cregit-Linux how code gets into the kernel

Release 4.11 drivers/xen/xenbus/xenbus_dev_backend.c


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/capability.h>

#include <xen/xen.h>
#include <xen/page.h>
#include <xen/xenbus.h>
#include <xen/xenbus_dev.h>
#include <xen/grant_table.h>
#include <xen/events.h>
#include <asm/xen/hypervisor.h>

#include "xenbus.h"


static int xenbus_backend_open(struct inode *inode, struct file *filp) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; return nonseekable_open(inode, filp); }

Contributors

PersonTokensPropCommitsCommitProp
Bastian Blank36100.00%1100.00%
Total36100.00%1100.00%


static long xenbus_alloc(domid_t domid) { struct evtchn_alloc_unbound arg; int err = -EEXIST; xs_suspend(); /* If xenstored_ready is nonzero, that means we have already talked to * xenstore and set up watches. These watches will be restored by * xs_resume, but that requires communication over the port established * below that is not visible to anyone until the ioctl returns. * * This can be resolved by splitting the ioctl into two parts * (postponing the resume until xenstored is active) but this is * unnecessarily complex for the intended use where xenstored is only * started once - so return -EEXIST if it's already running. */ if (xenstored_ready) goto out_err; gnttab_grant_foreign_access_ref(GNTTAB_RESERVED_XENSTORE, domid, virt_to_gfn(xen_store_interface), 0 /* writable */); arg.dom = DOMID_SELF; arg.remote_dom = domid; err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, &arg); if (err) goto out_err; if (xen_store_evtchn > 0) xb_deinit_comms(); xen_store_evtchn = arg.port; xs_resume(); return arg.port; out_err: xs_suspend_cancel(); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Daniel De Graaf10499.05%150.00%
Julien Grall10.95%150.00%
Total105100.00%2100.00%


static long xenbus_backend_ioctl(struct file *file, unsigned int cmd, unsigned long data) { if (!capable(CAP_SYS_ADMIN)) return -EPERM; switch (cmd) { case IOCTL_XENBUS_BACKEND_EVTCHN: if (xen_store_evtchn > 0) return xen_store_evtchn; return -ENODEV; case IOCTL_XENBUS_BACKEND_SETUP: return xenbus_alloc(data); default: return -ENOTTY; } }

Contributors

PersonTokensPropCommitsCommitProp
Bastian Blank5886.57%150.00%
Daniel De Graaf913.43%150.00%
Total67100.00%2100.00%


static int xenbus_backend_mmap(struct file *file, struct vm_area_struct *vma) { size_t size = vma->vm_end - vma->vm_start; if (!capable(CAP_SYS_ADMIN)) return -EPERM; if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0)) return -EINVAL; if (remap_pfn_range(vma, vma->vm_start, virt_to_pfn(xen_store_interface), size, vma->vm_page_prot)) return -EAGAIN; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Bastian Blank88100.00%1100.00%
Total88100.00%1100.00%

static const struct file_operations xenbus_backend_fops = { .open = xenbus_backend_open, .mmap = xenbus_backend_mmap, .unlocked_ioctl = xenbus_backend_ioctl, }; static struct miscdevice xenbus_backend_dev = { .minor = MISC_DYNAMIC_MINOR, .name = "xen/xenbus_backend", .fops = &xenbus_backend_fops, };
static int __init xenbus_backend_init(void) { int err; if (!xen_initial_domain()) return -ENODEV; err = misc_register(&xenbus_backend_dev); if (err) pr_err("Could not register xenbus backend device\n"); return err; }

Contributors

PersonTokensPropCommitsCommitProp
Bastian Blank4197.62%150.00%
Joe Perches12.38%150.00%
Total42100.00%2100.00%

device_initcall(xenbus_backend_init);

Overall Contributors

PersonTokensPropCommitsCommitProp
Bastian Blank30068.03%112.50%
Daniel De Graaf12528.34%112.50%
Joe Perches81.81%112.50%
Konrad Rzeszutek Wilk40.91%225.00%
Paul Gortmaker20.45%112.50%
Juergen Gross10.23%112.50%
Julien Grall10.23%112.50%
Total441100.00%8100.00%
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.