1 /* $OpenBSD: exec_subr.c,v 1.30 2012/08/20 23:25:07 matthew 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 #include <dev/rndvar.h> 46 47 #ifdef DEBUG 48 /* 49 * new_vmcmd(): 50 * create a new vmcmd structure and fill in its fields based 51 * on function call arguments. make sure objects ref'd by 52 * the vmcmd are 'held'. 53 * 54 * If not debugging, this is a macro, so it's expanded inline. 55 */ 56 57 void 58 new_vmcmd(struct exec_vmcmd_set *evsp, 59 int (*proc)(struct proc *, struct exec_vmcmd *), u_long len, u_long addr, 60 struct vnode *vp, u_long offset, u_int prot, int flags) 61 { 62 struct exec_vmcmd *vcp; 63 64 if (evsp->evs_used >= evsp->evs_cnt) 65 vmcmdset_extend(evsp); 66 vcp = &evsp->evs_cmds[evsp->evs_used++]; 67 vcp->ev_proc = proc; 68 vcp->ev_len = len; 69 vcp->ev_addr = addr; 70 if ((vcp->ev_vp = vp) != NULL) 71 vref(vp); 72 vcp->ev_offset = offset; 73 vcp->ev_prot = prot; 74 vcp->ev_flags = flags; 75 } 76 #endif /* DEBUG */ 77 78 void 79 vmcmdset_extend(struct exec_vmcmd_set *evsp) 80 { 81 struct exec_vmcmd *nvcp; 82 u_int ocnt; 83 84 #ifdef DIAGNOSTIC 85 if (evsp->evs_used < evsp->evs_cnt) 86 panic("vmcmdset_extend: not necessary"); 87 #endif 88 89 ocnt = evsp->evs_cnt; 90 KASSERT(ocnt > 0); 91 /* figure out number of entries in new set */ 92 evsp->evs_cnt += ocnt; 93 94 /* reallocate the command set */ 95 nvcp = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), M_EXEC, 96 M_WAITOK); 97 bcopy(evsp->evs_cmds, nvcp, (ocnt * sizeof(struct exec_vmcmd))); 98 if (evsp->evs_cmds != evsp->evs_start) 99 free(evsp->evs_cmds, M_EXEC); 100 evsp->evs_cmds = nvcp; 101 } 102 103 void 104 kill_vmcmds(struct exec_vmcmd_set *evsp) 105 { 106 struct exec_vmcmd *vcp; 107 int i; 108 109 for (i = 0; i < evsp->evs_used; i++) { 110 vcp = &evsp->evs_cmds[i]; 111 if (vcp->ev_vp != NULLVP) 112 vrele(vcp->ev_vp); 113 } 114 115 /* 116 * Free old vmcmds and reset the array. 117 */ 118 evsp->evs_used = 0; 119 if (evsp->evs_cmds != evsp->evs_start) 120 free(evsp->evs_cmds, M_EXEC); 121 evsp->evs_cmds = evsp->evs_start; 122 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 123 } 124 125 int 126 exec_process_vmcmds(struct proc *p, struct exec_package *epp) 127 { 128 struct exec_vmcmd *base_vc = NULL; 129 int error = 0; 130 int i; 131 132 for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) { 133 struct exec_vmcmd *vcp; 134 135 vcp = &epp->ep_vmcmds.evs_cmds[i]; 136 137 if (vcp->ev_flags & VMCMD_RELATIVE) { 138 #ifdef DIAGNOSTIC 139 if (base_vc == NULL) 140 panic("exec_process_vmcmds: RELATIVE no base"); 141 #endif 142 vcp->ev_addr += base_vc->ev_addr; 143 } 144 error = (*vcp->ev_proc)(p, vcp); 145 if (vcp->ev_flags & VMCMD_BASE) { 146 base_vc = vcp; 147 } 148 } 149 150 kill_vmcmds(&epp->ep_vmcmds); 151 152 return (error); 153 } 154 155 /* 156 * vmcmd_map_pagedvn(): 157 * handle vmcmd which specifies that a vnode should be mmap'd. 158 * appropriate for handling demand-paged text and data segments. 159 */ 160 161 int 162 vmcmd_map_pagedvn(struct proc *p, struct exec_vmcmd *cmd) 163 { 164 /* 165 * note that if you're going to map part of a process as being 166 * paged from a vnode, that vnode had damn well better be marked as 167 * VTEXT. that's handled in the routine which sets up the vmcmd to 168 * call this routine. 169 */ 170 struct uvm_object *uobj; 171 int error; 172 173 /* 174 * map the vnode in using uvm_map. 175 */ 176 177 if (cmd->ev_len == 0) 178 return (0); 179 if (cmd->ev_offset & PAGE_MASK) 180 return (EINVAL); 181 if (cmd->ev_addr & PAGE_MASK) 182 return (EINVAL); 183 if (cmd->ev_len & PAGE_MASK) 184 return (EINVAL); 185 186 /* 187 * first, attach to the object 188 */ 189 190 uobj = uvn_attach((void *)cmd->ev_vp, VM_PROT_READ|VM_PROT_EXECUTE); 191 if (uobj == NULL) 192 return (ENOMEM); 193 194 /* 195 * do the map 196 */ 197 198 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 199 uobj, cmd->ev_offset, 0, 200 UVM_MAPFLAG(cmd->ev_prot, VM_PROT_ALL, UVM_INH_COPY, 201 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 202 203 /* 204 * check for error 205 */ 206 207 if (error) { 208 /* 209 * error: detach from object 210 */ 211 uobj->pgops->pgo_detach(uobj); 212 } 213 214 return (error); 215 } 216 217 /* 218 * vmcmd_map_readvn(): 219 * handle vmcmd which specifies that a vnode should be read from. 220 * appropriate for non-demand-paged text/data segments, i.e. impure 221 * objects (a la OMAGIC and NMAGIC). 