Annotation of sys/kern/exec_subr.c, Revision 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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