library.h revision ab2dab55656a98068fac278b605c5cf780c4343b 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012 Petr Machata, Red Hat Inc.
4 * Copyright (C) 2006 Paul Gilliam, IBM Corporation
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21
22#ifndef _LIBRARY_H_
23#define _LIBRARY_H_
24
25#include <stdint.h>
26#include "callback.h"
27#include "sysdep.h"
28
29struct Process;
30struct library;
31
32enum toplt {
33	LS_TOPLT_NONE = 0,	/* PLT not used for this symbol. */
34	LS_TOPLT_EXEC,		/* PLT for this symbol is executable. */
35};
36
37/* Dict interface.  */
38unsigned int target_address_hash(const void *key);
39int target_address_cmp(const void *key1, const void *key2);
40
41/* For handling -l.  */
42struct library_exported_name {
43	struct library_exported_name *next;
44	const char *name;
45	int own_name : 1;
46};
47
48struct library_symbol {
49	struct library_symbol *next;
50	struct library *lib;
51	const char *name;
52	arch_addr_t enter_addr;
53	enum toplt plt_type;
54	int own_name : 1;
55
56	/* This is relevant for PLT symbols.  Latent PLT symbols are
57	 * those that don't match any of the -e rules, but that might
58	 * potentially become active if a library implementing them
59	 * appears that matches a -l rule.  Ltrace core is responsible
60	 * for clearing latent flag.  */
61	int latent : 1;
62
63	/* Delayed symbols are those for which a breakpoint shouldn't
64	 * be enabled yet.  They are similar to latent symbols, but
65	 * backend is responsible for clearing the delayed flag.  See
66	 * proc_activate_delayed_symbol.  */
67	int delayed : 1;
68
69	struct arch_library_symbol_data arch;
70};
71
72/* Init LIBSYM.  NAME will be freed when LIBSYM is destroyed if
73 * OWN_NAME.  ARCH has to be initialized by a separate call.  */
74int library_symbol_init(struct library_symbol *libsym,
75			arch_addr_t addr, const char *name, int own_name,
76			enum toplt type_of_plt);
77
78/* Copy library symbol SYM into the area pointed-to by RETP.  Return 0
79 * on success or a negative value on failure.  */
80int library_symbol_clone(struct library_symbol *retp,
81			 struct library_symbol *sym);
82
83/* Destroy library symbol.  This essentially just frees name if it's
84 * owned.  It doesn't free the memory associated with SYM pointer
85 * itself.  Returns 0 on success or a negative value in case of an
86 * error (which would be an out of memory condition).  */
87void library_symbol_destroy(struct library_symbol *sym);
88
89/* Compare two library symbols.  Returns a negative value, 0, or a
90 * positive value, much like strcmp.  The function compares symbol
91 * addresses, and if those are equal, it compares symbol names.  If
92 * those are equal, too, the symbols are considered equal.  */
93int library_symbol_cmp(struct library_symbol *a, struct library_symbol *b);
94
95/* Set a name for library symbol.  This frees the old name, if
96 * that is owned.  */
97void library_symbol_set_name(struct library_symbol *libsym,
98			     const char *name, int own_name);
99
100/* A function that can be used as library_each_symbol callback.  Looks
101 * for a symbol SYM for which library_symbol_cmp(SYM, STANDARD)
102 * returns 0.  */
103enum callback_status library_symbol_equal_cb(struct library_symbol *libsym,
104					     void *standard);
105
106/* A function that can be used as library_each_symbol callback.  Looks
107 * for a symbol SYM for which strcmp(SYM->name, NAME) == 0.  */
108enum callback_status library_symbol_named_cb(struct library_symbol *libsym,
109					     void *name);
110
111/* A function that can be used as library_each_symbol callback.  Looks
112 * for a delayed symbol.  */
113enum callback_status library_symbol_delayed_cb(struct library_symbol *libsym,
114					       void *unused);
115
116enum library_type {
117	LT_LIBTYPE_MAIN,
118	LT_LIBTYPE_DSO,
119};
120
121/* XXX we might consider sharing libraries across processes.  Things
122 * like libc will be opened by every single process, no point cloning
123 * these everywhere.  But for now, keep the ownership structure
124 * simple.  */
