freebsd-dev/include/link.h

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/*
* Copyright (c) 1993 Paul Kranenburg
* 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 Paul Kranenburg.
* 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.
*
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* $Id: link.h,v 1.13 1997/05/07 20:00:00 eivind Exp $
*/
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/*
* RRS section definitions.
*
* The layout of some data structures defined in this header file is
* such that we can provide compatibility with the SunOS 4.x shared
* library scheme.
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*/
#ifndef _LINK_H_
#define _LINK_H_
/*
* A `Shared Object Descriptor' describes a shared object that is needed
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* to complete the link edit process of the object containing it.
* A list of such objects (chained through `sod_next') is pointed at
* by `sdt_sods' in the section_dispatch_table structure.
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*/
struct sod { /* Shared Object Descriptor */
long sod_name; /* name (relative to load address) */
u_int sod_library : 1, /* Searched for by library rules */
sod_reserved : 31;
short sod_major; /* major version number */
short sod_minor; /* minor version number */
long sod_next; /* next sod */
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};
/*
* `Shared Object Map's are used by the run-time link editor (ld.so) to
* keep track of all shared objects loaded into a process' address space.
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* These structures are only used at run-time and do not occur within
* the text or data segment of an executable or shared library.
*/
struct so_map { /* Shared Object Map */
caddr_t som_addr; /* Address at which object mapped */
char *som_path; /* Path to mmap'ed file */
struct so_map *som_next; /* Next map in chain */
struct sod *som_sod; /* Sod responsible for this map */
caddr_t som_sodbase; /* Base address of this sod */
u_int som_write : 1; /* Text is currently writable */
struct _dynamic *som_dynamic; /* _dynamic structure */
caddr_t som_spd; /* Private data */
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};
/*
* Symbol description with size. This is simply an `nlist' with
* one field (nz_size) added.
* Used to convey size information on items in the data segment
* of shared objects. An array of these live in the shared object's
* text segment and is addressed by the `sdt_nzlist' field.
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*/
struct nzlist {
struct nlist nlist;
u_long nz_size;
#define nz_un nlist.n_un
#define nz_strx nlist.n_un.n_strx
#define nz_name nlist.n_un.n_name
#define nz_type nlist.n_type
#define nz_value nlist.n_value
#define nz_desc nlist.n_desc
#define nz_other nlist.n_other
};
#define N_AUX(p) ((p)->n_other & 0xf)
#define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
#define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
#define AUX_OBJECT 1
#define AUX_FUNC 2
/*#define BIND_LOCAL 0 not used */
/*#define BIND_GLOBAL 1 not used */
#define BIND_WEAK 2
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/*
* The `section_dispatch_table' structure contains offsets to various data
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* structures needed to do run-time relocation.
*/
struct section_dispatch_table {
struct so_map *sdt_loaded; /* List of loaded objects */
long sdt_sods; /* List of shared objects descriptors */
long sdt_paths; /* Library search paths */
long sdt_got; /* Global offset table */
long sdt_plt; /* Procedure linkage table */
long sdt_rel; /* Relocation table */
long sdt_hash; /* Symbol hash table */
long sdt_nzlist; /* Symbol table itself */
long sdt_filler2; /* Unused (was: stab_hash) */
long sdt_buckets; /* Number of hash buckets */
long sdt_strings; /* Symbol strings */
long sdt_str_sz; /* Size of symbol strings */
long sdt_text_sz; /* Size of text area */
long sdt_plt_sz; /* Size of procedure linkage table */
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};
/*
* RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
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* Used to quickly lookup symbols of the shared object by hashing
* on the symbol's name. `rh_symbolnum' is the index of the symbol
* in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
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* the next symbol in the hash bucket (in case of collisions).
*/
struct rrs_hash {
int rh_symbolnum; /* Symbol number */
int rh_next; /* Next hash entry */
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};
/*
* `rt_symbols' is used to keep track of run-time allocated commons
* and data items copied from shared objects.
*/
struct rt_symbol {
struct nzlist *rt_sp; /* The symbol */
struct rt_symbol *rt_next; /* Next in linear list */
struct rt_symbol *rt_link; /* Next in bucket */
caddr_t rt_srcaddr; /* Address of "master" copy */
struct so_map *rt_smp; /* Originating map */
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};
/*
* Debugger interface structure.
