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linux_exec_aout.c revision 1.1
      1 /*	$NetBSD: linux_exec_aout.c,v 1.1 1995/02/28 23:24:46 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_emul = EMUL_LINUX;
     97 	return error;
     98 }
     99 
    100 /*
    101  * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400
    102  * is very likely not page aligned on most architectures, it is treated
    103  * as an NMAGIC here. XXX
    104  */
    105 
    106 int
    107 exec_linux_aout_prep_zmagic(p, epp)
    108 	struct proc *p;
    109 	struct exec_package *epp;
    110 {
    111 	struct exec *execp = epp->ep_hdr;
    112 
    113 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC);
    114 	epp->ep_tsize = execp->a_text;
    115 	epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC);
    116 	epp->ep_dsize = execp->a_data + execp->a_bss;
    117 	epp->ep_entry = execp->a_entry;
    118 
    119 	/* set up command for text segment */
    120 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    121 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC),
    122 	    VM_PROT_READ|VM_PROT_EXECUTE);
    123 
    124 	/* set up command for data segment */
    125 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    126 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC),
    127 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    128 
    129 	/* set up command for bss segment */
    130 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    131 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    132 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    133 
    134 	return exec_aout_setup_stack(p, epp);
    135 }
    136 
    137 /*
    138  * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package.
    139  * Not different from the normal stuff.
    140  */
    141 
    142 int
    143 exec_linux_aout_prep_nmagic(p, epp)
    144 	struct proc *p;
    145 	struct exec_package *epp;
    146 {
    147 	struct exec *execp = epp->ep_hdr;
    148 	long bsize, baddr;
    149 
    150 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC);
    151 	epp->ep_tsize = execp->a_text;
    152 	epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC);
    153 	epp->ep_dsize = execp->a_data + execp->a_bss;
    154 	epp->ep_entry = execp->a_entry;
    155 
    156 	/* set up command for text segment */
    157 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
    158 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC),
    159 	    VM_PROT_READ|VM_PROT_EXECUTE);
    160 
    161 	/* set up command for data segment */
    162 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
    163 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC),
    164 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    165 
    166 	/* set up command for bss segment */
    167 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    168 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    169 	if (bsize > 0)
    170 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    171 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    172 
    173 	return exec_aout_setup_stack(p, epp);
    174 }
    175 
    176 /*
    177  * exec_aout_prep_omagic(): Prepare Linux OMAGIC package.
    178  * Business as usual.
    179  */
    180 
    181 int
    182 exec_linux_aout_prep_omagic(p, epp)
    183 	struct proc *p;
    184 	struct exec_package *epp;
    185 {
    186 	struct exec *execp = epp->ep_hdr;
    187 	long dsize, bsize, baddr;
    188 
    189 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC);
    190 	epp->ep_tsize = execp->a_text;
    191 	epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC);
    192 	epp->ep_dsize = execp->a_data + execp->a_bss;
    193 	epp->ep_entry = execp->a_entry;
    194 
    195 	/* set up command for text and data segments */
    196 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn,
    197 	    execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp,
    198 	    LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    199 
    200 	/* set up command for bss segment */
    201 	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
    202 	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
    203 	if (bsize > 0)
    204 		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
    205 		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    206 
    207 	/*
    208 	 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize);
    209 	 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are
    210 	 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize'
    211 	 * respectively to page boundaries.
    212 	 * Compensate `ep_dsize' for the amount of data covered by the last
    213 	 * text page.
    214 	 */
    215 	dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG);
    216 	epp->ep_dsize = (dsize > 0) ? dsize : 0;
    217 	return exec_aout_setup_stack(p, epp);
    218 }
    219 
    220 int
    221 exec_linux_aout_prep_qmagic(p, epp)
    222 	struct proc *p;
    223 	struct exec_package *epp;
    224 {
    225 	struct exec *execp = epp->ep_hdr;
    226 
    227 	epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC);
    228 	epp->ep_tsize = execp->a_text;
    229 	epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC);
    230 	epp->ep_dsize = execp->a_data + execp->a_bss;
    231 	epp->ep_entry = execp->a_entry;
    232 
    233 	/*
    234 	 * check if vnode is in open for writing, because we want to
    235 	 * demand-page out of it.  if it is, don't do it, for various
    236 	 * reasons
    237 	 */
    238 	if ((execp->a_text != 0 || execp->a_data != 0) &&
    239 	    epp->ep_vp->v_writecount != 0) {
    240 #ifdef DIAGNOSTIC
    241 		if (epp->ep_vp->v_flag & VTEXT)
    242 			panic("exec: a VTEXT vnode has writecount != 0\n");
    243 #endif
    244 		return ETXTBSY;
    245 	}
    246 	epp->ep_vp->v_flag |= VTEXT;
    247 
    248 	/* set up command for text segment */
    249 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text,
    250 	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC),
    251 	    VM_PROT_READ|VM_PROT_EXECUTE);
    252 
    253 	/* set up command for data segment */
    254 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data,
    255 	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC),
    256 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    257 
    258 	/* set up command for bss segment */
    259 	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
    260 	    epp->ep_daddr + execp->a_data, NULLVP, 0,
    261 	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    262 
    263 	return exec_aout_setup_stack(p, epp);
    264 }
    265 
    266 /*
    267  * The Linux system call to load shared libraries. The current shared
    268  * libraries are just (QMAGIC) a.out files that are mapped onto a fixed
    269  * address * in the process' address space. The address is given in
    270  * a_entry. Read in the header, set up some VM commands and run them.
