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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) | |
3 | * Licensed under the GPL | |
4 | */ | |
5 | ||
6 | #include <stdio.h> | |
7 | #include <stdlib.h> | |
8 | #include <unistd.h> | |
9 | #include <errno.h> | |
10 | #include <sched.h> | |
11 | #include <sys/signal.h> | |
12 | #include <sys/wait.h> | |
13 | #include "user.h" | |
14 | #include "kern_util.h" | |
15 | #include "user_util.h" | |
0d4579ed | 16 | #include "helper.h" |
1da177e4 LT |
17 | #include "os.h" |
18 | ||
19 | struct helper_data { | |
20 | void (*pre_exec)(void*); | |
21 | void *pre_data; | |
22 | char **argv; | |
23 | int fd; | |
24 | }; | |
25 | ||
26 | /* Debugging aid, changed only from gdb */ | |
27 | int helper_pause = 0; | |
28 | ||
29 | static void helper_hup(int sig) | |
30 | { | |
31 | } | |
32 | ||
33 | static int helper_child(void *arg) | |
34 | { | |
35 | struct helper_data *data = arg; | |
36 | char **argv = data->argv; | |
37 | int errval; | |
38 | ||
39 | if(helper_pause){ | |
40 | signal(SIGHUP, helper_hup); | |
41 | pause(); | |
42 | } | |
43 | if(data->pre_exec != NULL) | |
44 | (*data->pre_exec)(data->pre_data); | |
45 | execvp(argv[0], argv); | |
46 | errval = errno; | |
47 | printk("execvp of '%s' failed - errno = %d\n", argv[0], errno); | |
48 | os_write_file(data->fd, &errval, sizeof(errval)); | |
49 | os_kill_process(os_getpid(), 0); | |
50 | return(0); | |
51 | } | |
52 | ||
53 | /* Returns either the pid of the child process we run or -E* on failure. | |
54 | * XXX The alloc_stack here breaks if this is called in the tracing thread */ | |
55 | int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv, | |
56 | unsigned long *stack_out) | |
57 | { | |
58 | struct helper_data data; | |
59 | unsigned long stack, sp; | |
60 | int pid, fds[2], ret, n; | |
61 | ||
62 | if((stack_out != NULL) && (*stack_out != 0)) | |
63 | stack = *stack_out; | |
64 | else stack = alloc_stack(0, um_in_interrupt()); | |
65 | if(stack == 0) | |
66 | return(-ENOMEM); | |
67 | ||
68 | ret = os_pipe(fds, 1, 0); | |
69 | if(ret < 0){ | |
70 | printk("run_helper : pipe failed, ret = %d\n", -ret); | |
71 | goto out_free; | |
72 | } | |
73 | ||
74 | ret = os_set_exec_close(fds[1], 1); | |
75 | if(ret < 0){ | |
76 | printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n", | |
77 | -ret); | |
78 | goto out_close; | |
79 | } | |
80 | ||
81 | sp = stack + page_size() - sizeof(void *); | |
82 | data.pre_exec = pre_exec; | |
83 | data.pre_data = pre_data; | |
84 | data.argv = argv; | |
85 | data.fd = fds[1]; | |
86 | pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data); | |
87 | if(pid < 0){ | |
1da177e4 | 88 | ret = -errno; |
b4fd310e | 89 | printk("run_helper : clone failed, errno = %d\n", errno); |
1da177e4 LT |
90 | goto out_close; |
91 | } | |
92 | ||
93 | os_close_file(fds[1]); | |
94 | fds[1] = -1; | |
95 | ||
96 | /*Read the errno value from the child.*/ | |
97 | n = os_read_file(fds[0], &ret, sizeof(ret)); | |
98 | if(n < 0){ | |
99 | printk("run_helper : read on pipe failed, ret = %d\n", -n); | |
100 | ret = n; | |
101 | os_kill_process(pid, 1); | |
102 | } | |
103 | else if(n != 0){ | |
104 | CATCH_EINTR(n = waitpid(pid, NULL, 0)); | |
105 | ret = -errno; | |
106 | } else { | |
107 | ret = pid; | |
108 | } | |
109 | ||
110 | out_close: | |
111 | if (fds[1] != -1) | |
112 | os_close_file(fds[1]); | |
113 | os_close_file(fds[0]); | |
114 | out_free: | |
115 | if(stack_out == NULL) | |
116 | free_stack(stack, 0); | |
117 | else *stack_out = stack; | |
118 | return(ret); | |
119 | } | |
120 | ||
121 | int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags, | |
122 | unsigned long *stack_out, int stack_order) | |
123 | { | |
124 | unsigned long stack, sp; | |
b4fd310e | 125 | int pid, status, err; |
1da177e4 LT |
126 | |
127 | stack = alloc_stack(stack_order, um_in_interrupt()); | |
128 | if(stack == 0) return(-ENOMEM); | |
129 | ||
130 | sp = stack + (page_size() << stack_order) - sizeof(void *); | |
131 | pid = clone(proc, (void *) sp, flags | SIGCHLD, arg); | |
132 | if(pid < 0){ | |
b4fd310e | 133 | err = -errno; |
1da177e4 LT |
134 | printk("run_helper_thread : clone failed, errno = %d\n", |
135 | errno); | |
b4fd310e | 136 | return err; |
1da177e4 LT |
137 | } |
138 | if(stack_out == NULL){ | |
139 | CATCH_EINTR(pid = waitpid(pid, &status, 0)); | |
140 | if(pid < 0){ | |
b4fd310e | 141 | err = -errno; |
1da177e4 LT |
142 | printk("run_helper_thread - wait failed, errno = %d\n", |
143 | errno); | |
b4fd310e | 144 | pid = err; |
1da177e4 LT |
145 | } |
146 | if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) | |
147 | printk("run_helper_thread - thread returned status " | |
148 | "0x%x\n", status); | |
149 | free_stack(stack, stack_order); | |
150 | } | |
151 | else *stack_out = stack; | |
152 | return(pid); | |
153 | } | |
154 | ||
0d4579ed | 155 | int helper_wait(int pid) |
1da177e4 LT |
156 | { |
157 | int ret; | |
158 | ||
159 | CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG)); | |
160 | if(ret < 0){ | |
b4fd310e | 161 | ret = -errno; |
1da177e4 | 162 | printk("helper_wait : waitpid failed, errno = %d\n", errno); |
1da177e4 LT |
163 | } |
164 | return(ret); | |
165 | } |