From mboxrd@z Thu Jan 1 00:00:00 1970 From: trajber@gmail.com (Mauro Romano Trajber) Date: Wed, 12 Jan 2011 16:58:14 -0200 Subject: New proc entry under /proc/[pid] In-Reply-To: References: Message-ID: To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org Yes, /proc/[pid] handling is diferent and your solution is perfect just for the other proc directories. Informations under [pid] directories are about tasks (processes), and most of this information is represented by task_struct structure (defined in include/linux/sched.h). I think one easy way to solve this problem is: In include/linux/sched.h file 1 - add a new element in task_struct structure. struct task_struct { int my_value; ....... In fs/proc/base.c file 1 - Create a new entry in static pid_entry tgid_base_stuff[] array. e.g. ONE("MY_FILE", S_IRUSR, proc_pid_my_file), 2 - Create a callback function that will be invoked when the new proc entry is accessed (*task_struct is passed to this function). static int proc_pid_my_file(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task) { seq_printf(m, "%s %d\n", "here we go....", task->my_value); return 0; } Use the task_struct as usual: struct task_struct *task; task = pid_task(find_vpid(1), PIDTYPE_PID); I don't know if it is the best solution, but it seems it worked. If anyone know a more easy or correct solution please let me know. Thanks again, Mauro Romano Trajber On Wed, Jan 12, 2011 at 7:41 AM, Rajat Sharma wrote: > yes you are right, it gives NULL for directories under proc but > I tried changing pid to something else, say /proc/sys and it works. > Looks like handling of pid directories is entirely different. I didn't > get time to explore on that, will have to dig more into this. > > Rajat > > On Wed, Jan 12, 2011 at 12:50 AM, Mauro Romano Trajber > wrote: > > Following your recommendations parent->pde always returns NULL. You know > why > > ? > > // code... > > err = kern_path("/proc/1/", LOOKUP_FOLLOW, &path); > > if (err) { > > return err; > > } > > struct proc_inode *parent = PROC_I(path.dentry->d_inode); > > struct proc_dir_entry *parent_dir = parent->pde; > > if (parent_dir == NULL) { > > printk("parent_dir is NULL\n"); > > } else { > > create_proc_entry("SOMEFile", 0644, parent_dir); > > } > > > > Mauro! > > On Tue, Jan 11, 2011 at 4:39 AM, Rajat Sharma > wrote: > >> > >> Try this: > >> 1. do a path_lookup for parent proc dir e.g. /proc/1234 and get its > inode. > >> 2. get proc_inode structure for parent from vfs inode like this: > >> sruct proc_inode *parent = PROC_I(inode). > >> PROC_I is defined in proc_fs.h > >> 3. get parent proc_dir_entry object: > >> struct proc_dir_entry *parent_dir = parent->pde; > >> 4. now you can call: > >> create_proc_entry("SOME file", 0644, parent_dir); > >> 5. or you can create a directory if you want: > >> proc_mkdir("your dir", parent_dir); > >> > >> hope this helps. > >> > >> Rajat > >> > >> On Tue, Jan 11, 2011 at 12:19 AM, Mauro Romano Trajber > >> wrote: > >> > I think I found: > >> > static const struct pid_entry tgid_base_stuff[] at fs/proc/base.c has > >> > all > >> > /proc/[pid] entries. > >> > But unfortunately it does not use create_proc_entry function, and I'm > >> > trying > >> > to create a new syscall that creates a new proc_entry for the caller > >> > process. > >> > Adding a new element in tgid_base_stuff[] makes the things more > >> > complicated > >> > than simply call a create_proc_entry function. > >> > Is there another way to do it ? > >> > Mauro Romano Trajber > >> > > >> > On Mon, Jan 10, 2011 at 3:18 PM, Mauro Romano Trajber > >> > > >> > wrote: > >> >> > >> >> How can I create a new proc entry under /proc/[pid] ? > >> >> I using create_proc_entry("SOME_FILE", 0644, NULL /* here goes the > pid > >> >> proc entry */); > >> >> Is there any way to get PID directory as a parent proc entry ? How ? > >> >> Thanks, > >> >> Mauro > >> > > >> > _______________________________________________ > >> > Kernelnewbies mailing list > >> > Kernelnewbies at kernelnewbies.org > >> > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > >> > > >> > > > > > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20110112/3722a578/attachment.html