usr/src/cmd/sgs/rtld/common/object.c

   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 /*
  23  * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 /*
  27  * Object file dependent suport for ELF objects.
  28  */
  29
  30 #include        <sys/mman.h>
  31 #include        <stdio.h>
  32 #include        <unistd.h>
  33 #include        <libelf.h>
  34 #include        <string.h>
  35 #include        <dlfcn.h>
  36 #include        <debug.h>
  37 #include        <libld.h>
  38 #include        "_rtld.h"
  39 #include        "_audit.h"
  40 #include        "_elf.h"
  41
  42 static Rt_map   *olmp = NULL;
  43 static Alist    *mpalp = NULL;
  44
  45 static Ehdr     dehdr = { { ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3,
  46                             M_CLASS, M_DATA }, 0, M_MACH, EV_CURRENT };
  47
  48 /*
  49  * Process a relocatable object.  The static object link map pointer is used as
  50  * a flag to determine whether a concatenation is already in progress (ie. an
  51  * LD_PRELOAD may specify a list of objects).  The link map returned simply
  52  * specifies an `object' flag which the caller can interpret and thus call
  53  * elf_obj_fini() to complete the concatenation.
  54  */
  55 static Rt_map *
  56 elf_obj_init(Lm_list *lml, Aliste lmco, const char *oname)
  57 {
  58         Ofl_desc        *ofl;
  59         const char      *name;
  60         size_t          lmsz;
  61
  62         /*
  63          * Allocate the name of this object, as the original name may be
  64          * associated with a data buffer that can be reused to load the
  65          * dependencies needed to processes this object.
  66          */
  67         if ((name = stravl_insert(oname, 0, 0, 0)) == NULL)
  68                 return (NULL);
  69
  70         /*
  71          * Initialize an output file descriptor and the entrance criteria.
  72          */
  73         if ((ofl = calloc(sizeof (Ofl_desc), 1)) == NULL)
  74                 return (NULL);
  75
  76         ofl->ofl_dehdr = &dehdr;
  77
  78         ofl->ofl_flags = (FLG_OF_DYNAMIC | FLG_OF_SHAROBJ | FLG_OF_STRIP);
  79         ofl->ofl_flags1 = (FLG_OF1_RELDYN | FLG_OF1_TEXTOFF | FLG_OF1_MEMORY);
  80         ofl->ofl_lml = lml;
  81
  82         /*
  83          * As ent_setup() will effectively lazy load the necessary support
  84          * libraries, make sure ld.so.1 is initialized for plt relocations.
  85          * Then configure libld.so to process objects of the desired target
  86          * type (this is the first call to libld.so, which will effectively
  87          * lazyload it).
  88          */
  89         if ((elf_rtld_load() == 0) || (ld_init_target(lml, M_MACH) != 0)) {
  90                 free(ofl);
  91                 return (NULL);
  92         }
  93
  94         /*
  95          * Obtain a generic set of entrance criteria, and generate a link map
  96          * place holder and use the ELFPRV() element to maintain the output
  97          * file descriptor.
  98          */
  99         lmsz = S_DROUND(sizeof (Rt_map)) + sizeof (Rt_elfp);
 100         if ((ld_ent_setup(ofl, syspagsz) == S_ERROR) ||
 101             ((olmp = calloc(lmsz, 1)) == NULL)) {
 102                 free(ofl);
 103                 return (NULL);
 104         }
 105
 106         DBG_CALL(Dbg_file_elf(lml, name, 0, 0, lml->lm_lmidstr, lmco));
 107         FLAGS(olmp) |= FLG_RT_OBJECT;
 108         ELFPRV(olmp) = (void *)ofl;
 109
 110         /*
 111          * Initialize string tables.
 112          */
 113         if (ld_init_strings(ofl) == S_ERROR) {
 114                 free(ofl);
 115                 free(olmp);
 116                 olmp = NULL;
 117                 return (NULL);
 118         }
 119
 120         /*
 121          * Assign the output file name to be the initial object that got us
 122          * here.  This name is being used for diagnostic purposes only as we
 123          * don't actually generate an output file unless debugging is enabled.
