1 /* $NetBSD: exec_aout.c,v 1.20 2000/11/14 22:13:20 thorpej 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 #include <uvm/uvm_extern.h> 42 43 /* 44 * exec_aout_makecmds(): Check if it's an a.out-format executable. 45 * 46 * Given a proc pointer and an exec package pointer, see if the referent 47 * of the epp is in a.out format. First check 'standard' magic numbers for 48 * this architecture. If that fails, try a cpu-dependent hook. 49 * 50 * This function, in the former case, or the hook, in the latter, is 51 * responsible for creating a set of vmcmds which can be used to build 52 * the process's vm space and inserting them into the exec package. 53 */ 54 55 int 56 exec_aout_makecmds(struct proc *p, 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(struct proc *p, struct exec_package *epp) 104 { 105 struct exec *execp = epp->ep_hdr; 106 107 epp->ep_taddr = USRTEXT; 108 epp->ep_tsize = execp->a_text; 109 epp->ep_daddr = epp->ep_taddr + execp->a_text; 110 epp->ep_dsize = execp->a_data + execp->a_bss; 111 epp->ep_entry = execp->a_entry; 112 113 /* 114 * check if vnode is in open for writing, because we want to 115 * demand-page out of it. if it is, don't do it, for various 116 * reasons 117 */ 118 if ((execp->a_text != 0 || execp->a_data != 0) && 119 epp->ep_vp->v_writecount != 0) { 120 #ifdef DIAGNOSTIC 121 if (epp->ep_vp->v_flag & VTEXT) 122 panic("exec: a VTEXT vnode has writecount != 0\n"); 123 #endif 124 return ETXTBSY; 125 } 126 vn_marktext(epp->ep_vp); 127 128 /* set up command for text segment */ 129 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, round_page(execp->a_text), 130 epp->ep_taddr, epp->ep_vp, 0, VM_PROT_READ|VM_PROT_EXECUTE); 131 132 /* set up command for data segment */ 133 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, round_page(execp->a_data), 134 epp->ep_daddr, epp->ep_vp, execp->a_text, 135 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 136 137 /* set up command for bss segment */ 138 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss, 139 epp->ep_daddr + execp->a_data, NULLVP, 0, 140 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 141 142 return exec_aout_setup_stack(p, epp); 143 } 144 145 /* 146 * exec_aout_prep_nmagic(): Prepare a 'native' NMAGIC binary's exec package 147 */ 148 149 int 150 exec_aout_prep_nmagic(struct proc *p, struct exec_package *epp) 151 { 152 struct exec *execp = epp->ep_hdr; 153 long bsize, baddr; 154 155 epp->ep_taddr = USRTEXT; 156 epp->ep_tsize = execp->a_text; 157 epp->ep_daddr = roundup(epp->ep_taddr + execp->a_text, __LDPGSZ); 158 epp->ep_dsize = execp->a_data + execp->a_bss; 159 epp->ep_entry = execp->a_entry; 160 161 /* set up command for text segment */ 162 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text, 163 epp->ep_taddr, epp->ep_vp, sizeof(struct exec), 164 VM_PROT_READ|VM_PROT_EXECUTE); 165 166 /* set up command for data segment */ 167 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data, 168 epp->ep_daddr, epp->ep_vp, execp->a_text + sizeof(struct exec), 169 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 170 171 /* set up command for bss segment */ 172 baddr = round_page(epp->ep_daddr + execp->a_data); 173 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 174 if (bsize > 0) 175 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 176 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 177 178 return exec_aout_setup_stack(p, epp); 179 } 180 181 /* 182 * exec_aout_prep_omagic(): Prepare a 'native' OMAGIC binary's exec package 183 */ 184 185 int 186 exec_aout_prep_omagic(struct proc *p, struct exec_package *epp) 187 { 188 struct exec *execp = epp->ep_hdr; 189 long dsize, bsize, baddr; 190 191 epp->ep_taddr = USRTEXT; 192 epp->ep_tsize = execp->a_text; 193 epp->ep_daddr = epp->ep_taddr + execp->a_text; 194 epp->ep_dsize = execp->a_data + execp->a_bss; 195 epp->ep_entry = execp->a_entry; 196 197 /* set up command for text and data segments */ 198 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, 199 execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp, 200 sizeof(struct exec), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 201 202 /* set up command for bss segment */ 203 baddr = round_page(epp->ep_daddr + execp->a_data); 204 bsize = epp->ep_daddr + epp->ep_dsize - baddr; 205 if (bsize > 0) 206 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr, 207 NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 208 209 /* 210 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize); 211 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are 212 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize' 213 * respectively to page boundaries. 214 * Compensate `ep_dsize' for the amount of data covered by the last 215 * text page. 216 */ 217 dsize = epp->ep_dsize + execp->a_text - round_page(execp->a_text); 218 epp->ep_dsize = (dsize > 0) ? dsize : 0; 219 return exec_aout_setup_stack(p, epp); 220 } 221 222 /* 223 * exec_aout_setup_stack(): Set up the stack segment for an a.out 224 * executable. 225 * 226 * Note that the ep_ssize parameter must be set to be the current stack 227 * limit; this is adjusted in the body of execve() to yield the 228 * appropriate stack segment usage once the argument length is 229 * calculated. 230 * 231 * This function returns an int for uniformity with other (future) formats' 232 * stack setup functions. They might have errors to return. 233 */ 234 235 int 236 exec_aout_setup_stack(struct proc *p, struct exec_package *epp) 237 { 238 239 epp->ep_maxsaddr = USRSTACK - MAXSSIZ; 240 epp->ep_minsaddr = USRSTACK; 241 epp->ep_ssize = p->p_rlimit[RLIMIT_STACK].rlim_cur; 242 243 /* 244 * set up commands for stack. note that this takes *two*, one to 245 * map the part of the stack which we can access, and one to map 246 * the part which we can't. 247 * 248 * arguably, it could be made into one, but that would require the 249 * addition of another mapping proc, which is unnecessary 250 * 251 * note that in memory, things assumed to be: 0 ... ep_maxsaddr 252 * <stack> ep_minsaddr 253 */ 254 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, 255 ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr), 256 epp->ep_maxsaddr, NULLVP, 0, VM_PROT_NONE); 257 NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize, 258 (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0, 259 VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); 260 261 return 0; 262 } 263