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authorPaul Richards <paul@FreeBSD.org>1993-11-03 23:48:30 +0000
committerPaul Richards <paul@FreeBSD.org>1993-11-03 23:48:30 +0000
commit90f2ed3a8f966e570ae2dac9cfefda8ae9263e37 (patch)
treebe7ab2923734711c1c33fc16b0b13fc605353a02 /include/link.h
parentb9ae52e32a22d27416486dd65ba51ac1052384f4 (diff)
downloadsrc-90f2ed3a8f966e570ae2dac9cfefda8ae9263e37.tar.gz
src-90f2ed3a8f966e570ae2dac9cfefda8ae9263e37.zip
Added link.h for shared libs.
Notes
Notes: svn path=/head/; revision=697
Diffstat (limited to 'include/link.h')
-rw-r--r--include/link.h234
1 files changed, 234 insertions, 0 deletions
diff --git a/include/link.h b/include/link.h
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+/*
+ * RRS section definitions.
+ * Nomenclature and, more importantly, the layout of the various
+ * data structures defined in this header file are borrowed from
+ * Sun Microsystems' original <link.h>, so we can provide compatibility
+ * with the SunOS 4.x shared library scheme.
+ *
+ * $Id: link.h,v 1.2 1993/10/22 21:04:19 pk Exp $
+ * (derived from: @(#)link.h 1.6 88/08/19 SMI
+ * Copyright (c) 1987 by Sun Microsystems, Inc.)
+ */
+
+#ifndef _LINK_H_
+#define _LINK_H_
+
+/*
+ * A `link_object' structure descibes a shared object that is needed
+ * to complete the link edit process of the object containing it.
+ * A list of such objects (chained through `lo_next') is pointed at
+ * by `ld_need' in the link_dynamic_2 structure.
+ */
+
+struct link_object {
+ long lo_name; /* name (relative to load address) */
+ u_int lo_library : 1, /* searched for by library rules */
+ lo_unused : 31;
+ short lo_major; /* major version number */
+ short lo_minor; /* minor version number */
+ long lo_next; /* next one (often relative) */
+};
+
+/*
+ * `link_maps' are used by the run-time link editor (ld.so) to keep
+ * track of all shared objects loaded into a process' address space.
+ * 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 link_map {
+ caddr_t lm_addr; /* address at which object mapped */
+ char *lm_name; /* full name of loaded object */
+ struct link_map *lm_next; /* next object in map */
+ struct link_object *lm_lop; /* link object that got us here */
+ caddr_t lm_lob; /* base address for said link object */
+ u_int lm_rwt : 1; /* text is read/write */
+ struct link_dynamic *lm_ld; /* dynamic structure */
+ caddr_t lm_lpd; /* loader private data */
+};
+
+/*
+ * 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 address by the `ld_symbols' field.
+ */
+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
+};
+
+/*
+ * The `link_dynamic_2' structure contains offsets to various data
+ * structures needed to do run-time relocation.
+ */
+struct link_dynamic_2 {
+ struct link_map *ld_loaded; /* list of loaded objects */
+ long ld_need; /* list of needed objects */
+ long ld_rules; /* search rules for library objects */
+ long ld_got; /* global offset table */
+ long ld_plt; /* procedure linkage table */
+ long ld_rel; /* relocation table */
+ long ld_hash; /* symbol hash table */
+ long ld_symbols; /* symbol table itself */
+ long (*ld_stab_hash)(); /* "pointer" to symbol hash function */
+ long ld_buckets; /* number of hash buckets */
+ long ld_strings; /* symbol strings */
+ long ld_str_sz; /* size of symbol strings */
+ long ld_text_sz; /* size of text area */
+ long ld_plt_sz; /* size of procedure linkage table */
+};
+
+/*
+ * RRS symbol hash table, addressed by `ld_hash' in link_dynamic_2
+ * 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 (`ld_symbols'), `rh_next' is
+ * 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 */
+};
+
+/*
+ * `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 */
+};
+
+/*
+ * Debugger interface structure.
+ */
+struct ld_debug {
+ int ldd_version; /* version # of interface */
+ int ldd_in_debugger; /* a debugger is running us */
+ int ldd_sym_loaded; /* we loaded some symbols */
+ char *ldd_bp_addr; /* place for ld-generated bpt */
+ int ldd_bp_inst; /* instruction which was there */
+ struct rt_symbol *ldd_cp; /* commons we built */
+};
+
+/*
+ * Entry points into ld.so - user interface to the run-time linker.
+ * (see also libdl.a)
+ */
+struct ld_entry {
+ int (*dlopen)();
+ int (*dlclose)();
+ int (*dlsym)();
+};
+
+/*
+ * 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 `ld_un' provides for different versions of the dynamic
+ * linking mechanism (switched on by `ld_version'). The last version
+ * 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 link_dynamic {
+ int ld_version; /* version # of this structure */
+ struct ld_debug *ldd;
+ union {
+ struct link_dynamic_2 *ld_2;
+ } ld_un;
+ struct ld_entry *ld_entry;
+};
+
+#define LD_VERSION_SUN (3)
+#define LD_VERSION_BSD (8)
+#define LD_VERSION_NZLIST_P(v) ((v) >= 8)
+
+#define LD_GOT(x) ((x)->ld_un.ld_2->ld_got)
+#define LD_PLT(x) ((x)->ld_un.ld_2->ld_plt)
+#define LD_REL(x) ((x)->ld_un.ld_2->ld_rel)
+#define LD_SYMBOL(x) ((x)->ld_un.ld_2->ld_symbols)
+#define LD_HASH(x) ((x)->ld_un.ld_2->ld_hash)
+#define LD_STRINGS(x) ((x)->ld_un.ld_2->ld_strings)
+#define LD_NEED(x) ((x)->ld_un.ld_2->ld_need)
+#define LD_BUCKETS(x) ((x)->ld_un.ld_2->ld_buckets)
+
+#define LD_GOTSZ(x) ((x)->ld_un.ld_2->ld_plt - (x)->ld_un.ld_2->ld_got)
+#define LD_RELSZ(x) ((x)->ld_un.ld_2->ld_hash - (x)->ld_un.ld_2->ld_rel)
+#define LD_HASHSZ(x) ((x)->ld_un.ld_2->ld_symbols - (x)->ld_un.ld_2->ld_hash)
+#define LD_STABSZ(x) ((x)->ld_un.ld_2->ld_strings - (x)->ld_un.ld_2->ld_symbols)
+#define LD_PLTSZ(x) ((x)->ld_un.ld_2->ld_plt_sz)
+#define LD_STRSZ(x) ((x)->ld_un.ld_2->ld_str_sz)
+#define LD_TEXTSZ(x) ((x)->ld_un.ld_2->ld_text_sz)
+
+/*
+ * Interface to ld.so (see link(5))
+ */
+struct crt_ldso {
+ int crt_ba; /* Base address of ld.so */
+ int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */
+ int crt_ldfd; /* ld.so file descriptor */
+ struct link_dynamic *crt_dp;/* Main's __DYNAMIC */
+ char **crt_ep; /* environment strings */
+ caddr_t crt_bp; /* Breakpoint if run from debugger */
+};
+
+/*
+ * Version passed from crt0 to ld.so (1st argument to _rtld()).
+ */
+#define CRT_VERSION_SUN 1
+#define CRT_VERSION_BSD 2
+
+
+/*
+ * 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
+ 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) */
+};
+
+#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_ */
+