library.h revision 0092820afcd45fe045ccc294b061bce8da00a1f2 
1/*
2 * This file is part of ltrace.
3 * Copyright (C) 2012 Petr Machata, Red Hat Inc.
4 * Copyright (C) 2006 Paul Gilliam
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 "sysdep.h"
27
28struct Process;
29struct library;
30
31enum toplt {
32	LS_TOPLT_NONE = 0,	/* PLT not used for this symbol. */
33	LS_TOPLT_EXEC,		/* PLT for this symbol is executable. */
34	LS_TOPLT_POINT		/* PLT for this symbol is a non-executable. */
35};
36
37/* We should in general be able to trace 64-bit processes with 32-bit
38 * ltrace.  (At least PPC has several PTRACE requests related to
39 * tracing 64-on-32, so presumably it should be possible.)  But ltrace
40 * is currently hopelessly infested with using void* for host address.
41 * So keep with it, for now.  */
42typedef void *target_address_t;
43
44/* Dict interface.  */
45unsigned int target_address_hash(const void *key);
46int target_address_cmp(const void *key1, const void *key2);
47
48struct library_symbol {
49	struct library_symbol *next;
50	struct library *lib;
51	const char *name;
52	target_address_t enter_addr;
53	enum toplt plt_type;
54	char own_name;
55	struct arch_library_symbol_data arch;
56};
57
58/* Init LIBSYM.  NAME will be freed when LIBSYM is destroyed if
59 * OWN_NAME.  ARCH has to be initialized by a separate call.  */
60void library_symbol_init(struct library_symbol *libsym,
61			 target_address_t addr, const char *name, int own_name,
62			 enum toplt type_of_plt);
63
64/* Copy library symbol SYM into the area pointed-to by RETP.  Return 0
65 * on success or a negative value on failure.  */
66int library_symbol_clone(struct library_symbol *retp,
67			 struct library_symbol *sym);
68
69/* Destroy library symbol.  This essentially just frees name if it's
70 * owned.  It doesn't free the memory associated with SYM pointer
71 * itself.  Returns 0 on success or a negative value in case of an
72 * error (which would be an out of memory condition).  */
73void library_symbol_destroy(struct library_symbol *sym);
74
75/* Compare two library symbols.  Returns a negative value, 0, or a
76 * positive value, much like strcmp.  The function compares symbol
77 * addresses, and if those are equal, it compares symbol names.  If
78 * those are equal, too, the symbols are considered equal.  */
79int library_symbol_cmp(struct library_symbol *a, struct library_symbol *b);
80
81/* Set a name for library symbol.  This frees the old name, if
82 * that is owned.  */
83void library_symbol_set_name(struct library_symbol *libsym,
84			     const char *name, int own_name);
85
86/* A function that can be used as library_each_symbol callback.  Looks
87 * for a symbol SYM for which library_symbol_cmp(SYM, STANDARD)
88 * returns 0.  */
89enum callback_status library_symbol_equal_cb(struct library_symbol *libsym,
90					     void *standard);
91
92enum library_type {
93	LT_LIBTYPE_MAIN,
94	LT_LIBTYPE_DSO,
95};
96
97/* XXX we might consider sharing libraries across processes.  Things
98 * like libc will be opened by every single process, no point cloning
99 * these everywhere.  But for now, keep the ownership structure
100 * simple.  */
101struct library {
102	struct library *next;
103
104	/* Unique key. Two library objects are considered equal, if
105	 * they have the same key.  */
106	target_address_t key;
107
108	/* Address where the library is mapped.  Two library objects
109	 * are considered equal, if they have the same base.  */
110	target_address_t base;
111
112	/* Absolute address of the entry point.  Useful for main
113	 * binary, though I suppose the value might be useful for the
114	 * dynamic linker, too (in case we ever want to do early
115	 * process tracing).  */
116	target_address_t entry;
117
118	/* Address of PT_DYNAMIC segment.  */
119	target_address_t dyn_addr;
120
121	/* Symbols associated with the library.  */
122	struct library_symbol *symbols;
123
124	const char *soname;
125	const char *pathname;
126
127	enum library_type type;
128
129	char own_soname : 1;
130	char own_pathname : 1;
131};
132
133/* Init LIB.  */
134void library_init(struct library *lib, enum library_type type);
135
136/* Initialize RETP to a library identical to LIB.  Symbols are not
137 * shared, but copied over.  Returns 0 on success and a negative value
138 * in case of failure.  */
139int library_clone(struct library *retp, struct library *lib);
140
141/* Destroy library.  Doesn't free LIB itself.  */
142void library_destroy(struct library *lib);
143
144/* Set library soname.  Frees the old name if necessary.  */
145void library_set_soname(struct library *lib,
146			const char *new_name, int own_name);
147
148/* Set library pathname.  Frees the old name if necessary.  */
149void library_set_pathname(struct library *lib,
150			  const char *new_name, int own_name);
151
152/* Iterate through list of symbols of library LIB.  Restarts are
153 * supported via START_AFTER (see each_process for details of
154 * iteration interface).  */
155struct library_symbol *library_each_symbol
156	(struct library *lib, struct library_symbol *start_after,
157	 enum callback_status (*cb)(struct library_symbol *, void *),
158	 void *data);
159
160/* Add a new symbol SYM to LIB.  SYM is assumed owned, we need to
161 * overwrite SYM->next.  */
162void library_add_symbol(struct library *lib, struct library_symbol *sym);
163
164/* A function that can be used as proc_each_library callback.  Looks
165 * for a library with the name passed in DATA.  PROC is ignored.  */
166enum callback_status library_named_cb(struct Process *proc,
167				      struct library *lib, void *name);
168
169/* A function that can be used as proc_each_library callback.  Looks
170 * for a library with given base.
171 *
172 * NOTE: The key is passed as a POINTER to target_address_t (that
173 * because in general, target_address_t doesn't fit in void*).  */
174enum callback_status library_with_key_cb(struct Process *proc,
175					 struct library *lib, void *keyp);
176
177/* XXX this should really be in backend.h (as on pmachata/revamp
178 * branch), or, on this branch, in common.h.  But we need
179 * target_address_t (which should also be in backend.h, I reckon), so
180 * stuff it here for the time being.  */
181/* This function is implemented in the back end.  It is called for all
182 * raw addresses as gleaned from symbol tables etc.  If necessary on
183 * given architecture, this function should translate the address
184 * according to .opd or other indirection mechanism.  Returns 0 on
185 * success and a negative value on failure.  */
186int arch_translate_address(struct Process *proc,
187			   target_address_t addr, target_address_t *ret);
188
189#endif /* _LIBRARY_H_ */
190