1 /*
2 
3   Copyright (C) 2000,2002,2004 Silicon Graphics, Inc.  All Rights Reserved.
4   Portions Copyright 2002-2010 Sun Microsystems, Inc. All rights reserved.
5   Portions Copyright 2011-2017 David Anderson. All Rights Reserved.
6 
7   This program is free software; you can redistribute it and/or modify it
8   under the terms of version 2.1 of the GNU Lesser General Public License
9   as published by the Free Software Foundation.
10 
11   This program is distributed in the hope that it would be useful, but
12   WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
14 
15   Further, this software is distributed without any warranty that it is
16   free of the rightful claim of any third person regarding infringement
17   or the like.  Any license provided herein, whether implied or
18   otherwise, applies only to this software file.  Patent licenses, if
19   any, provided herein do not apply to combinations of this program with
20   other software, or any other product whatsoever.
21 
22   You should have received a copy of the GNU Lesser General Public
23   License along with this program; if not, write the Free Software
24   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301,
25   USA.
26 
27 */
28 
29 #include "libdwarfdefs.h"
30 
31 #define true                    1
32 #define false                   0
33 
34 /*  The DISTINGUISHED VALUE is 4 byte value defined by DWARF
35     since DWARF3. */
36 #define DISTINGUISHED_VALUE_ARRAY(x)  unsigned char x[4] = { 0xff,0xff,0xff,0xff }
37 #define DISTINGUISHED_VALUE 0xffffffff /* 64bit extension flag */
38 
39 /* to identify a cie */
40 #define DW_CIE_ID          ~(0x0)
41 #define DW_CIE_VERSION     1
42 
43 typedef signed char Dwarf_Sbyte;
44 typedef unsigned char Dwarf_Ubyte;
45 typedef signed short Dwarf_Shalf;
46 
47 /*
48     On any change that makes libdwarf producer
49     incompatible, increment this number.
50     1->2->3 ...  */
51 #define  PRO_VERSION_MAGIC 0xdead1
52 
53 
54 #define DWARF_HALF_SIZE 2
55 #define DWARF_32BIT_SIZE 4
56 #define DWARF_64BIT_SIZE 8
57 
58 /*
59     producer:
60     This struct is used to hold information about all
61     debug* sections. On creating a new section, section
62     names and indices are added to this struct
63     definition in pro_section.h */
64 typedef struct Dwarf_P_Section_Data_s *Dwarf_P_Section_Data;
65 
66 /*
67     producer:
68     This struct holds file entries or
69     include file entries for the statement prologue.
70     Defined in pro_line.h
71 */
72 typedef struct Dwarf_P_F_Entry_s *Dwarf_P_F_Entry;
73 
74 /*
75     producer:
76     This struct holds information for each cie. Defn in pro_frame.h
77 */
78 typedef struct Dwarf_P_Cie_s *Dwarf_P_Cie;
79 
80 /*
81     producer:
82     Struct to hold line number information, different from
83     Dwarf_Line opaque type.
84 */
85 typedef struct Dwarf_P_Line_s *Dwarf_P_Line;
86 
87 /*
88     producer:
89     Struct to hold information about address ranges.
90 */
91 typedef struct Dwarf_P_Simple_nameentry_s *Dwarf_P_Simple_nameentry;
92 typedef struct Dwarf_P_Simple_name_header_s *Dwarf_P_Simple_name_header;
93 typedef struct Dwarf_P_Arange_s *Dwarf_P_Arange;
94 typedef struct Dwarf_P_Per_Reloc_Sect_s *Dwarf_P_Per_Reloc_Sect;
95 typedef struct Dwarf_P_Per_Sect_String_Attrs_s *Dwarf_P_Per_Sect_String_Attrs;
96 typedef struct Dwarf_P_Dnames_s *Dwarf_P_Dnames;
97 
98 /* Defined to get at the elf section numbers and section name
99    indices in symtab for the dwarf sections
100    Must match .rel.* names in _dwarf_rel_section_names
101    exactly.
