xref: /freebsd/sys/kern/imgact_aout.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
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("$FreeBSD$");
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 	.sv_size	= SYS_MAXSYSCALL,
60 	.sv_table	= sysent,
61 	.sv_mask	= 0,
62 	.sv_sigsize	= 0,
63 	.sv_sigtbl	= NULL,
64 	.sv_errsize	= 0,
65 	.sv_errtbl	= NULL,
66 	.sv_transtrap	= NULL,
67 	.sv_fixup	= aout_fixup,
68 	.sv_sendsig	= sendsig,
69 	.sv_sigcode	= sigcode,
70 	.sv_szsigcode	= &szsigcode,
71 	.sv_prepsyscall	= NULL,
72 	.sv_name	= "FreeBSD a.out",
73 	.sv_coredump	= NULL,
74 	.sv_imgact_try	= NULL,
75 	.sv_minsigstksz	= MINSIGSTKSZ,
76 	.sv_pagesize	= PAGE_SIZE,
77 	.sv_minuser	= VM_MIN_ADDRESS,
78 	.sv_maxuser	= VM_MAXUSER_ADDRESS,
79 	.sv_usrstack	= USRSTACK,
80 	.sv_psstrings	= PS_STRINGS,
81 	.sv_stackprot	= VM_PROT_ALL,
82 	.sv_copyout_strings	= exec_copyout_strings,
83 	.sv_setregs	= exec_setregs,
84 	.sv_fixlimit	= NULL,
85 	.sv_maxssiz	= NULL,
86 	.sv_flags	= SV_ABI_FREEBSD | SV_AOUT |
87 #if defined(__i386__)
88 	SV_IA32 | SV_ILP32
89 #else
90 #error Choose SV_XXX flags for the platform
91 #endif
92 };
93 
94 static int
95 aout_fixup(stack_base, imgp)
96 	register_t **stack_base;
97 	struct image_params *imgp;
98 {
99 
100 	return (suword(--(*stack_base), imgp->args->argc));
101 }
102 
103 static int
104 exec_aout_imgact(imgp)
105 	struct image_params *imgp;
106 {
107 	const struct exec *a_out = (const struct exec *) imgp->image_header;
108 	struct vmspace *vmspace;
109 	vm_map_t map;
110 	vm_object_t object;
111 	vm_offset_t text_end, data_end;
112 	unsigned long virtual_offset;
113 	unsigned long file_offset;
114 	unsigned long bss_size;
115 	int error;
116 
117 	/*
118 	 * Linux and *BSD binaries look very much alike,
119 	 * only the machine id is different:
120 	 * 0x64 for Linux, 0x86 for *BSD, 0x00 for BSDI.
121 	 * NetBSD is in network byte order.. ugh.
122 	 */
123 	if (((a_out->a_magic >> 16) & 0xff) != 0x86 &&
124 	    ((a_out->a_magic >> 16) & 0xff) != 0 &&
125 	    ((((int)ntohl(a_out->a_magic)) >> 16) & 0xff) != 0x86)
126                 return -1;
127 
128 	/*
129 	 * Set file/virtual offset based on a.out variant.
130 	 *	We do two cases: host byte order and network byte order
131 	 *	(for NetBSD compatibility)
132 	 */
133 	switch ((int)(a_out->a_magic & 0xffff)) {
134 	case ZMAGIC:
135 		virtual_offset = 0;
136 		if (a_out->a_text) {
137 			file_offset = PAGE_SIZE;
138 		} else {
139 			/* Bill's "screwball mode" */
140 			file_offset = 0;
141 		}
142 		break;
143 	case QMAGIC:
144 		virtual_offset = PAGE_SIZE;
145 		file_offset = 0;
146 		/* Pass PS_STRINGS for BSD/OS binaries only. */
147 		if (N_GETMID(*a_out) == MID_ZERO)
148 			imgp->ps_strings = aout_sysvec.sv_psstrings;
149 		break;
150 	default:
151 		/* NetBSD compatibility */
152 		switch ((int)(ntohl(a_out->a_magic) & 0xffff)) {
153 		case ZMAGIC:
154 		case QMAGIC:
155 			virtual_offset = PAGE_SIZE;
156 			file_offset = 0;
157 			break;
158 		default:
159 			return (-1);
160 		}
161 	}
162 
163 	bss_size = roundup(a_out->a_bss, PAGE_SIZE);
164 
165 	/*
166 	 * Check various fields in header for validity/bounds.
