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linux_exec_aout.c revision 1.3
      1 /*	$NetBSD: linux_exec_aout.c,v 1.3 1995/04/07 22:23:22 fvdl Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1995 Frank van der Linden
      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 for the NetBSD Project
     18  *      by Frank van der Linden
     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  * based on kern/exec_aout.c and compat/sunos/sunos_exec.c
     34  */
     35 
     36 #include <sys/param.h>
     37 #include <sys/systm.h>
     38 #include <sys/filedesc.h>
     39 #include <sys/kernel.h>
     40 #include <sys/proc.h>
     41 #include <sys/mount.h>
     42 #include <sys/malloc.h>
     43 #include <sys/namei.h>
     44 #include <sys/vnode.h>
     45 #include <sys/file.h>
     46 #include <sys/resourcevar.h>
     47 #include <sys/wait.h>
     48 
     49 #include <sys/mman.h>
     50 #include <vm/vm.h>
     51 #include <vm/vm_param.h>
     52 #include <vm/vm_map.h>
     53 #include <vm/vm_kern.h>
     54 #include <vm/vm_pager.h>
     55 
     56 #include <machine/cpu.h>
     57 #include <machine/reg.h>
     58 #include <machine/exec.h>
     59 
     60 #include <compat/linux/linux_types.h>
     61 #include <compat/linux/linux_syscallargs.h>
     62 #include <compat/linux/linux_util.h>
     63 #include <compat/linux/linux_exec.h>
     64 
     65 int
     66 exec_linux_aout_makecmds(p, epp)
     67 	struct proc *p;
     68 	struct exec_package *epp;
     69 {
     70 	struct exec *linux_ep = epp->ep_hdr;
     71 	int machtype, magic;
     72 	int error = ENOEXEC;
     73 
     74 	magic = LINUX_N_MAGIC(linux_ep);
     75 	machtype = LINUX_N_MACHTYPE(linux_ep);
     76 
     77 
     78 	if (machtype != LINUX_MID_MACHINE)
     79 		return (ENOEXEC);
     80 
     81 	switch (magic) {
     82 	case QMAGIC:
     83 		error = exec_linux_aout_prep_qmagic(p, epp);
     84 		break;
     85 	case ZMAGIC:
     86 		error = exec_linux_aout_prep_zmagic(p, epp);
     87 		break;
     88 	case NMAGIC:
     89 		error = exec_linux_aout_prep_nmagic(p, epp);
     90 		break;
     91 	case OMAGIC:
     92 		error = exec_linux_aout_prep_omagic(p, epp);
     93 		break;
     94 	}
     95 	if (error == 0) {
     96 		epp->ep_sigcode = linux_sigcode;
     97 		epp->ep_esigcode = linux_esigcode;
     98 		epp->ep_emul = EMUL_LINUX;
     99 	}
    100 	return error;
    101 }
    102 
    103 /*
    104  * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400
    105  * is very likely not page aligned on most architectures, it is treated
    106  * as an NMAGIC here. XXX
    107  */
    108 
    109 int
    110 exec_linux_aout_prep_zmagic(p, epp)
    111 	struct proc *p;
    112 	struct exec_package *epp;
    113 {
    114 	struct exec *execp = epp->ep_hdr;
    115 
    116 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC);
    117 	epp->ep_tsize = execp->a_text;
    118 	epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC);
    119 	epp->ep_dsize = execp->a_data + execp->a_bss;
    120 	epp->ep_entry = execp->a_entry;
    121 
    122 	/* set up command for text segment */
    123 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    124 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC),
    125 	    VM_PROT_READ|VM_PROT_EXECUTE);
    126 
    127 	/* set up command for data segment */
    128 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    129 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC),
    130 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    131 
    132 	/* set up command for bss segment */
    133 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    134 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    135 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    136 
    137 	return exec_aout_setup_stack(p, epp);
    138 }
    139 
    140 /*
    141  * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package.
