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linux_exec_aout.c revision 1.4
      1 /*	$NetBSD: linux_exec_aout.c,v 1.4 1995/04/22 19:48:34 christos 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 #include <machine/linux_machdep.h>
     60 
     61 #include <compat/linux/linux_types.h>
     62 #include <compat/linux/linux_syscall.h>
     63 #include <compat/linux/linux_syscallargs.h>
     64 #include <compat/linux/linux_util.h>
     65 #include <compat/linux/linux_exec.h>
     66 
     67 static void *linux_copyargs __P((struct exec_package *, struct ps_strings *,
     68 				void *, void *));
     69 
     70 #define	LINUX_AUX_ARGSIZ	2
     71 
     72 extern int linux_error[];
     73 extern struct sysent linux_sysent[];
     74 extern char *linux_syscallnames[];
     75 
     76 struct emul emul_linux = {
     77 	"linux",
     78 	linux_error,
     79 	linux_sendsig,
     80 	LINUX_SYS_syscall,
     81 	LINUX_SYS_MAXSYSCALL,
     82 	linux_sysent,
     83 	linux_syscallnames,
     84 	LINUX_AUX_ARGSIZ,
     85 	linux_copyargs,
     86 	setregs,
     87 	linux_sigcode,
     88 	linux_esigcode,
     89 };
     90 
     91 
     92 static void *
     93 linux_copyargs(pack, arginfo, stack, argp)
     94 	struct exec_package *pack;
     95 	struct ps_strings *arginfo;
     96 	void *stack;
     97 	void *argp;
     98 {
     99 	char **cpp = stack;
    100 	char **stk = stack;
    101 	char *dp, *sp;
    102 	size_t len;
    103 	void *nullp = NULL;
    104 	int argc = arginfo->ps_nargvstr;
    105 	int envc = arginfo->ps_nenvstr;
    106 
    107 	if (copyout(&argc, cpp++, sizeof(argc)))
    108 		return NULL;
    109 
    110 	/* leave room for envp and argv */
    111 	cpp += 2;
    112 	if (copyout(&cpp, &stk[1], sizeof (cpp)))
    113 		return NULL;
    114 
    115 	dp = (char *) (cpp + argc + envc + 2);
    116 	sp = argp;
    117 
    118 	/* XXX don't copy them out, remap them! */
    119 	arginfo->ps_argvstr = dp; /* remember location of argv for later */
    120 
    121 	for (; --argc >= 0; sp += len, dp += len)
    122 		if (copyout(&dp, cpp++, sizeof(dp)) ||
    123 		    copyoutstr(sp, dp, ARG_MAX, &len))
    124 			return NULL;
    125 
    126 	if (copyout(&nullp, cpp++, sizeof(nullp)))
    127 		return NULL;
    128 
    129 	if (copyout(&cpp, &stk[2], sizeof (cpp)))
    130 		return NULL;
    131 
    132 	arginfo->ps_envstr = dp; /* remember location of envp for later */
    133 
    134 	for (; --envc >= 0; sp += len, dp += len)
    135 		if (copyout(&dp, cpp++, sizeof(dp)) ||
    136 		    copyoutstr(sp, dp, ARG_MAX, &len))
    137 			return NULL;
    138 
    139 	if (copyout(&nullp, cpp++, sizeof(nullp)))
    140 		return NULL;
    141 
    142 	return cpp;
    143 }
    144 
    145 
    146 int
    147 exec_linux_aout_makecmds(p, epp)
    148 	struct proc *p;
    149 	struct exec_package *epp;
    150 {
    151 	struct exec *linux_ep = epp->ep_hdr;
    152 	int machtype, magic;
    153 	int error = ENOEXEC;
    154 
    155 	magic = LINUX_N_MAGIC(linux_ep);
    156 	machtype = LINUX_N_MACHTYPE(linux_ep);
    157 
    158 
    159 	if (machtype != LINUX_MID_MACHINE)
    160 		return (ENOEXEC);
    161 
    162 	switch (magic) {
    163 	case QMAGIC:
    164 		error = exec_linux_aout_prep_qmagic(p, epp);
    165 		break;
    166 	case ZMAGIC:
    167 		error = exec_linux_aout_prep_zmagic(p, epp);
    168 		break;
    169 	case NMAGIC:
    170 		error = exec_linux_aout_prep_nmagic(p, epp);
    171 		break;
    172 	case OMAGIC:
    173 		error = exec_linux_aout_prep_omagic(p, epp);
    174 		break;
    175 	}
    176 	if (error == 0)
    177 		epp->ep_emul = &emul_linux;
    178 	return error;
    179 }
    180 
    181 /*
    182  * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400
    183  * is very likely not page aligned on most architectures, it is treated
    184  * as an NMAGIC here. XXX
    185  */
    186 
    187 int
    188 exec_linux_aout_prep_zmagic(p, epp)
    189 	struct proc *p;
    190 	struct exec_package *epp;
    191 {
    192 	struct exec *execp = epp->ep_hdr;
    193 
    194 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC);
    195 	epp->ep_tsize = execp->a_text;
    196 	epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC);
    197 	epp->ep_dsize = execp->a_data + execp->a_bss;
    198 	epp->ep_entry = execp->a_entry;
    199 
    200 	/* set up command for text segment */
    201 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    202 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC),
    203 	    VM_PROT_READ|VM_PROT_EXECUTE);
    204 
    205 	/* set up command for data segment */
    206 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    207 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC),
    208 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    209 
    210 	/* set up command for bss segment */
    211 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    212 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    213 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    214 
    215 	return exec_aout_setup_stack(p, epp);
    216 }
    217 
    218 /*
    219  * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package.
