/*      $NetBSD: rtld.h,v 1.156 2026/07/01 19:29:57 riastradh Exp $      */

/*
 * Copyright 1996 John D. Polstra.
 * Copyright 1996 Matt Thomas <matt@3am-software.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by John Polstra.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef RTLD_H
#define RTLD_H

#include <dlfcn.h>
#include <signal.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/param.h>
#include <sys/endian.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/exec_elf.h>
#include <sys/tls.h>
#include "rtldenv.h"
#include "link.h"

#if defined(_RTLD_SOURCE)

#if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__)
#include "unwind.h"
#endif

#ifndef RTLD_DEFAULT_LIBRARY_PATH
#define RTLD_DEFAULT_LIBRARY_PATH       "/usr/lib"
#endif
#define _PATH_LD_HINTS                  "/etc/ld.so.conf"

extern size_t _rtld_pagesz;

#define round_down(x)   ((x) & ~(_rtld_pagesz - 1))
#define round_up(x)     round_down((x) + _rtld_pagesz - 1)

#define NEW(type)       ((type *) xmalloc(sizeof(type)))
#define CNEW(type)      ((type *) xcalloc(sizeof(type)))

/*
 * Fill in a DoneList with an allocation large enough to hold all of
 * the currently-loaded objects. Keep this in a macro since it calls
 * alloca and we want that to occur within the scope of the caller.
 * Callers must be built with -Wno-stack-protector.
 */
#define _rtld_donelist_init(dlp)                                        \
    ((dlp)->num_alloc = _rtld_objcount,                                 \
    (dlp)->objs = alloca((dlp)->num_alloc * sizeof((dlp)->objs[0])),    \
    assert((dlp)->objs != NULL),                                        \
    (dlp)->num_used = 0)


typedef struct Struct_Elf_Hash {
        unsigned long sysv;
        unsigned long gnu;
} Elf_Hash;
#endif /* _RTLD_SOURCE */

/*
 * C++ has mandated the use of the following keywords for its new boolean
 * type.  We might as well follow their lead.
 */
struct Struct_Obj_Entry;

typedef struct Struct_Objlist_Entry {
        SIMPLEQ_ENTRY(Struct_Objlist_Entry) link;
        struct Struct_Obj_Entry *obj;
} Objlist_Entry;

typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist;

typedef struct Struct_Name_Entry {
        SIMPLEQ_ENTRY(Struct_Name_Entry) link;
        char    name[1];
} Name_Entry;

typedef struct Struct_Needed_Entry {
        struct Struct_Needed_Entry *next;
        struct Struct_Obj_Entry *obj;
        unsigned long   name;   /* Offset of name in string table */
} Needed_Entry;

typedef struct _rtld_search_path_t {
        struct _rtld_search_path_t *sp_next;
        const char     *sp_path;
        size_t          sp_pathlen;
} Search_Path;

typedef struct Struct_Ver_Entry {
        Elf_Word        hash;
        u_int           flags;
        const char     *name;
        const char     *file;
} Ver_Entry;

/* Ver_Entry.flags */
#define VER_INFO_HIDDEN 0x01

#define RTLD_MAX_ENTRY 10
#define RTLD_MAX_LIBRARY 4
#define RTLD_MAX_CTL 2
typedef struct _rtld_library_xform_t {
        struct _rtld_library_xform_t *next;
        char *name;
        const char *ctlname;
        struct {
                char *value;
                char *library[RTLD_MAX_LIBRARY];
        } entry[RTLD_MAX_ENTRY];
} Library_Xform;

/*
 * Shared object descriptor.
 *
 * Items marked with "(%)" are dynamically allocated, and must be freed
 * when the structure is destroyed.
 */

typedef void (*fptr_t)(void);

typedef struct Struct_Obj_Entry {
        struct Struct_Obj_Entry *next;
        char           *path;           /* Pathname of underlying file (%) */
        int             refcount;
        int             dl_refcount;    /* Number of times loaded by dlopen */

        /* These items are computed by map_object() or by digest_phdr(). */
        caddr_t         mapbase;        /* Base address of mapped region */
        size_t          mapsize;        /* Size of mapped region in bytes */
        size_t          textsize;       /* Size of text segment in bytes */
        Elf_Addr        vaddrbase;      /* Base address in shared object file */
        caddr_t         relocbase;      /* Reloc const = mapbase - *vaddrbase */
        Elf_Dyn        *dynamic;        /* Dynamic section */
        caddr_t         entry;          /* Entry point */
        const Elf_Phdr *phdr;           /* Program header (may be xmalloc'ed) */
        size_t          phsize;         /* Size of program header in bytes */

