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ctf-api.h revision 1.1.1.4
      1 /* Public API to libctf.
      2    Copyright (C) 2019-2025 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 /* This header file defines the interfaces available from the CTF debugger
     21    library, libctf.  This API can be used by a debugger to operate on data in
     22    the Compact ANSI-C Type Format (CTF).  */
     23 
     24 #ifndef	_CTF_API_H
     25 #define	_CTF_API_H
     26 
     27 #include <sys/types.h>
     28 #include <inttypes.h>
     29 #include <ctf.h>
     30 #include <zlib.h>
     31 
     32 #ifdef	__cplusplus
     33 extern "C"
     34 {
     35 #endif
     36 
     37 /* Clients can open one or more CTF containers and obtain a pointer to an
     38    opaque ctf_dict_t.  Types are identified by an opaque ctf_id_t token.
     39    They can also open or create read-only archives of CTF containers in a
     40    ctf_archive_t.
     41 
     42    These opaque definitions allow libctf to evolve without breaking clients.  */
     43 
     44 typedef struct ctf_dict ctf_dict_t;
     45 typedef struct ctf_archive_internal ctf_archive_t;
     46 typedef unsigned long ctf_id_t;
     47 
     48 /* This opaque definition allows libctf to accept BFD data structures without
     49    importing all the BFD noise into users' namespaces.  */
     50 
     51 struct bfd;
     52 
     53 /* If the debugger needs to provide the CTF library with a set of raw buffers
     54    for use as the CTF data, symbol table, and string table, it can do so by
     55    filling in ctf_sect_t structures and passing them to ctf_bufopen.
     56 
     57    The contents of this structure must always be in native endianness.  At read
     58    time, the symbol table endianness is derived from the BFD target (if BFD is
     59    in use): if a BFD target is not in use, please call ctf_symsect_endianness or
     60    ctf_arc_symsect_endianness.  */
     61 
     62 typedef struct ctf_sect
     63 {
     64   const char *cts_name;		  /* Section name (if any).  */
     65   const void *cts_data;		  /* Pointer to section data.  */
     66   size_t cts_size;		  /* Size of data in bytes.  */
     67   size_t cts_entsize;		  /* Size of each section entry (symtab only).  */
     68 } ctf_sect_t;
     69 
     70 /* A minimal symbol extracted from a linker's internal symbol table
     71    representation.  The symbol name can be given either via st_name or via a
     72    strtab offset in st_nameidx, which corresponds to one of the string offsets
     73    communicated via the ctf_link_add_strtab callback.   */
     74 
     75 typedef struct ctf_link_sym
     76 {
     77   /* The st_name and st_nameidx will not be accessed outside the call to
     78      ctf_link_shuffle_syms.  If you set st_nameidx to offset zero, make sure
     79      to set st_nameidx_set as well.  */
     80 
     81   const char *st_name;
     82   size_t st_nameidx;
     83   int st_nameidx_set;
     84   uint32_t st_symidx;
     85   uint32_t st_shndx;
     86   uint32_t st_type;
     87   uint32_t st_value;
     88 } ctf_link_sym_t;
     89 
     90 /* Flags applying to this specific link.  */
     91 
     92 /* Share all types that are not in conflict.  The default.  */
     93 #define CTF_LINK_SHARE_UNCONFLICTED 0x0
     94 
     95 /* Share only types that are used by multiple inputs.  */
     96 #define CTF_LINK_SHARE_DUPLICATED 0x1
     97 
     98 /* Do a nondeduplicating link, or otherwise deduplicate "less hard", trading off
     99    CTF output size for link time.  */
    100 #define CTF_LINK_NONDEDUP 0x2
    101 
    102 /* Create empty outputs for all registered CU mappings even if no types are
    103    emitted into them.  */
    104 #define CTF_LINK_EMPTY_CU_MAPPINGS 0x4
    105 
    106 /* Omit the content of the variables section.  */
    107 #define CTF_LINK_OMIT_VARIABLES_SECTION 0x8
    108 
    109 /* If *unset*, filter out entries corresponding to linker-reported symbols
    110    from the variable section, and filter out all entries with no linker-reported
    111    symbols from the data object and function info sections: if set, do no
    112    filtering and leave all entries in place.  (This is a negative-sense flag
    113    because it is rare to want symbols the linker has not reported as present to