    220  * Not different from the normal stuff.
    221  */
    222 
    223 int
    224 exec_linux_aout_prep_nmagic(p, epp)
    225 	struct proc *p;
    226 	struct exec_package *epp;
    227 {
    228 	struct exec *execp = epp->ep_hdr;
    229 	long bsize, baddr;
    230 
    231 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC);
    232 	epp->ep_tsize = execp->a_text;
    233 	epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC);
    234 	epp->ep_dsize = execp->a_data + execp->a_bss;
    235 	epp->ep_entry = execp->a_entry;
    236 
    237 	/* set up command for text segment */
    238 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    239 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC),
    240 	    VM_PROT_READ|VM_PROT_EXECUTE);
    241 
    242 	/* set up command for data segment */
    243 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    244 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC),
    245 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    246 
    247 	/* set up command for bss segment */
    248 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    249 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    250 	if (bsize > 0)
    251 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    252 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    253 
    254 	return exec_aout_setup_stack(p, epp);
    255 }
    256 
    257 /*
    258  * exec_aout_prep_omagic(): Prepare Linux OMAGIC package.
    259  * Business as usual.
    260  */
    261 
    262 int
    263 exec_linux_aout_prep_omagic(p, epp)
    264 	struct proc *p;
    265 	struct exec_package *epp;
    266 {
    267 	struct exec *execp = epp->ep_hdr;
    268 	long dsize, bsize, baddr;
    269 
    270 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC);
    271 	epp->ep_tsize = execp->a_text;
    272 	epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC);
    273 	epp->ep_dsize = execp->a_data + execp->a_bss;
    274 	epp->ep_entry = execp->a_entry;
    275 
    276 	/* set up command for text and data segments */
    277 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn,
    278 	    execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp,
    279 	    LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    280 
    281 	/* set up command for bss segment */
    282 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    283 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    284 	if (bsize > 0)
    285 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    286 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    287 
    288 	/*
    289 	 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize);
    290 	 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are
    291 	 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize'
    292 	 * respectively to page boundaries.
    293 	 * Compensate `ep_dsize' for the amount of data covered by the last
    294 	 * text page.
    295 	 */
    296 	dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG);
    297 	epp->ep_dsize = (dsize > 0) ? dsize : 0;
    298 	return exec_aout_setup_stack(p, epp);
    299 }
    300 
    301 int
    302 exec_linux_aout_prep_qmagic(p, epp)
    303 	struct proc *p;
    304 	struct exec_package *epp;
    305 {
    306 	struct exec *execp = epp->ep_hdr;
    307 
    308 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC);
    309 	epp->ep_tsize = execp->a_text;
    310 	epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC);
    311 	epp->ep_dsize = execp->a_data + execp->a_bss;
    312 	epp->ep_entry = execp->a_entry;
    313 
    314 	/*
    315 	 * check if vnode is in open for writing, because we want to
    316 	 * demand-page out of it.  if it is, don't do it, for various
    317 	 * reasons
    318 	 */
    319 	if ((execp->a_text != 0 || execp->a_data != 0) &&
    320 	    epp->ep_vp->v_writecount != 0) {
    321 #ifdef DIAGNOSTIC
    322 		if (epp->ep_vp->v_flag & VTEXT)
    323 			panic("exec: a VTEXT vnode has writecount != 0\n");
    324 #endif
    325 		return ETXTBSY;
    326 	}
    327 	epp->ep_vp->v_flag |= VTEXT;
    328 
    329 	/* set up command for text segment */
    330 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text,
    331 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC),
    332 	    VM_PROT_READ|VM_PROT_EXECUTE);
    333 
    334 	/* set up command for data segment */
    335 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data,
    336 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC),
    337 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    338 
    339 	/* set up command for bss segment */
    340 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    341 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    342 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    343 
    344 	return exec_aout_setup_stack(p, epp);
    345 }
    346 
    347 /*
    348  * The Linux system call to load shared libraries. The current shared
    349  * libraries are just (QMAGIC) a.out files that are mapped onto a fixed
    350  * address * in the process' address space. The address is given in
    351  * a_entry. Read in the header, set up some VM commands and run them.
