1 /* $NetBSD: exec_aout.c,v 1.13 1994/08/01 18:49:49 pk Exp $ */ 2 3 /* 4 * Copyright (c) 1993, 1994 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/param.h> 34 #include <sys/systm.h> 35 #include <sys/proc.h> 36 #include <sys/malloc.h> 37 #include <sys/vnode.h> 38 #include <sys/exec.h> 39 #include <sys/resourcevar.h> 40 #include <vm/vm.h> 41 42 /* 43 * exec_aout_makecmds(): Check if it's an a.out-format executable. 44 * 45 * Given a proc pointer and an exec package pointer, see if the referent 46 * of the epp is in a.out format. First check 'standard' magic numbers for 47 * this architecture. If that fails, try a cpu-dependent hook. 48 * 49 * This function, in the former case, or the hook, in the latter, is 50 * responsible for creating a set of vmcmds which can be used to build 51 * the process's vm space and inserting them into the exec package. 52 */ 53 54 int 55 exec_aout_makecmds(p, epp) 56 struct proc *p; 57 struct exec_package *epp; 58 { 59 u_long midmag, magic; 60 u_short mid; 61 int error; 62 struct exec *execp = epp->ep_hdr; 63 64 if (epp->ep_hdrvalid < sizeof(struct exec)) 65 return ENOEXEC; 66 67 midmag = ntohl(execp->a_midmag); 68 mid = (midmag >> 16) & 0x3ff; 69 magic = midmag & 0xffff; 70 71 midmag = mid << 16 | magic; 72 73 switch (midmag) { 74 case (MID_MACHINE << 16) | ZMAGIC: 75 error = exec_aout_prep_zmagic(p, epp); 76 break; 77 case (MID_MACHINE << 16) | NMAGIC: 78 error = exec_aout_prep_nmagic(p, epp); 79 break; 80 case (MID_MACHINE << 16) | OMAGIC: 81 error = exec_aout_prep_omagic(p, epp); 82 break; 83 default: 84 error = cpu_exec_aout_makecmds(p, epp); 85 } 86 87 if (error) 88 kill_vmcmds(&epp->ep_vmcmds); 89 90 bad: 91 return error; 92 } 93 94 /* 95 * exec_aout_prep_zmagic(): Prepare a 'native' ZMAGIC binary's exec package 96 * 97 * First, set of the various offsets/lengths in the exec package. 98 * 99 * Then, mark the text image busy (so it can be demand paged) or error 100 * out if this is not possible. Finally, set up vmcmds for the 101 * text, data, bss, and stack segments. 102 */ 103 104 int 105 exec_aout_prep_zmagic(p, epp) 106 struct proc *p; 107 struct exec_package *epp; 108 { 109 struct exec *execp = epp->ep_hdr; 110 111 epp->ep_taddr = USRTEXT; 112 epp->ep_tsize = execp->a_text; 113 epp->ep_daddr = epp->ep_taddr + execp->a_text; 114 epp->ep_dsize = execp->a_data + execp->a_bss; 115 epp->ep_entry = execp->a_entry; 116 117 /* 118 * check if vnode is in open for writing, because we want to 119 * demand-page out of it. if it is, don't do it, for various 120 * reasons 121 */ 122 if ((execp->a_text != 0 || execp->a_data != 0) && 123 epp->ep_vp->v_writecount != 0) { 124 #ifdef DIAGNOSTIC 125 if (epp->ep_vp->v_flag & VTEXT) 126 panic("exec: a VTEXT vnode has writecount != 0\n"); 127 #endif 128 return ETXTBSY; 129 } 130 epp->ep_vp->v_flag |= VTEXT; 131 132 /* set up command for text segment */ 133 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text, 134 epp->ep_taddr, epp->ep_vp, 0, VM_PROT_READ|VM_PROT_EXECUTE); 135 136 /* set up command for data segment */ 137 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data, 138 epp->ep_daddr, epp->ep_vp, execp->a_text, 139 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 140 141 /* set up command for bss segment */ 142 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 143 epp->ep_daddr + execp->a_data, NULLVP, 0, 144 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 145 146 return exec_aout_setup_stack(p, epp); 147 } 148 149 /* 150 * exec_aout_prep_nmagic(): Prepare a 'native' NMAGIC binary's exec package 151 */ 152 153 int 154 exec_aout_prep_nmagic(p, epp) 155 struct proc *p; 156 struct exec_package *epp; 157 { 158 struct exec *execp = epp->ep_hdr; 159 long bsize, baddr; 160 161 epp->ep_taddr = USRTEXT; 162 epp->ep_tsize = execp->a_text; 163 epp->ep_daddr = roundup(epp->ep_taddr + execp->a_text, __LDPGSZ); 