    114    stick around in the symtypetab sections nonetheless: relocatable links are
    115    the only likely case.)  */
    116 #define CTF_LINK_NO_FILTER_REPORTED_SYMS 0x10
    117 
    118 /* Symbolic names for CTF sections.  */
    119 
    120 typedef enum ctf_sect_names
    121   {
    122    CTF_SECT_HEADER,
    123    CTF_SECT_LABEL,
    124    CTF_SECT_OBJT,
    125    CTF_SECT_OBJTIDX = CTF_SECT_OBJT,
    126    CTF_SECT_FUNC,
    127    CTF_SECT_FUNCIDX = CTF_SECT_FUNC,
    128    CTF_SECT_VAR,
    129    CTF_SECT_TYPE,
    130    CTF_SECT_STR
    131   } ctf_sect_names_t;
    132 
    133 /* Encoding information for integers, floating-point values, and certain other
    134    intrinsics can be obtained by calling ctf_type_encoding, below.  The flags
    135    field will contain values appropriate for the type defined in <ctf.h>.  */
    136 
    137 typedef struct ctf_encoding
    138 {
    139   uint32_t cte_format;		 /* Data format (CTF_INT_* or CTF_FP_* flags).  */
    140   uint32_t cte_offset;		 /* Offset of value in bits.  */
    141   uint32_t cte_bits;		 /* Size of storage in bits.  */
    142 } ctf_encoding_t;
    143 
    144 typedef struct ctf_membinfo
    145 {
    146   ctf_id_t ctm_type;		/* Type of struct or union member.  */
    147   unsigned long ctm_offset;	/* Offset of member in bits.  */
    148 } ctf_membinfo_t;
    149 
    150 typedef struct ctf_arinfo
    151 {
    152   ctf_id_t ctr_contents;	/* Type of array contents.  */
    153   ctf_id_t ctr_index;		/* Type of array index.  */
    154   uint32_t ctr_nelems;		/* Number of elements.  */
    155 } ctf_arinfo_t;
    156 
    157 typedef struct ctf_funcinfo
    158 {
    159   ctf_id_t ctc_return;		/* Function return type.  */
    160   uint32_t ctc_argc;		/* Number of typed arguments to function.  */
    161   uint32_t ctc_flags;		/* Function attributes (see below).  */
    162 } ctf_funcinfo_t;
    163 
    164 typedef struct ctf_lblinfo
    165 {
    166   ctf_id_t ctb_type;		/* Last type associated with the label.  */
    167 } ctf_lblinfo_t;
    168 
    169 typedef struct ctf_snapshot_id
    170 {
    171   unsigned long dtd_id;		/* Highest DTD ID at time of snapshot.  */
    172   unsigned long snapshot_id;	/* Snapshot id at time of snapshot.  */
    173 } ctf_snapshot_id_t;
    174 
    175 #define	CTF_FUNC_VARARG	0x1	/* Function arguments end with varargs.  */
    176 
    177 /* Functions that return a ctf_id_t use the following value to indicate failure.
    178    ctf_errno can be used to obtain an error code.  Functions that return
    179    a straight integral -1 also use ctf_errno.  */
    180 #define	CTF_ERR	((ctf_id_t) -1L)
    181 
    182 /* This macro holds information about all the available ctf errors.
    183    It is used to form both an enum holding all the error constants,
    184    and also the error strings themselves.  To use, define _CTF_FIRST
    185    and _CTF_ITEM to expand as you like, then mention the macro name.
    186    See the enum after this for an example.  */
    187 #define _CTF_ERRORS \
    188   _CTF_FIRST (ECTF_FMT, "File is not in CTF or ELF format.")	\
    189   _CTF_ITEM (ECTF_BFDERR, "BFD error.")				\
    190   _CTF_ITEM (ECTF_CTFVERS, "CTF dict version is too new for libctf.") \
    191   _CTF_ITEM (ECTF_BFD_AMBIGUOUS, "Ambiguous BFD target.")	\
    192   _CTF_ITEM (ECTF_SYMTAB, "Symbol table uses invalid entry size.") \
    193   _CTF_ITEM (ECTF_SYMBAD, "Symbol table data buffer is not valid.") \
    194   _CTF_ITEM (ECTF_STRBAD, "String table data buffer is not valid.") \
    195   _CTF_ITEM (ECTF_CORRUPT, "File data structure corruption detected.") \
    196   _CTF_ITEM (ECTF_NOCTFDATA, "File does not contain CTF data.") \
    197   _CTF_ITEM (ECTF_NOCTFBUF, "Buffer does not contain CTF data.") \
    198   _CTF_ITEM (ECTF_NOSYMTAB, "Symbol table information is not available.") \
    199   _CTF_ITEM (ECTF_NOPARENT, "The parent CTF dictionary is needed but unavailable.") \
    200   _CTF_ITEM (ECTF_DMODEL, "Data model mismatch.") \
    201   _CTF_ITEM (ECTF_LINKADDEDLATE, "File added to link too late.") \
    202   _CTF_ITEM (ECTF_ZALLOC, "Failed to allocate (de)compression buffer.") \
    203   _CTF_ITEM (ECTF_DECOMPRESS, "Failed to decompress CTF data.") \
    204   _CTF_ITEM (ECTF_STRTAB, "External string table is not available.") \
    205   _CTF_ITEM (ECTF_BADNAME, "String name offset is corrupt.") \