102 */
103 #define         DEBUG_INFO      0
104 #define         DEBUG_LINE      1
105 #define         DEBUG_ABBREV    2
106 #define         DEBUG_FRAME     3
107 #define         DEBUG_ARANGES   4
108 #define         DEBUG_PUBNAMES  5
109 #define         DEBUG_FUNCNAMES 6
110 #define         DEBUG_TYPENAMES 7
111 #define         DEBUG_VARNAMES  8
112 #define         DEBUG_WEAKNAMES 9
113 #define         DEBUG_MACINFO   10 /* DWARF 2,3,4 only */
114 #define         DEBUG_LOC       11
115 #define         DEBUG_RANGES    12
116 #define         DEBUG_TYPES     13
117 #define         DEBUG_PUBTYPES  14
118 #define         DEBUG_NAMES     15 /* DWARF5. aka dnames */
119 #define         DEBUG_STR       16
120 #define         DEBUG_LINE_STR  17
121 #define         DEBUG_MACRO     18 /* DWARF 5. */
122 #define         DEBUG_LOCLISTS  19 /* DWARF 5. */
123 #define         DEBUG_RNGLISTS  20 /* DWARF 5. */
124 
125 /* Maximum number of debug_* sections not including the relocations */
126 #define         NUM_DEBUG_SECTIONS      21
127 
128 /*  The FORM codes available are defined in DWARF5
129     on page 158, DW_LNCT_path  */
130 struct Dwarf_P_Line_format_s {
131     /* DW_LNCT_path etc. */
132     unsigned def_content_type;
133 
134     /* DW_FORM_string or DW_FORM_strp or DW_FORM_strp
135         or DW_FORM_strp_sup or for dwo, some others. */
136     unsigned def_form_code;
137 };
138 
139 #define DW_LINE_FORMATS_MAX 6
140 /*  Describes the data needed to generate line table header info
141     so we can vary the init at runtime. */
142 struct Dwarf_P_Line_Inits_s {
143     unsigned pi_linetable_version; /* line table version number */
144     unsigned pi_default_is_stmt; /* default value for is_stmt */
145 
146     /* Size of the smallest instruction, in bytes. */
147     unsigned pi_minimum_instruction_length;
148 
149     /*  Normally opcode_base is determined by pi_version, but we
150         allow manual setting here so we can generate data like
151         GNU with a DWARF3 opcode base in a DWARF2 section.
152         This determines how much of the header_opcode_lengths
153         table is emitted in the line table header */
154     unsigned pi_opcode_base;
155 
156     int      pi_line_base;   /* For line table header. */
157     int      pi_line_range;  /* For line table header. */
158 
159     /* Make this >1 for VLIW machines.  DWARF4,DWARF5 */
160     unsigned pi_maximum_operations_per_instruction;
161 
162     /* DWARF 5  */
163     unsigned pi_segment_selector_size;
164     unsigned pi_address_size;
165     unsigned pi_segment_size;
166     unsigned pi_directory_entry_format_count;
167     struct Dwarf_P_Line_format_s pi_incformats[DW_LINE_FORMATS_MAX];
168 
169     unsigned pi_file_entry_format_count;
170     struct Dwarf_P_Line_format_s pi_fileformats[DW_LINE_FORMATS_MAX];
171 };
172 
173 
174 struct Dwarf_P_Die_s {
175     Dwarf_Unsigned di_offset; /* offset in debug info */
176     char *di_abbrev;  /* abbreviation */
177     Dwarf_Unsigned di_abbrev_nbytes; /* # of bytes in abbrev */
178     Dwarf_Tag di_tag;
179     Dwarf_P_Die di_parent; /* parent of current die */
180     Dwarf_P_Die di_child; /* first child */
181     /*  The last child field makes linking up children an O(1) operation,
182         See pro_die.c. */
183     Dwarf_P_Die di_last_child;
184     Dwarf_P_Die di_left; /* left sibling */
185     Dwarf_P_Die di_right; /* right sibling */
186     Dwarf_P_Attribute di_attrs; /* list of attributes */
187     Dwarf_P_Attribute di_last_attr; /* last attribute */
188     int di_n_attr;  /* number of attributes */
189     Dwarf_P_Debug di_dbg; /* For memory management */
190     Dwarf_Unsigned di_marker;   /* used to attach symbols to dies */
191 };
192 
193 
194 /* producer fields */
195 struct Dwarf_P_Attribute_s {
196     Dwarf_Half ar_attribute; /* Attribute Value. */
197     Dwarf_Half ar_attribute_form; /* Attribute Form. */
198     Dwarf_P_Die ar_ref_die; /* die pointer if form ref */
199     char *ar_data; /* data, format given by form */
200     Dwarf_Unsigned ar_nbytes; /* no. of bytes of data */
201     Dwarf_Unsigned ar_rel_symidx; /* when attribute has a
202         relocatable value, holds
203         index of symbol in SYMTAB */
204     Dwarf_Unsigned ar_debug_str_offset; /* Offset in .debug_str
205         if non-zero. Zero offset never assigned a string. */
206     Dwarf_Ubyte ar_rel_type;  /* relocation type */
207     Dwarf_Unsigned ar_rel_offset; /* Offset of relocation within block */
208     char ar_reloc_len; /* Number of bytes that relocation
209         applies to. 4 or 8. Unused and may
210         be 0 if if ar_rel_type is
211         R_MIPS_NONE */
212     Dwarf_P_Attribute ar_next;
213     /*  set if form = DW_FORM_implicit_const; */
214     Dwarf_Signed  ar_implicit_const;
215 };
216 
217 /* A block of .debug_macinfo data: this forms a series of blocks.