125struct library {
126	struct library *next;
127
128	/* Unique key. Two library objects are considered equal, if
129	 * they have the same key.  */
130	arch_addr_t key;
131
132	/* Address where the library is mapped.  */
133	arch_addr_t base;
134
135	/* Absolute address of the entry point.  Useful for main
136	 * binary, though I suppose the value might be useful for the
137	 * dynamic linker, too (in case we ever want to do early
138	 * process tracing).  */
139	arch_addr_t entry;
140
141	/* Address of PT_DYNAMIC segment.  */
142	arch_addr_t dyn_addr;
143
144	/* Symbols associated with the library.  This includes a
145	 * symbols that don't have a breakpoint attached (yet).  */
146	struct library_symbol *symbols;
147
148	/* List of names that this library implements, and that match
149	 * -l filter.  Each time a new library is mapped, its list of
150	 * exports is examined, and corresponding PLT slots are
151	 * enabled.  */
152	struct library_exported_name *exported_names;
153
154	const char *soname;
155	const char *pathname;
156
157	enum library_type type;
158
159	char own_soname : 1;
160	char own_pathname : 1;
161
162	struct arch_library_data arch;
163};
164
165/* Init LIB.  */
166void library_init(struct library *lib, enum library_type type);
167
168/* Initialize RETP to a library identical to LIB.  Symbols are not
169 * shared, but copied over.  Returns 0 on success and a negative value
170 * in case of failure.  */
171int library_clone(struct library *retp, struct library *lib);
172
173/* Destroy library.  Doesn't free LIB itself.  Symbols are destroyed
174 * and freed.  */
175void library_destroy(struct library *lib);
176
177/* Set library soname.  Frees the old name if necessary.  */
178void library_set_soname(struct library *lib,
179			const char *new_name, int own_name);
180
181/* Set library pathname.  Frees the old name if necessary.  */
182void library_set_pathname(struct library *lib,
183			  const char *new_name, int own_name);
184
185/* Iterate through list of symbols of library LIB.  See callback.h for
186 * notes on this interface.  */
187struct library_symbol *library_each_symbol
188	(struct library *lib, struct library_symbol *start_after,
189	 enum callback_status (*cb)(struct library_symbol *, void *),
190	 void *data);
191
192/* Add a new symbol SYM to LIB.  SYM is assumed owned, we need to
193 * overwrite SYM->next.  */
194void library_add_symbol(struct library *lib, struct library_symbol *sym);
195
196/* A function that can be used as proc_each_library callback.  Looks
197 * for a library with the name passed in DATA.  PROC is ignored.  */
198enum callback_status library_named_cb(struct Process *proc,
199				      struct library *lib, void *name);
200
201/* A function that can be used as proc_each_library callback.  Looks
202 * for a library with given base.
203 *
204 * NOTE: The key is passed as a POINTER to arch_addr_t (that
205 * because in general, arch_addr_t doesn't fit in void*).  */
206enum callback_status library_with_key_cb(struct Process *proc,
207					 struct library *lib, void *keyp);
208
209/* XXX this should really be in backend.h (as on pmachata/revamp
210 * branch), or, on this branch, in common.h.  But we need
211 * arch_addr_t (which should also be in backend.h, I reckon), so
212 * stuff it here for the time being.  */
213/* This function is implemented in the back end.  It is called for all
214 * raw addresses as read from symbol tables etc.  If necessary on
215 * given architecture, this function should translate the address
216 * according to .opd or other indirection mechanism.  Returns 0 on
217 * success and a negative value on failure.  */
218struct ltelf;
219int arch_translate_address(struct ltelf *lte,
220			   arch_addr_t addr, arch_addr_t *ret);
221/* This is the same function as arch_translate_address, except it's
222 * used at the point that we don't have ELF available anymore.  */
223int arch_translate_address_dyn(struct Process *proc,
224			       arch_addr_t addr, arch_addr_t *ret);
225
226#endif /* _LIBRARY_H_ */
227