    206   _CTF_ITEM (ECTF_BADID, "Invalid type identifier.") \
    207   _CTF_ITEM (ECTF_NOTSOU, "Type is not a struct or union.") \
    208   _CTF_ITEM (ECTF_NOTENUM, "Type is not an enum.") \
    209   _CTF_ITEM (ECTF_NOTSUE, "Type is not a struct, union, or enum.") \
    210   _CTF_ITEM (ECTF_NOTINTFP, "Type is not an integer, float, or enum.") \
    211   _CTF_ITEM (ECTF_NOTARRAY, "Type is not an array.") \
    212   _CTF_ITEM (ECTF_NOTREF, "Type does not reference another type.") \
    213   _CTF_ITEM (ECTF_NAMELEN, "Buffer is too small to hold type name.") \
    214   _CTF_ITEM (ECTF_NOTYPE, "No type found corresponding to name.") \
    215   _CTF_ITEM (ECTF_SYNTAX, "Syntax error in type name.") \
    216   _CTF_ITEM (ECTF_NOTFUNC, "Symbol table entry or type is not a function.") \
    217   _CTF_ITEM (ECTF_NOFUNCDAT, "No function information available for function.") \
    218   _CTF_ITEM (ECTF_NOTDATA, "Symbol table entry does not refer to a data object.") \
    219   _CTF_ITEM (ECTF_NOTYPEDAT, "No type information available for symbol.") \
    220   _CTF_ITEM (ECTF_NOLABEL, "No label found corresponding to name.") \
    221   _CTF_ITEM (ECTF_NOLABELDATA, "File does not contain any labels.") \
    222   _CTF_ITEM (ECTF_NOTSUP, "Feature not supported.") \
    223   _CTF_ITEM (ECTF_NOENUMNAM, "Enumerator name not found.") \
    224   _CTF_ITEM (ECTF_NOMEMBNAM, "Member name not found.") \
    225   _CTF_ITEM (ECTF_RDONLY, "CTF container is read-only.") \
    226   _CTF_ITEM (ECTF_DTFULL, "CTF type is full (no more members allowed).") \
    227   _CTF_ITEM (ECTF_FULL, "CTF container is full.") \
    228   _CTF_ITEM (ECTF_DUPLICATE, "Duplicate member, enumerator, or variable name.") \
    229   _CTF_ITEM (ECTF_CONFLICT, "Conflicting type is already defined.") \
    230   _CTF_ITEM (ECTF_OVERROLLBACK, "Attempt to roll back past a ctf_update.") \
    231   _CTF_ITEM (ECTF_COMPRESS, "Failed to compress CTF data.") \
    232   _CTF_ITEM (ECTF_ARCREATE, "Error creating CTF archive.") \
    233   _CTF_ITEM (ECTF_ARNNAME, "Name not found in CTF archive.") \
    234   _CTF_ITEM (ECTF_SLICEOVERFLOW, "Overflow of type bitness or offset in slice.") \
    235   _CTF_ITEM (ECTF_DUMPSECTUNKNOWN, "Unknown section number in dump.") \
    236   _CTF_ITEM (ECTF_DUMPSECTCHANGED, "Section changed in middle of dump.") \
    237   _CTF_ITEM (ECTF_NOTYET, "Feature not yet implemented.") \
    238   _CTF_ITEM (ECTF_INTERNAL, "Internal error: assertion failure.") \
    239   _CTF_ITEM (ECTF_NONREPRESENTABLE, "Type not representable in CTF.") \
    240   _CTF_ITEM (ECTF_NEXT_END, "End of iteration.") \
    241   _CTF_ITEM (ECTF_NEXT_WRONGFUN, "Wrong iteration function called.") \
    242   _CTF_ITEM (ECTF_NEXT_WRONGFP, "Iteration entity changed in mid-iterate.") \
    243   _CTF_ITEM (ECTF_FLAGS, "CTF header contains flags unknown to libctf.") \
    244   _CTF_ITEM (ECTF_NEEDSBFD, "This feature needs a libctf with BFD support.") \
    245   _CTF_ITEM (ECTF_INCOMPLETE, "Type is not a complete type.") \
    246   _CTF_ITEM (ECTF_NONAME, "Type name must not be empty.") \
    247   _CTF_ITEM (ECTF_BADFLAG, "Invalid CTF dict flag specified.")
    248 
    249 #define	ECTF_BASE	1000	/* Base value for libctf errnos.  */
    250 
    251 enum
    252   {
    253 #define _CTF_FIRST(NAME, STR) NAME = ECTF_BASE
    254 #define _CTF_ITEM(NAME, STR) , NAME
    255 _CTF_ERRORS
    256 #undef _CTF_ITEM
    257 #undef _CTF_FIRST
    258   };
    259 
    260 #define ECTF_NERR (ECTF_BADFLAG - ECTF_BASE + 1) /* Count of CTF errors.  */
    261 
    262 /* The CTF data model is inferred to be the caller's data model or the data
    263    model of the given object, unless ctf_setmodel is explicitly called.  */
    264 #define	CTF_MODEL_ILP32 1	/* Object data model is ILP32.  */
    265 #define	CTF_MODEL_LP64  2	/* Object data model is LP64.  */
    266 #ifdef _LP64
    267 # define CTF_MODEL_NATIVE CTF_MODEL_LP64
    268 #else
    269 # define CTF_MODEL_NATIVE CTF_MODEL_ILP32
    270 #endif
    271 
    272 /* Dynamic CTF containers can be created using ctf_create.  The ctf_add_*
    273    routines can be used to add new definitions to the dynamic container.  New
    274    types are labeled as root or non-root to determine whether they are visible
    275    at the top-level program scope when subsequently doing a lookup.