167 	 */
168 	if (/* entry point must lay with text region */
169 	    a_out->a_entry < virtual_offset ||
170 	    a_out->a_entry >= virtual_offset + a_out->a_text ||
171 
172 	    /* text and data size must each be page rounded */
173 	    a_out->a_text & PAGE_MASK || a_out->a_data & PAGE_MASK)
174 		return (-1);
175 
176 	/* text + data can't exceed file size */
177 	if (a_out->a_data + a_out->a_text > imgp->attr->va_size)
178 		return (EFAULT);
179 
180 	/*
181 	 * text/data/bss must not exceed limits
182 	 */
183 	PROC_LOCK(imgp->proc);
184 	if (/* text can't exceed maximum text size */
185 	    a_out->a_text > maxtsiz ||
186 
187 	    /* data + bss can't exceed rlimit */
188 	    a_out->a_data + bss_size > lim_cur(imgp->proc, RLIMIT_DATA)) {
189 			PROC_UNLOCK(imgp->proc);
190 			return (ENOMEM);
191 	}
192 	PROC_UNLOCK(imgp->proc);
193 
194 	/*
195 	 * Avoid a possible deadlock if the current address space is destroyed
196 	 * and that address space maps the locked vnode.  In the common case,
197 	 * the locked vnode's v_usecount is decremented but remains greater
198 	 * than zero.  Consequently, the vnode lock is not needed by vrele().
199 	 * However, in cases where the vnode lock is external, such as nullfs,
200 	 * v_usecount may become zero.
201 	 */
202 	VOP_UNLOCK(imgp->vp, 0);
203 
204 	/*
205 	 * Destroy old process VM and create a new one (with a new stack)
206 	 */
207 	error = exec_new_vmspace(imgp, &aout_sysvec);
208 
209 	vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
210 	if (error)
211 		return (error);
212 
213 	/*
214 	 * The vm space can be changed by exec_new_vmspace
215 	 */
216 	vmspace = imgp->proc->p_vmspace;
217 
218 	object = imgp->object;
219 	map = &vmspace->vm_map;
220 	vm_map_lock(map);
221 	vm_object_reference(object);
222 
223 	text_end = virtual_offset + a_out->a_text;
224 	error = vm_map_insert(map, object,
225 		file_offset,
226 		virtual_offset, text_end,
227 		VM_PROT_READ | VM_PROT_EXECUTE, VM_PROT_ALL,
228 		MAP_COPY_ON_WRITE | MAP_PREFAULT);
229 	if (error) {
230 		vm_map_unlock(map);
231 		vm_object_deallocate(object);
232 		return (error);
233 	}
234 	data_end = text_end + a_out->a_data;
235 	if (a_out->a_data) {
236 		vm_object_reference(object);
237 		error = vm_map_insert(map, object,
238 			file_offset + a_out->a_text,
239 			text_end, data_end,
240 			VM_PROT_ALL, VM_PROT_ALL,
241 			MAP_COPY_ON_WRITE | MAP_PREFAULT);
242 		if (error) {
243 			vm_map_unlock(map);
244 			vm_object_deallocate(object);
245 			return (error);
246 		}
247 	}
248 
249 	if (bss_size) {
250 		error = vm_map_insert(map, NULL, 0,
251 			data_end, data_end + bss_size,
252 			VM_PROT_ALL, VM_PROT_ALL, 0);
253 		if (error) {
254 			vm_map_unlock(map);
255 			return (error);
256 		}
257 	}
258 	vm_map_unlock(map);
259 
260 	/* Fill in process VM information */
261 	vmspace->vm_tsize = a_out->a_text >> PAGE_SHIFT;
262 	vmspace->vm_dsize = (a_out->a_data + bss_size) >> PAGE_SHIFT;
263 	vmspace->vm_taddr = (caddr_t) (uintptr_t) virtual_offset;
264 	vmspace->vm_daddr = (caddr_t) (uintptr_t)
265 			    (virtual_offset + a_out->a_text);
266 
267 	/* Fill in image_params */
268 	imgp->interpreted = 0;
269 	imgp->entry_addr = a_out->a_entry;
270 
271 	imgp->proc->p_sysent = &aout_sysvec;
272 
273 	return (0);
274 }
275 
276 /*
277  * Tell kern_execve.c about it, with a little help from the linker.
278  */
279 static struct execsw aout_execsw = { exec_aout_imgact, "a.out" };
280 EXEC_SET(aout, aout_execsw);
281