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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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 (hch@infradead.org)
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 u_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(u_long personality)
60{
61 struct exec_domain * ep;
62 u_long pers = personality(personality);
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-%ld", 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
138__set_personality(u_long personality)
139{
140 struct exec_domain *ep, *oep;
141
142 ep = lookup_exec_domain(personality);
143 if (ep == current_thread_info()->exec_domain) {
144 current->personality = personality;
145 module_put(ep->module);
146 return 0;
147 }
148
149 current->personality = personality;
150 oep = current_thread_info()->exec_domain;
151 current_thread_info()->exec_domain = ep;
152
153 module_put(oep->module);
154 return 0;
155}
156
157#ifdef CONFIG_PROC_FS
158static int execdomains_proc_show(struct seq_file *m, void *v)
159{
160 struct exec_domain *ep;
161
162 read_lock(&exec_domains_lock);
163 for (ep = exec_domains; ep; ep = ep->next)
164 seq_printf(m, "%d-%d\t%-16s\t[%s]\n",
165 ep->pers_low, ep->pers_high, ep->name,
166 module_name(ep->module));
167 read_unlock(&exec_domains_lock);
168 return 0;
169}
170
171static int execdomains_proc_open(struct inode *inode, struct file *file)
172{
173 return single_open(file, execdomains_proc_show, NULL);
174}
175
176static const struct file_operations execdomains_proc_fops = {
177 .open = execdomains_proc_open,
178 .read = seq_read,
179 .llseek = seq_lseek,
180 .release = single_release,
181};
182
183static int __init proc_execdomains_init(void)
184{
185 proc_create("execdomains", 0, NULL, &execdomains_proc_fops);
186 return 0;
187}
188module_init(proc_execdomains_init);
189#endif
190
191SYSCALL_DEFINE1(personality, u_long, personality)
192{
193 u_long old = current->personality;
194
195 if (personality != 0xffffffff) {
196 set_personality(personality);
197 if (current->personality != personality)
198 return -EINVAL;
199 }
200
201 return (long)old;
202}
203
204
205EXPORT_SYMBOL(register_exec_domain);
206EXPORT_SYMBOL(unregister_exec_domain);
207EXPORT_SYMBOL(__set_personality);