164 epp->ep_dsize = execp->a_data + execp->a_bss; 165 epp->ep_entry = execp->a_entry; 166 167 /* set up command for text segment */ 168 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 169 epp->ep_taddr, epp->ep_vp, sizeof(struct exec), 170 VM_PROT_READ|VM_PROT_EXECUTE); 171 172 /* set up command for data segment */ 173 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 174 epp->ep_daddr, epp->ep_vp, execp->a_text + sizeof(struct exec), 175 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 176 177 /* set up command for bss segment */ 178 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 179 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 180 if (bsize > 0) 181 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 182 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 183 184 return exec_aout_setup_stack(p, epp); 185 } 186 187 /* 188 * exec_aout_prep_omagic(): Prepare a 'native' OMAGIC binary's exec package 189 */ 190 191 int 192 exec_aout_prep_omagic(p, epp) 193 struct proc *p; 194 struct exec_package *epp; 195 { 196 struct exec *execp = epp->ep_hdr; 197 long dsize, bsize, baddr; 198 199 epp->ep_taddr = USRTEXT; 200 epp->ep_tsize = execp->a_text; 201 epp->ep_daddr = epp->ep_taddr + execp->a_text; 202 epp->ep_dsize = execp->a_data + execp->a_bss; 203 epp->ep_entry = execp->a_entry; 204 205 /* set up command for text and data segments */ 206 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 207 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 208 sizeof(struct exec), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 209 210 /* set up command for bss segment */ 211 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 212 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 213 if (bsize > 0) 214 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 215 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 216 217 /* 218 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 219 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 220 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 221 * respectively to page boundaries. 222 * Compensate `ep_dsize' for the amount of data covered by the last 223 * text page. 224 */ 225 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 226 epp->ep_dsize = (dsize > 0) ? dsize : 0; 227 return exec_aout_setup_stack(p, epp); 228 } 229 230 /* 231 * exec_aout_setup_stack(): Set up the stack segment for an a.out 232 * executable. 233 * 234 * Note that the ep_ssize parameter must be set to be the current stack 235 * limit; this is adjusted in the body of execve() to yield the 236 * appropriate stack segment usage once the argument length is 237 * calculated. 238 * 239 * This function returns an int for uniformity with other (future) formats' 240 * stack setup functions. They might have errors to return. 241 */ 242 243 int 244 exec_aout_setup_stack(p, epp) 245 struct proc *p; 246 struct exec_package *epp; 247 { 248 249 epp->ep_maxsaddr = USRSTACK - MAXSSIZ; 250 epp->ep_minsaddr = USRSTACK; 251 epp->ep_ssize = p->p_rlimit[RLIMIT_STACK].rlim_cur; 252 253 /* 254 * set up commands for stack. note that this takes *two*, one to 255 * map the part of the stack which we can access, and one to map 256 * the part which we can't. 257 * 258 * arguably, it could be made into one, but that would require the 259 * addition of another mapping proc, which is unnecessary 260 * 261 * note that in memory, things assumed to be: 0 ....... ep_maxsaddr 262 * <stack> ep_minsaddr 263 */ 264 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 265 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 266 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE); 267 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 268 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0, 269 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 270 271 return 0; 272 } 273