1 /* $OpenBSD: exec_subr.c,v 1.29 2011/06/29 12:16:17 tedu 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(struct exec_vmcmd_set *evsp, 58 int (*proc)(struct proc *, struct exec_vmcmd *), u_long len, u_long addr, 59 struct vnode *vp, u_long offset, u_int prot, int flags) 60 { 61 struct exec_vmcmd *vcp; 62 63 if (evsp->evs_used >= evsp->evs_cnt) 64 vmcmdset_extend(evsp); 65 vcp = &evsp->evs_cmds[evsp->evs_used++]; 66 vcp->ev_proc = proc; 67 vcp->ev_len = len; 68 vcp->ev_addr = addr; 69 if ((vcp->ev_vp = vp) != NULL) 70 vref(vp); 71 vcp->ev_offset = offset; 72 vcp->ev_prot = prot; 73 vcp->ev_flags = flags; 74 } 75 #endif /* DEBUG */ 76 77 void 78 vmcmdset_extend(struct exec_vmcmd_set *evsp) 79 { 80 struct exec_vmcmd *nvcp; 81 u_int ocnt; 82 83 #ifdef DIAGNOSTIC 84 if (evsp->evs_used < evsp->evs_cnt) 85 panic("vmcmdset_extend: not necessary"); 86 #endif 87 88 ocnt = evsp->evs_cnt; 89 KASSERT(ocnt > 0); 90 /* figure out number of entries in new set */ 91 evsp->evs_cnt += ocnt; 92 93 /* reallocate the command set */ 94 nvcp = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), M_EXEC, 95 M_WAITOK); 96 bcopy(evsp->evs_cmds, nvcp, (ocnt * sizeof(struct exec_vmcmd))); 97 if (evsp->evs_cmds != evsp->evs_start) 98 free(evsp->evs_cmds, M_EXEC); 99 evsp->evs_cmds = nvcp; 100 } 101 102 void 103 kill_vmcmds(struct exec_vmcmd_set *evsp) 104 { 105 struct exec_vmcmd *vcp; 106 int i; 107 108 for (i = 0; i < evsp->evs_used; i++) { 109 vcp = &evsp->evs_cmds[i]; 110 if (vcp->ev_vp != NULLVP) 111 vrele(vcp->ev_vp); 112 } 113 114 /* 115 * Free old vmcmds and reset the array. 116 */ 117 evsp->evs_used = 0; 118 if (evsp->evs_cmds != evsp->evs_start) 119 free(evsp->evs_cmds, M_EXEC); 120 evsp->evs_cmds = evsp->evs_start; 121 evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; 122 } 123 124 int 125 exec_process_vmcmds(struct proc *p, struct exec_package *epp) 126 { 127 struct exec_vmcmd *base_vc = NULL; 128 int error = 0; 129 int i; 130 131 for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) { 132 struct exec_vmcmd *vcp; 133 134 vcp = &epp->ep_vmcmds.evs_cmds[i]; 135 136 if (vcp->ev_flags & VMCMD_RELATIVE) { 137 #ifdef DIAGNOSTIC 138 if (base_vc == NULL) 139 panic("exec_process_vmcmds: RELATIVE no base"); 140 #endif 141 vcp->ev_addr += base_vc->ev_addr; 142 } 143 error = (*vcp->ev_proc)(p, vcp); 144 if (vcp->ev_flags & VMCMD_BASE) { 145 base_vc = vcp; 146 } 147 } 148 149 kill_vmcmds(&epp->ep_vmcmds); 150 151 return (error); 152 } 153 154 /* 155 * vmcmd_map_pagedvn(): 156 * handle vmcmd which specifies that a vnode should be mmap'd. 157 * appropriate for handling demand-paged text and data segments. 158 */ 159 160 int 161 vmcmd_map_pagedvn(struct proc *p, struct exec_vmcmd *cmd) 162 { 163 /* 164 * note that if you're going to map part of a process as being 165 * paged from a vnode, that vnode had damn well better be marked as 166 * VTEXT. that's handled in the routine which sets up the vmcmd to 167 * call this routine. 168 */ 169 struct uvm_object *uobj; 170 int error; 171 172 /* 173 * map the vnode in using uvm_map. 174 */ 175 176 if (cmd->ev_len == 0) 177 return (0); 178 if (cmd->ev_offset & PAGE_MASK) 179 return (EINVAL); 180 if (cmd->ev_addr & PAGE_MASK) 181 return (EINVAL); 182 if (cmd->ev_len & PAGE_MASK) 183 return (EINVAL); 184 185 /* 186 * first, attach to the object 187 */ 188 189 uobj = uvn_attach((void *)cmd->ev_vp, VM_PROT_READ|VM_PROT_EXECUTE); 190 if (uobj == NULL) 191 return (ENOMEM); 192 193 /* 194 * do the map 195 */ 196 197 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, 198 uobj, cmd->ev_offset, 0, 199 UVM_MAPFLAG(cmd->ev_prot, VM_PROT_ALL, UVM_INH_COPY, 200 UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); 201 202 /* 203 * check for error 204 */ 205 206 if (error) { 207 /* 208 * error: detach from object 209 */ 210 uobj->pgops->pgo_detach(uobj); 211 } 212 213 return (error); 214 } 215 216 /* 217 * vmcmd_map_readvn(): 218 * handle vmcmd which specifies that a vnode should be read from. 219 * appropriate for non-demand-paged text/data segments, i.e. impure 220 * objects (a la OMAGIC and NMAGIC). 