GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-29 10:01:25 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

[PATCH] replace cad_pid by a struct pid

Browse source 
There are a few places in the kernel where the init task is signaled.  The
ctrl+alt+del sequence is one them.  It kills a task, usually init, using a
cached pid (cad_pid).

This patch replaces the pid_t by a struct pid to avoid pid wrap around
problem.  The struct pid is initialized at boot time in init() and can be
modified through systctl with

	/proc/sys/kernel/cad_pid

[ I haven't found any distro using it ? ]

It also introduces a small helper routine kill_cad_pid() which is used
where it seemed ok to use cad_pid instead of pid 1.

[akpm@osdl.org: cleanups, build fix]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Cedric Le Goater 2006-10-02 02:19:00 -07:00 • committed by Linus Torvalds
parent 1a657f78dc
commit 9ec52099e4
11 changed files with 48 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

30
kernel/sysctl.c
View file

@ -68,7 +68,6 @@ extern int sysrq_enabled;
extern int core_uses_pid;
extern int suid_dumpable;
extern char core_pattern[];
extern int cad_pid;
extern int pid_max;
extern int min_free_kbytes;
extern int printk_ratelimit_jiffies;
@ -137,6 +136,9 @@ static int parse_table(int __user *, int, void __user *, size_t __user *,
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);
static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos);
static ctl_table root_table[];
static struct ctl_table_header root_table_header =
{ root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };
@ -543,10 +545,10 @@ static ctl_table kern_table[] = {
{
.ctl_name = KERN_CADPID,
.procname = "cad_pid",
.data = &cad_pid,
.data = NULL,
.maxlen = sizeof (int),
.mode = 0600,
.proc_handler = &proc_dointvec,
.proc_handler = &proc_do_cad_pid,
},
{
.ctl_name = KERN_MAX_THREADS,
@ -2427,6 +2429,28 @@ proc_minmax:
}
#endif
static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct pid *new_pid;
pid_t tmp;
int r;
tmp = pid_nr(cad_pid);
r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
lenp, ppos, NULL, NULL);
if (r || !write)
return r;
new_pid = find_get_pid(tmp);
if (!new_pid)
return -ESRCH;
put_pid(xchg(&cad_pid, new_pid));
return 0;
}
#else /* CONFIG_PROC_FS */
int proc_dostring(ctl_table *table, int write, struct file *filp,