    276    (Identifiers contained within non-root types, like enumeration constants, are
    277    also not visible.)  */
    278 
    279 #define	CTF_ADD_NONROOT	0	/* Type only visible in nested scope.  */
    280 #define	CTF_ADD_ROOT	1	/* Type visible at top-level scope.  */
    281 
    282 /* Flags for ctf_member_next.  */
    283 
    284 #define CTF_MN_RECURSE 0x1	/* Recurse into unnamed members.  */
    285 
    286 /* Flags for ctf_dict_set_flag.  */
    287 
    288 /* If set, duplicate enumerators in a single dict fail with ECTF_DUPLICATE.  */
    289 
    290 #define CTF_STRICT_NO_DUP_ENUMERATORS	0x1
    291 
    292 /* These typedefs are used to define the signature for callback functions that
    293    can be used with the iteration and visit functions below.  There is also a
    294    family of iteration functions that do not require callbacks.  */
    295 
    296 typedef int ctf_visit_f (const char *name, ctf_id_t type, unsigned long offset,
    297 			 int depth, void *arg);
    298 typedef int ctf_member_f (const char *name, ctf_id_t membtype,
    299 			  unsigned long offset, void *arg);
    300 typedef int ctf_enum_f (const char *name, int val, void *arg);
    301 typedef int ctf_variable_f (const char *name, ctf_id_t type, void *arg);
    302 typedef int ctf_type_f (ctf_id_t type, void *arg);
    303 typedef int ctf_type_all_f (ctf_id_t type, int flag, void *arg);
    304 typedef int ctf_label_f (const char *name, const ctf_lblinfo_t *info,
    305 			 void *arg);
    306 typedef int ctf_archive_member_f (ctf_dict_t *fp, const char *name, void *arg);
    307 typedef int ctf_archive_raw_member_f (const char *name, const void *content,
    308 				      size_t len, void *arg);
    309 typedef char *ctf_dump_decorate_f (ctf_sect_names_t sect,
    310 				   char *line, void *arg);
    311 
    312 typedef struct ctf_dump_state ctf_dump_state_t;
    313 
    314 /* Iteration state for the _next functions, and allocators/copiers/freers for
    315    it.  (None of these are needed for the simple case of iterating to the end:
    316    the _next functions allocate and free the iterators for you.)
    317 
    318    The _next iterators all work in similar ways: they take things to query (a
    319    dict, a name, a type ID, something like that), then a ctf_next_t iterator
    320    arg which must be the address of a variable whose value is NULL on first
    321    call, and will be set to NULL again once iteration has completed.
    322 
    323    They return something important about the thing being iterated over (often a
    324    type ID or a name); on end of iteration they instead return return CTF_ERR,
    325    -1, or NULL and set the error ECTF_NEXT_END on the dict.  They can often
    326    provide more information too: this is done via pointer parameters (e.g. the
    327    membname and membtype in ctf_member_next()).  These parameters are always
    328    optional and can be set to NULL if not needed.
    329 
    330    Errors other than end-of-iteration will return CTF_ERR/-1/NULL and set the
    331    error to something other than ECTF_NEXT_END, and *not* destroy the iterator:
    332    you should either recover somehow and continue iterating, or call
    333    ctf_next_destroy() on it.  (You can call ctf_next_destroy() on a NULL
    334    iterator, so it's safe to just unconditionally do it after iteration has
    335    completed.)  */
    336 
    337 typedef struct ctf_next ctf_next_t;
    338 extern ctf_next_t *ctf_next_create (void);
    339 extern void ctf_next_destroy (ctf_next_t *);
    340 extern ctf_next_t *ctf_next_copy (ctf_next_t *);
    341 
    342 /* Opening.  These mostly return an abstraction over both CTF files and CTF
    343    archives: so they can be used to open both.  CTF files will appear to be an
    344    archive with one member named '.ctf'.
    345 
    346    All these functions except for ctf_close use BFD and can open anything BFD
    347    can open, hunting down the .ctf section for you, so are not available in the
    348    libctf-nobfd flavour of the library.  If you want to provide the CTF section
    349    yourself, you can do that with ctf_bfdopen_ctfsect.  */
    350 
    351 extern ctf_archive_t *ctf_bfdopen (struct bfd *, int *);
    352 extern ctf_archive_t *ctf_bfdopen_ctfsect (struct bfd *, const ctf_sect_t *,
    353 					   int *);
    354 extern ctf_archive_t *ctf_fdopen (int fd, const char *filename,
    355 				  const char *target, int *errp);
    356 extern ctf_archive_t *ctf_open (const char *filename,
    357 				const char *target, int *errp);
    358 extern void ctf_close (ctf_archive_t *);
    359 
    360 /* Set or unset dict-wide boolean flags, and get the value of these flags.  */
    361 
    362 extern int ctf_dict_set_flag (ctf_dict_t *, uint64_t flag, int set);
    363 extern int ctf_dict_get_flag (ctf_dict_t *, uint64_t flag);
    364 
    365 /* Return the data, symbol, or string sections used by a given CTF dict.  */
    366 extern ctf_sect_t ctf_getdatasect (const ctf_dict_t *);
    367 extern ctf_sect_t ctf_getsymsect (const ctf_dict_t *);
    368 extern ctf_sect_t ctf_getstrsect (const ctf_dict_t *);
    369 
    370 /* Set the endianness of the symbol section, which may be different from
    371    the endianness of the CTF dict. Done for you by ctf_open and ctf_fdopen,
    372    but direct calls to ctf_bufopen etc with symbol sections provided must
    373    do so explicitly.  */
    374 
    375 extern void ctf_symsect_endianness (ctf_dict_t *, int little_endian);
    376 extern void ctf_arc_symsect_endianness (ctf_archive_t *, int little_endian);
    377 
    378 /* Open CTF archives from files or raw section data, and close them again.
    379    Closing may munmap() the data making up the archive, so should not be
    380    done until all dicts are finished with and closed themselves.
    381 
    382    Almost all functions that open archives will also open raw CTF dicts, which
    383    are treated as if they were archives with only one member.
