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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     27 
     28 /*
     29  * Routines used to read stabs data from a file, and to build a tdata structure
     30  * based on the interesting parts of that data.
     31  */
     32 
     33 #if HAVE_NBTOOL_CONFIG_H
     34 # include "nbtool_config.h"
     35 #endif
     36 
     37 #include <stdio.h>
     38 #include <stdlib.h>
     39 #include <fcntl.h>
     40 #include <unistd.h>
     41 #include <assert.h>
     42 #include <string.h>
     43 #include <libgen.h>
     44 #include <errno.h>
     45 #include <sys/types.h>
     46 #include <sys/param.h>
     47 
     48 #include "ctftools.h"
     49 #include "list.h"
     50 #include "stack.h"
     51 #include "memory.h"
     52 #include "traverse.h"
     53 
     54 char *curhdr;
     55 
     56 /*
     57  * The stabs generator will sometimes reference types before they've been
     58  * defined.  If this is the case, a TYPEDEF_UNRES tdesc will be generated.
     59  * Note that this is different from a forward declaration, in which the
     60  * stab is defined, but is defined as something that doesn't exist yet.
     61  * When we have read all of the stabs from the file, we can go back and
     62  * fix up all of the unresolved types.  We should be able to fix all of them.
     63  */
     64 /*ARGSUSED2*/
     65 static int
     66 resolve_tou_node(tdesc_t *node, tdesc_t **nodep, void *private __unused)
     67 {
     68 	tdesc_t *new;
     69 
     70 	debug(3, "Trying to resolve %s (%d)\n", tdesc_name(node), node->t_id);
     71 	new = lookup(node->t_id);
     72 
     73 	if (new == NULL) {
     74 		terminate("Couldn't resolve type %d\n", node->t_id);
     75 	}
     76 
     77 	debug(3, " Resolving to %d\n", new->t_id);
     78 
     79 	*nodep = new;
     80 
     81 	return (1);
     82 }
     83 
     84 /*ARGSUSED*/
     85 static int
     86 resolve_fwd_node(tdesc_t *node, tdesc_t **nodep, void *private __unused)
     87 {
     88 	tdesc_t *new = lookupname(node->t_name);
     89 
     90 	debug(3, "Trying to unforward %s (%d)\n", tdesc_name(node), node->t_id);
     91 
     92 	if (!new || (new->t_type != STRUCT && new->t_type != UNION))
     93 		return (0);
     94 
     95 	debug(3, " Unforwarded to %d\n", new->t_id);
     96 
     97 	*nodep = new;
     98 
     99 	return (1);
    100 }
    101 
    102 static tdtrav_cb_f resolve_cbs[] = {
    103 	NULL,
    104 	NULL,			/* intrinsic */
    105 	NULL,			/* pointer */
    106 	NULL,			/* array */
    107 	NULL,			/* function */
    108 	NULL,			/* struct */
    109 	NULL,			/* union */
    110 	NULL,			/* enum */
    111 	resolve_fwd_node,	/* forward */
    112 	NULL,			/* typedef */
    113 	resolve_tou_node,	/* typedef unres */
    114 	NULL,			/* volatile */
    115 	NULL,			/* const */
    116 	NULL,			/* restrict */
    117 };
    118 
    119 static void
    120 resolve_nodes(tdata_t *td)
    121 {
    122 	debug(2, "Resolving unresolved stabs\n");
    123 
    124 	(void) iitraverse_hash(td->td_iihash, &td->td_curvgen, resolve_cbs,
    125 	    NULL, NULL, td);
    126 }
    127 
    128 static char *
    129 concat(char *s1, char *s2, int s2strip)
    130 {
    131 	int savelen = strlen(s2) - s2strip;
    132 	int newlen = (s1 ? strlen(s1) : 0) + savelen + 1;
    133 	char *out;
    134 
    135 	out = xrealloc(s1, newlen);
    136 	if (s1)
    137 		strncpy(out + strlen(out), s2, savelen);
    138 	else
    139 		strncpy(out, s2, savelen);
    140 
    141 	out[newlen - 1] = '\0';
    142 
    143 	return (out);
    144 }
    145 
    146 /*
    147  * N_FUN stabs come with their arguments in promoted form.  In order to get the
    148  * actual arguments, we need to wait for the N_PSYM stabs that will come towards
    149  * the end of the function.  These routines free the arguments (fnarg_free) we
    150  * got from the N_FUN stab and add (fnarg_add) the ones from the N_PSYM stabs.
