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![Alex Dewar](/assets/img/avatar_default.png)
Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
164 lines
3.7 KiB
C
164 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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*/
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sched.h>
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#include <linux/limits.h>
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#include <sys/socket.h>
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#include <sys/wait.h>
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#include <kern_util.h>
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#include <os.h>
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#include <um_malloc.h>
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struct helper_data {
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void (*pre_exec)(void*);
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void *pre_data;
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char **argv;
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int fd;
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char *buf;
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};
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static int helper_child(void *arg)
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{
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struct helper_data *data = arg;
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char **argv = data->argv;
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int err, ret;
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if (data->pre_exec != NULL)
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(*data->pre_exec)(data->pre_data);
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err = execvp_noalloc(data->buf, argv[0], argv);
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/* If the exec succeeds, we don't get here */
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CATCH_EINTR(ret = write(data->fd, &err, sizeof(err)));
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return 0;
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}
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/* Returns either the pid of the child process we run or -E* on failure. */
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int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
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{
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struct helper_data data;
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unsigned long stack, sp;
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int pid, fds[2], ret, n;
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stack = alloc_stack(0, __cant_sleep());
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if (stack == 0)
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return -ENOMEM;
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ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
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if (ret < 0) {
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ret = -errno;
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printk(UM_KERN_ERR "run_helper : pipe failed, errno = %d\n",
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errno);
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goto out_free;
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}
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ret = os_set_exec_close(fds[1]);
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if (ret < 0) {
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printk(UM_KERN_ERR "run_helper : setting FD_CLOEXEC failed, "
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"ret = %d\n", -ret);
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goto out_close;
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}
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sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
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data.pre_exec = pre_exec;
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data.pre_data = pre_data;
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data.argv = argv;
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data.fd = fds[1];
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data.buf = __cant_sleep() ? uml_kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
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uml_kmalloc(PATH_MAX, UM_GFP_KERNEL);
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pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
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if (pid < 0) {
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ret = -errno;
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printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n",
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errno);
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goto out_free2;
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}
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close(fds[1]);
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fds[1] = -1;
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/*
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* Read the errno value from the child, if the exec failed, or get 0 if
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* the exec succeeded because the pipe fd was set as close-on-exec.
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*/
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n = read(fds[0], &ret, sizeof(ret));
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if (n == 0) {
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ret = pid;
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} else {
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if (n < 0) {
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n = -errno;
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printk(UM_KERN_ERR "run_helper : read on pipe failed, "
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"ret = %d\n", -n);
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ret = n;
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}
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CATCH_EINTR(waitpid(pid, NULL, __WALL));
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}
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out_free2:
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kfree(data.buf);
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out_close:
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if (fds[1] != -1)
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close(fds[1]);
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close(fds[0]);
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out_free:
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free_stack(stack, 0);
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return ret;
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}
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int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
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unsigned long *stack_out)
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{
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unsigned long stack, sp;
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int pid, status, err;
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stack = alloc_stack(0, __cant_sleep());
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if (stack == 0)
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return -ENOMEM;
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sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
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pid = clone(proc, (void *) sp, flags, arg);
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if (pid < 0) {
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err = -errno;
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printk(UM_KERN_ERR "run_helper_thread : clone failed, "
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"errno = %d\n", errno);
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return err;
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}
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if (stack_out == NULL) {
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CATCH_EINTR(pid = waitpid(pid, &status, __WALL));
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if (pid < 0) {
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err = -errno;
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printk(UM_KERN_ERR "run_helper_thread - wait failed, "
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"errno = %d\n", errno);
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pid = err;
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}
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if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
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printk(UM_KERN_ERR "run_helper_thread - thread "
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"returned status 0x%x\n", status);
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free_stack(stack, 0);
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} else
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*stack_out = stack;
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return pid;
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}
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int helper_wait(int pid)
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{
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int ret, status;
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int wflags = __WALL;
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CATCH_EINTR(ret = waitpid(pid, &status, wflags));
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if (ret < 0) {
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printk(UM_KERN_ERR "helper_wait : waitpid process %d failed, "
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"errno = %d\n", pid, errno);
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return -errno;
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} else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
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printk(UM_KERN_ERR "helper_wait : process %d exited with "
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"status 0x%x\n", pid, status);
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return -ECHILD;
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} else
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return 0;
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}
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