 124          */
 125         ofl->ofl_name = name;
 126         NAME(olmp) = (char *)name;
 127         LIST(olmp) = lml;
 128
 129         lm_append(lml, lmco, olmp);
 130         return (olmp);
 131 }
 132
 133 /*
 134  * Define a structure to retain the mapping information of the original
 135  * relocatable object.  Typically, mmapobj(2) maps a relocatable object into one
 136  * mapping.  However, if padding has been enabled by a debugger, then additional
 137  * padding segments may have been added.  elf_obj_file() needs to know which
 138  * segment is the relocatable objects data, and retain the initial segment and
 139  * the associated segment number for unmapping this object later (see
 140  * elf_obj_fini()).  Note, even if padding is enabled, the final shared object
 141  * that is created by the link-editor for this relocatable object will have no
 142  * associated padding, as ld(1) has no capabilities to provide padding.
 143  */
 144 typedef struct {
 145         mmapobj_result_t        *md_mpp;
 146         uint_t                  md_mnum;
 147 } Mmap_desc;
 148
 149 /*
 150  * Initial processing of a relocatable object.  If this is the first object
 151  * encountered we need to initialize some structures, then simply call the
 152  * link-edit functionality to provide the initial processing of the file (ie.
 153  * reads in sections and symbols, performs symbol resolution if more that one
 154  * object file have been specified, and assigns input sections to output
 155  * sections).
 156  */
 157 Rt_map *
 158 elf_obj_file(Lm_list *lml, Aliste lmco, Rt_map *clmp, const char *name,
 159     mmapobj_result_t *hmpp, mmapobj_result_t *mpp, uint_t mnum)
 160 {
 161         Rej_desc        rej;
 162         Mmap_desc       md;
 163
 164         /*
 165          * If this is the first relocatable object (LD_PRELOAD could provide a
 166          * list of objects), initialize an input file descriptor and a link map.
 167          */
 168         if ((olmp == NULL) && ((olmp = elf_obj_init(lml, lmco, name)) == NULL))
 169                 return (NULL);
 170
 171         DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
 172
 173         /*
 174          * Keep track of the input image, as this must be free'd after all ELF
 175          * processing is completed.
 176          */
 177         md.md_mpp = mpp;
 178         md.md_mnum = mnum;
 179         if (alist_append(&mpalp, &md, sizeof (Mmap_desc),
 180             AL_CNT_MPOBJS) == NULL) {
 181                 remove_so(lml, olmp, clmp);
 182                 return (NULL);
 183         }
 184
 185         /*
 186          * Pass the object mapping to the link-editor to commence processing the
 187          * file.
 188          */
 189         if (ld_process_mem(name, name, hmpp->mr_addr, hmpp->mr_msize,
 190             (Ofl_desc *)ELFPRV(olmp), &rej) == (Ifl_desc *)S_ERROR) {
 191                 remove_so(lml, olmp, clmp);
 192                 return (NULL);
 193         }
 194
 195         return (olmp);
 196 }
 197
 198 /*
 199  * Ensure any platform or machine capability names are valid.
 200  */
 201 inline static int
 202 check_plat_names(Syscapset *scapset, Alist *caps, Rej_desc *rej)
 203 {
 204         Capstr  *capstr;
 205         Aliste  idx;
 206
 207         for (ALIST_TRAVERSE(caps, idx, capstr)) {
 208                 if (platcap_check(scapset, capstr->cs_str, rej) == 1)
 209                         return (1);
 210         }
 211         return (0);
 212 }
 213
 214 inline static int
 215 check_mach_names(Syscapset *scapset, Alist *caps, Rej_desc *rej)
 216 {
 217         Capstr  *capstr;
 218         Aliste  idx;
 219
 220         for (ALIST_TRAVERSE(caps, idx, capstr)) {
 221                 if (machcap_check(scapset, capstr->cs_str, rej) == 1)
 222                         return (1);
 223         }
 224         return (0);
 225 }
 226
 227 /*
 228  * Finish relocatable object processing.  Having already initially processed one
 229  * or more objects, complete the generation of a shared object image by calling
 230  * the appropriate link-edit functionality (refer to sgs/ld/common/main.c).