218 ** Each macinfo input is compressed immediately and put into
219 ** the current block if room, else a newblock allocated.
220 ** The space allocation is such that the block and the macinfo
221 ** data are one malloc block: free with a pointer to this and the
222 ** mb_data is freed automatically.
223 ** Like the struct hack, but legal ANSI C.
224 */
225 struct dw_macinfo_block_s {
226     struct dw_macinfo_block_s *mb_next;
227     unsigned long mb_avail_len;
228     unsigned long mb_used_len;
229     unsigned long mb_macinfo_data_space_len;
230     char *mb_data;/* original malloc ptr. */
231 };
232 
233 /*  dwarf_sn_kind is for the array of similarly-treated
234     name -> cu ties
235 */
236 enum dwarf_sn_kind { dwarf_snk_pubname,  /* .debug_pubnames */
237     dwarf_snk_funcname,  /* SGI extension. */
238     dwarf_snk_weakname,  /* SGI extension. */
239     dwarf_snk_typename,  /* SGI extension. */
240     dwarf_snk_varname,   /* SGI extension. */
241     dwarf_snk_pubtype,   /* .debug_pubtypes */
242     dwarf_snk_entrycount /* this one must be last */
243 };
244 
245 
246 
247 /* The calls to add a varname etc use a list of
248    these as the list.
249 */
250 struct Dwarf_P_Simple_nameentry_s {
251     Dwarf_P_Die sne_die;
252     char *sne_name;
253     int sne_name_len;
254     Dwarf_P_Simple_nameentry sne_next;
255 };
256 
257 /*  An array of these, each of which heads a list
258     of Dwarf_P_Simple_nameentry
259 */
260 struct Dwarf_P_Simple_name_header_s {
261     Dwarf_P_Simple_nameentry sn_head;
262     Dwarf_P_Simple_nameentry sn_tail;
263     Dwarf_Signed sn_count;
264 
265     /*  Length that will be generated, not counting fixed header or
266         trailer */
267     Dwarf_Signed sn_net_len;
268 };
269 typedef int (*_dwarf_pro_reloc_name_func_ptr) (Dwarf_P_Debug dbg,
270     int sec_index,
271     Dwarf_Unsigned offset,/* r_offset */
272     Dwarf_Unsigned symidx,
273     enum Dwarf_Rel_Type type,
274     int reltarget_length);
275 
276 typedef int (*_dwarf_pro_reloc_length_func_ptr) (Dwarf_P_Debug dbg,
277     int sec_index, Dwarf_Unsigned offset,/* r_offset */
278     Dwarf_Unsigned start_symidx,
279     Dwarf_Unsigned end_symidx,
280     enum Dwarf_Rel_Type type,
281     int reltarget_length);
282 typedef int (*_dwarf_pro_transform_relocs_func_ptr) (Dwarf_P_Debug dbg,
283     Dwarf_Signed *
284     new_sec_count);
285 
286 /*
287     Each slot in a block of slots could be:
288     a binary stream relocation entry (32 or 64bit relocation data)
289     a SYMBOLIC relocation entry.
