kernel/irq/proc.c: unprotected iteration over the IRQ action list in name_unique()
[linux-2.6.git] / kernel / irq / proc.c
1 /*
2  * linux/kernel/irq/proc.c
3  *
4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains the /proc/irq/ handling code.
7  */
8
9 #include <linux/irq.h>
10 #include <linux/proc_fs.h>
11 #include <linux/interrupt.h>
12
13 #include "internals.h"
14
15 static struct proc_dir_entry *root_irq_dir;
16
17 #ifdef CONFIG_SMP
18
19 static int irq_affinity_read_proc(char *page, char **start, off_t off,
20                                   int count, int *eof, void *data)
21 {
22         int len = cpumask_scnprintf(page, count, irq_desc[(long)data].affinity);
23
24         if (count - len < 2)
25                 return -EINVAL;
26         len += sprintf(page + len, "\n");
27         return len;
28 }
29
30 int no_irq_affinity;
31 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
32                                    unsigned long count, void *data)
33 {
34         unsigned int irq = (int)(long)data, full_count = count, err;
35         cpumask_t new_value, tmp;
36
37         if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
38             irq_balancing_disabled(irq))
39                 return -EIO;
40
41         err = cpumask_parse_user(buffer, count, new_value);
42         if (err)
43                 return err;
44
45         /*
46          * Do not allow disabling IRQs completely - it's a too easy
47          * way to make the system unusable accidentally :-) At least
48          * one online CPU still has to be targeted.
49          */
50         cpus_and(tmp, new_value, cpu_online_map);
51         if (cpus_empty(tmp))
52                 /* Special case for empty set - allow the architecture
53                    code to set default SMP affinity. */
54                 return select_smp_affinity(irq) ? -EINVAL : full_count;
55
56         irq_set_affinity(irq, new_value);
57
58         return full_count;
59 }
60
61 #endif
62
63 #define MAX_NAMELEN 128
64
65 static int name_unique(unsigned int irq, struct irqaction *new_action)
66 {
67         struct irq_desc *desc = irq_desc + irq;
68         struct irqaction *action;
69         unsigned long flags;
70         int ret = 1;
71
72         spin_lock_irqsave(&desc->lock, flags);
73         for (action = desc->action ; action; action = action->next) {
74                 if ((action != new_action) && action->name &&
75                                 !strcmp(new_action->name, action->name)) {
76                         ret = 0;
77                         break;
78                 }
79         }
80         spin_unlock_irqrestore(&desc->lock, flags);
81         return ret;
82 }
83
84 void register_handler_proc(unsigned int irq, struct irqaction *action)
85 {
86         char name [MAX_NAMELEN];
87
88         if (!irq_desc[irq].dir || action->dir || !action->name ||
89                                         !name_unique(irq, action))
90                 return;
91
92         memset(name, 0, MAX_NAMELEN);
93         snprintf(name, MAX_NAMELEN, "%s", action->name);
94
95         /* create /proc/irq/1234/handler/ */
96         action->dir = proc_mkdir(name, irq_desc[irq].dir);
97 }
98
99 #undef MAX_NAMELEN
100
101 #define MAX_NAMELEN 10
102
103 void register_irq_proc(unsigned int irq)
104 {
105         char name [MAX_NAMELEN];
106
107         if (!root_irq_dir ||
108                 (irq_desc[irq].chip == &no_irq_chip) ||
109                         irq_desc[irq].dir)
110                 return;
111
112         memset(name, 0, MAX_NAMELEN);
113         sprintf(name, "%d", irq);
114
115         /* create /proc/irq/1234 */
116         irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
117
118 #ifdef CONFIG_SMP
119         {
120                 struct proc_dir_entry *entry;
121
122                 /* create /proc/irq/<irq>/smp_affinity */
123                 entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
124
125                 if (entry) {
126                         entry->data = (void *)(long)irq;
127                         entry->read_proc = irq_affinity_read_proc;
128                         entry->write_proc = irq_affinity_write_proc;
129                 }
130         }
131 #endif
132 }
133
134 #undef MAX_NAMELEN
135
136 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
137 {
138         if (action->dir)
139                 remove_proc_entry(action->dir->name, irq_desc[irq].dir);
140 }
141
142 void init_irq_proc(void)
143 {
144         int i;
145
146         /* create /proc/irq */
147         root_irq_dir = proc_mkdir("irq", NULL);
148         if (!root_irq_dir)
149                 return;
150
151         /*
152          * Create entries for all existing IRQs.
153          */
154         for (i = 0; i < NR_IRQS; i++)
155                 register_irq_proc(i);
156 }
157