    151  */
    152 static void
    153 fnarg_add(iidesc_t *curfun, iidesc_t *arg)
    154 {
    155 	curfun->ii_nargs++;
    156 
    157 	if (curfun->ii_nargs == 1)
    158 		curfun->ii_args = xmalloc(sizeof (tdesc_t *) * FUNCARG_DEF);
    159 	else if (curfun->ii_nargs > FUNCARG_DEF) {
    160 		curfun->ii_args = xrealloc(curfun->ii_args,
    161 		    sizeof (tdesc_t *) * curfun->ii_nargs);
    162 	}
    163 
    164 	curfun->ii_args[curfun->ii_nargs - 1] = arg->ii_dtype;
    165 	arg->ii_dtype = NULL;
    166 }
    167 
    168 static void
    169 fnarg_free(iidesc_t *ii)
    170 {
    171 	ii->ii_nargs = 0;
    172 	free(ii->ii_args);
    173 	ii->ii_args = NULL;
    174 }
    175 
    176 /*
    177  * Read the stabs from the stab ELF section, and turn them into a tdesc tree,
    178  * assembled under an iidesc list.
    179  */
    180 int
    181 stabs_read(tdata_t *td, Elf *elf, char *file)
    182 {
    183 	Elf_Scn *scn;
    184 	Elf_Data *data;
    185 	stab_t *stab;
    186 	stk_t *file_stack;
    187 	iidesc_t *iidescp;
    188 	iidesc_t *curfun = NULL;
    189 	char curpath[MAXPATHLEN];
    190 	char *curfile = NULL;
    191 	char *str;
    192 	char *fstr = NULL, *ofstr = NULL;
    193 	int stabidx, stabstridx;
    194 	int nstabs, rc, i;
    195 	int scope = 0;
    196 
    197 	if (!((stabidx = findelfsecidx(elf, file, ".stab.excl")) >= 0 &&
    198 	    (stabstridx = findelfsecidx(elf, file, ".stab.exclstr")) >= 0) &&
    199 	    !((stabidx = findelfsecidx(elf, file, ".stab")) >= 0 &&
    200 	    (stabstridx = findelfsecidx(elf, file, ".stabstr")) >= 0)) {
    201 		errno = ENOENT;
    202 		return (-1);
    203 	}
    204 
    205 	file_stack = stack_new(free);
    206 
    207 	stack_push(file_stack, file);
    208 	curhdr = file;
    209 
    210 	debug(3, "Found stabs in %d, strings in %d\n", stabidx, stabstridx);
    211 
    212 	scn = elf_getscn(elf, stabidx);
    213 	data = elf_rawdata(scn, NULL);
    214 	nstabs = data->d_size / sizeof (stab_t);
    215 
    216 	parse_init(td);
    217 	for (i = 0; i < nstabs; i++) {
    218 		stab = &((stab_t *)data->d_buf)[i];
    219 
    220 		/* We don't want any local definitions */
    221 		if (stab->n_type == N_LBRAC) {
    222 			scope++;
    223 			debug(3, "stab %d: opening scope (%d)\n", i + 1, scope);
    224 			continue;
    225 		} else if (stab->n_type == N_RBRAC) {
    226 			scope--;
    227 			debug(3, "stab %d: closing scope (%d)\n", i + 1, scope);
    228 			continue;
    229 		} else if (stab->n_type == N_EINCL) {
    230 			/*
    231 			 * There's a bug in the 5.2 (Taz) compilers that causes
    232 			 * them to emit an extra N_EINCL if there's no actual
    233 			 * text in the file being compiled.  To work around this
    234 			 * bug, we explicitly check to make sure we're not
    235 			 * trying to pop a stack that only has the outer scope
    236 			 * on it.
    237 			 */
    238 			if (stack_level(file_stack) != 1) {
    239 				str = (char *)stack_pop(file_stack);
    240 				free(str);
    241 				curhdr = (char *)stack_peek(file_stack);
    242 			}
    243 		}
    244 
    245 		/* We only care about a subset of the stabs */
    246 		if (!(stab->n_type == N_FUN || stab->n_type == N_GSYM ||
    247 		    stab->n_type == N_LCSYM || stab->n_type == N_LSYM ||
    248 		    stab->n_type == N_PSYM || stab->n_type == N_ROSYM ||
    249 		    stab->n_type == N_RSYM ||
    250 		    stab->n_type == N_STSYM || stab->n_type == N_BINCL ||
    251 		    stab->n_type == N_SO || stab->n_type == N_OPT))
    252 			continue;
    253 
    254 		if ((str = elf_strptr(elf, stabstridx,
    255 		    (size_t)stab->n_strx)) == NULL) {
    256 			terminate("%s: Can't find string at %u for stab %d\n",
    257 			    file, stab->n_strx, i);
    258 		}
    259 
    260 		if (stab->n_type == N_BINCL) {
    261 			curhdr = xstrdup(str);
    262 			stack_push(file_stack, curhdr);
    263 			continue;
    264 		} else if (stab->n_type == N_SO) {
    265 			if (str[strlen(str) - 1] != '/') {
    266 				strcpy(curpath, str);
    267 				curfile = basename(curpath);
    268 			}
    269 			continue;
    270 		} else if (stab->n_type == N_OPT) {
    271 			if (strcmp(str, "gcc2_compiled.") == 0) {
    272 				terminate("%s: GCC-generated stabs are "
    273 				    "unsupported. Use DWARF instead.\n", file);
    274 			}
    275 			continue;
    276 		}
    277 
    278 		if (str[strlen(str) - 1] == '\\') {
    279 			int offset = 1;
    280 			/*
    281 			 * There's a bug in the compilers that causes them to
    282 			 * generate \ for continuations with just -g (this is
    283 			 * ok), and \\ for continuations with -g -O (this is
    284 			 * broken).  This bug is "fixed" in the 6.2 compilers
    285 			 * via the elimination of continuation stabs.
