1 /* $NetBSD: exec_aout.c,v 1.18 2000/06/27 17:41:07 mrg 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 41 /* 42 * exec_aout_makecmds(): Check if it's an a.out-format executable. 43 * 44 * Given a proc pointer and an exec package pointer, see if the referent 45 * of the epp is in a.out format. First check 'standard' magic numbers for 46 * this architecture. If that fails, try a cpu-dependent hook. 47 * 48 * This function, in the former case, or the hook, in the latter, is 49 * responsible for creating a set of vmcmds which can be used to build 50 * the process's vm space and inserting them into the exec package. 51 */ 52 53 int 54 exec_aout_makecmds(p, epp) 55 struct proc *p; 56 struct exec_package *epp; 57 { 58 u_long midmag, magic; 59 u_short mid; 60 int error; 61 struct exec *execp = epp->ep_hdr; 62 63 if (epp->ep_hdrvalid < sizeof(struct exec)) 64 return ENOEXEC; 65 66 midmag = ntohl(execp->a_midmag); 67 mid = (midmag >> 16) & 0x3ff; 68 magic = midmag & 0xffff; 69 70 midmag = mid << 16 | magic; 71 72 switch (midmag) { 73 case (MID_MACHINE << 16) | ZMAGIC: 74 error = exec_aout_prep_zmagic(p, epp); 75 break; 76 case (MID_MACHINE << 16) | NMAGIC: 77 error = exec_aout_prep_nmagic(p, epp); 78 break; 79 case (MID_MACHINE << 16) | OMAGIC: 80 error = exec_aout_prep_omagic(p, epp); 81 break; 82 default: 83 error = cpu_exec_aout_makecmds(p, epp); 84 } 85 86 if (error) 87 kill_vmcmds(&epp->ep_vmcmds); 88 89 return error; 90 } 91 92 /* 93 * exec_aout_prep_zmagic(): Prepare a 'native' ZMAGIC binary's exec package 94 * 95 * First, set of the various offsets/lengths in the exec package. 96 * 97 * Then, mark the text image busy (so it can be demand paged) or error 98 * out if this is not possible. Finally, set up vmcmds for the 99 * text, data, bss, and stack segments. 100 */ 101 102 int 103 exec_aout_prep_zmagic(p, epp) 104 struct proc *p; 105 struct exec_package *epp; 106 { 107 struct exec *execp = epp->ep_hdr; 108 109 epp->ep_taddr = USRTEXT; 110 epp->ep_tsize = execp->a_text; 111 epp->ep_daddr = epp->ep_taddr + execp->a_text; 112 epp->ep_dsize = execp->a_data + execp->a_bss; 113 epp->ep_entry = execp->a_entry; 114 115 /* 116 * check if vnode is in open for writing, because we want to 117 * demand-page out of it. if it is, don't do it, for various 118 * reasons 119 */ 120 if ((execp->a_text != 0 || execp->a_data != 0) && 121 epp->ep_vp->v_writecount != 0) { 122 #ifdef DIAGNOSTIC 123 if (epp->ep_vp->v_flag & VTEXT) 124 panic("exec: a VTEXT vnode has writecount != 0\n"); 125 #endif 126 return ETXTBSY; 127 } 128 vn_marktext(epp->ep_vp); 129 130 /* set up command for text segment */ 131 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, round_page(execp->a_text), 132 epp->ep_taddr, epp->ep_vp, 0, VM_PROT_READ|VM_PROT_EXECUTE); 133 134 /* set up command for data segment */ 135 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, round_page(execp->a_data), 136 epp->ep_daddr, epp->ep_vp, execp->a_text, 137 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 138 139 /* set up command for bss segment */ 140 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 141 epp->ep_daddr + execp->a_data, NULLVP, 0, 142 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 143 144 return exec_aout_setup_stack(p, epp); 145 } 146 147 /* 148 * exec_aout_prep_nmagic(): Prepare a 'native' NMAGIC binary's exec package 149 */ 150 151 int 152 exec_aout_prep_nmagic(p, epp) 153 struct proc *p; 154 struct exec_package *epp; 155 { 156 struct exec *execp = epp->ep_hdr; 157 long bsize, baddr; 158 159 epp->ep_taddr = USRTEXT; 160 epp->ep_tsize = execp->a_text; 161 epp->ep_daddr = roundup(epp->ep_taddr + execp->a_text, __LDPGSZ); 162 epp->ep_dsize = execp->a_data + execp->a_bss; 163 epp->ep_entry = execp->a_entry; 164 165 /* set up command for text segment */ 166 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 167 epp->ep_taddr, epp->ep_vp, sizeof(struct exec), 168 VM_PROT_READ|VM_PROT_EXECUTE); 169 170 /* set up command for data segment */ 171 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 172 epp->ep_daddr, epp->ep_vp, execp->a_text + sizeof(struct exec), 173 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 174 175 /* set up command for bss segment */ 176 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 177 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 178 if (bsize > 0) 179 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 180 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 181 182 return exec_aout_setup_stack(p, epp); 183 } 184 185 /* 186 * exec_aout_prep_omagic(): Prepare a 'native' OMAGIC binary's exec package 187 */ 188 189 int 190 exec_aout_prep_omagic(p, epp) 191 struct proc *p; 192 struct exec_package *epp; 193 { 194 struct exec *execp = epp->ep_hdr; 195 long dsize, bsize, baddr; 196 197 epp->ep_taddr = USRTEXT; 198 epp->ep_tsize = execp->a_text; 199 epp->ep_daddr = epp->ep_taddr + execp->a_text; 200 epp->ep_dsize = execp->a_data + execp->a_bss; 201 epp->ep_entry = execp->a_entry; 202 203 /* set up command for text and data segments */ 204 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 205 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 206 sizeof(struct exec), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 207 208 /* set up command for bss segment */ 209 baddr = roundup(epp->ep_daddr + execp->a_data, NBPG); 210 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 211 if (bsize > 0) 212 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 213 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 214 215 /* 216 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 217 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 218 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 219 * respectively to page boundaries. 220 * Compensate `ep_dsize' for the amount of data covered by the last 221 * text page. 222 */ 223 dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG); 224 epp->ep_dsize = (dsize > 0) ? dsize : 0; 225 return exec_aout_setup_stack(p, epp); 226 } 227 228 /* 229 * exec_aout_setup_stack(): Set up the stack segment for an a.out 230 * executable. 231 * 232 * Note that the ep_ssize parameter must be set to be the current stack 233 * limit; this is adjusted in the body of execve() to yield the 234 * appropriate stack segment usage once the argument length is 235 * calculated. 236 * 237 * This function returns an int for uniformity with other (future) formats' 238 * stack setup functions. They might have errors to return. 239 */ 240 241 int 242 exec_aout_setup_stack(p, epp) 243 struct proc *p; 244 struct exec_package *epp; 245 { 246 247 epp->ep_maxsaddr = USRSTACK - MAXSSIZ; 248 epp->ep_minsaddr = USRSTACK; 249 epp->ep_ssize = p->p_rlimit[RLIMIT_STACK].rlim_cur; 250 251 /* 252 * set up commands for stack. note that this takes *two*, one to 253 * map the part of the stack which we can access, and one to map 254 * the part which we can't. 255 * 256 * arguably, it could be made into one, but that would require the 257 * addition of another mapping proc, which is unnecessary 258 * 259 * note that in memory, things assumed to be: 0 ... ep_maxsaddr 260 * <stack> ep_minsaddr 261 */ 262 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 263 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 264 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE); 265 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 266 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0, 267 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 268 269 return 0; 270 } 271