1 /*-
2 * Copyright (c) 1993, David Greenman
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/6.4/sys/kern/imgact_aout.c 158637 2006-05-16 00:23:44Z davidxu $");
29
30 #include <sys/param.h>
31 #include <sys/exec.h>
32 #include <sys/imgact.h>
33 #include <sys/imgact_aout.h>
34 #include <sys/kernel.h>
35 #include <sys/lock.h>
36 #include <sys/malloc.h>
37 #include <sys/mutex.h>
38 #include <sys/proc.h>
39 #include <sys/resourcevar.h>
40 #include <sys/signalvar.h>
41 #include <sys/syscall.h>
42 #include <sys/sysent.h>
43 #include <sys/systm.h>
44 #include <sys/vnode.h>
45
46 #include <machine/frame.h>
47 #include <machine/md_var.h>
48
49 #include <vm/vm.h>
50 #include <vm/pmap.h>
51 #include <vm/vm_map.h>
52 #include <vm/vm_object.h>
53 #include <vm/vm_param.h>
54
55 static int exec_aout_imgact(struct image_params *imgp);
56 static int aout_fixup(register_t **stack_base, struct image_params *imgp);
57
58 struct sysentvec aout_sysvec = {
59 SYS_MAXSYSCALL,
60 sysent,
61 0,
62 0,
63 NULL,
64 0,
65 NULL,
66 NULL,
67 aout_fixup,
68 sendsig,
69 sigcode,
70 &szsigcode,
71 NULL,
72 "FreeBSD a.out",
73 NULL,
74 NULL,
75 MINSIGSTKSZ,
76 PAGE_SIZE,
77 VM_MIN_ADDRESS,
78 VM_MAXUSER_ADDRESS,
79 USRSTACK,
80 PS_STRINGS,
81 VM_PROT_ALL,
82 exec_copyout_strings,
83 exec_setregs,
84 NULL
85 };
86
87 static int
88 aout_fixup(stack_base, imgp)
89 register_t **stack_base;
90 struct image_params *imgp;
91 {
92
93 return (suword(--(*stack_base), imgp->args->argc));
94 }
95
96 static int
97 exec_aout_imgact(imgp)
98 struct image_params *imgp;
99 {
100 const struct exec *a_out = (const struct exec *) imgp->image_header;
101 struct thread *td = curthread;
102 struct vmspace *vmspace;
103 vm_map_t map;
104 vm_object_t object;
105 vm_offset_t text_end, data_end;
106 unsigned long virtual_offset;
107 unsigned long file_offset;
108 unsigned long bss_size;
109 int error;
110
111 /*
112 * Linux and *BSD binaries look very much alike,
113 * only the machine id is different:
114 * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
115 * NetBSD is in network byte order.. ugh.
116 */
117 if (((a_out->a_magic >> 16) & 0xff) != 0x86 &&
118 ((a_out->a_magic >> 16) & 0xff) != 0 &&
119 ((((int)ntohl(a_out->a_magic)) >> 16) & 0xff) != 0x86)
120 return -1;
121
122 /*
123 * Set file/virtual offset based on a.out variant.
124 * We do two cases: host byte order and network byte order
125 * (for NetBSD compatibility)
126 */
127 switch ((int)(a_out->a_magic & 0xffff)) {
128 case ZMAGIC:
129 virtual_offset = 0;
130 if (a_out->a_text) {
131 file_offset = PAGE_SIZE;
132 } else {
133 /* Bill's "screwball mode" */
134 file_offset = 0;
135 }
136 break;
137 case QMAGIC:
138 virtual_offset = PAGE_SIZE;
139 file_offset = 0;
140 /* Pass PS_STRINGS for BSD/OS binaries only. */
141 if (N_GETMID(*a_out) == MID_ZERO)
142 imgp->ps_strings = aout_sysvec.sv_psstrings;
143 break;
144 default:
145 /* NetBSD compatibility */
146 switch ((int)(ntohl(a_out->a_magic) & 0xffff)) {
147 case ZMAGIC:
148 case QMAGIC:
149 virtual_offset = PAGE_SIZE;
150 file_offset = 0;
151 break;
152 default:
153 return (-1);
154 }
155 }
156
157 bss_size = roundup(a_out->a_bss, PAGE_SIZE);
158
159 /*
160 * Check various fields in header for validity/bounds.
