diff options
Diffstat (limited to 'arch/um/os-Linux/helper.c')
| -rw-r--r-- | arch/um/os-Linux/helper.c | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c new file mode 100644 index 000000000..89c2ad2a4 --- /dev/null +++ b/arch/um/os-Linux/helper.c @@ -0,0 +1,236 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) + */ + +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <errno.h> +#include <sched.h> +#include <pthread.h> +#include <linux/limits.h> +#include <sys/socket.h> +#include <sys/wait.h> +#include <kern_util.h> +#include <os.h> +#include <um_malloc.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 err, ret; + + if (data->pre_exec != NULL) + (*data->pre_exec)(data->pre_data); + err = execvp_noalloc(data->buf, argv[0], argv); + + /* If the exec succeeds, we don't get here */ + CATCH_EINTR(ret = write(data->fd, &err, sizeof(err))); + + return 0; +} + +/* Returns either the pid of the child process we run or -E* on failure. */ +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, __uml_cant_sleep()); + if (stack == 0) + return -ENOMEM; + + ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds); + if (ret < 0) { + ret = -errno; + printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n", + errno); + goto out_free; + } + + ret = os_set_exec_close(fds[1]); + if (ret < 0) { + printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, " + "ret = %d\n", -ret); + goto out_close; + } + + sp = stack + UM_KERN_PAGE_SIZE; + data.pre_exec = pre_exec; + data.pre_data = pre_data; + data.argv = argv; + data.fd = fds[1]; + data.buf = __uml_cant_sleep() ? uml_kmalloc(PATH_MAX, UM_GFP_ATOMIC) : + uml_kmalloc(PATH_MAX, UM_GFP_KERNEL); + pid = clone(helper_child, (void *) sp, CLONE_VM, &data); + if (pid < 0) { + ret = -errno; + printk(UM_KERN_ERR "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(UM_KERN_ERR "run_helper : read on pipe failed, " + "ret = %d\n", -n); + ret = n; + } + CATCH_EINTR(waitpid(pid, NULL, __WALL)); + } + + if (ret < 0) + printk(UM_KERN_ERR "run_helper : failed to exec %s on host: %s\n", + argv[0], strerror(-ret)); + +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; + + /* To share memory space, use os_run_helper_thread() instead. */ + if (flags & CLONE_VM) + return -EINVAL; + + stack = alloc_stack(0, __uml_cant_sleep()); + if (stack == 0) + return -ENOMEM; + + sp = stack + UM_KERN_PAGE_SIZE; + pid = clone(proc, (void *) sp, flags, arg); + if (pid < 0) { + err = -errno; + printk(UM_KERN_ERR "run_helper_thread : clone failed, " + "errno = %d\n", errno); + return err; + } + if (stack_out == NULL) { + CATCH_EINTR(pid = waitpid(pid, &status, __WALL)); + if (pid < 0) { + err = -errno; + printk(UM_KERN_ERR "run_helper_thread - wait failed, " + "errno = %d\n", errno); + pid = err; + } + if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0)) + printk(UM_KERN_ERR "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 ret, status; + int wflags = __WALL; + + CATCH_EINTR(ret = waitpid(pid, &status, wflags)); + if (ret < 0) { + printk(UM_KERN_ERR "helper_wait : waitpid process %d failed, " + "errno = %d\n", pid, errno); + return -errno; + } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { + printk(UM_KERN_ERR "helper_wait : process %d exited with " + "status 0x%x\n", pid, status); + return -ECHILD; + } else + return 0; +} + +struct os_helper_thread { + pthread_t handle; +}; + +int os_run_helper_thread(struct os_helper_thread **td_out, + void *(*routine)(void *), void *arg) +{ + struct os_helper_thread *td; + sigset_t sigset, oset; + int err, flags; + + flags = __uml_cant_sleep() ? UM_GFP_ATOMIC : UM_GFP_KERNEL; + td = uml_kmalloc(sizeof(*td), flags); + if (!td) + return -ENOMEM; + + sigfillset(&sigset); + if (sigprocmask(SIG_SETMASK, &sigset, &oset) < 0) { + err = -errno; + kfree(td); + return err; + } + + err = pthread_create(&td->handle, NULL, routine, arg); + + if (sigprocmask(SIG_SETMASK, &oset, NULL) < 0) + panic("Failed to restore the signal mask: %d", errno); + + if (err != 0) + kfree(td); + else + *td_out = td; + + return -err; +} + +void os_kill_helper_thread(struct os_helper_thread *td) +{ + pthread_cancel(td->handle); + pthread_join(td->handle, NULL); + kfree(td); +} + +void os_fix_helper_thread_signals(void) +{ + sigset_t sigset; + + sigemptyset(&sigset); + + sigaddset(&sigset, SIGWINCH); + sigaddset(&sigset, SIGPIPE); + sigaddset(&sigset, SIGPROF); + sigaddset(&sigset, SIGINT); + sigaddset(&sigset, SIGTERM); + sigaddset(&sigset, SIGCHLD); + sigaddset(&sigset, SIGALRM); + sigaddset(&sigset, SIGIO); + sigaddset(&sigset, SIGUSR1); + + pthread_sigmask(SIG_SETMASK, &sigset, NULL); +} |