221 */ 222 223 int 224 vmcmd_map_readvn(struct proc *p, struct exec_vmcmd *cmd) 225 { 226 int error; 227 vm_prot_t prot; 228 229 if (cmd->ev_len == 0) 230 return (0); 231 232 prot = cmd->ev_prot; 233 234 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */ 235 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 236 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 237 UVM_MAPFLAG(prot | UVM_PROT_WRITE, UVM_PROT_ALL, UVM_INH_COPY, 238 UVM_ADV_NORMAL, 239 UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); 240 241 if (error) 242 return (error); 243 244 error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr, 245 cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, 246 p->p_ucred, NULL, p); 247 if (error) 248 return (error); 249 250 if (cmd->ev_prot != (VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE)) { 251 /* 252 * we had to map in the area at PROT_ALL so that vn_rdwr() 253 * could write to it. however, the caller seems to want 254 * it mapped read-only, so now we are going to have to call 255 * uvm_map_protect() to fix up the protection. ICK. 256 */ 257 return (uvm_map_protect(&p->p_vmspace->vm_map, 258 trunc_page(cmd->ev_addr), 259 round_page(cmd->ev_addr + cmd->ev_len), 260 prot, FALSE)); 261 } 262 return (0); 263 } 264 265 /* 266 * vmcmd_map_zero(): 267 * handle vmcmd which specifies a zero-filled address space region. The 268 * address range must be first allocated, then protected appropriately. 269 */ 270 271 int 272 vmcmd_map_zero(struct proc *p, struct exec_vmcmd *cmd) 273 { 274 int error; 275 276 if (cmd->ev_len == 0) 277 return (0); 278 279 cmd->ev_addr = trunc_page(cmd->ev_addr); /* required by uvm_map */ 280 error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, 281 round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, 282 UVM_MAPFLAG(cmd->ev_prot, UVM_PROT_ALL, UVM_INH_COPY, 283 UVM_ADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); 284 285 if (error) 286 return error; 287 288 return (0); 289 } 290 291 /* 292 * exec_setup_stack(): Set up the stack segment for an a.out 293 * executable. 294 * 295 * Note that the ep_ssize parameter must be set to be the current stack 296 * limit; this is adjusted in the body of execve() to yield the 297 * appropriate stack segment usage once the argument length is 298 * calculated. 299 * 300 * This function returns an int for uniformity with other (future) formats' 301 * stack setup functions. They might have errors to return. 302 */ 303 304 int 305 exec_setup_stack(struct proc *p, struct exec_package *epp) 306 { 307 308 #ifdef MACHINE_STACK_GROWS_UP 309 epp->ep_maxsaddr = USRSTACK; 310 epp->ep_minsaddr = USRSTACK + MAXSSIZ; 311 #else 312 epp->ep_maxsaddr = USRSTACK - MAXSSIZ; 313 epp->ep_minsaddr = USRSTACK; 314 #endif 315 epp->ep_ssize = round_page(p->p_rlimit[RLIMIT_STACK].rlim_cur); 316 317 /* 318 * set up commands for stack. note that this takes *two*, one to 319 * map the part of the stack which we can access, and one to map 320 * the part which we can't. 321 * 322 * arguably, it could be made into one, but that would require the 323 * addition of another mapping proc, which is unnecessary 324 * 325 * note that in memory, things assumed to be: 0 ....... ep_maxsaddr 326 * <stack> ep_minsaddr 327 */ 328 #ifdef MACHINE_STACK_GROWS_UP 329 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 330 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 331 epp->ep_maxsaddr + epp->ep_ssize, NULLVP, 0, VM_PROT_NONE); 332 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 333 epp->ep_maxsaddr, NULLVP, 0, 334 VM_PROT_READ|VM_PROT_WRITE); 335 #else 336 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 337 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 338 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE); 339 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 340 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0, 341 VM_PROT_READ|VM_PROT_WRITE); 342 #endif 343 344 return (0); 345 } 346