1 /* $OpenBSD: exec_subr.c,v 1.28 2006/11/14 18:00:27 jmc Exp $ */
2 /* $NetBSD: exec_subr.c,v 1.9 1994/12/04 03:10:42 mycroft Exp $ */
3
4 /*
5 * Copyright (c) 1993, 1994 Christopher G. Demetriou
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Christopher G. Demetriou.
19 * 4. The name of the author may not be used to endorse or promote products
20 * derived from this software without specific prior written permission
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/proc.h>
37 #include <sys/malloc.h>
38 #include <sys/vnode.h>
39 #include <sys/filedesc.h>
40 #include <sys/exec.h>
41 #include <sys/mman.h>
42 #include <sys/resourcevar.h>
43
44 #include <uvm/uvm.h>
45
46 #ifdef DEBUG
47 /*
48 * new_vmcmd():
49 * create a new vmcmd structure and fill in its fields based
50 * on function call arguments. make sure objects ref'd by
51 * the vmcmd are 'held'.
52 *
53 * If not debugging, this is a macro, so it's expanded inline.
54 */
55
56 void
57 new_vmcmd(evsp, proc, len, addr, vp, offset, prot, flags)
58 struct exec_vmcmd_set *evsp;
59 int (*proc)(struct proc * p, struct exec_vmcmd *);
60 u_long len;
61 u_long addr;
62 struct vnode *vp;
63 u_long offset;
64 u_int prot;
65 int flags;
66 {
67 struct exec_vmcmd *vcp;
68
69 if (evsp->evs_used >= evsp->evs_cnt)
70 vmcmdset_extend(evsp);
71 vcp = &evsp->evs_cmds[evsp->evs_used++];
72 vcp->ev_proc = proc;
73 vcp->ev_len = len;
74 vcp->ev_addr = addr;
75 if ((vcp->ev_vp = vp) != NULL)
76 vref(vp);
77 vcp->ev_offset = offset;
78 vcp->ev_prot = prot;
79 vcp->ev_flags = flags;
80 }
81 #endif /* DEBUG */
82
83 void
84 vmcmdset_extend(evsp)
85 struct exec_vmcmd_set *evsp;
86 {
87 struct exec_vmcmd *nvcp;
88 u_int ocnt;
89
90 #ifdef DIAGNOSTIC
91 if (evsp->evs_used < evsp->evs_cnt)
92 panic("vmcmdset_extend: not necessary");
93 #endif
94
95 ocnt = evsp->evs_cnt;
96 KASSERT(ocnt > 0);
97 /* figure out number of entries in new set */
98 evsp->evs_cnt += ocnt;
99
100 /* reallocate the command set */
101 nvcp = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), M_EXEC,
102 M_WAITOK);
103 bcopy(evsp->evs_cmds, nvcp, (ocnt * sizeof(struct exec_vmcmd)));
104 if (evsp->evs_cmds != evsp->evs_start)
105 free(evsp->evs_cmds, M_EXEC);
106 evsp->evs_cmds = nvcp;
107 }
108
109 void
110 kill_vmcmds(struct exec_vmcmd_set *evsp)
111 {
112 struct exec_vmcmd *vcp;
113 int i;
114
115 for (i = 0; i < evsp->evs_used; i++) {
116 vcp = &evsp->evs_cmds[i];
117 if (vcp->ev_vp != NULLVP)
118 vrele(vcp->ev_vp);
119 }
120
121 /*
122 * Free old vmcmds and reset the array.
123 */
124 evsp->evs_used = 0;
125 if (evsp->evs_cmds != evsp->evs_start)
126 free(evsp->evs_cmds, M_EXEC);
127 evsp->evs_cmds = evsp->evs_start;
128 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE;
129 }
130
131 int
132 exec_process_vmcmds(struct proc *p, struct exec_package *epp)
133 {
134 struct exec_vmcmd *base_vc = NULL;
135 int error = 0;
136 int i;
137
138 for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) {
139 struct exec_vmcmd *vcp;
140
141 vcp = &epp->ep_vmcmds.evs_cmds[i];
142
143 if (vcp->ev_flags & VMCMD_RELATIVE) {
144 #ifdef DIAGNOSTIC
145 if (base_vc == NULL)
146 panic("exec_process_vmcmds: RELATIVE no base");
147 #endif
148 vcp->ev_addr += base_vc->ev_addr;
149 }
150 error = (*vcp->ev_proc)(p, vcp);
151 if (vcp->ev_flags & VMCMD_BASE) {
152 base_vc = vcp;
153 }
154 }
155
156 kill_vmcmds(&epp->ep_vmcmds);
157
158 return (error);
159 }
160
161 /*
162 * vmcmd_map_pagedvn():
163 * handle vmcmd which specifies that a vnode should be mmap'd.
164 * appropriate for handling demand-paged text and data segments.
165 */
166
167 int
168 vmcmd_map_pagedvn(p, cmd)
169 struct proc *p;
170 struct exec_vmcmd *cmd;
171 {
172 /*
173 * note that if you're going to map part of a process as being
174 * paged from a vnode, that vnode had damn well better be marked as
175 * VTEXT. that's handled in the routine which sets up the vmcmd to
176 * call this routine.
