xref: /netbsd-src/external/gpl3/gcc/dist/include/ctf.h (revision b1e838363e3c6fc78a55519254d99869742dd33c)
1 /* CTF format description.
2    Copyright (C) 2021-2022 Free Software Foundation, Inc.
3 
4    This file is part of libctf.
5 
6    libctf is free software; you can redistribute it and/or modify it under
7    the terms of the GNU General Public License as published by the Free
8    Software Foundation; either version 3, or (at your option) any later
9    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.
14    See the GNU 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; see the file COPYING.  If not see
18    <http://www.gnu.org/licenses/>.  */
19 
20 #ifndef	_CTF_H
21 #define	_CTF_H
22 
23 #include <sys/types.h>
24 #include <limits.h>
25 #include <stdint.h>
26 
27 
28 #ifdef	__cplusplus
29 extern "C"
30 {
31 #endif
32 
33 /* CTF - Compact ANSI-C Type Format
34 
35    This file format can be used to compactly represent the information needed
36    by a debugger to interpret the ANSI-C types used by a given program.
37    Traditionally, this kind of information is generated by the compiler when
38    invoked with the -g flag and is stored in "stabs" strings or in the more
39    modern DWARF format.  CTF provides a representation of only the information
40    that is relevant to debugging a complex, optimized C program such as the
41    operating system kernel in a form that is significantly more compact than
42    the equivalent stabs or DWARF representation.  The format is data-model
43    independent, so consumers do not need different code depending on whether
44    they are 32-bit or 64-bit programs; libctf automatically compensates for
45    endianness variations.  CTF assumes that a standard ELF symbol table is
46    available for use in the debugger, and uses the structure and data of the
47    symbol table to avoid storing redundant information.  The CTF data may be
48    compressed on disk or in memory, indicated by a bit in the header.  CTF may
49    be interpreted in a raw disk file, or it may be stored in an ELF section,
50    typically named .ctf.  Data structures are aligned so that a raw CTF file or
51    CTF ELF section may be manipulated using mmap(2).
52 
53    The CTF file or section itself has the following structure:
54 
55    +--------+--------+---------+----------+--------+----------+...
56    |  file  |  type  |  data   | function | object | function |...
57    | header | labels | objects |   info   | index  |  index   |...
58    +--------+--------+---------+----------+--------+----------+...
59 
60    ...+----------+-------+--------+
61    ...| variable | data  | string |
62    ...|   info   | types | table  |
63       +----------+-------+--------+
64 
65    The file header stores a magic number and version information, encoding
66    flags, and the byte offset of each of the sections relative to the end of the
67    header itself.  If the CTF data has been uniquified against another set of
68    CTF data, a reference to that data also appears in the the header.  This
69    reference is the name of the label corresponding to the types uniquified
70    against.
71 
72    Following the header is a list of labels, used to group the types included in
73    the data types section.  Each label is accompanied by a type ID i.  A given
74    label refers to the group of types whose IDs are in the range [0, i].
75 
76    Data object and function records (collectively, "symtypetabs") are stored in
77    the same order as they appear in the corresponding symbol table, except that
78    symbols marked SHN_UNDEF are not stored and symbols that have no type data
79    are padded out with zeroes.  For each entry in these tables, the type ID (a
80    small integer) is recorded.  (Functions get CTF_K_FUNCTION types, just like
81    data objects that are function pointers.)
82 
83    For situations in which the order of the symbols in the symtab is not known,
84    or most symbols have no type in this dict and most entries would be
85    zero-pads, a pair of optional indexes follow the data object and function
86    info sections: each of these is an array of strtab indexes, mapped 1:1 to the
87    corresponding data object / function info section, giving each entry in those
88    sections a name so that the linker can correlate them with final symtab
89    entries and reorder them accordingly (dropping the indexes in the process).
90 
91    Variable records (as distinct from data objects) provide a modicum of support
92    for non-ELF systems, mapping a variable name to a CTF type ID.  The variable
93    names are sorted into ASCIIbetical order, permitting binary searching.  We do
94    not define how the consumer maps these variable names to addresses or
95    anything else, or indeed what these names represent: they might be names
96    looked up at runtime via dlsym() or names extracted at runtime by a debugger
97    or anything else the consumer likes.  Variable records with identically-
98    named entries in the data object section are removed.
