/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include        <stdio.h>
#include        <dlfcn.h>
#include        <libelf.h>
#include        <link.h>
#include        <debug.h>
#include        "msg.h"
#include        "_libld.h"

/*
 * Table which defines the default functions to be called by the library
 * SUPPORT (-S <libname>).  These functions can be redefined by the
 * ld_support_loadso() routine.
 */
static Support_list support[LDS_NUM] = {
        {MSG_ORIG(MSG_SUP_VERSION),     NULL},  /* LDS_VERSION */
        {MSG_ORIG(MSG_SUP_INPUT_DONE),  NULL},  /* LDS_INPUT_DONE */
#if     defined(_ELF64)
        {MSG_ORIG(MSG_SUP_START_64),    NULL},  /* LDS_START */
        {MSG_ORIG(MSG_SUP_ATEXIT_64),   NULL},  /* LDS_ATEXIT */
        {MSG_ORIG(MSG_SUP_OPEN_64),     NULL},  /* LDS_OPEN */
        {MSG_ORIG(MSG_SUP_FILE_64),     NULL},  /* LDS_FILE */
        {MSG_ORIG(MSG_SUP_INSEC_64),    NULL},  /* LDS_INSEC */
        {MSG_ORIG(MSG_SUP_SEC_64),      NULL}   /* LDS_SEC */
#else   /* Elf32 */
        {MSG_ORIG(MSG_SUP_START),       NULL},  /* LDS_START */
        {MSG_ORIG(MSG_SUP_ATEXIT),      NULL},  /* LDS_ATEXIT */
        {MSG_ORIG(MSG_SUP_OPEN),        NULL},  /* LDS_OPEN */
        {MSG_ORIG(MSG_SUP_FILE),        NULL},  /* LDS_FILE */
        {MSG_ORIG(MSG_SUP_INSEC),       NULL},  /* LDS_INSEC */
        {MSG_ORIG(MSG_SUP_SEC),         NULL}   /* LDS_SEC */
#endif
};

/*
 * Loads in a support shared object specified using the SGS_SUPPORT environment
 * variable or the -S ld option, and determines which interface functions are
 * provided by that object.
 */
uintptr_t
ld_sup_loadso(Ofl_desc *ofl, const char *obj)
{
        void    *handle, *fptr;
        uint_t  interface, version = LD_SUP_VERSION1;

        /*
         * Load the required support library.  If we are unable to load it fail
         * with a fatal error.
         */
        if ((handle = dlopen(obj, (RTLD_LAZY | RTLD_FIRST))) == NULL) {
                ld_eprintf(ofl, ERR_FATAL, MSG_INTL(MSG_SUP_NOLOAD),
                    obj, dlerror());
                return (S_ERROR);
        }

        for (interface = 0; interface < LDS_NUM; interface++) {
                Func_list       fl;

                if ((fptr = dlsym(handle, support[interface].sup_name)) == NULL)
                        continue;

                DBG_CALL(Dbg_support_load(ofl->ofl_lml, obj,
                    support[interface].sup_name));

                if (interface == LDS_VERSION) {
                        DBG_CALL(Dbg_support_action(ofl->ofl_lml, obj,
                            support[LDS_VERSION].sup_name, LDS_VERSION, 0));

                        version = ((uint_t(*)())fptr)(LD_SUP_VCURRENT);

                        /*
                         * If version is LD_SUP_VNONE, unload the support
                         * library and act as if it was never requested.
                         * This provides the support library with a mechanism
                         * for opting out of the process.
                         *
                         * Note that this depends on LDS_VERSION being the
                         * first item in support[]. If this were not true,
                         * then other functions from the library might be
                         * entered into the function lists, and unloading
                         * the object would cause corruption.
                         */
                        assert(LDS_VERSION == 0);
                        if (version == LD_SUP_VNONE) {
                                DBG_CALL(Dbg_support_vnone(ofl->ofl_lml,
                                    obj));
                                (void) dlclose(handle);
                                return (1);
                        }