161 */
162 if (/* entry point must lay with text region */
163 a_out->a_entry < virtual_offset ||
164 a_out->a_entry >= virtual_offset + a_out->a_text ||
165
166 /* text and data size must each be page rounded */
167 a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK)
168 return (-1);
169
170 /* text + data can't exceed file size */
171 if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
172 return (EFAULT);
173
174 /*
175 * text/data/bss must not exceed limits
176 */
177 PROC_LOCK(imgp->proc);
178 if (/* text can't exceed maximum text size */
179 a_out->a_text > maxtsiz ||
180
181 /* data + bss can't exceed rlimit */
182 a_out->a_data + bss_size > lim_cur(imgp->proc, RLIMIT_DATA)) {
183 PROC_UNLOCK(imgp->proc);
184 return (ENOMEM);
185 }
186 PROC_UNLOCK(imgp->proc);
187
188 /*
189 * Avoid a possible deadlock if the current address space is destroyed
190 * and that address space maps the locked vnode. In the common case,
191 * the locked vnode's v_usecount is decremented but remains greater
192 * than zero. Consequently, the vnode lock is not needed by vrele().
193 * However, in cases where the vnode lock is external, such as nullfs,
194 * v_usecount may become zero.
195 */
196 VOP_UNLOCK(imgp->vp, 0, td);
197
198 /*
199 * Destroy old process VM and create a new one (with a new stack)
200 */
201 exec_new_vmspace(imgp, &aout_sysvec);
202
203 vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY, td);
204
205 /*
206 * The vm space can be changed by exec_new_vmspace
207 */
208 vmspace = imgp->proc->p_vmspace;
209
210 object = imgp->object;
211 map = &vmspace->vm_map;
212 vm_map_lock(map);
213 vm_object_reference(object);
214
215 text_end = virtual_offset + a_out->a_text;
216 error = vm_map_insert(map, object,
217 file_offset,
218 virtual_offset, text_end,
219 VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
220 MAP_COPY_ON_WRITE | MAP_PREFAULT);
221 if (error) {
222 vm_map_unlock(map);
223 vm_object_deallocate(object);
224 return (error);
225 }
226 data_end = text_end + a_out->a_data;
227 if (a_out->a_data) {
228 vm_object_reference(object);
229 error = vm_map_insert(map, object,
230 file_offset + a_out->a_text,
231 text_end, data_end,
232 VM_PROT_ALL, VM_PROT_ALL,
233 MAP_COPY_ON_WRITE | MAP_PREFAULT);
234 if (error) {
235 vm_map_unlock(map);
236 vm_object_deallocate(object);
237 return (error);
238 }
239 }
240
241 if (bss_size) {
242 error = vm_map_insert(map, NULL, 0,
243 data_end, data_end + bss_size,
244 VM_PROT_ALL, VM_PROT_ALL, 0);
245 if (error) {
246 vm_map_unlock(map);
247 return (error);
248 }
249 }
250 vm_map_unlock(map);
251
252 /* Fill in process VM information */
253 vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
254 vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
255 vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
256 vmspace->vm_daddr = (caddr_t) (uintptr_t)
257 (virtual_offset + a_out->a_text);
258
259 /* Fill in image_params */
260 imgp->interpreted = 0;
261 imgp->entry_addr = a_out->a_entry;
262
263 imgp->proc->p_sysent = &aout_sysvec;
264
265 return (0);
266 }
267
268 /*
269 * Tell kern_execve.c about it, with a little help from the linker.
270 */
271 static struct execsw aout_execsw = { exec_aout_imgact, "a.out" };
272 EXEC_SET(aout, aout_execsw);
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