99 
100    The data types section is a list of variable size records that represent each
101    type, in order by their ID.  The types themselves form a directed graph,
102    where each node may contain one or more outgoing edges to other type nodes,
103    denoted by their ID.  Most type nodes are standalone or point backwards to
104    earlier nodes, but this is not required: nodes can point to later nodes,
105    particularly structure and union members.
106 
107    Strings are recorded as a string table ID (0 or 1) and a byte offset into the
108    string table.  String table 0 is the internal CTF string table.  String table
109    1 is the external string table, which is the string table associated with the
110    ELF dynamic symbol table for this object.  CTF does not record any strings
111    that are already in the symbol table, and the CTF string table does not
112    contain any duplicated strings.
113 
114    If the CTF data has been merged with another parent CTF object, some outgoing
115    edges may refer to type nodes that exist in another CTF object.  The debugger
116    and libctf library are responsible for connecting the appropriate objects
117    together so that the full set of types can be explored and manipulated.
118 
119    This connection is done purely using the ctf_import() function.  The
120    ctf_archive machinery (and thus ctf_open et al) automatically imports archive
121    members named ".ctf" into child dicts if available in the same archive, to
122    match the relationship set up by the linker, but callers can call ctf_import
123    themselves as well if need be, if they know a different relationship is in
124    force.  */
125 
126 #define CTF_MAX_TYPE	0xfffffffe	/* Max type identifier value.  */
127 #define CTF_MAX_PTYPE	0x7fffffff	/* Max parent type identifier value.  */
128 #define CTF_MAX_NAME 0x7fffffff		/* Max offset into a string table.  */
129 #define CTF_MAX_VLEN	0xffffff /* Max struct, union, enum members or args.  */
130 
131 /* See ctf_type_t */
132 #define CTF_MAX_SIZE	0xfffffffe	/* Max size of a v2 type in bytes. */
133 #define CTF_LSIZE_SENT	0xffffffff	/* Sentinel for v2 ctt_size.  */
134 
135   /* Start of actual data structure definitions.
136 
137      Every field in these structures must have corresponding code in the
138      endianness-swapping machinery in libctf/ctf-open.c.  */
139 
140 typedef struct ctf_preamble
141 {
142   unsigned short ctp_magic;	/* Magic number (CTF_MAGIC).  */
143   unsigned char ctp_version;	/* Data format version number (CTF_VERSION).  */
144   unsigned char ctp_flags;	/* Flags (see below).  */
145 } ctf_preamble_t;
146 
147 typedef struct ctf_header
148 {
149   ctf_preamble_t cth_preamble;
150   uint32_t cth_parlabel;	/* Ref to name of parent lbl uniq'd against.  */
151   uint32_t cth_parname;		/* Ref to basename of parent.  */
152   uint32_t cth_cuname;		/* Ref to CU name (may be 0).  */
153   uint32_t cth_lbloff;		/* Offset of label section.  */
154   uint32_t cth_objtoff;		/* Offset of object section.  */
155   uint32_t cth_funcoff;		/* Offset of function section.  */
156   uint32_t cth_objtidxoff;	/* Offset of object index section.  */
157   uint32_t cth_funcidxoff;	/* Offset of function index section.  */
158   uint32_t cth_varoff;		/* Offset of variable section.  */
159   uint32_t cth_typeoff;		/* Offset of type section.  */
160   uint32_t cth_stroff;		/* Offset of string section.  */
161   uint32_t cth_strlen;		/* Length of string section in bytes.  */
162 } ctf_header_t;
163 
164 #define cth_magic   cth_preamble.ctp_magic
165 #define cth_version cth_preamble.ctp_version
166 #define cth_flags   cth_preamble.ctp_flags
167 
168 #define CTF_MAGIC	0xdff2	/* Magic number identifying header.  */
169 
170 /* Data format version number.  */
171 
172 /* v1 upgraded to a later version is not quite the same as the native form,
173    because the boundary between parent and child types is different but not
174    recorded anywhere, and you can write it out again via ctf_compress_write(),
175    so we must track whether the thing was originally v1 or not.  If we were
176    writing the header from scratch, we would add a *pair* of version number
177    fields to allow for this, but this will do for now.  (A flag will not do,
178    because we need to encode both the version we came from and the version we
179    went to, not just "we were upgraded".) */
180 
181 # define CTF_VERSION_1 1
182 # define CTF_VERSION_1_UPGRADED_3 2
183 # define CTF_VERSION_2 3
184 
185 /* Note: some flags may be valid only in particular format versions.  */
186 
187 #define CTF_VERSION_3 4
188 #define CTF_VERSION CTF_VERSION_3 /* Current version.  */
189 
190 #define CTF_F_COMPRESS	0x1	/* Data buffer is compressed by libctf.  */
191 #define CTF_F_NEWFUNCINFO 0x2	/* New v3 func info section format.  */
192 
193 typedef struct ctf_lblent
194 {
195   uint32_t ctl_label;		/* Ref to name of label.  */
196   uint32_t ctl_type;		/* Last type associated with this label.  */
197 } ctf_lblent_t;
198 
199 typedef struct ctf_varent
200 {
201   uint32_t ctv_name;		/* Reference to name in string table.  */
202   uint32_t ctv_type;		/* Index of type of this variable.  */
203 } ctf_varent_t;
204 
205 /* In format v2, type sizes, measured in bytes, come in two flavours.  Nearly
206    all of them fit into a (UINT_MAX - 1), and thus can be stored in the ctt_size
207    member of a ctf_stype_t.  The maximum value for these sizes is CTF_MAX_SIZE.
