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 <fcntl.h>
11 #include <sched.h>
12 #include <sys/signal.h>
13 #include <sys/wait.h>
14 #include "user.h"
15 #include "kern_util.h"
16 #include "os.h"
17
18 struct helper_data {
19 void (*pre_exec)(void*);
20 void *pre_data;
21 char **argv;
22 int fd;
23 };
24
25 /* Debugging aid, changed only from gdb */
26 int helper_pause = 0;
27
28 static void helper_hup(int sig)
29 {
30 }
31
32 static int helper_child(void *arg)
33 {
34 struct helper_data *data = arg;
35 char **argv = data->argv;
36
37 if(helper_pause){
38 signal(SIGHUP, helper_hup);
39 pause();
40 }
41 if(data->pre_exec != NULL)
42 (*data->pre_exec)(data->pre_data);
43 execvp(argv[0], argv);
44 printk("execvp of '%s' failed - errno = %d\n", argv[0], errno);
45 write(data->fd, &errno, sizeof(errno));
46 os_kill_process(os_getpid(), 0);
47 return(0);
48 }
49
50 /* XXX The alloc_stack here breaks if this is called in the tracing thread */
51
52 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
53 unsigned long *stack_out)
54 {
55 struct helper_data data;
56 unsigned long stack, sp;
57 int pid, fds[2], err, n;
58
59 if((stack_out != NULL) && (*stack_out != 0))
60 stack = *stack_out;
61 else stack = alloc_stack(0, um_in_interrupt());
62 if(stack == 0) return(-ENOMEM);
63
64 err = os_pipe(fds, 1, 0);
65 if(err){
66 printk("run_helper : pipe failed, errno = %d\n", -err);
67 return(err);
68 }
69 if(fcntl(fds[1], F_SETFD, 1) != 0){
70 printk("run_helper : setting FD_CLOEXEC failed, errno = %d\n",
71 errno);
72 return(-errno);
73 }
74
75 sp = stack + page_size() - sizeof(void *);
76 data.pre_exec = pre_exec;
77 data.pre_data = pre_data;
78 data.argv = argv;
79 data.fd = fds[1];
80 pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data);
81 if(pid < 0){
82 printk("run_helper : clone failed, errno = %d\n", errno);
83 return(-errno);
84 }
85 close(fds[1]);
86 n = read(fds[0], &err, sizeof(err));
87 if(n < 0){
88 printk("run_helper : read on pipe failed, errno = %d\n",
89 errno);
90 return(-errno);
91 }
92 else if(n != 0){
93 waitpid(pid, NULL, 0);
94 pid = -err;
95 }
96
97 if(stack_out == NULL) free_stack(stack, 0);
98 else *stack_out = stack;
99 return(pid);
100 }
101
102 int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
103 unsigned long *stack_out, int stack_order)
104 {
105 unsigned long stack, sp;
106 int pid, status;
107
108 stack = alloc_stack(stack_order, um_in_interrupt());
109 if(stack == 0) return(-ENOMEM);
110
111 sp = stack + (page_size() << stack_order) - sizeof(void *);
112 pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
113 if(pid < 0){
114 printk("run_helper_thread : clone failed, errno = %d\n",
115 errno);
116 return(-errno);
117 }
118 if(stack_out == NULL){
119 pid = waitpid(pid, &status, 0);
120 if(pid < 0)
121 printk("run_helper_thread - wait failed, errno = %d\n",
122 pid);
123 if(!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
124 printk("run_helper_thread - thread returned status "
125 "0x%x\n", status);
126 free_stack(stack, stack_order);
127 }
128 else *stack_out = stack;
129 return(pid);
130 }
131
132 int helper_wait(int pid, int block)
133 {
134 int ret;
135
136 ret = waitpid(pid, NULL, WNOHANG);
137 if(ret < 0){
138 printk("helper_wait : waitpid failed, errno = %d\n", errno);
139 return(-errno);
140 }
141 return(ret);
142 }
143
144 /*
145 * Overrides for Emacs so that we follow Linus's tabbing style.
146 * Emacs will notice this stuff at the end of the file and automatically
147 * adjust the settings for this buffer only. This must remain at the end
148 * of the file.
149 * ---------------------------------------------------------------------------
150 * Local variables:
151 * c-file-style: "linux"
152 * End:
153 */
154
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