exec_subr.c revision 1.48
1 /* $NetBSD: exec_subr.c,v 1.48 2006/05/20 15:45:37 elad Exp $ */ 2 3 /* 4 * Copyright (c) 1993, 1994, 1996 Christopher G. Demetriou 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Christopher G. Demetriou. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #include <sys/cdefs.h> 34 __KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.48 2006/05/20 15:45:37 elad Exp $"); 35 36 #include "opt_pax.h" 37 38 #include <sys/param.h> 39 #include <sys/systm.h> 40 #include <sys/proc.h> 41 #include <sys/malloc.h> 42 #include <sys/vnode.h> 43 #include <sys/filedesc.h> 44 #include <sys/exec.h> 45 #include <sys/mman.h> 46 #include <sys/resourcevar.h> 47 #include <sys/device.h> 48 49 #ifdef PAX_MPROTECT 50 #include <sys/pax.h> 51 #endif /* PAX_MPROTECT */ 52 53 #include <uvm/uvm.h> 54 55 #define VMCMD_EVCNT_DECL(name) \ 56 static struct evcnt vmcmd_ev_##name = \ 57 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \ 58 EVCNT_ATTACH_STATIC(vmcmd_ev_##name) 59 60 #define VMCMD_EVCNT_INCR(name) \ 61 vmcmd_ev_##name.ev_count++ 62 63 VMCMD_EVCNT_DECL(calls); 64 VMCMD_EVCNT_DECL(extends); 65 VMCMD_EVCNT_DECL(kills); 66 67 /* 68 * new_vmcmd(): 69 * create a new vmcmd structure and fill in its fields based 70 * on function call arguments. make sure objects ref'd by 71 * the vmcmd are 'held'. 72 */ 73 74 void 75 new_vmcmd(struct exec_vmcmd_set *evsp, 76 int (*proc)(struct lwp * l, struct exec_vmcmd *), 77 u_long len, u_long addr, struct vnode *vp, u_long offset, 78 u_int prot, int flags) 79 { 80 struct exec_vmcmd *vcp; 81 82 VMCMD_EVCNT_INCR(calls); 83 84 if (evsp->evs_used >= evsp->evs_cnt) 85 vmcmdset_extend(evsp); 86 vcp = &evsp->evs_cmds[evsp->evs_used++]; 87 vcp->ev_proc = proc; 88 vcp->ev_len = len; 89 vcp->ev_addr = addr; 90 if ((vcp->ev_vp = vp) != NULL) 91 vref(vp); 92 vcp->ev_offset = offset; 93 vcp->ev_prot = prot; 94 vcp->ev_flags = flags; 95 } 96 97 void 98 vmcmdset_extend(struct exec_vmcmd_set *evsp) 99 { 100 struct exec_vmcmd *nvcp; 101 u_int ocnt; 102 103 #ifdef DIAGNOSTIC 104 if (evsp->evs_used < evsp->evs_cnt) 105 panic("vmcmdset_extend: not necessary"); 106 #endif 107 108 /* figure out number of entries in new set */ 109 if ((ocnt = evsp->evs_cnt) != 0) { 110 evsp->evs_cnt += ocnt; 111 VMCMD_EVCNT_INCR(extends); 112 } else 113 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 114 115 /* allocate it */ 116 nvcp = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), 117 M_EXEC, M_WAITOK); 118 119 /* free the old struct, if there was one, and record the new one */ 120 if (ocnt) { 121 memcpy(nvcp, evsp->evs_cmds, 122 (ocnt * sizeof(struct exec_vmcmd))); 123 free(evsp->evs_cmds, M_EXEC); 124 } 125 evsp->evs_cmds = nvcp; 126 } 127 128 void 129 kill_vmcmds(struct exec_vmcmd_set *evsp) 130 { 131 struct exec_vmcmd *vcp; 132 u_int i; 133 134 VMCMD_EVCNT_INCR(kills); 135 136 if (evsp->evs_cnt == 0) 137 return; 138 139 for (i = 0; i < evsp->evs_used; i++) { 140 vcp = &evsp->evs_cmds[i]; 141 if (vcp->ev_vp != NULL) 142 vrele(vcp->ev_vp); 143 } 144 evsp->evs_used = evsp->evs_cnt = 0; 145 free(evsp->evs_cmds, M_EXEC); 146 } 147 148 /* 149 * vmcmd_map_pagedvn(): 150 * handle vmcmd which specifies that a vnode should be mmap'd. 151 * appropriate for handling demand-paged text and data segments. 