208    Types larger than this must be stored in the ctf_lsize member of a
209    ctf_type_t.  Use of this member is indicated by the presence of
210    CTF_LSIZE_SENT in ctt_size.  */
211 
212 typedef struct ctf_stype
213 {
214   uint32_t ctt_name;		/* Reference to name in string table.  */
215   uint32_t ctt_info;		/* Encoded kind, variant length (see below).  */
216 #ifndef __GNUC__
217   union
218   {
219     uint32_t _size;		/* Size of entire type in bytes.  */
220     uint32_t _type;		/* Reference to another type.  */
221   } _u;
222 #else
223   __extension__
224   union
225   {
226     uint32_t ctt_size;		/* Size of entire type in bytes.  */
227     uint32_t ctt_type;		/* Reference to another type.  */
228   };
229 #endif
230 } ctf_stype_t;
231 
232 typedef struct ctf_type
233 {
234   uint32_t ctt_name;		/* Reference to name in string table.  */
235   uint32_t ctt_info;		/* Encoded kind, variant length (see below).  */
236 #ifndef __GNUC__
237 union
238   {
239     uint32_t _size;		/* Always CTF_LSIZE_SENT.  */
240     uint32_t _type;		/* Do not use.  */
241   } _u;
242 #else
243   __extension__
244   union
245   {
246     uint32_t ctt_size;		/* Always CTF_LSIZE_SENT.  */
247     uint32_t ctt_type;		/* Do not use.  */
248   };
249 #endif
250   uint32_t ctt_lsizehi;		/* High 32 bits of type size in bytes.  */
251   uint32_t ctt_lsizelo;		/* Low 32 bits of type size in bytes.  */
252 } ctf_type_t;
253 
254 #ifndef __GNUC__
255 #define ctt_size _u._size	/* For fundamental types that have a size.  */
256 #define ctt_type _u._type	/* For types that reference another type.  */
257 #endif
258 
259 /* The following macros and inline functions compose and decompose values for
260    ctt_info and ctt_name, as well as other structures that contain name
261    references.  Use outside libdtrace-ctf itself is explicitly for access to CTF