    142  * Not different from the normal stuff.
    143  */
    144 
    145 int
    146 exec_linux_aout_prep_nmagic(p, epp)
    147 	struct proc *p;
    148 	struct exec_package *epp;
    149 {
    150 	struct exec *execp = epp->ep_hdr;
    151 	long bsize, baddr;
    152 
    153 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC);
    154 	epp->ep_tsize = execp->a_text;
    155 	epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC);
    156 	epp->ep_dsize = execp->a_data + execp->a_bss;
    157 	epp->ep_entry = execp->a_entry;
    158 
    159 	/* set up command for text segment */
    160 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    161 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC),
    162 	    VM_PROT_READ|VM_PROT_EXECUTE);
    163 
    164 	/* set up command for data segment */
    165 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    166 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC),
    167 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    168 
    169 	/* set up command for bss segment */
    170 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    171 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    172 	if (bsize > 0)
    173 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    174 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    175 
    176 	return exec_aout_setup_stack(p, epp);
    177 }
    178 
    179 /*
    180  * exec_aout_prep_omagic(): Prepare Linux OMAGIC package.
    181  * Business as usual.
    182  */
    183 
    184 int
    185 exec_linux_aout_prep_omagic(p, epp)
    186 	struct proc *p;
    187 	struct exec_package *epp;
    188 {
    189 	struct exec *execp = epp->ep_hdr;
    190 	long dsize, bsize, baddr;
    191 
    192 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC);
    193 	epp->ep_tsize = execp->a_text;
    194 	epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC);
    195 	epp->ep_dsize = execp->a_data + execp->a_bss;
    196 	epp->ep_entry = execp->a_entry;
    197 
    198 	/* set up command for text and data segments */
    199 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn,
    200 	    execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp,
    201 	    LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    202 
    203 	/* set up command for bss segment */
    204 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    205 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    206 	if (bsize > 0)
    207 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    208 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    209 
    210 	/*
    211 	 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize);
    212 	 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are
    213 	 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize'
    214 	 * respectively to page boundaries.
    215 	 * Compensate `ep_dsize' for the amount of data covered by the last
    216 	 * text page.
    217 	 */
    218 	dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG);
    219 	epp->ep_dsize = (dsize > 0) ? dsize : 0;
    220 	return exec_aout_setup_stack(p, epp);
    221 }
    222 
    223 int
    224 exec_linux_aout_prep_qmagic(p, epp)
    225 	struct proc *p;
    226 	struct exec_package *epp;
    227 {
    228 	struct exec *execp = epp->ep_hdr;
    229 
    230 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC);
    231 	epp->ep_tsize = execp->a_text;
    232 	epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC);
    233 	epp->ep_dsize = execp->a_data + execp->a_bss;
    234 	epp->ep_entry = execp->a_entry;
    235 
    236 	/*
    237 	 * check if vnode is in open for writing, because we want to
    238 	 * demand-page out of it.  if it is, don't do it, for various
    239 	 * reasons
    240 	 */
    241 	if ((execp->a_text != 0 || execp->a_data != 0) &&
    242 	    epp->ep_vp->v_writecount != 0) {
    243 #ifdef DIAGNOSTIC
    244 		if (epp->ep_vp->v_flag & VTEXT)
    245 			panic("exec: a VTEXT vnode has writecount != 0\n");
    246 #endif
    247 		return ETXTBSY;
    248 	}
    249 	epp->ep_vp->v_flag |= VTEXT;
    250 
    251 	/* set up command for text segment */
    252 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text,
    253 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC),
    254 	    VM_PROT_READ|VM_PROT_EXECUTE);
    255 
    256 	/* set up command for data segment */
    257 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data,
    258 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC),
    259 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    260 
    261 	/* set up command for bss segment */
    262 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    263 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    264 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    265 
    266 	return exec_aout_setup_stack(p, epp);
    267 }
    268 
    269 /*
    270  * The Linux system call to load shared libraries. The current shared
    271  * libraries are just (QMAGIC) a.out files that are mapped onto a fixed
    272  * address * in the process' address space. The address is given in
    273  * a_entry. Read in the header, set up some VM commands and run them.