    384 
    385    Some of these functions take optional raw symtab and strtab section content
    386    in the form of ctf_sect_t structures.  For CTF in ELF files, the more
    387    convenient opening functions above extract these .dynsym and its associated
    388    string table (usually .dynsym) whenever the CTF_F_DYNSTR flag is set in the
    389    CTF preamble (which it almost always will be for linked objects, but not for
    390    .o files).  If you use ctf_arc_bufopen and do not specify symbol/string
    391    tables, the ctf_*_lookuup_symbol functions will fail with ECTF_NOSYMTAB.
    392 
    393    Like many other convenient opening functions, ctf_arc_open needs BFD and is
    394    not available in libctf-nobfd.  */
    395 
    396 extern ctf_archive_t *ctf_arc_open (const char *, int *);
    397 extern ctf_archive_t *ctf_arc_bufopen (const ctf_sect_t *ctfsect,
    398 				       const ctf_sect_t *symsect,
    399 				       const ctf_sect_t *strsect,
    400 				       int *);
    401 extern void ctf_arc_close (ctf_archive_t *);
    402 
    403 /* Get the archive a given dictionary came from (if any).  */
    404 
    405 extern ctf_archive_t *ctf_get_arc (const ctf_dict_t *);
    406 
    407 /* Return the number of members in an archive.  */
    408 
    409 extern size_t ctf_archive_count (const ctf_archive_t *);
    410 
    411 /* Open a dictionary with a given name, given a CTF archive and
    412    optionally symbol and string table sections to accompany it (if the
    413    archive was oriiginally opened from an ELF file via ctf_open*, or
    414    if string or symbol tables were explicitly passed when the archive
    415    was opened, this can be used to override that choice).  The dict
    416    should be closed with ctf_dict_close() when done.
    417 
    418    (The low-level functions ctf_simple_open and ctf_bufopen return
    419    ctf_dict_t's directly, and cannot be used on CTF archives: use these
    420    functions instead.)  */
    421 
    422 extern ctf_dict_t *ctf_dict_open (const ctf_archive_t *,
    423 				  const char *, int *);
    424 extern ctf_dict_t *ctf_dict_open_sections (const ctf_archive_t *,
    425 					   const ctf_sect_t *symsect,
    426 					   const ctf_sect_t *strsect,
    427 					   const char *, int *);
    428 
    429 /* Look up symbols' types in archives by index or name, returning the dict
    430    and optionally type ID in which the type is found.  Lookup results are
    431    cached so future lookups are faster.  Needs symbol tables and (for name
    432    lookups) string tables to be known for this CTF archive.  */
    433 
    434 extern ctf_dict_t *ctf_arc_lookup_symbol (ctf_archive_t *,
    435 					  unsigned long symidx,
    436 					  ctf_id_t *, int *errp);
    437 extern ctf_dict_t *ctf_arc_lookup_symbol_name (ctf_archive_t *,
    438 					       const char *name,
    439 					       ctf_id_t *, int *errp);
    440 extern void ctf_arc_flush_caches (ctf_archive_t *);
    441 
    442 /* The next functions return or close real CTF files, or write out CTF
    443    archives, not archives or ELF files containing CTF content.  As with
    444    ctf_dict_open_sections, they can be passed symbol and string table
    445    sections.  */
    446 
    447 extern ctf_dict_t *ctf_simple_open (const char *ctfsect, size_t ctfsect_size,
    448 				    const char *symsect, size_t symsect_size,
    449 				    size_t symsect_entsize,
    450 				    const char *strsect, size_t strsect_size,
    451 				    int *errp);
    452 extern ctf_dict_t *ctf_bufopen (const ctf_sect_t *ctfsect,
    453 				const ctf_sect_t *symsect,
    454 				const ctf_sect_t *strsect, int *);
    455 extern void ctf_ref (ctf_dict_t *);
    456 extern void ctf_dict_close (ctf_dict_t *);
    457 
    458 /* CTF dicts may be in a parent/child relationship, where the child dicts
    459    contain the name of their originating compilation unit and the name of
    460    their parent.  Dicts opened from CTF archives have this relationship set
    461    up already, but if opening via raw low-level calls, you need to figure
    462    out which dict is the parent and set it on the child via ctf_import(). */
    463 
    464 extern const char *ctf_cuname (ctf_dict_t *);
    465 extern ctf_dict_t *ctf_parent_dict (ctf_dict_t *);
    466 extern const char *ctf_parent_name (ctf_dict_t *);
    467 extern int ctf_type_isparent (ctf_dict_t *, ctf_id_t);
    468 extern int ctf_type_ischild (ctf_dict_t *, ctf_id_t);
    469 extern int ctf_import (ctf_dict_t *, ctf_dict_t *);
    470 
    471 /* Set these names (used when creating dicts).  */
    472 
    473 extern int ctf_cuname_set (ctf_dict_t *, const char *);
    474 extern int ctf_parent_name_set (ctf_dict_t *, const char *);
    475 
    476 /* Set and get the CTF data model (see above).  */
    477 
    478 extern int ctf_setmodel (ctf_dict_t *, int);
    479 extern int ctf_getmodel (ctf_dict_t *);
    480 
    481 /* CTF dicts can carry a single (in-memory-only) non-persistent pointer to
    482    arbitrary data.  No meaning is attached to this data and the dict does
    483    not own it: nothing is done to it when the dict is closed.  */
    484 
    485 extern void ctf_setspecific (ctf_dict_t *, void *);
    486 extern void *ctf_getspecific (ctf_dict_t *);
    487 
    488 /* Error handling.  ctf dicts carry a system errno value or one of the
    489    CTF_ERRORS above, which are returned via ctf_errno.  The return value of
    490    ctf_errno is only meaningful when the immediately preceding CTF function
    491    call returns an error code.