262    files directly: types returned from the library will always appear to be
263    CTF_V2.
264 
265    v1: (transparently upgraded to v2 at open time: may be compiled out of the
266    library)
267                ------------------------
268    ctt_info:   | kind | isroot | vlen |
269                ------------------------
270                15   11    10    9     0
271 
272    v2:
273                ------------------------
274    ctt_info:   | kind | isroot | vlen |
275                ------------------------
276                31    26    25  24     0
277 
278    CTF_V1 and V2 _INFO_VLEN have the same interface:
279 
280    kind = CTF_*_INFO_KIND(c.ctt_info);     <-- CTF_K_* value (see below)
281    vlen = CTF_*_INFO_VLEN(fp, c.ctt_info); <-- length of variable data list
282 
283    stid = CTF_NAME_STID(c.ctt_name);     <-- string table id number (0 or 1)
284    offset = CTF_NAME_OFFSET(c.ctt_name); <-- string table byte offset
285 
286    c.ctt_info = CTF_TYPE_INFO(kind, vlen);
287    c.ctt_name = CTF_TYPE_NAME(stid, offset);  */
288 
289 #define CTF_V1_INFO_KIND(info)		(((info) & 0xf800) >> 11)
290 #define CTF_V1_INFO_ISROOT(info)	(((info) & 0x0400) >> 10)
291 #define CTF_V1_INFO_VLEN(info)		(((info) & CTF_MAX_VLEN_V1))
292 
293 #define CTF_V2_INFO_KIND(info)		(((info) & 0xfc000000) >> 26)
294 #define CTF_V2_INFO_ISROOT(info)	(((info) & 0x2000000) >> 25)
295 #define CTF_V2_INFO_VLEN(info)		(((info) & CTF_MAX_VLEN))
296 
297 #define CTF_NAME_STID(name)		((name) >> 31)
298 #define CTF_NAME_OFFSET(name)		((name) & CTF_MAX_NAME)
299 #define CTF_SET_STID(name, stid)	((name) | ((unsigned int) stid) << 31)
300 
301 /* V2 only. */
302 #define CTF_TYPE_INFO(kind, isroot, vlen) \
303 	(((kind) << 26) | (((isroot) ? 1 : 0) << 25) | ((vlen) & CTF_MAX_VLEN))
304 
305 #define CTF_TYPE_NAME(stid, offset) \
306 	(((stid) << 31) | ((offset) & CTF_MAX_NAME))
307 
308 /* The next set of macros are for public consumption only.  Not used internally,
309    since the relevant type boundary is dependent upon the version of the file at
310    *opening* time, not the version after transparent upgrade.  Use
311    ctf_type_isparent() / ctf_type_ischild() for that.  */
312 
313 #define CTF_V2_TYPE_ISPARENT(fp, id)	((id) <= CTF_MAX_PTYPE)
314 #define CTF_V2_TYPE_ISCHILD(fp, id)	((id) > CTF_MAX_PTYPE)
315 #define CTF_V2_TYPE_TO_INDEX(id)	((id) & CTF_MAX_PTYPE)
316 #define CTF_V2_INDEX_TO_TYPE(id, child) ((child) ? ((id) | (CTF_MAX_PTYPE+1)) : (id))
317 
318 #define CTF_V1_TYPE_ISPARENT(fp, id)	((id) <= CTF_MAX_PTYPE_V1)
319 #define CTF_V1_TYPE_ISCHILD(fp, id)	((id) > CTF_MAX_PTYPE_V1)
320 #define CTF_V1_TYPE_TO_INDEX(id)	((id) & CTF_MAX_PTYPE_V1)
321 #define CTF_V1_INDEX_TO_TYPE(id, child) ((child) ? ((id) | (CTF_MAX_PTYPE_V1+1)) : (id))
322 
323 /* Valid for both V1 and V2. */
324 #define CTF_TYPE_LSIZE(cttp) \
325 	(((uint64_t)(cttp)->ctt_lsizehi) << 32 | (cttp)->ctt_lsizelo)
326 #define CTF_SIZE_TO_LSIZE_HI(size)	((uint32_t)((uint64_t)(size) >> 32))
327 #define CTF_SIZE_TO_LSIZE_LO(size)	((uint32_t)(size))
328 
329 #define CTF_STRTAB_0	0	/* String table id 0 (in-CTF).  */
330 #define CTF_STRTAB_1	1	/* String table id 1 (ELF strtab).  */
331 
332 /* Values for CTF_TYPE_KIND().  If the kind has an associated data list,
333    CTF_INFO_VLEN() will extract the number of elements in the list, and
334    the type of each element is shown in the comments below. */
335 
336 #define CTF_K_UNKNOWN	0	/* Unknown type (used for padding and
337 				   unrepresentable types).  */
338 #define CTF_K_INTEGER	1	/* Variant data is CTF_INT_DATA (see below).  */
339 #define CTF_K_FLOAT	2	/* Variant data is CTF_FP_DATA (see below).  */
340 #define CTF_K_POINTER	3	/* ctt_type is referenced type.  */
341 #define CTF_K_ARRAY	4	/* Variant data is single ctf_array_t.  */
342 #define CTF_K_FUNCTION	5	/* ctt_type is return type, variant data is
343 				   list of argument types (unsigned short's for v1,
344 				   uint32_t's for v2).  */
345 #define CTF_K_STRUCT	6	/* Variant data is list of ctf_member_t's.  */
346 #define CTF_K_UNION	7	/* Variant data is list of ctf_member_t's.  */
347 #define CTF_K_ENUM	8	/* Variant data is list of ctf_enum_t's.  */
348 #define CTF_K_FORWARD	9	/* No additional data; ctt_name is tag.  */
349 #define CTF_K_TYPEDEF	10	/* ctt_type is referenced type.  */
350 #define CTF_K_VOLATILE	11	/* ctt_type is base type.  */
351 #define CTF_K_CONST	12	/* ctt_type is base type.  */
352 #define CTF_K_RESTRICT	13	/* ctt_type is base type.  */
353 #define CTF_K_SLICE	14	/* Variant data is a ctf_slice_t.  */
354 
355 #define CTF_K_MAX	63	/* Maximum possible (V2) CTF_K_* value.  */
356 
357 /* Values for ctt_type when kind is CTF_K_INTEGER.  The flags, offset in bits,
358    and size in bits are encoded as a single word using the following macros.