290     During creation sometimes we create multiple chained blocks,
291     but sometimes we create a single long block.
292     Before returning reloc data to caller,
293     we switch to a single, long-enough,
294     block.
295 
296     We make counters here Dwarf_Unsigned so that we
297     get sufficient alignment. Since we use space after
298     the struct (at malloc time) for user data which
299     must have Dwarf_Unsigned alignment, this
300     struct must have that alignment too.
301 */
302 struct Dwarf_P_Relocation_Block_s {
303     Dwarf_Unsigned rb_slots_in_block; /* slots in block, as created */
304     Dwarf_Unsigned rb_next_slot_to_use; /* counter, start at 0. */
305     struct Dwarf_P_Relocation_Block_s *rb_next;
306     char *rb_where_to_add_next; /* pointer to next slot (might be past
307         end, depending on
308         rb_next_slot_to_use) */
309     char *rb_data; /* data area */
310 };
311 
312 /* One of these per potential relocation section
313    So one per actual dwarf section.
314    Left zeroed when not used (some sections have
315    no relocations).
316 */
317 struct Dwarf_P_Per_Reloc_Sect_s {
318     unsigned long pr_reloc_total_count; /* total number of entries
319         across all blocks */
320 
321     unsigned long pr_slots_per_block_to_alloc; /* at Block alloc, this
322         is the default number of slots to use */
323 
324     int pr_sect_num_of_reloc_sect; /* sect number returned by
325         de_callback_func() or de_callback_func_b() or_c()
326         call, this is the sect
327         number of the relocation section. */
328 
329     /* singly-linked list. add at and ('last') with count of blocks */
330     struct Dwarf_P_Relocation_Block_s *pr_first_block;
331     struct Dwarf_P_Relocation_Block_s *pr_last_block;
332     unsigned long pr_block_count;
333 };
334 
335 #define DEFAULT_SLOTS_PER_BLOCK 3
336 
337 typedef struct memory_list_s {
338   struct memory_list_s *prev;
339   struct memory_list_s *next;
340 } memory_list_t;
341 
342 struct Dwarf_P_Per_Sect_String_Attrs_s {
343     int sect_sa_section_number;
344     unsigned sect_sa_n_alloc;
345     unsigned sect_sa_n_used;
346     Dwarf_P_String_Attr sect_sa_list;
347 };
348 
349 struct Dwarf_P_debug_str_entry_s {
350     Dwarf_P_Debug  dse_dbg;
351     /*  Name used initially with tfind. */
352     char *dse_name;
353 
354     Dwarf_Unsigned dse_slen; /* includes space for NUL terminator */
355 
356     /*  See dse_has_table_offset below. */
357     Dwarf_Unsigned dse_table_offset;
358 
359     /*  For tsearch a hash table exists and we have a table offset.
360         dse_dbg->de_debug_str->ds_data + dse_table_offset
361         points to the string iff dse_has_table_offset != 0. */
362     unsigned char  dse_has_table_offset;
363 };
364 
365 struct Dwarf_P_Str_stats_s {
366     Dwarf_Unsigned ps_strp_count_debug_str;
367     Dwarf_Unsigned ps_strp_len_debug_str;
368     Dwarf_Unsigned ps_strp_len_debug_line_str;
369     Dwarf_Unsigned ps_strp_reused_count;
370     Dwarf_Unsigned ps_strp_reused_len;
371 };
372 
373 struct Dwarf_P_Stats_s {
374     Dwarf_Unsigned ps_str_count;
375     Dwarf_Unsigned ps_str_total_length;
376     struct Dwarf_P_Str_stats_s ps_strp;
377     struct Dwarf_P_Str_stats_s ps_line_strp;
378 };
379 
380 /* Fields used by producer */
381 struct Dwarf_P_Debug_s {
382     /*  Used to catch dso passing dbg to another DSO with incompatible
383         version of libdwarf See PRO_VERSION_MAGIC */
384     int de_version_magic_number;
385 
386     Dwarf_Handler de_errhand;
387     /*  de_user_data is provided so users can use it to readily tie
388         a callback to anything they desire.  The contents are not
389         used by libdwarf except to pass the data as a callback
390         argument.  New in June 2011. Available in
391         dwarf_pro_init_c() and its callback function.  */
392     void *    de_user_data;
393     Dwarf_Ptr de_errarg;
394 
395     /*  Call back function, used to create .debug* sections. Provided
396         By user.  */
397     Dwarf_Callback_Func de_callback_func;
398 
399     /*  Flags from producer_init call */
400     Dwarf_Unsigned de_flags;
401 
402     /*  This holds information on debug info section
403         stream output, including the stream data */
404     Dwarf_P_Section_Data de_debug_sects;
405 
406     /*  Defaults set as DW_FORM_string,
407         meaning not using .debug_str by default.