                        /*
                         * If the support library has a version higher
                         * than we support, we are unable to accept it.
                         */
                        if (version > LD_SUP_VCURRENT) {
                                ld_eprintf(ofl, ERR_FATAL,
                                    MSG_INTL(MSG_SUP_BADVERSION), obj,
                                    LD_SUP_VCURRENT, version);
                                (void) dlclose(handle);
                                return (S_ERROR);
                        }
                }

                fl.fl_obj = obj;
                fl.fl_fptr = fptr;
                fl.fl_version = version;
                if (alist_append(&support[interface].sup_funcs, &fl,
                    sizeof (Func_list), AL_CNT_SUPPORT) == NULL)
                        return (S_ERROR);
        }
        return (1);
}

/*
 * Wrapper routines for the ld support library calls.
 */
void
ld_sup_start(Ofl_desc *ofl, const Half etype, const char *caller)
{
        Func_list       *flp;
        Aliste          idx;

        for (ALIST_TRAVERSE(support[LDS_START].sup_funcs, idx, flp)) {
                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_START].sup_name, LDS_START, ofl->ofl_name));
                (*flp->fl_fptr)(ofl->ofl_name, etype, caller);
        }
}

void
ld_sup_atexit(Ofl_desc *ofl, int ecode)
{
        Func_list       *flp;
        Aliste          idx;

        for (ALIST_TRAVERSE(support[LDS_ATEXIT].sup_funcs, idx, flp)) {
                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_ATEXIT].sup_name, LDS_ATEXIT, 0));
                (*flp->fl_fptr)(ecode);
        }
}

void
ld_sup_open(Ofl_desc *ofl, const char **opath, const char **ofile, int *ofd,
    int flags, Elf **oelf, Elf *ref, size_t off, const Elf_Kind ekind)
{
        Func_list       *flp;
        Aliste          idx;

        for (ALIST_TRAVERSE(support[LDS_OPEN].sup_funcs, idx, flp)) {
                const char      *npath = *opath;
                const char      *nfile = *ofile;
                Elf             *nelf = *oelf;
                int             nfd = *ofd;
                int             _flags = 0;

                /*
                 * This interface was introduced in VERSION3.  Only call this
                 * function for libraries reporting support for version 3 or
                 * above.
                 */
                if (flp->fl_version < LD_SUP_VERSION3)
                        continue;

                if (!(flags & FLG_IF_CMDLINE))
                        _flags |= LD_SUP_DERIVED;
                if (!(flags & FLG_IF_NEEDED))
                        _flags |= LD_SUP_INHERITED;
                if (flags & FLG_IF_EXTRACT)
                        _flags |= LD_SUP_EXTRACTED;

                /*
                 * If the present object is an extracted archive member, make
                 * sure the archive offset is reset so that the caller can
                 * obtain an ELF descriptor to the same member (an elf_begin()
                 * moves the offset to the next member).
                 */
                if (flags & FLG_IF_EXTRACT)
                        (void) elf_rand(ref, off);

                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_OPEN].sup_name, LDS_OPEN, *opath));
                (*flp->fl_fptr)(&npath, &nfile, &nfd, _flags, &nelf, ref, off,
                    ekind);

                /*
                 * If the file descriptor, ELF descriptor, or file names have
                 * been modified, then diagnose the differences and return the
                 * new data.  As a basic test, make sure the support library
                 * hasn't nulled out data ld(1) will try and dereference.
                 */
                if ((npath != *opath) || (nfd != *ofd) || (nelf != *oelf)) {
                        DBG_CALL(Dbg_file_modified(ofl->ofl_lml, flp->fl_obj,
                            *opath, npath, *ofd, nfd, *oelf, nelf));
                        if (npath)
                                *opath = npath;
                        if (nfile)
                                *ofile = nfile;
                        *ofd = nfd;
                        *oelf = nelf;
                }
        }
}

