| /* |
| * backfire - send signal back to caller |
| * |
| * Copyright (C) 2007 Carsten Emde <C.Emde@osadl.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, |
| * USA. |
| */ |
| |
| #include <linux/module.h> |
| |
| #include <linux/sched.h> |
| #include <linux/cpumask.h> |
| #include <linux/time.h> |
| #include <linux/smp_lock.h> |
| #include <linux/types.h> |
| #include <linux/errno.h> |
| #include <linux/miscdevice.h> |
| #include <linux/proc_fs.h> |
| #include <linux/spinlock.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/system.h> |
| |
| #define BACKFIRE_MINOR MISC_DYNAMIC_MINOR |
| |
| static spinlock_t backfire_state_lock = SPIN_LOCK_UNLOCKED; |
| static int backfire_open_cnt; /* #times opened */ |
| static int backfire_open_mode; /* special open modes */ |
| static struct timeval sendtime; /* when the most recent signal was sent */ |
| #define BACKFIRE_WRITE 1 /* opened for writing (exclusive) */ |
| #define BACKFIRE_EXCL 2 /* opened with O_EXCL */ |
| |
| /* |
| * These are the file operation function for user access to /dev/backfire |
| */ |
| static ssize_t |
| backfire_read(struct file *file, char *buf, size_t count, loff_t *ppos) |
| { |
| return snprintf(buf, count, "%d,%d\n", (int) sendtime.tv_sec, |
| (int) sendtime.tv_usec); |
| } |
| |
| static ssize_t |
| backfire_write(struct file *file, const char *buf, size_t count, loff_t *ppos) |
| { |
| int signo; |
| struct pid *pid; |
| |
| if (sscanf(buf, "%d", &signo) >= 1) { |
| if (signo > 0 && signo < 32) { |
| pid = get_pid(task_pid(current)); |
| do_gettimeofday(&sendtime); |
| kill_pid(pid, signo, 1); |
| } else |
| printk(KERN_ERR "Invalid signal no. %d\n", signo); |
| } |
| return strlen(buf); |
| } |
| |
| static int |
| backfire_open(struct inode *inode, struct file *file) |
| { |
| spin_lock(&backfire_state_lock); |
| |
| if ((backfire_open_cnt && (file->f_flags & O_EXCL)) || |
| (backfire_open_mode & BACKFIRE_EXCL)) { |
| spin_unlock(&backfire_state_lock); |
| return -EBUSY; |
| } |
| |
| if (file->f_flags & O_EXCL) |
| backfire_open_mode |= BACKFIRE_EXCL; |
| if (file->f_mode & 2) |
| backfire_open_mode |= BACKFIRE_WRITE; |
| backfire_open_cnt++; |
| |
| spin_unlock(&backfire_state_lock); |
| |
| return 0; |
| } |
| |
| static int |
| backfire_release(struct inode *inode, struct file *file) |
| { |
| spin_lock(&backfire_state_lock); |
| |
| backfire_open_cnt--; |
| |
| if (backfire_open_cnt == 1 && backfire_open_mode & BACKFIRE_EXCL) |
| backfire_open_mode &= ~BACKFIRE_EXCL; |
| if (file->f_mode & 2) |
| backfire_open_mode &= ~BACKFIRE_WRITE; |
| |
| spin_unlock(&backfire_state_lock); |
| |
| return 0; |
| } |
| |
| static struct file_operations backfire_fops = { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .open = backfire_open, |
| .read = backfire_read, |
| .write = backfire_write, |
| .release = backfire_release, |
| }; |
| |
| static struct miscdevice backfire_dev = { |
| BACKFIRE_MINOR, |
| "backfire", |
| &backfire_fops |
| }; |
| |
| static int __init backfire_init(void) |
| { |
| int ret; |
| |
| ret = misc_register(&backfire_dev); |
| if (ret) |
| printk(KERN_ERR "backfire: can't register dynamic misc device\n"); |
| else |
| printk(KERN_INFO "backfire driver misc device %d\n", |
| backfire_dev.minor); |
| return ret; |
| } |
| |
| static void __exit backfire_exit(void) |
| { |
| misc_deregister(&backfire_dev); |
| } |
| |
| module_init(backfire_init); |
| module_exit(backfire_exit); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Carsten Emde <C.Emde@osadl.org>"); |
| MODULE_DESCRIPTION("Send signal back to caller"); |