1 /* $NetBSD: exec_subr.c,v 1.46 2005/12/11 12:24:29 christos 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 1.46 2005/12/11 12:24:29 christos Exp $"); 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/proc.h> 39 #include <sys/malloc.h> 40 #include <sys/vnode.h> 41 #include <sys/filedesc.h> 42 #include <sys/exec.h> 43 #include <sys/mman.h> 44 #include <sys/resourcevar.h> 45 #include <sys/device.h> 46 47 #include <uvm/uvm.h> 48 49 #define VMCMD_EVCNT_DECL(name) \ 50 static struct evcnt vmcmd_ev_##name = \ 51 EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \ 52 EVCNT_ATTACH_STATIC(vmcmd_ev_##name) 53 54 #define VMCMD_EVCNT_INCR(name) \ 55 vmcmd_ev_##name.ev_count++ 56 57 VMCMD_EVCNT_DECL(calls); 58 VMCMD_EVCNT_DECL(extends); 59 VMCMD_EVCNT_DECL(kills); 60 61 /* 62 * new_vmcmd(): 63 * create a new vmcmd structure and fill in its fields based 64 * on function call arguments. make sure objects ref'd by 65 * the vmcmd are 'held'. 66 */ 67 68 void 69 new_vmcmd(struct exec_vmcmd_set *evsp, 70 int (*proc)(struct lwp * l, struct exec_vmcmd *), 71 u_long len, u_long addr, struct vnode *vp, u_long offset, 72 u_int prot, int flags) 73 { 74 struct exec_vmcmd *vcp; 75 76 VMCMD_EVCNT_INCR(calls); 77 78 if (evsp->evs_used >= evsp->evs_cnt) 79 vmcmdset_extend(evsp); 80 vcp = &evsp->evs_cmds[evsp->evs_used++]; 81 vcp->ev_proc = proc; 82 vcp->ev_len = len; 83 vcp->ev_addr = addr; 84 if ((vcp->ev_vp = vp) != NULL) 85 vref(vp); 86 vcp->ev_offset = offset; 87 vcp->ev_prot = prot; 88 vcp->ev_flags = flags; 89 } 90 91 void 92 vmcmdset_extend(struct exec_vmcmd_set *evsp) 93 { 94 struct exec_vmcmd *nvcp; 95 u_int ocnt; 96 97 #ifdef DIAGNOSTIC 98 if (evsp->evs_used < evsp->evs_cnt) 99 panic("vmcmdset_extend: not necessary"); 100 #endif 101 102 /* figure out number of entries in new set */ 103 if ((ocnt = evsp->evs_cnt) != 0) { 104 evsp->evs_cnt += ocnt; 105 VMCMD_EVCNT_INCR(extends); 106 } else 107 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 108 109 /* allocate it */ 110 nvcp = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), 111 M_EXEC, M_WAITOK); 112 113 /* free the old struct, if there was one, and record the new one */ 114 if (ocnt) { 115 memcpy(nvcp, evsp->evs_cmds, 116 (ocnt * sizeof(struct exec_vmcmd))); 117 free(evsp->evs_cmds, M_EXEC); 118 } 119 evsp->evs_cmds = nvcp; 120 } 121 122 void 123 kill_vmcmds(struct exec_vmcmd_set *evsp) 124 { 125 struct exec_vmcmd *vcp; 126 u_int i; 127 128 VMCMD_EVCNT_INCR(kills); 129 130 if (evsp->evs_cnt == 0) 131 return; 132 133 for (i = 0; i < evsp->evs_used; i++) { 134 vcp = &evsp->evs_cmds[i]; 135 if (vcp->ev_vp != NULL) 136 vrele(vcp->ev_vp); 137 } 138 evsp->evs_used = evsp->evs_cnt = 0; 139 free(evsp->evs_cmds, M_EXEC); 140 } 141 142 /* 143 * vmcmd_map_pagedvn(): 144 * handle vmcmd which specifies that a vnode should be mmap'd. 145 * appropriate for handling demand-paged text and data segments. 146 */ 147 148 int 149 vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd) 150 { 151 struct uvm_object *uobj; 152 struct proc *p = l->l_proc; 153 int error; 154 155 KASSERT(cmd->ev_vp->v_flag & VTEXT); 156 157 /* 158 * map the vnode in using uvm_map. 159 */ 160 161 if (cmd->ev_len == 0) 162 return(0); 163 if (cmd->ev_offset & PAGE_MASK) 164 return(EINVAL); 165 if (cmd->ev_addr & PAGE_MASK) 166 return(EINVAL); 167 if (cmd->ev_len & PAGE_MASK) 168 return(EINVAL); 169 170 /* 171 * first, attach to the object 172 */ 173 174 uobj = uvn_attach(cmd->ev_vp, VM_PROT_READ|VM_PROT_EXECUTE); 175 if (uobj == NULL) 176 return(ENOMEM); 177 VREF(cmd->ev_vp); 178 179 /* 180 * do the map 181 */ 182 183 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 184 uobj, cmd->ev_offset, 0, 185 UVM_MAPFLAG(cmd->ev_prot, VM_PROT_ALL, UVM_INH_COPY, 186 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 187 if (error) { 188 uobj->pgops->pgo_detach(uobj); 189 } 190 return error; 191 } 192 193 /* 194 * vmcmd_map_readvn(): 195 * handle vmcmd which specifies that a vnode should be read from. 196 * appropriate for non-demand-paged text/data segments, i.e. impure 197 * objects (a la OMAGIC and NMAGIC). 