359    (However, you can also encode the offset and bitness in a slice.)  */
360 
361 #define CTF_INT_ENCODING(data) (((data) & 0xff000000) >> 24)
362 #define CTF_INT_OFFSET(data)   (((data) & 0x00ff0000) >> 16)
363 #define CTF_INT_BITS(data)     (((data) & 0x0000ffff))
364 
365 #define CTF_INT_DATA(encoding, offset, bits) \
366        (((encoding) << 24) | ((offset) << 16) | (bits))
367 
368 #define CTF_INT_SIGNED	0x01	/* Integer is signed (otherwise unsigned).  */
369 #define CTF_INT_CHAR	0x02	/* Character display format.  */
370 #define CTF_INT_BOOL	0x04	/* Boolean display format.  */
371 #define CTF_INT_VARARGS	0x08	/* Varargs display format.  */
372 
373 /* Use CTF_CHAR to produce a char that agrees with the system's native
374    char signedness.  */
375 #if CHAR_MIN == 0
376 # define CTF_CHAR (CTF_INT_CHAR)
377 #else
378 # define CTF_CHAR (CTF_INT_CHAR | CTF_INT_SIGNED)
379 #endif
380 
381 /* Values for ctt_type when kind is CTF_K_FLOAT.  The encoding, offset in bits,
382    and size in bits are encoded as a single word using the following macros.
383    (However, you can also encode the offset and bitness in a slice.)  */
384 
385 #define CTF_FP_ENCODING(data)  (((data) & 0xff000000) >> 24)
386 #define CTF_FP_OFFSET(data)    (((data) & 0x00ff0000) >> 16)
387 #define CTF_FP_BITS(data)      (((data) & 0x0000ffff))
388 
389 #define CTF_FP_DATA(encoding, offset, bits) \
390        (((encoding) << 24) | ((offset) << 16) | (bits))
391 
392 /* Variant data when kind is CTF_K_FLOAT is an encoding in the top eight bits.  */
393 #define CTF_FP_ENCODING(data)	(((data) & 0xff000000) >> 24)
394 
395 #define CTF_FP_SINGLE	1	/* IEEE 32-bit float encoding.  */
396 #define CTF_FP_DOUBLE	2	/* IEEE 64-bit float encoding.  */
397 #define CTF_FP_CPLX	3	/* Complex encoding.  */
398 #define CTF_FP_DCPLX	4	/* Double complex encoding.  */
399 #define CTF_FP_LDCPLX	5	/* Long double complex encoding.  */
400 #define CTF_FP_LDOUBLE	6	/* Long double encoding.  */
401 #define CTF_FP_INTRVL	7	/* Interval (2x32-bit) encoding.  */
402 #define CTF_FP_DINTRVL	8	/* Double interval (2x64-bit) encoding.  */
403 #define CTF_FP_LDINTRVL	9	/* Long double interval (2x128-bit) encoding.  */
404 #define CTF_FP_IMAGRY	10	/* Imaginary (32-bit) encoding.  */
405 #define CTF_FP_DIMAGRY	11	/* Long imaginary (64-bit) encoding.  */
406 #define CTF_FP_LDIMAGRY	12	/* Long double imaginary (128-bit) encoding.  */
407 
408 #define CTF_FP_MAX	12	/* Maximum possible CTF_FP_* value */
409 
410 /* A slice increases the offset and reduces the bitness of the referenced
411    ctt_type, which must be a type which has an encoding (fp, int, or enum).  We
412    also store the referenced type in here, because it is easier to keep the
413    ctt_size correct for the slice than to shuffle the size into here and keep
414    the ctt_type where it is for other types.