152 */ 153 154 int 155 vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd) 156 { 157 struct uvm_object *uobj; 158 struct proc *p = l->l_proc; 159 int error; 160 vm_prot_t prot, maxprot; 161 162 KASSERT(cmd->ev_vp->v_flag & VTEXT); 163 164 /* 165 * map the vnode in using uvm_map. 166 */ 167 168 if (cmd->ev_len == 0) 169 return(0); 170 if (cmd->ev_offset & PAGE_MASK) 171 return(EINVAL); 172 if (cmd->ev_addr & PAGE_MASK) 173 return(EINVAL); 174 if (cmd->ev_len & PAGE_MASK) 175 return(EINVAL); 176 177 /* 178 * first, attach to the object 179 */ 180 181 uobj = uvn_attach(cmd->ev_vp, VM_PROT_READ|VM_PROT_EXECUTE); 182 if (uobj == NULL) 183 return(ENOMEM); 184 VREF(cmd->ev_vp); 185 186 prot = cmd->ev_prot; 187 maxprot = UVM_PROT_ALL; 188 #ifdef PAX_MPROTECT 189 pax_mprotect(l, &prot, &maxprot); 190 #endif /* PAX_MPROTECT */ 191 192 /* 193 * do the map 194 */ 195 196 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 197 uobj, cmd->ev_offset, 0, 198 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 199 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 200 if (error) { 201 uobj->pgops->pgo_detach(uobj); 202 } 203 return error; 204 } 205 206 /* 207 * vmcmd_map_readvn(): 208 * handle vmcmd which specifies that a vnode should be read from. 209 * appropriate for non-demand-paged text/data segments, i.e. impure 210 * objects (a la OMAGIC and NMAGIC). 211 */ 212 int 213 vmcmd_map_readvn(struct lwp *l, struct exec_vmcmd *cmd) 214 { 215 struct proc *p = l->l_proc; 216 int error; 217 long diff; 218 219 if (cmd->ev_len == 0) 220 return 0; 221 222 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 223 cmd->ev_addr -= diff; /* required by uvm_map */ 224 cmd->ev_offset -= diff; 225 cmd->ev_len += diff; 226 227 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 228 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 229 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY, 230 UVM_ADV_NORMAL, 231 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 232 233 if (error) 234 return error; 235 236 return vmcmd_readvn(l, cmd); 237 } 238 239 int 240 vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd) 241 { 242 struct proc *p = l->l_proc; 243 int error; 244 vm_prot_t prot, maxprot; 245 246 error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr, 247 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 248 p->p_cred, NULL, l); 249 if (error) 250 return error; 251 252 prot = cmd->ev_prot; 253 maxprot = VM_PROT_ALL; 254 #ifdef PAX_MPROTECT 255 pax_mprotect(l, &prot, &maxprot); 256 #endif /* PAX_MPROTECT */ 257 258 #ifdef PMAP_NEED_PROCWR 259 /* 260 * we had to write the process, make sure the pages are synched 261 * with the instruction cache. 262 */ 263 if (prot & VM_PROT_EXECUTE) 264 pmap_procwr(p, cmd->ev_addr, cmd->ev_len); 265 #endif 266 267 /* 268 * we had to map in the area at PROT_ALL so that vn_rdwr() 269 * could write to it. however, the caller seems to want 270 * it mapped read-only, so now we are going to have to call 271 * uvm_map_protect() to fix up the protection. ICK. 272 */ 273 if (maxprot != VM_PROT_ALL) { 274 error = uvm_map_protect(&p->p_vmspace->vm_map, 275 trunc_page(cmd->ev_addr), 276 round_page(cmd->ev_addr + cmd->ev_len), 277 maxprot, TRUE); 278 if (error) 279 return (error); 280 } 281 282 if (prot != maxprot) { 283 error = uvm_map_protect(&p->p_vmspace->vm_map, 284 trunc_page(cmd->ev_addr), 285 round_page(cmd->ev_addr + cmd->ev_len), 286 prot, FALSE); 287 if (error) 288 return (error); 289 } 290 291 return 0; 292 } 293 294 /* 295 * vmcmd_map_zero(): 296 * handle vmcmd which specifies a zero-filled address space region. The 297 * address range must be first allocated, then protected appropriately. 