198 */ 199 int 200 vmcmd_map_readvn(struct lwp *l, struct exec_vmcmd *cmd) 201 { 202 struct proc *p = l->l_proc; 203 int error; 204 long diff; 205 206 if (cmd->ev_len == 0) 207 return 0; 208 209 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 210 cmd->ev_addr -= diff; /* required by uvm_map */ 211 cmd->ev_offset -= diff; 212 cmd->ev_len += diff; 213 214 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 215 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 216 UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY, 217 UVM_ADV_NORMAL, 218 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 219 220 if (error) 221 return error; 222 223 return vmcmd_readvn(l, cmd); 224 } 225 226 int 227 vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd) 228 { 229 struct proc *p = l->l_proc; 230 int error; 231 232 error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr, 233 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 234 p->p_ucred, NULL, l); 235 if (error) 236 return error; 237 238 #ifdef PMAP_NEED_PROCWR 239 /* 240 * we had to write the process, make sure the pages are synched 241 * with the instruction cache. 242 */ 243 if (cmd->ev_prot & VM_PROT_EXECUTE) 244 pmap_procwr(p, cmd->ev_addr, cmd->ev_len); 245 #endif 246 247 if (cmd->ev_prot != (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)) { 248 249 /* 250 * we had to map in the area at PROT_ALL so that vn_rdwr() 251 * could write to it. however, the caller seems to want 252 * it mapped read-only, so now we are going to have to call 253 * uvm_map_protect() to fix up the protection. ICK. 254 */ 255 256 return uvm_map_protect(&p->p_vmspace->vm_map, 257 trunc_page(cmd->ev_addr), 258 round_page(cmd->ev_addr + cmd->ev_len), 259 cmd->ev_prot, FALSE); 260 } 261 return 0; 262 } 263 264 /* 265 * vmcmd_map_zero(): 266 * handle vmcmd which specifies a zero-filled address space region. The 267 * address range must be first allocated, then protected appropriately. 268 */ 269 270 int 271 vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd) 272 { 273 struct proc *p = l->l_proc; 274 int error; 275 long diff; 276 277 diff = cmd->ev_addr - trunc_page(cmd->ev_addr); 278 cmd->ev_addr -= diff; /* required by uvm_map */ 279 cmd->ev_len += diff; 280 281 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, 285 UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 286 return error; 287 } 288 289 /* 290 * exec_read_from(): 291 * 292 * Read from vnode into buffer at offset. 293 */ 294 int 295 exec_read_from(struct lwp *l, struct vnode *vp, u_long off, void *bf, 296 size_t size) 297 { 298 int error; 299 size_t resid; 300 301 if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE, 302 0, l->l_proc->p_ucred, &resid, NULL)) != 0) 303 return error; 304 /* 305 * See if we got all of it 306 */ 307 if (resid != 0) 308 return ENOEXEC; 309 return 0; 310 } 311 312 /* 313 * exec_setup_stack(): Set up the stack segment for an elf 314 * executable. 315 * 316 * Note that the ep_ssize parameter must be set to be the current stack 317 * limit; this is adjusted in the body of execve() to yield the 318 * appropriate stack segment usage once the argument length is 319 * calculated. 320 * 321 * This function returns an int for uniformity with other (future) formats' 322 * stack setup functions. They might have errors to return. 323 */ 324 325 int 326 exec_setup_stack(struct lwp *l, struct exec_package *epp) 327 { 328 u_long max_stack_size; 329 u_long access_linear_min, access_size; 330 u_long noaccess_linear_min, noaccess_size; 331 332 #ifndef USRSTACK32 333 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) 334 #endif 335 336 if (epp->ep_flags & EXEC_32) { 337 epp->ep_minsaddr = USRSTACK32; 338 max_stack_size = MAXSSIZ; 339 } else { 340 epp->ep_minsaddr = USRSTACK; 341 max_stack_size = MAXSSIZ; 342 } 343 epp->ep_maxsaddr = (u_long)STACK_GROW(epp->ep_minsaddr, 344 max_stack_size); 345 epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur; 346 347 /* 348 * set up commands for stack. note that this takes *two*, one to 349 * map the part of the stack which we can access, and one to map 350 * the part which we can't. 351 * 352 * arguably, it could be made into one, but that would require the 353 * addition of another mapping proc, which is unnecessary 354 */ 355 access_size = epp->ep_ssize; 356 access_linear_min = (u_long)STACK_ALLOC(epp->ep_minsaddr, access_size); 357 noaccess_size = max_stack_size - access_size; 358 noaccess_linear_min = (u_long)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, 359 access_size), noaccess_size); 360 if (noaccess_size > 0) { 361 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, 362 noaccess_linear_min, NULL, 0, VM_PROT_NONE); 363 } 364 KASSERT(access_size > 0); 365 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, access_size, 366 access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE); 367 368 return 0; 369 } 370