library.h revision 0b55b5852b9fe2ed6cceada004db303fe6efe6ce 
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
44struct library_symbol {
45	struct library_symbol *next;
46	struct library *lib;
47	const char *name;
48	target_address_t enter_addr;
49	enum toplt plt_type;
50	char own_name;
51	struct arch_library_symbol_data arch;
52};
53
54/* Init LIBSYM.  NAME will be freed when LIBSYM is destroyed if
55 * OWN_NAME.  ARCH has to be initialized by a separate call.  */
56void library_symbol_init(struct library_symbol *libsym,
57			 target_address_t addr, const char *name, int own_name,
58			 enum toplt type_of_plt);
59
60/* Copy library symbol SYM into the area pointed-to by RETP.  Return 0
61 * on success or a negative value on failure.  */
62int library_symbol_clone(struct library_symbol *retp,
63			 struct library_symbol *sym);
64
65/* Destroy library symbol.  This essentially just frees name if it's
66 * owned.  It doesn't free the memory associated with SYM pointer
67 * itself.  Returns 0 on success or a negative value in case of an
68 * error (which would be an out of memory condition).  */
69void library_symbol_destroy(struct library_symbol *sym);
70
71/* Compare two library symbols.  Returns a negative value, 0, or a
72 * positive value, much like strcmp.  The function compares symbol
73 * addresses, and if those are equal, it compares symbol names.  If
74 * those are equal, too, the symbols are considered equal.  */
75int library_symbol_cmp(struct library_symbol *a, struct library_symbol *b);
76
77/* A function that can be used as library_each_symbol callback.  Looks
78 * for a symbol SYM for which library_symbol_cmp(SYM, STANDARD)
79 * returns 0.  */
80enum callback_status library_symbol_equal_cb(struct library_symbol *libsym,
81					     void *standard);
82
83/* XXX we might consider sharing libraries across processes.  Things
84 * like libc will be opened by every single process, no point cloning
85 * these everywhere.  But for now, keep the ownership structure
86 * simple.  */
87struct library {
88	struct library *next;
89
90	/* Address where the library is mapped.  Two library objects
91	 * are considered equal, if they have the same base.  */
92	target_address_t base;
93
94	/* Absolute address of the entry point.  Useful for main
95	 * binary, though I suppose the value might be useful for the
96	 * dynamic linker, too (in case we ever want to do early
97	 * process tracing).  */
98	target_address_t entry;
99
100	/* Address of PT_DYNAMIC segment.  */
101	target_address_t dyn_addr;
102
103	/* Symbols associated with the library.  */
104	struct library_symbol *symbols;
105
106	const char *soname;
107	const char *pathname;
108
109	char own_soname : 1;
110	char own_pathname : 1;
111};
112
113/* Init LIB.  */
114void library_init(struct library *lib);
115
116/* Initialize RETP to a library identical to LIB.  Symbols are not
117 * shared, but copied over.  Returns 0 on success and a negative value
118 * in case of failure.  */
119int library_clone(struct library *retp, struct library *lib);
120
121/* Destroy library.  Doesn't free LIB itself.  */
122void library_destroy(struct library *lib);
123
124/* Set library soname.  Frees the old name if necessary.  */
125void library_set_soname(struct library *lib,
126			const char *new_name, int own_name);
127
128/* Set library pathname.  Frees the old name if necessary.  */
129void library_set_pathname(struct library *lib,
130			  const char *new_name, int own_name);
131
132/* Iterate through list of symbols of library LIB.  Restarts are
133 * supported via START_AFTER (see each_process for details of
134 * iteration interface).  */
135struct library_symbol *library_each_symbol
136	(struct library *lib, struct library_symbol *start_after,
137	 enum callback_status (*cb)(struct library_symbol *, void *),
138	 void *data);
139
140/* Add a new symbol SYM to LIB.  SYM is assumed owned, we need to
141 * overwrite SYM->next.  */
142void library_add_symbol(struct library *lib, struct library_symbol *sym);
143
144/* A function that can be used as proc_each_library callback.  Looks
145 * for a library with the name passed in DATA.  PROC is ignored.  */
146enum callback_status library_named_cb(struct Process *proc,
147				      struct library *lib, void *name);
148
149/* A function that can be used as proc_each_library callback.  Looks
150 * for a library with given base.
151 *
152 * NOTE: The base is passed as a POINTER to target_address_t (that
153 * because in general, target_address_t doesn't fit in void*). */
154enum callback_status library_with_base_cb(struct Process *proc,
155					  struct library *lib, void *basep);
156
157/* XXX this should really be in backend.h (as on pmachata/revamp
158 * branch), or, on this branch, in common.h.  But we need
159 * target_address_t (which should also be in backend.h, I reckon), so
160 * stuff it here for the time being.  */
161/* This function is implemented in the back end.  It is called for all
162 * raw addresses as gleaned from symbol tables etc.  If necessary on
163 * given architecture, this function should translate the address
164 * according to .opd or other indirection mechanism.  Returns 0 on
165 * success and a negative value on failure.  */
166int arch_translate_address(struct Process *proc,
167			   target_address_t addr, target_address_t *ret);
168
169#endif /* _LIBRARY_H_ */
170