    271  *
    272  * Yes, both text and data are mapped at once, so we're left with
    273  * writeable text for the shared libs. The Linux crt0 seemed to break
    274  * sometimes when data was mapped seperately. It munmapped a uselib()
    275  * of ld.so by hand, which failed with shared text and data for ld.so
    276  * Yuck.
    277  *
    278  * Because of the problem with ZMAGIC executables (text starts
    279  * at 0x400 in the file, but needs t be mapped at 0), ZMAGIC
    280  * shared libs are not handled very efficiently :-(
    281  */
    282 
    283 int
    284 linux_uselib(p, uap, retval)
    285 	struct proc *p;
    286 	struct linux_uselib_args /* {
    287 		syscallarg(char *) path;
    288 	} */ *uap;
    289 	register_t *retval;
    290 {
    291 	caddr_t sg;
    292 	long bsize, dsize, tsize, taddr, baddr, daddr;
    293 	struct nameidata ni;
    294 	struct vnode *vp;
    295 	struct exec hdr;
    296 	struct exec_vmcmd_set vcset;
    297 	int rem, i, magic, error;
    298 
    299 	sg = stackgap_init();
    300 	CHECK_ALT(p, &sg, SCARG(uap, path));
    301 
    302 	NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
    303 
    304 	if ((error = namei(&ni)))
    305 		return error;
    306 
    307 	vp = ni.ni_vp;
    308 
    309 	if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE,
    310 			     0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
    311 			     &rem, p))) {
    312 		vrele(vp);
    313 		return error;
    314 	}
    315 
    316 	if (rem != 0) {
    317 		vrele(vp);
    318 		return ENOEXEC;
    319 	}
    320 
    321 	magic = LINUX_N_MAGIC(&hdr);
    322 	taddr = hdr.a_entry & (~(NBPG - 1));
    323 	tsize = hdr.a_text;
    324 	daddr = taddr + tsize;
    325 	dsize = hdr.a_data + hdr.a_bss;
    326 
    327 	if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) {
    328 		vrele(vp);
    329                 return ETXTBSY;
    330         }
    331 	vp->v_flag |= VTEXT;
    332 
    333 	vcset.evs_cnt = 0;
    334 	vcset.evs_used = 0;
    335 
    336 	NEW_VMCMD(&vcset,
    337 		  magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
    338 		  hdr.a_text + hdr.a_data, taddr,
    339 		  vp, LINUX_N_TXTOFF(hdr, magic),
    340 		  VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);
    341 
    342 	baddr = roundup(daddr + hdr.a_data, NBPG);
    343 	bsize = daddr + dsize - baddr;
    344         if (bsize > 0) {
    345                 NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
    346                     NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
    347 	}
    348 
    349 	for (i = 0; i < vcset.evs_used && !error; i++) {
    350 		struct exec_vmcmd *vcp;
    351 
    352 		vcp = &vcset.evs_cmds[i];
    353 		error = (*vcp->ev_proc)(p, vcp);
    354 	}
    355 
    356 	kill_vmcmds(&vcset);
    357 
    358 	vrele(vp);
    359 
    360 	return error;
    361 }
    362 
    363 /*
    364  * Execve(2). Just check the alternate emulation path, and pass it on
    365  * to the NetBSD execve().
    366  */
    367 int
    368 linux_execve(p, uap, retval)
    369 	struct proc *p;
    370 	struct linux_execve_args /* {
    371 		syscallarg(char *) path;
    372 		syscallarg(char **) argv;
    373 		syscallarg(char **) envp;
    374 	} */ *uap;
    375 	register_t *retval;
    376 {
    377 	caddr_t sg;
    378 
    379 	sg = stackgap_init();
    380 	CHECK_ALT(p, &sg, SCARG(uap, path));
    381 
    382 	return execve(p, uap, retval);
    383 }
    384