298 */ 299 300 int 301 vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd) 302 { 303 struct proc *p = l->l_proc; 304 int error; 305 long diff; 306 vm_prot_t prot, maxprot; 307 308 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 309 cmd->ev_addr -= diff; /* required by uvm_map */ 310 cmd->ev_len += diff; 311 312 prot = cmd->ev_prot; 313 maxprot = UVM_PROT_ALL; 314 #ifdef PAX_MPROTECT 315 pax_mprotect(l, &prot, &maxprot); 316 #endif /* PAX_MPROTECT */ 317 318 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 319 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 320 UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, 321 UVM_ADV_NORMAL, 322 UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 323 return error; 324 } 325 326 /* 327 * exec_read_from(): 328 * 329 * Read from vnode into buffer at offset. 330 */ 331 int 332 exec_read_from(struct lwp *l, struct vnode *vp, u_long off, void *bf, 333 size_t size) 334 { 335 int error; 336 size_t resid; 337 338 if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE, 339 0, l->l_proc->p_cred, &resid, NULL)) != 0) 340 return error; 341 /* 342 * See if we got all of it 343 */ 344 if (resid != 0) 345 return ENOEXEC; 346 return 0; 347 } 348 349 /* 350 * exec_setup_stack(): Set up the stack segment for an elf 351 * executable. 352 * 353 * Note that the ep_ssize parameter must be set to be the current stack 354 * limit; this is adjusted in the body of execve() to yield the 355 * appropriate stack segment usage once the argument length is 356 * calculated. 357 * 358 * This function returns an int for uniformity with other (future) formats' 359 * stack setup functions. They might have errors to return. 360 */ 361 362 int 363 exec_setup_stack(struct lwp *l, struct exec_package *epp) 364 { 365 u_long max_stack_size; 366 u_long access_linear_min, access_size; 367 u_long noaccess_linear_min, noaccess_size; 368 369 #ifndef USRSTACK32 370 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) 371 #endif 372 373 if (epp->ep_flags & EXEC_32) { 374 epp->ep_minsaddr = USRSTACK32; 375 max_stack_size = MAXSSIZ; 376 } else { 377 epp->ep_minsaddr = USRSTACK; 378 max_stack_size = MAXSSIZ; 379 } 380 epp->ep_maxsaddr = (u_long)STACK_GROW(epp->ep_minsaddr, 381 max_stack_size); 382 epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur; 383 384 /* 385 * set up commands for stack. note that this takes *two*, one to 386 * map the part of the stack which we can access, and one to map 387 * the part which we can't. 388 * 389 * arguably, it could be made into one, but that would require the 390 * addition of another mapping proc, which is unnecessary 391 */ 392 access_size = epp->ep_ssize; 393 access_linear_min = (u_long)STACK_ALLOC(epp->ep_minsaddr, access_size); 394 noaccess_size = max_stack_size - access_size; 395 noaccess_linear_min = (u_long)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, 396 access_size), noaccess_size); 397 if (noaccess_size > 0) { 398 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, 399 noaccess_linear_min, NULL, 0, VM_PROT_NONE); 400 } 401 KASSERT(access_size > 0); 402 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, access_size, 403 access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE); 404 405 return 0; 406 } 407
Indexes created Tue Sep 23 22:09:46 GMT 2025