        /* Items from the dynamic section. */
        Elf_Addr       *pltgot;         /* PLTGOT table */
        const Elf_Rel  *rel;            /* Relocation entries */
        const Elf_Rel  *rellim;         /* Limit of Relocation entries */
        const Elf_Rela *rela;           /* Relocation entries */
        const Elf_Rela *relalim;        /* Limit of Relocation entries */
        const Elf_Relr *relr;           /* Relative relocations */
        const Elf_Relr *relrlim;        /* Limit of relative relocations */
        const Elf_Rel  *pltrel;         /* PLT relocation entries */
        const Elf_Rel  *pltrellim;      /* Limit of PLT relocation entries */
        const Elf_Rela *pltrela;        /* PLT relocation entries */
        const Elf_Rela *pltrelalim;     /* Limit of PLT relocation entries */
        const Elf_Sym  *symtab;         /* Symbol table */
        const char     *strtab;         /* String table */
        unsigned long   strsize;        /* Size in bytes of string table */
#if defined(__mips__) || defined(__riscv__)
        Elf_Word        local_gotno;    /* Number of local GOT entries */
        Elf_Word        symtabno;       /* Number of dynamic symbols */
        Elf_Word        gotsym;         /* First dynamic symbol in GOT */
#endif

        /* SysV Hash fields */
        const Elf_Symindx *buckets;     /* Hash table buckets array */
        unsigned long   unused1;        /* Used to be nbuckets */
        const Elf_Symindx *chains;      /* Hash table chain array */
        unsigned long   nchains;        /* Number of chains */

        Search_Path    *rpaths;         /* Search path specified in object */
        Needed_Entry   *needed;         /* Shared objects needed by this (%) */

        fptr_t          init;           /* Initialization function to call */
        fptr_t          fini;           /* Termination function to call */

        u_int32_t       mainprog:1,     /* True if this is the main program */
                        rtld:1,         /* True if this is the dynamic linker */
                        textrel:1,      /* True if there are relocations to
                                         * text seg */
                        symbolic:1,     /* True if generated with
                                         * "-Bsymbolic" */
                        printed:1,      /* True if ldd has printed it */
                        isdynamic:1,    /* True if this is a pure PIC object */
                        mainref:1,      /* True if on _rtld_list_main */
                        globalref:1,    /* True if on _rtld_list_global */
                        init_done:1,    /* True if .init has been added */
                        init_called:1,  /* True if .init function has been
                                         * called */
                        fini_called:1,  /* True if .fini function has been
                                         * called */
                        z_now:1,        /* True if object's symbols should be
                                           bound immediately */
                        z_nodelete:1,   /* True if object should never be
                                           unloaded */
                        z_initfirst:1,  /* True if object's .init/.fini take
                                         * priority over others */
                        z_noopen:1,     /* True if object should never be
                                           dlopen'ed */
                        phdr_loaded:1,  /* Phdr is loaded and doesn't need to
                                         * be freed. */
#ifdef __alpha__
                        secureplt:1,    /* True if PLT is read-only format */
#endif
#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
                        tls_static:1,   /* True if static TLS offset
                                         * has been allocated */
                        tls_dynamic:1,  /* True if any non-static DTV entry
                                         * has been allocated */
#endif
                        ref_nodel:1,    /* Refcount increased to prevent dlclose */
                        sysv_hash:1,    /* SysV Hash available */
                        gnu_hash:1;     /* GNU Hash available */

        struct link_map linkmap;        /* for the debugger */

        /* These items are computed by map_object() or by digest_phdr(). */
        const char     *interp; /* Pathname of the interpreter, if any */
        Objlist         dldags; /* Object belongs to these dlopened DAGs (%) */
        Objlist         dagmembers;     /* DAG has these members (%) */
        dev_t           dev;            /* Object's filesystem's device */
        ino_t           ino;            /* Object's inode number */

        void            *ehdr;

        /* SysV Hash fields */
        uint32_t        nbuckets;       /* Number of buckets */
        uint32_t        nbuckets_m;     /* Precomputed for fast remainder */
        uint8_t         nbuckets_s1;
        uint8_t         nbuckets_s2;