    274  *
    275  * Yes, both text and data are mapped at once, so we're left with
    276  * writeable text for the shared libs. The Linux crt0 seemed to break
    277  * sometimes when data was mapped seperately. It munmapped a uselib()
    278  * of ld.so by hand, which failed with shared text and data for ld.so
    279  * Yuck.
    280  *
    281  * Because of the problem with ZMAGIC executables (text starts
    282  * at 0x400 in the file, but needs t be mapped at 0), ZMAGIC
    283  * shared libs are not handled very efficiently :-(
    284  */
    285 
    286 int
    287 linux_uselib(p, uap, retval)
    288 	struct proc *p;
    289 	struct linux_uselib_args /* {
    290 		syscallarg(char *) path;
    291 	} */ *uap;
    292 	register_t *retval;
    293 {
    294 	caddr_t sg;
    295 	long bsize, dsize, tsize, taddr, baddr, daddr;
    296 	struct nameidata ni;
    297 	struct vnode *vp;
    298 	struct exec hdr;
    299 	struct exec_vmcmd_set vcset;
    300 	int rem, i, magic, error;
    301 
    302 	sg = stackgap_init();
    303 	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
    304 
    305 	NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
    306 
    307 	if ((error = namei(&ni)))
    308 		return error;
    309 
    310 	vp = ni.ni_vp;
    311 
    312 	if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE,
    313 			     0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
    314 			     &rem, p))) {
    315 		vrele(vp);
    316 		return error;
    317 	}
    318 
    319 	if (rem != 0) {
    320 		vrele(vp);
    321 		return ENOEXEC;
    322 	}
    323 
    324 	magic = LINUX_N_MAGIC(&hdr);
    325 	taddr = hdr.a_entry & (~(NBPG - 1));
    326 	tsize = hdr.a_text;
    327 	daddr = taddr + tsize;
    328 	dsize = hdr.a_data + hdr.a_bss;
    329 
    330 	if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) {
    331 		vrele(vp);
    332                 return ETXTBSY;
    333         }
    334 	vp->v_flag |= VTEXT;
    335 
    336 	vcset.evs_cnt = 0;
    337 	vcset.evs_used = 0;
    338 
    339 	NEW_VMCMD(&vcset,
    340 		  magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
    341 		  hdr.a_text + hdr.a_data, taddr,
    342 		  vp, LINUX_N_TXTOFF(hdr, magic),
    343 		  VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);
    344 
    345 	baddr = roundup(daddr + hdr.a_data, NBPG);
    346 	bsize = daddr + dsize - baddr;
    347         if (bsize > 0) {
    348                 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
    349                     NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    350 	}
    351 
    352 	for (i = 0; i < vcset.evs_used && !error; i++) {
    353 		struct exec_vmcmd *vcp;
    354 
    355 		vcp = &vcset.evs_cmds[i];
    356 		error = (*vcp->ev_proc)(p, vcp);
    357 	}
    358 
    359 	kill_vmcmds(&vcset);
    360 
    361 	vrele(vp);
    362 
    363 	return error;
    364 }
    365 
    366 /*
    367  * Execve(2). Just check the alternate emulation path, and pass it on
    368  * to the NetBSD execve().
    369  */
    370 int
    371 linux_execve(p, uap, retval)
    372 	struct proc *p;
    373 	struct linux_execve_args /* {
    374 		syscallarg(char *) path;
    375 		syscallarg(char **) argv;
    376 		syscallarg(char **) envp;
    377 	} */ *uap;
    378 	register_t *retval;
    379 {
    380 	caddr_t sg;
    381 
    382 	sg = stackgap_init();
    383 	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
    384 
    385 	return execve(p, uap, retval);
    386 }
    387