Annotation of sys/kern/exec_subr.c, Revision 1.1.1.1
1.1 nbrk 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: }
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