        /* GNU Hash fields */
        const uint32_t *buckets_gnu;    /* Hash table buckets array */
        uint32_t        nbuckets_gnu;   /* Number of GNU hash buckets */
        uint32_t        nbuckets_m_gnu; /* Precomputed for fast remainder */
        uint8_t         nbuckets_s1_gnu;
        uint8_t         nbuckets_s2_gnu;
        const uint32_t *chains_gnu;     /* Hash table chain array */
#define nchains_gnu     nchains         /* Number of symbols, shared with SysV Hash */
        const Elf_Addr *bloom_gnu;
        uint32_t        symndx_gnu;     /* First accessible symbol on dynsym table */
        uint32_t        mask_bm_gnu;    /* Bloom filter words - 1 (bitmask) */
        uint32_t        shift2_gnu;     /* Bloom filter shift count */

        size_t          pathlen;        /* Pathname length */
        SIMPLEQ_HEAD(, Struct_Name_Entry) names; /* List of names for this
                                                  * object we know about. */

#ifdef __powerpc__
#ifdef _LP64
        Elf_Addr        glink;          /* global linkage */
#else
        Elf_Addr       *gotptr;         /* GOT table (secure-plt only) */
#endif
#endif

#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
        /* Thread Local Storage support for this module */
        size_t          tlsindex;       /* Index in DTV */
        void            *tlsinit;       /* Base address of TLS init block */
        size_t          tlsinitsize;    /* Size of TLS init block */
        size_t          tlssize;        /* Size of TLS block */
        size_t          tlsoffset;      /* Offset in the static TLS block */
        size_t          tlsalign;       /* Needed alignment for static TLS */
#endif

#ifdef GNU_RELRO
        /* relocation readonly */
        void            *relro_page;
        size_t          relro_size;
#endif

        /* symbol versioning */
        const Elf_Verneed *verneed;     /* Required versions. */
        Elf_Word        verneednum;     /* Number of entries in verneed table */
        const Elf_Verdef  *verdef;      /* Provided versions. */
        Elf_Word        verdefnum;      /* Number of entries in verdef table */
        const Elf_Versym *versyms;      /* Symbol versions table */

        Ver_Entry       *vertab;        /* Versions required/defined by this
                                         * object */
        int             vertabnum;      /* Number of entries in vertab */

        /* init_array/fini_array */
        fptr_t          *init_array;    /* start of init array */
        size_t          init_arraysz;   /* # of entries in it */
        fptr_t          *fini_array;    /* start of fini array */
        size_t          fini_arraysz;   /* # of entries in it */
        fptr_t          *preinit_array; /* start of preinit array */
        size_t          preinit_arraysz;/* # of entries in it */
        /* IRELATIVE relocations */
        size_t          ifunc_remaining;
#if \
    defined(__aarch64__) || \
    defined(__arm__) || \
    defined(__i386__) || \
    defined(__powerpc__) || \
    defined(__sparc__) || \
    defined(__x86_64__)
#define IFUNC_NONPLT
        /* On SPARC, the PLT variant is called JMP_IREL and counted above. */
        size_t          ifunc_remaining_nonplt;
#endif
        size_t          cxa_refcount;   /* For TLS destructors. */
#ifdef __ARM_EABI__
        void            *exidx_start;
        size_t          exidx_sz;
#endif
        int             finiwaiter;     /* dlopen thread waiting for dlclose */
        int             initfinilock;   /* thread running init/fini */
        int             initfinilockwaiter; /* thread waiting to init/fini */
        int             neededrefcount; /* #threads loading obj's deps */
        int             neededwaiter;   /* thread waiting for neededrefcount */
        bool            relocated;      /* true if already relocated */
        bool            dlclosing;      /* true if being dlclosed now */
} Obj_Entry;

typedef struct Struct_DoneList {
        const Obj_Entry **objs;         /* Array of object pointers */
        unsigned int num_alloc;         /* Allocated size of the array */
        unsigned int num_used;          /* Number of array slots used */
} DoneList;


