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" 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 int errval; 37 38 if(helper_pause){ 39 signal(SIGHUP, helper_hup); 40 pause(); 41 } 42 if(data->pre_exec != NULL) 43 (*data->pre_exec)(data->pre_data); 44 execvp(argv[0], argv); 45 errval = errno; 46 printk("execvp of '%s' failed - errno = %d\n", argv[0], errno); 47 os_write_file(data->fd, &errval, sizeof(errval)); 48 kill(os_getpid(), SIGKILL); 49 return(0); 50 } 51 52 /* Returns either the pid of the child process we run or -E* on failure. 53 * XXX The alloc_stack here breaks if this is called in the tracing thread */ 54 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv, 55 unsigned long *stack_out) 56 { 57 struct helper_data data; 58 unsigned long stack, sp; 59 int pid, fds[2], ret, n; 60 61 if((stack_out != NULL) && (*stack_out != 0)) 62 stack = *stack_out; 63 else stack = alloc_stack(0, __cant_sleep()); 64 if(stack == 0) 65 return(-ENOMEM); 66 67 ret = os_pipe(fds, 1, 0); 68 if(ret < 0){ 69 printk("run_helper : pipe failed, ret = %d\n", -ret); 70 goto out_free; 71 } 72 73 ret = os_set_exec_close(fds[1], 1); 74 if(ret < 0){ 75 printk("run_helper : setting FD_CLOEXEC failed, ret = %d\n", 76 -ret); 77 goto out_close; 78 } 79 80 sp = stack + page_size() - sizeof(void *); 81 data.pre_exec = pre_exec; 82 data.pre_data = pre_data; 83 data.argv = argv; 84 data.fd = fds[1]; 85 pid = clone(helper_child, (void *) sp, CLONE_VM | SIGCHLD, &data); 86 if(pid < 0){ 87 ret = -errno; 88 printk("run_helper : clone failed, errno = %d\n", errno); 89 goto out_close; 90 } 91 92 close(fds[1]); 93 fds[1] = -1; 94 95 /*Read the errno value from the child.*/ 96 n = os_read_file(fds[0], &ret, sizeof(ret)); 97 if(n < 0){ 98 printk("run_helper : read on pipe failed, ret = %d\n", -n); 99 ret = n; 100 kill(pid, SIGKILL); 101 CATCH_EINTR(waitpid(pid, NULL, 0)); 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 close(fds[1]); 113 close(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; 125 int pid, status, err; 126 127 stack = alloc_stack(stack_order, __cant_sleep()); 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){ 133 err = -errno; 134 printk("run_helper_thread : clone failed, errno = %d\n", 135 errno); 136 return err; 137 } 138 if(stack_out == NULL){ 139 CATCH_EINTR(pid = waitpid(pid, &status, 0)); 140 if(pid < 0){ 141 err = -errno; 142 printk("run_helper_thread - wait failed, errno = %d\n", 143 errno); 144 pid = err; 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 } 154 155 int helper_wait(int pid) 156 { 157 int ret; 158 159 CATCH_EINTR(ret = waitpid(pid, NULL, WNOHANG)); 160 if(ret < 0){ 161 ret = -errno; 162 printk("helper_wait : waitpid failed, errno = %d\n", errno); 163 } 164 return(ret); 165 } 166