    352  *
    353  * Yes, both text and data are mapped at once, so we're left with
    354  * writeable text for the shared libs. The Linux crt0 seemed to break
    355  * sometimes when data was mapped seperately. It munmapped a uselib()
    356  * of ld.so by hand, which failed with shared text and data for ld.so
    357  * Yuck.
    358  *
    359  * Because of the problem with ZMAGIC executables (text starts
    360  * at 0x400 in the file, but needs t be mapped at 0), ZMAGIC
    361  * shared libs are not handled very efficiently :-(
    362  */
    363 
    364 int
    365 linux_uselib(p, uap, retval)
    366 	struct proc *p;
    367 	struct linux_uselib_args /* {
    368 		syscallarg(char *) path;
    369 	} */ *uap;
    370 	register_t *retval;
    371 {
    372 	caddr_t sg;
    373 	long bsize, dsize, tsize, taddr, baddr, daddr;
    374 	struct nameidata ni;
    375 	struct vnode *vp;
    376 	struct exec hdr;
    377 	struct exec_vmcmd_set vcset;
    378 	int rem, i, magic, error;
    379 
    380 	sg = stackgap_init();
    381 	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
    382 
    383 	NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
    384 
    385 	if ((error = namei(&ni)))
    386 		return error;
    387 
    388 	vp = ni.ni_vp;
    389 
    390 	if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE,
    391 			     0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
    392 			     &rem, p))) {
    393 		vrele(vp);
    394 		return error;
    395 	}
    396 
    397 	if (rem != 0) {
    398 		vrele(vp);
    399 		return ENOEXEC;
    400 	}
    401 
    402 	magic = LINUX_N_MAGIC(&hdr);
    403 	taddr = hdr.a_entry & (~(NBPG - 1));
    404 	tsize = hdr.a_text;
    405 	daddr = taddr + tsize;
    406 	dsize = hdr.a_data + hdr.a_bss;
    407 
    408 	if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) {
    409 		vrele(vp);
    410                 return ETXTBSY;
    411         }
    412 	vp->v_flag |= VTEXT;
    413 
    414 	vcset.evs_cnt = 0;
    415 	vcset.evs_used = 0;
    416 
    417 	NEW_VMCMD(&vcset,
    418 		  magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
    419 		  hdr.a_text + hdr.a_data, taddr,
    420 		  vp, LINUX_N_TXTOFF(hdr, magic),
    421 		  VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);
    422 
    423 	baddr = roundup(daddr + hdr.a_data, NBPG);
    424 	bsize = daddr + dsize - baddr;
    425         if (bsize > 0) {
    426                 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
    427                     NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    428 	}
    429 
    430 	for (i = 0; i < vcset.evs_used && !error; i++) {
    431 		struct exec_vmcmd *vcp;
    432 
    433 		vcp = &vcset.evs_cmds[i];
    434 		error = (*vcp->ev_proc)(p, vcp);
    435 	}
    436 
    437 	kill_vmcmds(&vcset);
    438 
    439 	vrele(vp);
    440 
    441 	return error;
    442 }
    443 
    444 /*
    445  * Execve(2). Just check the alternate emulation path, and pass it on
    446  * to the NetBSD execve().
    447  */
    448 int
    449 linux_execve(p, uap, retval)
    450 	struct proc *p;
    451 	struct linux_execve_args /* {
    452 		syscallarg(char *) path;
    453 		syscallarg(char **) argv;
    454 		syscallarg(char **) envp;
    455 	} */ *uap;
    456 	register_t *retval;
    457 {
    458 	caddr_t sg;
    459 
    460 	sg = stackgap_init();
    461 	CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
    462 
    463 	return execve(p, uap, retval);
    464 }
    465