#if defined(_RTLD_SOURCE)

extern struct r_debug _rtld_debug;
extern Search_Path *_rtld_default_paths;
extern Obj_Entry *_rtld_objlist;
extern Obj_Entry **_rtld_objtail;
extern u_int _rtld_objrelocpending;
extern u_int _rtld_objcount;
extern u_int _rtld_objloads;
extern const uintptr_t _rtld_compat_obj[];
extern Obj_Entry *_rtld_objmain;
extern Obj_Entry _rtld_objself;
extern Search_Path *_rtld_paths;
extern Library_Xform *_rtld_xforms;
extern bool _rtld_trust;
extern Objlist _rtld_list_global;
extern Objlist _rtld_list_main;
extern Elf_Sym _rtld_sym_zero;
extern u_int _rtld_objgen;

#define RTLD_MODEMASK 0x3

/* Flags to be passed into _rtld_symlook_ family of functions. */
#define SYMLOOK_IN_PLT  0x01    /* Lookup for PLT symbol */
#define SYMLOOK_DLSYM   0x02    /* Return newest versioned symbol.
                                   Used by dlsym. */

/* Flags for _rtld_load_object() and friends. */
#define _RTLD_GLOBAL    0x01    /* Add object to global DAG. */
#define _RTLD_MAIN      0x02
#define _RTLD_NOLOAD    0x04    /* dlopen() specified RTLD_NOLOAD. */
#define _RTLD_DLOPEN    0x08    /* Load_object() called from dlopen(). */

/* Preallocation for static TLS model */
#define RTLD_STATIC_TLS_RESERVATION     64

/* rtld.c */
__dso_public char *dlerror(void);
__dso_public void *dlopen(const char *, int);
__dso_public void *dlsym(void *, const char *);
__dso_public int dlclose(void *);
__dso_public int dladdr(const void *, Dl_info *);
__dso_public int dlinfo(void *, int, void *);
__dso_public int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *),
    void *);

__dso_public void *_dlauxinfo(void) __pure;
__dso_public void __dl_cxa_refcount(void *addr, ssize_t delta);

__dso_public pid_t __locked_fork(int *);

#if defined(__ARM_EABI__) && !defined(__ARM_DWARF_EH__)
/*
 * This is used by libgcc to find the start and length of the exception table
 * associated with a PC.
 */
__dso_public _Unwind_Ptr __gnu_Unwind_Find_exidx(_Unwind_Ptr, int *);
#endif

/* These aren't exported */
void _rtld_error(const char *, ...) __printflike(1,2);
void _rtld_die(void) __dead;
void *_rtld_objmain_sym(const char *);
__dso_public void _rtld_debug_state(void) __noinline;
void _rtld_linkmap_add(Obj_Entry *);
void _rtld_linkmap_delete(Obj_Entry *);
void _rtld_objlist_push_head(Objlist *, Obj_Entry *);
void _rtld_objlist_push_tail(Objlist *, Obj_Entry *);
Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *);
void _rtld_ref_dag(Obj_Entry *);

#ifdef RTLD_LOADER
void _rtld_load_needed_enter(Obj_Entry *);
void _rtld_load_needed_exit(Obj_Entry *);
bool _rtld_wait_for_fini(Obj_Entry **, sigset_t *);
#else
static inline void
_rtld_load_needed_enter(Obj_Entry *obj)
{
        obj->neededrefcount++;
}
static inline void
_rtld_load_needed_exit(Obj_Entry *obj)
{
        obj->neededrefcount--;
}
static inline bool
_rtld_wait_for_fini(Obj_Entry **objp, sigset_t *mask)
{
        assert((*objp)->refcount);
        return false;
}
#endif

void _rtld_shared_enter(void);
void _rtld_shared_exit(void);
void _rtld_exclusive_enter(sigset_t *);
void _rtld_exclusive_exit(sigset_t *);

int _rtld_relro(const Obj_Entry *, bool);

/* expand.c */
size_t _rtld_expand_path(char *, size_t, const char *, const char *,\
    const char *);

/* headers.c */
void _rtld_digest_dynamic(const char *, Obj_Entry *);
Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t);

/* load.c */
Obj_Entry *_rtld_load_object(const char *, int, sigset_t *);
int _rtld_load_needed_objects(Obj_Entry *, int, sigset_t *);
int _rtld_preload(const char *, sigset_t *);

/* arch/<arch>/fixup.c */
int _rtld_map_segment_fixup(const char *, int, Elf_Ehdr *, Elf_Phdr *,
    caddr_t, size_t, int);