    492 
    493    There are four possible sorts of error return:
    494 
    495     - From opening functions, a return value of NULL and the error returned
    496       via an errp instead of via ctf_errno; all other functions return return
    497       errors via ctf_errno.
    498 
    499     - Functions returning a ctf_id_t are in error if the return value == CTF_ERR
    500     - Functions returning an int are in error if their return value < 0
    501     - Functions returning a pointer are in error if their return value ==
    502       NULL.  */
    503 
    504 extern int ctf_errno (ctf_dict_t *);
    505 extern const char *ctf_errmsg (int);
    506 
    507 /* Return the version of CTF dicts written by writeout functions.  The
    508    argument must currently be zero.  All dicts with versions below the value
    509    returned by this function can be read by the library.  CTF dicts written
    510    by other non-GNU CTF libraries (e.g. that in FreeBSD) are not compatible
    511    and cannot be read by this library.  */
    512 
    513 extern int ctf_version (int);
    514 
    515 /* Given a symbol table index corresponding to a function symbol, return info on
    516    the type of a given function's arguments or return value.  Vararg functions
    517    have a final arg with CTF_FUNC_VARARG on in ctc_flags.  */
    518 
    519 extern int ctf_func_info (ctf_dict_t *, unsigned long, ctf_funcinfo_t *);
    520 extern int ctf_func_args (ctf_dict_t *, unsigned long, uint32_t, ctf_id_t *);
    521 
    522 /* As above, but for CTF_K_FUNCTION types in CTF dicts.  */
    523 
    524 extern int ctf_func_type_info (ctf_dict_t *, ctf_id_t, ctf_funcinfo_t *);
    525 extern int ctf_func_type_args (ctf_dict_t *, ctf_id_t, uint32_t, ctf_id_t *);
    526 
    527 /* Look up function or data symbols by name and return their CTF type ID,
    528   if any.  (For both function symbols and data symbols that are function
    529   pointers, the types are of kind CTF_K_FUNCTION.)  */
    530 
    531 extern ctf_id_t ctf_lookup_by_symbol (ctf_dict_t *, unsigned long);
    532 extern ctf_id_t ctf_lookup_by_symbol_name (ctf_dict_t *, const char *);
    533 
    534 /* Traverse all (function or data) symbols in a dict, one by one, and return the
    535    type of each and (if NAME is non-NULL) optionally its name.  */
    536 
    537 extern ctf_id_t ctf_symbol_next (ctf_dict_t *, ctf_next_t **,
    538 				 const char **name, int functions);
    539 
    540 /* Look up a type by name: some simple C type parsing is done, but this is by no
    541    means comprehensive.  Structures, unions and enums need "struct ", "union "
    542    or "enum " on the front, as usual in C.  */
    543 
    544 extern ctf_id_t ctf_lookup_by_name (ctf_dict_t *, const char *);
    545 
    546 /* Look up a variable, which is a name -> type mapping with no specific
    547    relationship to a symbol table.  Before linking, everything with types in the
    548    symbol table will be in the variable table as well; after linking, only those
    549    typed functions and data objects that are not asssigned to symbols by the
    550    linker are left in the variable table here.  */
    551 
    552 extern ctf_id_t ctf_lookup_variable (ctf_dict_t *, const char *);
    553 
    554 /* Look up a single enumerator by enumeration constant name.  Returns the ID of
    555    the enum it is contained within and optionally its value.  Error out with
    556    ECTF_DUPLICATE if multiple exist (which can happen in some older dicts).  See
    557    ctf_lookup_enumerator_next in that case.  Enumeration constants in non-root
    558    types are not returned, but constants in parents are, if not overridden by
    559    an enum in the child.  */
    560 
    561 extern ctf_id_t ctf_lookup_enumerator (ctf_dict_t *, const char *,
    562 				       int64_t *enum_value);
    563 
    564 /* Type lookup functions.  */
    565 
    566 /* Strip qualifiers and typedefs off a type, returning the base type.
    567 
    568    Stripping also stops when we hit slices (see ctf_add_slice below), so it is
    569    possible (given a chain looking like const -> slice -> typedef -> int) to
    570    still have a typedef after you're done with this, but in that case it is a
    571    typedef of a type with a *different width* (because this slice has not been
    572    applied to it).
    573 
    574    Most of the time you don't need to call this: the type-querying functions
    575    will do it for you (as noted below).  */
    576 
    577 extern ctf_id_t ctf_type_resolve (ctf_dict_t *, ctf_id_t);
    578 
    579 /* Get the name of a type, including any const/volatile/restrict qualifiers
    580    (cvr-quals), and return it as a new dynamically-allocated string.
    581    (The 'a' stands for 'a'llocated.) */
    582 
    583 extern char *ctf_type_aname (ctf_dict_t *, ctf_id_t);
    584 
    585 /* As above, but with no cvr-quals.  */
    586 
    587 extern char *ctf_type_aname_raw (ctf_dict_t *, ctf_id_t);
    588 
    589 /* A raw name that is owned by the ctf_dict_t and will live as long as it
    590    does.  Do not change the value this function returns!  */
    591 
    592 extern const char *ctf_type_name_raw (ctf_dict_t *, ctf_id_t);
    593 
    594 /* Like ctf_type_aname, but print the string into the passed buffer, truncating
    595    if necessary and setting ECTF_NAMELEN on the errno: return the actual number
    596    of bytes needed (not including the trailing \0).  Consider using
    597    ctf_type_aname instead.  */
    598 
    599 extern ssize_t ctf_type_lname (ctf_dict_t *, ctf_id_t, char *, size_t);
    600 
    601 /* Like ctf_type_lname, but return the string, or NULL if truncated.