void
ld_sup_file(Ofl_desc *ofl, const char *ifile, const Elf_Kind ekind, int flags,
    Elf *elf)
{
        Func_list       *flp;
        Aliste          idx;

        for (ALIST_TRAVERSE(support[LDS_FILE].sup_funcs, idx, flp)) {
                int     _flags = 0;

                if (!(flags & FLG_IF_CMDLINE))
                        _flags |= LD_SUP_DERIVED;
                if (!(flags & FLG_IF_NEEDED))
                        _flags |= LD_SUP_INHERITED;
                if (flags & FLG_IF_EXTRACT)
                        _flags |= LD_SUP_EXTRACTED;

                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_FILE].sup_name, LDS_FILE, ifile));
                (*flp->fl_fptr)(ifile, ekind, _flags, elf);
        }
}

uintptr_t
ld_sup_input_section(Ofl_desc *ofl, Ifl_desc *ifl, const char *sname,
    Shdr **oshdr, Word ndx, Elf_Scn *scn, Elf *elf)
{
        Func_list       *flp;
        Aliste          idx;
        uint_t          flags = 0;
        Elf_Data        *data = NULL;

        for (ALIST_TRAVERSE(support[LDS_INSEC].sup_funcs, idx, flp)) {
                Shdr    *nshdr = *oshdr;

                /*
                 * This interface was introduced in VERSION2.  Only call this
                 * function for libraries reporting support for version 2 or
                 * above.
                 */
                if (flp->fl_version < LD_SUP_VERSION2)
                        continue;

                if ((data == NULL) &&
                    ((data = elf_getdata(scn, NULL)) == NULL)) {
                        ld_eprintf(ofl, ERR_ELF, MSG_INTL(MSG_ELF_GETDATA),
                            ifl->ifl_name);
                        return (S_ERROR);
                }

                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_INSEC].sup_name, LDS_INSEC, sname));
                (*flp->fl_fptr)(sname, &nshdr, ndx, data, elf, &flags);

                /*
                 * If the section header has been re-allocated (known to occur
                 * with libCCexcept.so), then diagnose the section header
                 * difference and return the new section header.
                 */
                if (nshdr != *oshdr) {
                        Ehdr    *ehdr = ifl->ifl_ehdr;

                        DBG_CALL(Dbg_shdr_modified(ofl->ofl_lml, flp->fl_obj,
                            ehdr->e_ident[EI_OSABI], ehdr->e_machine, ndx,
                            *oshdr, nshdr, sname));
                        *oshdr = nshdr;
                }
        }
        return (0);
}

void
ld_sup_section(Ofl_desc *ofl, const char *scn, Shdr *shdr, Word ndx,
    Elf_Data *data, Elf *elf)
{
        Func_list       *flp;
        Aliste          idx;

        for (ALIST_TRAVERSE(support[LDS_SEC].sup_funcs, idx, flp)) {
                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_SEC].sup_name, LDS_SEC, scn));
                (*flp->fl_fptr)(scn, shdr, ndx, data, elf);
        }
}

void
ld_sup_input_done(Ofl_desc *ofl)
{
        Func_list       *flp;
        Aliste          idx;
        uint_t          flags = 0;

        for (ALIST_TRAVERSE(support[LDS_INPUT_DONE].sup_funcs, idx, flp)) {
                /*
                 * This interface was introduced in VERSION2.  Only call this
                 * function for libraries reporting support for version 2 or
                 * above.
                 */
                if (flp->fl_version < LD_SUP_VERSION2)
                        continue;

                DBG_CALL(Dbg_support_action(ofl->ofl_lml, flp->fl_obj,
                    support[LDS_INPUT_DONE].sup_name, LDS_INPUT_DONE, 0));
                (*flp->fl_fptr)(&flags);
        }
}