177 */
178 struct uvm_object *uobj;
179 int error;
180
181 /*
182 * map the vnode in using uvm_map.
183 */
184
185 if (cmd->ev_len == 0)
186 return(0);
187 if (cmd->ev_offset & PAGE_MASK)
188 return(EINVAL);
189 if (cmd->ev_addr & PAGE_MASK)
190 return(EINVAL);
191 if (cmd->ev_len & PAGE_MASK)
192 return(EINVAL);
193
194 /*
195 * first, attach to the object
196 */
197
198 uobj = uvn_attach((void *) cmd->ev_vp, VM_PROT_READ|VM_PROT_EXECUTE);
199 if (uobj == NULL)
200 return(ENOMEM);
201
202 /*
203 * do the map
204 */
205
206 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len,
207 uobj, cmd->ev_offset, 0,
208 UVM_MAPFLAG(cmd->ev_prot, VM_PROT_ALL, UVM_INH_COPY,
209 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED));
210
211 /*
212 * check for error
213 */
214
215 if (error) {
216 /*
217 * error: detach from object
218 */
219 uobj->pgops->pgo_detach(uobj);
220 }
221
222 return (error);
223 }
224
225 /*
226 * vmcmd_map_readvn():
227 * handle vmcmd which specifies that a vnode should be read from.
228 * appropriate for non-demand-paged text/data segments, i.e. impure
229 * objects (a la OMAGIC and NMAGIC).
230 */
231
232 int
233 vmcmd_map_readvn(struct proc *p, struct exec_vmcmd *cmd)
234 {
235 int error;
236 vm_prot_t prot;
237
238 if (cmd->ev_len == 0)
239 return (0);
240
241 prot = cmd->ev_prot;
242
243 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */
244 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
245 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
246 UVM_MAPFLAG(prot | UVM_PROT_WRITE, UVM_PROT_ALL, UVM_INH_COPY,
247 UVM_ADV_NORMAL,
248 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
249
250 if (error)
251 return (error);
252
253 error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr,
254 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT,
255 p->p_ucred, NULL, p);
256 if (error)
257 return (error);
258
259 if (cmd->ev_prot != (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)) {
260 /*
261 * we had to map in the area at PROT_ALL so that vn_rdwr()
262 * could write to it. however, the caller seems to want
263 * it mapped read-only, so now we are going to have to call
264 * uvm_map_protect() to fix up the protection. ICK.
265 */
266 return (uvm_map_protect(&p->p_vmspace->vm_map,
267 trunc_page(cmd->ev_addr),
268 round_page(cmd->ev_addr + cmd->ev_len),
269 prot, FALSE));
270 }
271 return (0);
272 }
273
274 /*
275 * vmcmd_map_zero():
276 * handle vmcmd which specifies a zero-filled address space region. The
277 * address range must be first allocated, then protected appropriately.
278 */
279
280 int
281 vmcmd_map_zero(p, cmd)
282 struct proc *p;
283 struct exec_vmcmd *cmd;
284 {
285 int error;
286
287 if (cmd->ev_len == 0)
288 return (0);
289
290 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */
291 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
292 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
293 UVM_MAPFLAG(cmd->ev_prot, UVM_PROT_ALL, UVM_INH_COPY,
294 UVM_ADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW));
295
296 if (error)
297 return error;
298
299 return (0);
300 }
301
302 /*
303 * exec_setup_stack(): Set up the stack segment for an a.out
304 * executable.
305 *
306 * Note that the ep_ssize parameter must be set to be the current stack
307 * limit; this is adjusted in the body of execve() to yield the
308 * appropriate stack segment usage once the argument length is
309 * calculated.
310 *
311 * This function returns an int for uniformity with other (future) formats'
312 * stack setup functions. They might have errors to return.
313 */
314
315 int
316 exec_setup_stack(p, epp)
317 struct proc *p;
318 struct exec_package *epp;
319 {
320
321 #ifdef MACHINE_STACK_GROWS_UP
322 epp->ep_maxsaddr = USRSTACK;
323 epp->ep_minsaddr = USRSTACK + MAXSSIZ;
324 #else
325 epp->ep_maxsaddr = USRSTACK - MAXSSIZ;
326 epp->ep_minsaddr = USRSTACK;
327 #endif
328 epp->ep_ssize = round_page(p->p_rlimit[RLIMIT_STACK].rlim_cur);
329
330 /*
331 * set up commands for stack. note that this takes *two*, one to
332 * map the part of the stack which we can access, and one to map
333 * the part which we can't.
334 *
335 * arguably, it could be made into one, but that would require the
336 * addition of another mapping proc, which is unnecessary
337 *
338 * note that in memory, things assumed to be: 0 ....... ep_maxsaddr
339 * <stack> ep_minsaddr
340 */
341 #ifdef MACHINE_STACK_GROWS_UP
342 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero,
343 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
344 epp->ep_maxsaddr + epp->ep_ssize, NULLVP, 0, VM_PROT_NONE);
345 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
346 epp->ep_maxsaddr, NULLVP, 0,
347 VM_PROT_READ|VM_PROT_WRITE);
348 #else
349 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero,
350 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
351 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE);
352 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
353 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0,
354 VM_PROT_READ|VM_PROT_WRITE);
355 #endif
356
357 return 0;
358 }