408         This intended for the .debug_info section. */
409     int de_debug_default_str_form;
410 
411     /* If form DW_FORM_strp */
412     Dwarf_P_Section_Data de_debug_str;
413     void *de_debug_str_hashtab; /* for tsearch */
414 
415     /* .debug_line_str section data if form DW_FORM_line_strp */
416     Dwarf_P_Section_Data de_debug_line_str;
417     void *de_debug_line_str_hashtab; /* for tsearch */
418 
419     /*  Pointer to the 'current active' section */
420     Dwarf_P_Section_Data de_current_active_section;
421 
422     /*  Number of debug data streams globs. */
423     Dwarf_Unsigned de_n_debug_sect;
424 
425     /*  File entry information, null terminated singly-linked list */
426     Dwarf_P_F_Entry de_file_entries;
427     Dwarf_P_F_Entry de_last_file_entry;
428     Dwarf_Unsigned de_n_file_entries;
429 
430     /*  Has the directories used to search for source files */
431     Dwarf_P_F_Entry de_inc_dirs;
432     Dwarf_P_F_Entry de_last_inc_dir;
433     Dwarf_Unsigned de_n_inc_dirs;
434 
435     /*  Has all the line number info for the stmt program */
436     Dwarf_P_Line de_lines;
437     Dwarf_P_Line de_last_line;
438 
439     /*  List of cie's for the debug unit */
440     Dwarf_P_Cie de_frame_cies;
441     Dwarf_P_Cie de_last_cie;
442     Dwarf_Unsigned de_n_cie;
443 
444     /* Singly-linked list of fde's for the debug unit */
445     Dwarf_P_Fde de_frame_fdes;
446     Dwarf_P_Fde de_last_fde;
447     Dwarf_Unsigned de_n_fde;
448 
449     /* First die, leads to all others */
450     Dwarf_P_Die de_dies;
451 
452     /* Pointer to chain of aranges */
453     Dwarf_P_Arange de_arange;
454     Dwarf_P_Arange de_last_arange;
455     Dwarf_Signed de_arange_count;
456 
457     /*  debug_names  de_dnames is base of dnames info
458         before disk form */
459     Dwarf_P_Dnames de_dnames;
460     Dwarf_P_Section_Data de_dnames_sect;
461 
462     /* macinfo controls. */
463     /* first points to beginning of the list during creation */
464     struct dw_macinfo_block_s *de_first_macinfo;
465 
466     /* current points to the current, unfilled, block */
467     struct dw_macinfo_block_s *de_current_macinfo;
468 
469     /* Pointer to the first section, to support reset_section_bytes */
470     Dwarf_P_Section_Data de_first_debug_sect;
471 
472     /*  Handles pubnames, weaknames, etc. See dwarf_sn_kind in
473         pro_opaque.h */
474     struct Dwarf_P_Simple_name_header_s
475         de_simple_name_headers[dwarf_snk_entrycount];
476 
477     /*  Relocation data. not all sections will actally have relocation
478         info, of course.  de_reloc_sect, de_elf_sects, and de_sect_name_idx
479         arrays are exactly in parallel. Not every de_elf_sect has
480         any relocations for it, of course. */
481     struct Dwarf_P_Per_Reloc_Sect_s de_reloc_sect[NUM_DEBUG_SECTIONS];
482     int de_reloc_next_to_return; /* iterator on reloc sections
483         (SYMBOLIC output) */
484 
485     /*  Used in remembering sections. See de_reloc_sect above.  */
486     int de_elf_sects[NUM_DEBUG_SECTIONS];  /* elf sect number of
487         the section itself, DEBUG_LINE for example */
488 
489     /*  Section name index or handle for the name of the symbol for
490         DEBUG_LINE for example */
491     Dwarf_Unsigned de_sect_name_idx[NUM_DEBUG_SECTIONS];
492 
493     int de_offset_reloc; /* offset reloc type, R_MIPS_32 for
494         example. Specific to the ABI being
495         produced. Relocates offset size
496         field */
497     int de_exc_reloc; /* reloc type specific to exception
498         table relocs. */