 231  */
 232 Rt_map *
 233 elf_obj_fini(Lm_list *lml, Rt_map *lmp, Rt_map *clmp, int *in_nfavl)
 234 {
 235         Ofl_desc                *ofl = (Ofl_desc *)ELFPRV(lmp);
 236         Rt_map                  *nlmp, *tlmp;
 237         Ehdr                    *ehdr;
 238         Phdr                    *phdr;
 239         mmapobj_result_t        *mpp, *hmpp;
 240         uint_t                  phnum;
 241         int                     mnum;
 242         Lm_cntl                 *lmc;
 243         Aliste                  idx1;
 244         Mmap_desc               *mdp;
 245         Fdesc                   fd = { 0 };
 246         Grp_hdl                 *ghp;
 247         Rej_desc                rej = { 0 };
 248         Syscapset               *scapset;
 249         elfcap_mask_t           omsk;
 250         Alist                   *oalp;
 251
 252         DBG_CALL(Dbg_util_nl(lml, DBG_NL_STD));
 253
 254         if (ld_reloc_init(ofl) == S_ERROR)
 255                 return (NULL);
 256         if (ld_sym_validate(ofl) == S_ERROR)
 257                 return (NULL);
 258
 259         /*
 260          * At this point, all input section processing is complete.  If any
 261          * capabilities have been established, ensure that they are appropriate
 262          * for this system.
 263          */
 264         if (pnavl_recorded(&capavl, ofl->ofl_name, 0, NULL))
 265                 scapset = alt_scapset;
 266         else
 267                 scapset = org_scapset;
 268
 269         if ((((omsk = ofl->ofl_ocapset.oc_hw_1.cm_val) != 0) &&
 270             (hwcap1_check(scapset, omsk, &rej) == 0)) ||
 271             (((omsk = ofl->ofl_ocapset.oc_sf_1.cm_val) != 0) &&
 272             (sfcap1_check(scapset, omsk, &rej) == 0)) ||
 273             (((omsk = ofl->ofl_ocapset.oc_hw_2.cm_val) != 0) &&
 274             (hwcap2_check(scapset, omsk, &rej) == 0)) ||
 275             (((oalp = ofl->ofl_ocapset.oc_plat.cl_val) != NULL) &&
 276             (check_plat_names(scapset, oalp, &rej) == 0)) ||
 277             (((oalp = ofl->ofl_ocapset.oc_mach.cl_val) != NULL) &&
 278             (check_mach_names(scapset, oalp, &rej) == 0))) {
 279                 if ((lml_main.lm_flags & LML_FLG_TRC_LDDSTUB) && lmp &&
 280                     (FLAGS1(lmp) & FL1_RT_LDDSTUB) && (NEXT(lmp) == NULL)) {
 281                         /* LINTED */
 282                         (void) printf(MSG_INTL(ldd_reject[rej.rej_type]),
 283                             ofl->ofl_name, rej.rej_str);
 284                 }
 285                 return (NULL);
 286         }
 287
 288         /*
 289          * Finish creating the output file.
 290          */
 291         if (ld_make_sections(ofl) == S_ERROR)
 292                 return (NULL);
 293         if (ld_create_outfile(ofl) == S_ERROR)
 294                 return (NULL);
 295         if (ld_update_outfile(ofl) == S_ERROR)
 296                 return (NULL);
 297         if (ld_reloc_process(ofl) == S_ERROR)
 298                 return (NULL);
 299
 300         /*
 301          * At this point we have a memory image of the shared object.  The link
 302          * editor would normally simply write this to the required output file.
 303          * If we're debugging generate a standard temporary output file.
 304          */
 305         DBG_CALL(Dbg_file_output(ofl));
 306
 307         /*
 308          * Allocate a mapping array to retain mapped segment information.
 309          */
 310         ehdr = ofl->ofl_nehdr;
 311         phdr = ofl->ofl_phdr;
 312
 313         if ((mpp = hmpp = calloc(ehdr->e_phnum,
 314             sizeof (mmapobj_result_t))) == NULL)
 315                 return (NULL);
 316         for (mnum = 0, phnum = 0; phnum < ehdr->e_phnum; phnum++) {
 317                 if (phdr[phnum].p_type != PT_LOAD)
 318                         continue;
 319
 320                 mpp[mnum].mr_addr = (caddr_t)((uintptr_t)phdr[phnum].p_vaddr +
 321                     (uintptr_t)ehdr);
 322                 mpp[mnum].mr_msize = phdr[phnum].p_memsz;
 323                 mpp[mnum].mr_fsize = phdr[phnum].p_filesz;
 324                 mpp[mnum].mr_prot = (PROT_READ | PROT_WRITE | PROT_EXEC);
 325                 mnum++;
 326         }
 327
 328         /*
 329          * Generate a new link map representing the memory image created.
