 93 | ret = pid; |
8b028bcd PBG |
94 | } else { |
95 | if (n < 0) { | |
a61f334f | 96 | n = -errno; |
1aa351a3 JD |
97 | printk(UM_KERN_ERR "run_helper : read on pipe failed, " |
98 | "ret = %d\n", -n); | |
6b7aaad9 | 99 | ret = n; |
6b7aaad9 | 100 | } |
4dbed85a | 101 | CATCH_EINTR(waitpid(pid, NULL, __WCLONE)); |
1da177e4 LT |
102 | } |
103 | ||
5d48545e PBG |
104 | out_free2: |
105 | kfree(data.buf); | |
1da177e4 LT |
106 | out_close: |
107 | if (fds[1] != -1) | |
ff5c6ff5 JD |
108 | close(fds[1]); |
109 | close(fds[0]); | |
1da177e4 | 110 | out_free: |
c4399016 | 111 | free_stack(stack, 0); |
8b028bcd | 112 | return ret; |
1da177e4 LT |
113 | } |
114 | ||
ff5c6ff5 | 115 | int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, |
c4399016 | 116 | unsigned long *stack_out) |
1da177e4 LT |
117 | { |
118 | unsigned long stack, sp; | |
b4fd310e | 119 | int pid, status, err; |
1da177e4 | 120 | |
c4399016 | 121 | stack = alloc_stack(0, __cant_sleep()); |
8b028bcd PBG |
122 | if (stack == 0) |
123 | return -ENOMEM; | |
1da177e4 | 124 | |
c4399016 | 125 | sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *); |
4dbed85a | 126 | pid = clone(proc, (void *) sp, flags, arg); |
8b028bcd | 127 | if (pid < 0) { |
b4fd310e | 128 | err = -errno; |
1aa351a3 JD |
129 | printk(UM_KERN_ERR "run_helper_thread : clone failed, " |
130 | "errno = %d\n", errno); | |
b4fd310e | 131 | return err; |
1da177e4 | 132 | } |
8b028bcd | 133 | if (stack_out == NULL) { |
4dbed85a | 134 | CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE)); |
8b028bcd | 135 | if (pid < 0) { |
b4fd310e | 136 | err = -errno; |
1aa351a3 JD |
137 | printk(UM_KERN_ERR "run_helper_thread - wait failed, " |
138 | "errno = %d\n", errno); | |
b4fd310e | 139 | pid = err; |
1da177e4 | 140 | } |
8b028bcd | 141 | if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) |
1aa351a3 JD |
142 | printk(UM_KERN_ERR "run_helper_thread - thread " |
143 | "returned status 0x%x\n", status); | |
c4399016 | 144 | free_stack(stack, 0); |
8b028bcd PBG |
145 | } else |
146 | *stack_out = stack; | |
147 | return pid; | |
1da177e4 LT |
148 | } |
149 | ||
1aa351a3 | 150 | int helper_wait(int pid) |
1da177e4 | 151 | { |
4dbed85a SG |
152 | int ret, status; |
153 | int wflags = __WCLONE; | |
1da177e4 | 154 | |
4dbed85a | 155 | CATCH_EINTR(ret = waitpid(pid, &status, wflags)); |
8b028bcd | 156 | if (ret < 0) { |
1aa351a3 JD |
157 | printk(UM_KERN_ERR "helper_wait : waitpid process %d failed, " |
158 | "errno = %d\n", pid, errno); | |
4dbed85a | 159 | return -errno; |
4dbed85a | 160 | } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
1aa351a3 JD |
161 | printk(UM_KERN_ERR "helper_wait : process %d exited with " |
162 | "status 0x%x\n", pid, status); | |
4dbed85a SG |
163 | return -ECHILD; |
164 | } else | |
165 | return 0; | |
1da177e4 | 166 | } |