    286 			 */
    287 			if (str[strlen(str) - 2] == '\\')
    288 				offset = 2;
    289 			fstr = concat(fstr, str, offset);
    290 			continue;
    291 		} else
    292 			fstr = concat(fstr, str, 0);
    293 
    294 		debug(3, "%4d: .stabs \"%s\", %#x, %d, %hd, %d (from %s)\n", i,
    295 		    fstr, stab->n_type, 0, stab->n_desc,
    296 		    stab->n_value, curhdr);
    297 
    298 		if (debug_level >= 3)
    299 			check_hash();
    300 
    301 		/*
    302 		 * Sometimes the compiler stutters, and emits the same stab
    303 		 * twice.  This is bad for the parser, which will attempt to
    304 		 * redefine the type IDs indicated in the stabs.  This is
    305 		 * compiler bug 4433511.
    306 		 */
    307 		if (ofstr && strcmp(fstr, ofstr) == 0) {
    308 			debug(3, "Stutter stab\n");
    309 			free(fstr);
    310 			fstr = NULL;
    311 			continue;
    312 		}
    313 
    314 		if (ofstr)
    315 			free(ofstr);
    316 		ofstr = fstr;
    317 
    318 		iidescp = NULL;
    319 
    320 		if ((rc = parse_stab(stab, fstr, &iidescp)) < 0) {
    321 			terminate("%s: Couldn't parse stab \"%s\" "
    322 			    "(source file %s)\n", file, str, curhdr);
    323 		}
    324 
    325 		if (rc == 0)
    326 			goto parse_loop_end;
    327 
    328 		/* Make sure the scope tracking is working correctly */
    329 		assert(stab->n_type != N_FUN || (iidescp->ii_type != II_GFUN &&
    330 		    iidescp->ii_type != II_SFUN) || scope == 0);
    331 
    332 		/*
    333 		 * The only things we care about that are in local scope are
    334 		 * the N_PSYM stabs.
    335 		 */
    336 		if (scope && stab->n_type != N_PSYM) {
    337 			if (iidescp)
    338 				iidesc_free(iidescp, NULL);
    339 			goto parse_loop_end;
    340 		}
    341 
    342 		switch (iidescp->ii_type) {
    343 		case II_SFUN:
    344 			iidescp->ii_owner = xstrdup(curfile);
    345 			/*FALLTHROUGH*/
    346 		case II_GFUN:
    347 			curfun = iidescp;
    348 			fnarg_free(iidescp);
    349 			iidesc_add(td->td_iihash, iidescp);
    350 			break;
    351 
    352 		case II_SVAR:
    353 			iidescp->ii_owner = xstrdup(curfile);
    354 			/*FALLTHROUGH*/
    355 		case II_GVAR:
    356 		case II_TYPE:
    357 		case II_SOU:
    358 			iidesc_add(td->td_iihash, iidescp);
    359 			break;
    360 
    361 		case II_PSYM:
    362 			fnarg_add(curfun, iidescp);
    363 			iidesc_free(iidescp, NULL);
    364 			break;
    365 		default:
    366 			aborterr("invalid ii_type %d for stab type %d",
    367 			    iidescp->ii_type, stab->n_type);
    368 		}
    369 
    370 parse_loop_end:
    371 		fstr = NULL;
    372 	}
    373 
    374 	if (ofstr)
    375 		free(ofstr);
    376 
    377 	resolve_nodes(td);
    378 	resolve_typed_bitfields();
    379 	parse_finish(td);
    380 
    381 	cvt_fixstabs(td);
    382 	cvt_fixups(td, elf_ptrsz(elf));
    383 
    384 	return (0);
    385 }
    386