 330          */
 331         fd.fd_nname = ofl->ofl_name;
 332         if ((nlmp = elf_new_lmp(lml, CNTL(olmp), &fd, (Addr)hmpp->mr_addr,
 333             ofl->ofl_size, NULL, clmp, in_nfavl)) == NULL)
 334                 return (NULL);
 335
 336         MMAPS(nlmp) = hmpp;
 337         MMAPCNT(nlmp) = mnum;
 338         PADSTART(nlmp) = (ulong_t)hmpp->mr_addr;
 339         PADIMLEN(nlmp) = mpp->mr_addr + mpp->mr_msize - hmpp->mr_addr;
 340
 341         /*
 342          * Replace the original (temporary) link map with the new link map.
 343          */
 344         /* LINTED */
 345         lmc = (Lm_cntl *)alist_item_by_offset(lml->lm_lists, CNTL(nlmp));
 346         lml->lm_obj--;
 347
 348         if ((tlmp = PREV_RT_MAP(nlmp)) == olmp)
 349                 tlmp = nlmp;
 350
 351         if (PREV(olmp)) {
 352                 NEXT(PREV_RT_MAP(olmp)) = (Link_map *)nlmp;
 353                 PREV(nlmp) = PREV(olmp);
 354         } else {
 355                 PREV(nlmp) = NULL;
 356                 lmc->lc_head = nlmp;
 357                 if (CNTL(nlmp) == ALIST_OFF_DATA)
 358                         lml->lm_head = nlmp;
 359         }
 360
 361         if (NEXT(olmp) != (Link_map *)nlmp) {
 362                 NEXT(nlmp) = NEXT(olmp);
 363                 PREV(NEXT_RT_MAP(olmp)) = (Link_map *)nlmp;
 364         }
 365
 366         NEXT(tlmp) = NULL;
 367
 368         lmc->lc_tail = tlmp;
 369         if (CNTL(nlmp) == ALIST_OFF_DATA)
 370                 lml->lm_tail = tlmp;
 371
 372         HANDLES(nlmp) = HANDLES(olmp);
 373         GROUPS(nlmp) = GROUPS(olmp);
 374         STDEV(nlmp) = STDEV(olmp);
 375         STINO(nlmp) = STINO(olmp);
 376
 377         FLAGS(nlmp) |= ((FLAGS(olmp) & ~FLG_RT_OBJECT) | FLG_RT_IMGALLOC);
 378         FLAGS1(nlmp) |= FLAGS1(olmp);
 379         MODE(nlmp) |= MODE(olmp);
 380
 381         NAME(nlmp) = NAME(olmp);
 382
 383         /*
 384          * Reassign any original handles to the new link-map.
 385          */
 386         for (APLIST_TRAVERSE(HANDLES(nlmp), idx1, ghp)) {
 387                 Grp_desc        *gdp;
 388                 Aliste          idx2;
 389
 390                 ghp->gh_ownlmp = nlmp;
 391
 392                 for (ALIST_TRAVERSE(ghp->gh_depends, idx2, gdp)) {
 393                         if (gdp->gd_depend == olmp) {
 394                                 gdp->gd_depend = nlmp;
 395                                 break;
 396                         }
 397                 }
 398         }
 399
 400         ld_ofl_cleanup(ofl);
 401         free(ELFPRV(olmp));
 402         free(olmp);
 403         olmp = 0;
 404
 405         /*
 406          * Unmap the original relocatable object.
 407          */
 408         for (ALIST_TRAVERSE(mpalp, idx1, mdp)) {
 409                 unmap_obj(mdp->md_mpp, mdp->md_mnum);
 410                 free(mdp->md_mpp);
 411         }
 412         free(mpalp);
 413         mpalp = NULL;
 414
 415         /*
 416          * Now that we've allocated our permanent link map structure, expand the
 417          * PATHNAME() and insert this path name into the FullPathNode AVL tree.
 418          */
 419         (void) fullpath(nlmp, 0);
 420         if (fpavl_insert(lml, nlmp, PATHNAME(nlmp), 0) == 0)
 421                 return (NULL);
 422
 423         /*
 424          * If we're being audited tell the audit library of the file we've just
 425          * opened.
 426          */
 427         if ((lml->lm_tflags | AFLAGS(nlmp)) & LML_TFLG_AUD_MASK) {
 428                 if (audit_objopen(nlmp, nlmp) == 0)
 429                         return (NULL);
 430         }
 431         return (nlmp);
 432 }