projects/linux·blob v3.5-rc2 · refs

195 lines · 4.3 KiB

1/*
2 * Handling of different ABIs (personalities).
3 *
4 * We group personalities into execution domains which have their
5 * own handlers for kernel entry points, signal mapping, etc...
6 *
7 * 2001-05-06 Complete rewrite, Christoph Hellwig ([email protected])
8 */
9
10#include <linux/init.h>
11#include <linux/kernel.h>
12#include <linux/kmod.h>
13#include <linux/module.h>
14#include <linux/personality.h>
15#include <linux/proc_fs.h>
16#include <linux/sched.h>
17#include <linux/seq_file.h>
18#include <linux/syscalls.h>
19#include <linux/sysctl.h>
20#include <linux/types.h>
21#include <linux/fs_struct.h>
22
23
24static void default_handler(int, struct pt_regs *);
25
26static struct exec_domain *exec_domains = &default_exec_domain;
27static DEFINE_RWLOCK(exec_domains_lock);
28
29
30static unsigned long ident_map[32] = {
31 0, 1, 2, 3, 4, 5, 6, 7,
32 8, 9, 10, 11, 12, 13, 14, 15,
33 16, 17, 18, 19, 20, 21, 22, 23,
34 24, 25, 26, 27, 28, 29, 30, 31
35};
36
37struct exec_domain default_exec_domain = {
38 .name = "Linux", /* name */
39 .handler = default_handler, /* lcall7 causes a seg fault. */
40 .pers_low = 0, /* PER_LINUX personality. */
41 .pers_high = 0, /* PER_LINUX personality. */
42 .signal_map = ident_map, /* Identity map signals. */
43 .signal_invmap = ident_map, /* - both ways. */
44};
45
46
47static void
48default_handler(int segment, struct pt_regs *regp)
49{
50 set_personality(0);
51
52 if (current_thread_info()->exec_domain->handler != default_handler)
53 current_thread_info()->exec_domain->handler(segment, regp);
54 else
55 send_sig(SIGSEGV, current, 1);
56}
57
58static struct exec_domain *
59lookup_exec_domain(unsigned int personality)
60{
61 unsigned int pers = personality(personality);
62 struct exec_domain *ep;
63
64 read_lock(&exec_domains_lock);
65 for (ep = exec_domains; ep; ep = ep->next) {
66 if (pers >= ep->pers_low && pers <= ep->pers_high)
67 if (try_module_get(ep->module))
68 goto out;
69 }
70
71#ifdef CONFIG_MODULES
72 read_unlock(&exec_domains_lock);
73 request_module("personality-%d", pers);
74 read_lock(&exec_domains_lock);
75
76 for (ep = exec_domains; ep; ep = ep->next) {
77 if (pers >= ep->pers_low && pers <= ep->pers_high)
78 if (try_module_get(ep->module))
79 goto out;
80 }
81#endif
82
83 ep = &default_exec_domain;
84out:
85 read_unlock(&exec_domains_lock);
86 return (ep);
87}
88
89int
90register_exec_domain(struct exec_domain *ep)
91{
92 struct exec_domain *tmp;
93 int err = -EBUSY;
94
95 if (ep == NULL)
96 return -EINVAL;
97
98 if (ep->next != NULL)
99 return -EBUSY;
100
101 write_lock(&exec_domains_lock);
102 for (tmp = exec_domains; tmp; tmp = tmp->next) {
103 if (tmp == ep)
104 goto out;
105 }
106
107 ep->next = exec_domains;
108 exec_domains = ep;
109 err = 0;
110
111out:
112 write_unlock(&exec_domains_lock);
113 return (err);
114}
115
116int
117unregister_exec_domain(struct exec_domain *ep)
118{
119 struct exec_domain **epp;
120
121 epp = &exec_domains;
122 write_lock(&exec_domains_lock);
123 for (epp = &exec_domains; *epp; epp = &(*epp)->next) {
124 if (ep == *epp)
125 goto unregister;
126 }
127 write_unlock(&exec_domains_lock);
128 return -EINVAL;
129
130unregister:
131 *epp = ep->next;
132 ep->next = NULL;
133 write_unlock(&exec_domains_lock);
134 return 0;
135}
136
137int __set_personality(unsigned int personality)
138{
139 struct exec_domain *oep = current_thread_info()->exec_domain;
140
141 current_thread_info()->exec_domain = lookup_exec_domain(personality);
142 current->personality = personality;
143 module_put(oep->module);
144
145 return 0;
146}
147
148#ifdef CONFIG_PROC_FS
149static int execdomains_proc_show(struct seq_file *m, void *v)
150{
151 struct exec_domain *ep;
152
153 read_lock(&exec_domains_lock);
154 for (ep = exec_domains; ep; ep = ep->next)
155 seq_printf(m, "%d-%d\t%-16s\t[%s]\n",
156 ep->pers_low, ep->pers_high, ep->name,
157 module_name(ep->module));
158 read_unlock(&exec_domains_lock);
159 return 0;
160}
161
162static int execdomains_proc_open(struct inode *inode, struct file *file)
163{
164 return single_open(file, execdomains_proc_show, NULL);
165}
166
167static const struct file_operations execdomains_proc_fops = {
168 .open = execdomains_proc_open,
169 .read = seq_read,
170 .llseek = seq_lseek,
171 .release = single_release,
172};
173
174static int __init proc_execdomains_init(void)
175{
176 proc_create("execdomains", 0, NULL, &execdomains_proc_fops);
177 return 0;
178}
179module_init(proc_execdomains_init);
180#endif
181
182SYSCALL_DEFINE1(personality, unsigned int, personality)
183{
184 unsigned int old = current->personality;
185
186 if (personality != 0xffffffff)
187 set_personality(personality);
188
189 return old;
190}
191
192
193EXPORT_SYMBOL(register_exec_domain);
194EXPORT_SYMBOL(unregister_exec_domain);
195EXPORT_SYMBOL(__set_personality);