222 */ 223 224 int 225 vmcmd_map_readvn(struct proc *p, struct exec_vmcmd *cmd) 226 { 227 int error; 228 vm_prot_t prot; 229 230 if (cmd->ev_len == 0) 231 return (0); 232 233 prot = cmd->ev_prot; 234 235 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */ 236 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 237 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 238 UVM_MAPFLAG(prot | UVM_PROT_WRITE, UVM_PROT_ALL, UVM_INH_COPY, 239 UVM_ADV_NORMAL, 240 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 241 242 if (error) 243 return (error); 244 245 error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr, 246 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 247 p->p_ucred, NULL, p); 248 if (error) 249 return (error); 250 251 if (cmd->ev_prot != (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)) { 252 /* 253 * we had to map in the area at PROT_ALL so that vn_rdwr() 254 * could write to it. however, the caller seems to want 255 * it mapped read-only, so now we are going to have to call 256 * uvm_map_protect() to fix up the protection. ICK. 257 */ 258 return (uvm_map_protect(&p->p_vmspace->vm_map, 259 trunc_page(cmd->ev_addr), 260 round_page(cmd->ev_addr + cmd->ev_len), 261 prot, FALSE)); 262 } 263 return (0); 264 } 265 266 /* 267 * vmcmd_map_zero(): 268 * handle vmcmd which specifies a zero-filled address space region. The 269 * address range must be first allocated, then protected appropriately. 270 */ 271 272 int 273 vmcmd_map_zero(struct proc *p, struct exec_vmcmd *cmd) 274 { 275 int error; 276 277 if (cmd->ev_len == 0) 278 return (0); 279 280 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */ 281 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 282 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 283 UVM_MAPFLAG(cmd->ev_prot, UVM_PROT_ALL, UVM_INH_COPY, 284 UVM_ADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 285 286 if (error) 287 return error; 288 289 return (0); 290 } 291 292 /* 293 * vmcmd_randomize(): 294 * handle vmcmd which specifies a randomized address space region. 295 */ 296 297 int 298 vmcmd_randomize(struct proc *p, struct exec_vmcmd *cmd) 299 { 300 char *buf; 301 int error; 302 303 if (cmd->ev_len == 0) 304 return (0); 305 if (cmd->ev_len > 1024) 306 return (EINVAL); 307 308 buf = malloc(cmd->ev_len, M_TEMP, M_WAITOK); 309 arc4random_buf(buf, cmd->ev_len); 310 error = copyout(buf, (void *)cmd->ev_addr, cmd->ev_len); 311 free(buf, M_TEMP); 312 313 return (error); 314 } 315 316 /* 317 * exec_setup_stack(): Set up the stack segment for an a.out 318 * executable. 319 * 320 * Note that the ep_ssize parameter must be set to be the current stack 321 * limit; this is adjusted in the body of execve() to yield the 322 * appropriate stack segment usage once the argument length is 323 * calculated. 324 * 325 * This function returns an int for uniformity with other (future) formats' 326 * stack setup functions. They might have errors to return. 327 */ 328 329 int 330 exec_setup_stack(struct proc *p, struct exec_package *epp) 331 { 332 333 #ifdef MACHINE_STACK_GROWS_UP 334 epp->ep_maxsaddr = USRSTACK; 335 epp->ep_minsaddr = USRSTACK + MAXSSIZ; 336 #else 337 epp->ep_maxsaddr = USRSTACK - MAXSSIZ; 338 epp->ep_minsaddr = USRSTACK; 339 #endif 340 epp->ep_ssize = round_page(p->p_rlimit[RLIMIT_STACK].rlim_cur); 341 342 /* 343 * set up commands for stack. note that this takes *two*, one to 344 * map the part of the stack which we can access, and one to map 345 * the part which we can't. 346 * 347 * arguably, it could be made into one, but that would require the 348 * addition of another mapping proc, which is unnecessary 349 * 350 * note that in memory, things assumed to be: 0 ....... ep_maxsaddr 351 * <stack> ep_minsaddr 352 */ 353 #ifdef MACHINE_STACK_GROWS_UP 354 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 355 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 356 epp->ep_maxsaddr + epp->ep_ssize, NULLVP, 0, VM_PROT_NONE); 357 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 358 epp->ep_maxsaddr, NULLVP, 0, 359 VM_PROT_READ|VM_PROT_WRITE); 360 #else 361 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 362 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 363 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE); 364 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 365 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0, 366 VM_PROT_READ|VM_PROT_WRITE); 367 #endif 368 369 return (0); 370 } 371