#define OBJ_ERR (Obj_Entry *)(-1)
/* path.c */
void _rtld_add_paths(const char *, Search_Path **, const char *);
void _rtld_process_hints(const char *, Search_Path **, Library_Xform **,
    const char *);
int _rtld_sysctl(const char *, void *, size_t *);

/* reloc.c */
int _rtld_do_copy_relocations(const Obj_Entry *);
int _rtld_relocate_objects(Obj_Entry *, bool);
int _rtld_relocate_nonplt_objects(Obj_Entry *);
int _rtld_relocate_plt_lazy(Obj_Entry *);
int _rtld_relocate_plt_objects(const Obj_Entry *);
void _rtld_setup_pltgot(const Obj_Entry *);
Elf_Addr _rtld_resolve_ifunc(const Obj_Entry *, const Elf_Sym *);
Elf_Addr _rtld_resolve_ifunc2(const Obj_Entry *, Elf_Addr);

void _rtld_call_ifunc(Obj_Entry *, sigset_t *, u_int);

/* search.c */
Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int,
    sigset_t *);

/* symbol.c */
const Elf_Sym *_rtld_symlook_obj(const char *, Elf_Hash *,
    const Obj_Entry *, u_int, const Ver_Entry *);
const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *,
    const Obj_Entry **, u_int);
const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *,
    const Obj_Entry **, bool);

const Elf_Sym *_rtld_symlook_list(const char *, Elf_Hash *,
    const Objlist *, const Obj_Entry **, u_int, const Ver_Entry *, DoneList *);
const Elf_Sym *_rtld_symlook_default(const char *, Elf_Hash *,
    const Obj_Entry *, const Obj_Entry **, u_int, const Ver_Entry *);
const Elf_Sym *_rtld_symlook_needed(const char *, Elf_Hash *,
    const Needed_Entry *, const Obj_Entry **, u_int, const Ver_Entry *,
    DoneList *, DoneList *);

/* symver.c */
void _rtld_object_add_name(Obj_Entry *, const char *);
int _rtld_object_match_name(const Obj_Entry *, const char *);
int _rtld_verify_object_versions(Obj_Entry *);

static __inline const Ver_Entry *
_rtld_fetch_ventry(const Obj_Entry *obj, unsigned long symnum)
{
        Elf_Half vernum;

        if (obj->vertab) {
                vernum = VER_NDX(obj->versyms[symnum]);
                if (vernum >= obj->vertabnum) {
                        _rtld_error("%s: symbol %s has wrong verneed value %d",
                            obj->path, &obj->strtab[symnum], vernum);
                } else if (obj->vertab[vernum].hash) {
                        return &obj->vertab[vernum];
                }
        }
        return NULL;
}

#if defined(__HAVE_TLS_VARIANT_I) || defined(__HAVE_TLS_VARIANT_II)
/* tls.c */
void *_rtld_tls_get_addr(void *, size_t, size_t);
void _rtld_tls_initial_allocation(void);
int _rtld_tls_offset_allocate(Obj_Entry *);
void _rtld_tls_offset_free(Obj_Entry *);

extern size_t _rtld_tls_dtv_generation;
extern size_t _rtld_tls_max_index;

__dso_public extern void *__tls_get_addr(void *);
#ifdef __i386__
__dso_public extern void *___tls_get_addr(void *)
    __attribute__((__regparm__(1)));
#endif
#endif

/* map_object.c */
struct stat;
Obj_Entry *_rtld_map_object(const char *, int, const struct stat *);
void _rtld_obj_free(Obj_Entry *);
Obj_Entry *_rtld_obj_new(void);

#ifdef RTLD_LOADER
/* function descriptors */
#ifdef __HAVE_FUNCTION_DESCRIPTORS
Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *,
    const Elf_Sym *, Elf_Addr);
const void *_rtld_function_descriptor_function(const void *);

Elf_Addr _rtld_call_function_addr(const Obj_Entry *, Elf_Addr);
#else
static inline Elf_Addr
_rtld_call_function_addr(const Obj_Entry *obj, Elf_Addr addr)
{
        return ((Elf_Addr(*)(void))addr)();
}
#endif /* __HAVE_FUNCTION_DESCRIPTORS */
#endif /* RTLD_LOADER */

#endif /* _RTLD_SOURCE */

#endif /* RTLD_H */