    602    Consider using ctf_type_aname instead.  */
    603 
    604 extern char *ctf_type_name (ctf_dict_t *, ctf_id_t, char *, size_t);
    605 
    606 /* Return the size or alignment of a type.  Types with no meaningful size, like
    607    function types, return 0 as their size; incomplete types set ECTF_INCOMPLETE.
    608    The type is resolved for you, so cvr-quals and typedefs can be passsed in.  */
    609 
    610 extern ssize_t ctf_type_size (ctf_dict_t *, ctf_id_t);
    611 extern ssize_t ctf_type_align (ctf_dict_t *, ctf_id_t);
    612 
    613 /* Return the kind of a type (CTF_K_* constant).  Slices are considered to be
    614    the kind they are a slice of.  Forwards to incomplete structs, etc, return
    615    CTF_K_FORWARD (but deduplication resolves most forwards to their concrete
    616    types).  */
    617 
    618 extern int ctf_type_kind (ctf_dict_t *, ctf_id_t);
    619 
    620 /* Return the kind of a type (CTF_K_* constant).  Slices are considered to be
    621    the kind they are a slice of; forwards are considered to be the kind they are
    622    a forward of.  */
    623 
    624 extern int ctf_type_kind_forwarded (ctf_dict_t *, ctf_id_t);
    625 
    626 /* Return the type a pointer, typedef, cvr-qual, or slice refers to, or return
    627    an ECTF_NOTREF error otherwise.  ctf_type_kind pretends that slices are
    628    actually the type they are a slice of: this is usually want you want, but if
    629    you want to find out if a type was actually a slice of some (usually-wider)
    630    base type, you can call ctf_type_reference on it: a non-error return means
    631    it was a slice.  */
    632 
    633 extern ctf_id_t ctf_type_reference (ctf_dict_t *, ctf_id_t);
    634 
    635 /* Return the encoding of a given type.  No attempt is made to resolve the
    636    type first, so passing in typedefs etc will yield an error.  */
    637 
    638 extern int ctf_type_encoding (ctf_dict_t *, ctf_id_t, ctf_encoding_t *);
    639 
    640 /* Given a type, return some other type that is a pointer to this type (if any
    641    exists), or return ECTF_NOTYPE otherwise.  If non exists, try resolving away
    642    typedefs and cvr-quals and check again (so if you call this on foo_t, you
    643    might get back foo *).  No attempt is made to hunt for pointers to qualified
    644    versions of the type passed in.  */
    645 
    646 extern ctf_id_t ctf_type_pointer (ctf_dict_t *, ctf_id_t);
    647 
    648 /* Return 1 if two types are assignment-compatible.  */
    649 
    650 extern int ctf_type_compat (ctf_dict_t *, ctf_id_t, ctf_dict_t *, ctf_id_t);
    651 
    652 /* Recursively visit the members of any type, calling the ctf_visit_f for each.  */
    653 
    654 extern int ctf_type_visit (ctf_dict_t *, ctf_id_t, ctf_visit_f *, void *);
    655 
    656 /* Comparison function that defines an ordering over types.  If the types are in
    657    different dicts, the ordering may vary between different openings of the same
    658    dicts.  */
    659 
    660 extern int ctf_type_cmp (ctf_dict_t *, ctf_id_t, ctf_dict_t *, ctf_id_t);
    661 
    662 /* Get the name of an enumerator given its value, or vice versa.  If many
    663    enumerators have the same value, the first with that value is returned.  */
    664 
    665 extern const char *ctf_enum_name (ctf_dict_t *, ctf_id_t, int);
    666 extern int ctf_enum_value (ctf_dict_t *, ctf_id_t, const char *, int *);
    667 
    668 /* Get the size and member type of an array.  */
    669 
    670 extern int ctf_array_info (ctf_dict_t *, ctf_id_t, ctf_arinfo_t *);
    671 
    672 /* Get info on specific named members of structs or unions, and count the number
    673    of members in a struct, union, or enum.  */
    674 
    675 extern int ctf_member_info (ctf_dict_t *, ctf_id_t, const char *,
    676 			    ctf_membinfo_t *);
    677 extern int ctf_member_count (ctf_dict_t *, ctf_id_t);
    678 
    679 /* Iterators.  */
    680 
    681 /* ctf_member_next is a _next-style iterator that can additionally traverse into
    682    the members of unnamed structs nested within this struct as if they were
    683    direct members, if CTF_MN_RECURSE is passed in the flags.  */
    684 
    685 extern int ctf_member_iter (ctf_dict_t *, ctf_id_t, ctf_member_f *, void *);
    686 extern ssize_t ctf_member_next (ctf_dict_t *, ctf_id_t, ctf_next_t **,
    687 				const char **name, ctf_id_t *membtype,
    688 				int flags);
    689 
    690 /* Return all enumeration constants in a given enum type.  */
    691 extern int ctf_enum_iter (ctf_dict_t *, ctf_id_t, ctf_enum_f *, void *);
    692 extern const char *ctf_enum_next (ctf_dict_t *, ctf_id_t, ctf_next_t **,
    693 				  int *);
    694 
    695 /* Return all enumeration constants with a given name in a given dict, similar
    696    to ctf_lookup_enumerator above but capable of returning multiple values.