415 
416    In a future version, where we loosen requirements on alignment in the CTF
417    file, the cts_offset and cts_bits will be chars: but for now they must be
418    shorts or everything after a slice will become unaligned.  */
419 
420 typedef struct ctf_slice
421 {
422   uint32_t cts_type;
423   unsigned short cts_offset;
424   unsigned short cts_bits;
425 } ctf_slice_t;
426 
427 typedef struct ctf_array
428 {
429   uint32_t cta_contents;	/* Reference to type of array contents.  */
430   uint32_t cta_index;		/* Reference to type of array index.  */
431   uint32_t cta_nelems;		/* Number of elements.  */
432 } ctf_array_t;
433 
434 /* Most structure members have bit offsets that can be expressed using a short.
435    Some don't.  ctf_member_t is used for structs which cannot contain any of
436    these large offsets, whereas ctf_lmember_t is used in the latter case.  If
437    any member of a given struct has an offset that cannot be expressed using a
438    uint32_t, all members will be stored as type ctf_lmember_t.  This is expected
439    to be very rare (but nonetheless possible).  */
440 
441 #define CTF_LSTRUCT_THRESH	536870912
442 
443 typedef struct ctf_member_v2
444 {
445   uint32_t ctm_name;		/* Reference to name in string table.  */
446   uint32_t ctm_offset;		/* Offset of this member in bits.  */
447   uint32_t ctm_type;		/* Reference to type of member.  */
448 } ctf_member_t;
449 
450 typedef struct ctf_lmember_v2
451 {
452   uint32_t ctlm_name;		/* Reference to name in string table.  */
453   uint32_t ctlm_offsethi;	/* High 32 bits of member offset in bits.  */
454   uint32_t ctlm_type;		/* Reference to type of member.  */
455   uint32_t ctlm_offsetlo;	/* Low 32 bits of member offset in bits.  */
456 } ctf_lmember_t;
457 
458 #define	CTF_LMEM_OFFSET(ctlmp) \
459 	(((uint64_t)(ctlmp)->ctlm_offsethi) << 32 | (ctlmp)->ctlm_offsetlo)
460 #define	CTF_OFFSET_TO_LMEMHI(offset)	((uint32_t)((uint64_t)(offset) >> 32))
461 #define	CTF_OFFSET_TO_LMEMLO(offset)	((uint32_t)(offset))
462 
463 typedef struct ctf_enum
464 {
465   uint32_t cte_name;		/* Reference to name in string table.  */
466   int32_t cte_value;		/* Value associated with this name.  */
467 } ctf_enum_t;
468 
469 /* The ctf_archive is a collection of ctf_dict_t's stored together. The format
470    is suitable for mmap()ing: this control structure merely describes the
471    mmap()ed archive (and overlaps the first few bytes of it), hence the
472    greater care taken with integral types.  All CTF files in an archive
473    must have the same data model.  (This is not validated.)
474 
475    All integers in this structure are stored in little-endian byte order.
476 
477    The code relies on the fact that everything in this header is a uint64_t
478    and thus the header needs no padding (in particular, that no padding is
479    needed between ctfa_ctfs and the unnamed ctfa_archive_modent array
480    that follows it).
481 
482    This is *not* the same as the data structure returned by the ctf_arc_*()
483    functions:  this is the low-level on-disk representation.  */
484 
485 #define CTFA_MAGIC 0x8b47f2a4d7623eeb	/* Random.  */
486 struct ctf_archive
487 {
488   /* Magic number.  (In loaded files, overwritten with the file size
489      so ctf_arc_close() knows how much to munmap()).  */
490   uint64_t ctfa_magic;
491 
492   /* CTF data model.  */
493   uint64_t ctfa_model;
494 
495   /* Number of CTF dicts in the archive.  */
496   uint64_t ctfa_ndicts;
497 
498   /* Offset of the name table.  */
499   uint64_t ctfa_names;
500 
501   /* Offset of the CTF table.  Each element starts with a size (a uint64_t
502      in network byte order) then a ctf_dict_t of that size.  */
503   uint64_t ctfa_ctfs;
504 };
505 
506 /* An array of ctfa_nnamed of this structure lies at
507    ctf_archive[ctf_archive->ctfa_modents] and gives the ctfa_ctfs or
508    ctfa_names-relative offsets of each name or ctf_dict_t.  */
509 
510 typedef struct ctf_archive_modent
511 {
512   uint64_t name_offset;
513   uint64_t ctf_offset;
514 } ctf_archive_modent_t;
515 
516 #ifdef	__cplusplus
517 }
518 #endif
519 
520 #endif				/* _CTF_H */
521