*/
struct so_debug {
int dd_version; /* Version # of interface */
int dd_in_debugger; /* Set when run by debugger */
int dd_sym_loaded; /* Run-time linking brought more
symbols into scope */
char *dd_bpt_addr; /* Address of rtld-generated bpt */
int dd_bpt_shadow; /* Original contents of bpt */
struct rt_symbol *dd_cc; /* Allocated commons/copied data */
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};
/*
* Version returned to crt0 from ld.so
*/
#define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */
#define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */
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#define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */
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/*
* Entry points into ld.so - user interface to the run-time linker.
* Entries are valid for the given version numbers returned by ld.so
* to crt0.
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*/
struct ld_entry {
void *(*dlopen) __P((char *, int)); /* NONE */
int (*dlclose) __P((void *)); /* NONE */
void *(*dlsym) __P((void *, char *)); /* NONE */
char *(*dlerror) __P((void)); /* NONE */
void (*dlexit) __P((void)); /* HAS_DLEXIT */
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void *(*dlsym3) __P((void *, char *, void *)); /* HAS_DLSYM3 */
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};
/*
* dl*() prototypes.
*/
extern void *dlopen __P((char *, int));
extern int dlclose __P((void *));
extern void *dlsym __P((void *, char *));
extern char *dlerror __P((void));
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/*
* This is the structure pointed at by the __DYNAMIC symbol if an
* executable requires the attention of the run-time link editor.
* __DYNAMIC is given the value zero if no run-time linking needs to
* be done (it is always present in shared objects).
* The union `d_un' provides for different versions of the dynamic
* linking mechanism (switched on by `d_version'). The last version
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* used by Sun is 3. We leave some room here and go to version number
* 8 for NetBSD, the main difference lying in the support for the
* `nz_list' type of symbols.
*/
struct _dynamic {
int d_version; /* version # of this interface */
struct so_debug *d_debug;
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union {
struct section_dispatch_table *d_sdt;
} d_un;
struct ld_entry *d_entry; /* XXX */
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};
#define LD_VERSION_SUN (3)
#define LD_VERSION_BSD (8)
#define LD_VERSION_NZLIST_P(v) ((v) >= 8)
#define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
#define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
#define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
#define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
#define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
#define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
#define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
#define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
#define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
#define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
#define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
#define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
#define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
#define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
#define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
#define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
/*
* Interface to ld.so
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*/
struct crt_ldso {
int crt_ba; /* Base address of ld.so */
int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */
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int crt_ldfd; /* ld.so file descriptor */
struct _dynamic *crt_dp; /* Main's __DYNAMIC */
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char **crt_ep; /* environment strings */
caddr_t crt_bp; /* Breakpoint if run from debugger */
char *crt_prog; /* Program name (v3) */
char *crt_ldso; /* Link editor name (v4) */
struct ld_entry *crt_ldentry; /* dl*() access (v4) */
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};
/*
* Version passed from crt0 to ld.so (1st argument to _rtld()).
*/
#define CRT_VERSION_SUN 1
#define CRT_VERSION_BSD_2 2
#define CRT_VERSION_BSD_3 3
#define CRT_VERSION_BSD_4 4
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/*
* Maximum number of recognized shared object version numbers.
*/
#define MAXDEWEY 8
/*
* Header of the hints file.
*/
struct hints_header {
long hh_magic;
#define HH_MAGIC 011421044151
long hh_version; /* Interface version number */
#define LD_HINTS_VERSION_1 1
#define LD_HINTS_VERSION_2 2
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long hh_hashtab; /* Location of hash table */
long hh_nbucket; /* Number of buckets in hashtab */
long hh_strtab; /* Location of strings */
long hh_strtab_sz; /* Size of strings */
long hh_ehints; /* End of hints (max offset in file) */
long hh_dirlist; /* Colon-separated list of srch dirs */
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};
#define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
/*
* Hash table element in hints file.
*/
struct hints_bucket {
/* namex and pathx are indices into the string table */
int hi_namex; /* Library name */
int hi_pathx; /* Full path */
int hi_dewey[MAXDEWEY]; /* The versions */
int hi_ndewey; /* Number of version numbers */
#define hi_major hi_dewey[0]
#define hi_minor hi_dewey[1]
int hi_next; /* Next in this bucket */
};
#define _PATH_LD_HINTS "/var/run/ld.so.hints"
#endif /* _LINK_H_ */