499     int de_ptr_reloc;  /* standard reloc type, R_MIPS_32 for
500         example. Specific to the ABI being
501         produced. relocates pointer size
502         field */
503     unsigned char de_irix_exc_augmentation; /* If non-zero means
504         that producing an IRIX exception-table offset in a CIE header
505         is allowed (depending on the augmentation string). */
506 
507     unsigned char de_dwarf_offset_size; /* dwarf  offset size. */
508     unsigned char de_elf_offset_size;  /* object section offset size. */
509     unsigned char de_pointer_size; /* size of address in target. */
510 
511     /*  Added April 19, 2017.  For DWARF5 */
512     unsigned char de_segment_selector_size;
513 
514     unsigned char de_relocation_record_size; /* reloc record size
515         varies by ABI and
516         relocation-output
517         method (stream or
518         symbolic) */
519 
520     unsigned char de_64bit_extension;/* non-zero if creating 64 bit
521         offsets using dwarf2-99
522         extension proposal */
523 
524     unsigned char de_output_version; /* 2,3,4, or 5. The version number
525         of the output. (not necessarily that of each section,
526         which depends on the base version). */
527 
528     /*  Defaults will be mostly useless, but such do exist */
529     unsigned       de_big_endian; /* if 0 target is little-endian */
530 
531     int de_ar_data_attribute_form; /* data8, data4 abi &version dependent */
532     int de_ar_ref_attr_form; /* ref8 ref4 , abi dependent */
533 
534     /* simple name relocations */
535     _dwarf_pro_reloc_name_func_ptr de_relocate_by_name_symbol;
536 
537     /* relocations for a length, requiring a pair of symbols */
538     _dwarf_pro_reloc_length_func_ptr de_relocate_pair_by_symbol;
539 
540     _dwarf_pro_transform_relocs_func_ptr de_transform_relocs_to_disk;
541 
542     /* following used for macro buffers */
543     unsigned long de_compose_avail;
544     unsigned long de_compose_used_len;
545 
546     unsigned char de_same_endian;
547     void (*de_copy_word) (void *, const void *, unsigned long);
548 
549     /*  Add new fields at the END of this struct to preserve some hope
550         of sensible behavior on dbg passing between DSOs linked with
551         mismatched libdwarf producer versions. */
552 
553     Dwarf_P_Marker de_markers;  /* pointer to array of markers */
554     unsigned de_marker_n_alloc;
555     unsigned de_marker_n_used;
556     int de_sect_sa_next_to_return;  /* Iterator on sring attrib sects */
557     /* String attributes data of each section. */
558     struct Dwarf_P_Per_Sect_String_Attrs_s de_sect_string_attr[NUM_DEBUG_SECTIONS];
559 
560     /* Hold data needed to init line output flexibly. */
561     struct Dwarf_P_Line_Inits_s de_line_inits;
562 
563     struct Dwarf_P_Stats_s de_stats;
564 };
565 
566 #define CURRENT_VERSION_STAMP   2
567 
568 int _dwarf_add_simple_name_entry(Dwarf_P_Debug dbg,
569     Dwarf_P_Die die,
570     char *entry_name,
571     enum dwarf_sn_kind
572     entrykind,
573     Dwarf_Error * error);
574 
575 enum dwarf_which_hash {
576     _dwarf_hash_debug_str,
577     _dwarf_hash_debug_line_str,
578     _dwarf_hash_debug_str_sup
579 };
580 
581 int
582 _dwarf_insert_or_find_in_debug_str(Dwarf_P_Debug dbg,
583     char *name,
584     enum  dwarf_which_hash,
585     unsigned slen, /* includes space for trailing NUL */
586     Dwarf_Unsigned *offset_in_debug_str,
587     Dwarf_Error *error);
588 
589 int _dwarf_log_extra_flagstrings(Dwarf_P_Debug dbg,
590   const char *extra,
591   int *err);
592