    697    Enumerators in parent dictionaries are not returned: enumerators in non-root
    698    types *are* returned.  This operation internally iterates over all types in
    699    the dict, so is relatively expensive in large dictionaries.
    700 
    701    There is nothing preventing NAME from being changed by the caller in the
    702    middle of iteration: the results might be slightly confusing, but they are
    703    well-defined.  */
    704 
    705 extern ctf_id_t ctf_lookup_enumerator_next (ctf_dict_t *, const char *name,
    706 					    ctf_next_t **, int64_t *enum_value);
    707 
    708 /* Likewise, across all dicts in an archive (parent first).  The DICT and ERRP
    709    arguments are not optional: without the forer you can't tell which dict the
    710    returned type is in, and without the latter you can't distinguish real errors
    711    from end-of-iteration.  DICT should be NULL before the first call and is set
    712    to NULL after the last and on error: on successful call it is set to the dict
    713    containing the returned enum, and it is the caller's responsibility to
    714    ctf_dict_close() it.  The caller should otherwise pass it back in unchanged
    715    (do not reassign it during iteration, just as with the ctf_next_t iterator
    716    itself).  */
    717 
    718 extern ctf_id_t ctf_arc_lookup_enumerator_next (ctf_archive_t *, const char *name,
    719 						ctf_next_t **, int64_t *enum_value,
    720 						ctf_dict_t **dict, int *errp);
    721 
    722 /* Iterate over all types in a dict.  ctf_type_iter_all recurses over all types:
    723    ctf_type_iter recurses only over types with user-visible names (for which
    724    CTF_ADD_ROOT was passed).  All such types are returned, even if they are
    725    things like pointers that intrinsically have no name: this is the only effect
    726    of CTF_ADD_ROOT for such types.  ctf_type_next allows you to choose whether
    727    to see non-root types or not with the want_hidden arg: if set, the flag (if
    728    passed) returns the non-root state of each type in turn.  Types in parent
    729    dictionaries are not returned.  */
    730 
    731 extern int ctf_type_iter (ctf_dict_t *, ctf_type_f *, void *);
    732 extern int ctf_type_iter_all (ctf_dict_t *, ctf_type_all_f *, void *);
    733 extern ctf_id_t ctf_type_next (ctf_dict_t *, ctf_next_t **,
    734 			       int *flag, int want_hidden);
    735 
    736 extern int ctf_variable_iter (ctf_dict_t *, ctf_variable_f *, void *);
    737 extern ctf_id_t ctf_variable_next (ctf_dict_t *, ctf_next_t **,
    738 				   const char **);
    739 
    740 /* ctf_archive_iter and ctf_archive_next open each member dict for you,
    741    automatically importing any parent dict as usual: ctf_archive_iter closes the
    742    dict on return from ctf_archive_member_f, but for ctf_archive_next the caller
    743    must close each dict returned.  If skip_parent is set, the parent dict is
    744    skipped on the basis that it's already been seen in every child dict (but if
    745    no child dicts exist, this will lead to nothing being returned).
    746 
    747    If an open fails, ctf_archive_iter returns -1 early (losing the error), but
    748    ctf_archive_next both passes back the error in the passed errp and allows you
    749    to iterate past errors (until the usual ECTF_NEXT_END is returned).  */
    750 
    751 extern int ctf_archive_iter (const ctf_archive_t *, ctf_archive_member_f *,
    752 			     void *);
    753 extern ctf_dict_t *ctf_archive_next (const ctf_archive_t *, ctf_next_t **,
    754 				     const char **, int skip_parent, int *errp);
    755 
    756 /* Pass the raw content of each archive member in turn to
    757    ctf_archive_raw_member_f.
    758 
    759    This function alone does not currently operate on CTF files masquerading as
    760    archives, and returns -EINVAL: the raw data is no longer available.  It is
    761    expected to be used only by archiving tools, in any case, which have no need
    762    to deal with non-archives at all.  (There is currently no _next analogue of
    763    this function.)  */
    764 
    765 extern int ctf_archive_raw_iter (const ctf_archive_t *,
    766 				 ctf_archive_raw_member_f *, void *);
    767 
    768 /* Dump the contents of a section in a CTF dict.  STATE is an
    769    iterator which should be a pointer to a variable set to NULL.  The decorator
    770    is called with each line in turn and can modify it or allocate and return a
    771    new one.  ctf_dump accumulates all the results and returns a single giant
    772    multiline string.  */
    773 
    774 extern char *ctf_dump (ctf_dict_t *, ctf_dump_state_t **state,
    775 		       ctf_sect_names_t sect, ctf_dump_decorate_f *,
    776 		       void *arg);
    777 
    778 /* Error-warning reporting: an 'iterator' that returns errors and warnings from
    779    the error/warning list, in order of emission.  Errors and warnings are popped
    780    after return: the caller must free the returned error-text pointer.  */
    781 extern char *ctf_errwarning_next (ctf_dict_t *, ctf_next_t **,
    782 				  int *is_warning, int *errp);
    783 
    784 /* Creation.  */
    785 
    786 /* Create a new, empty dict.  If creation fails, return NULL and put a CTF error
    787    code in the passed-in int (if set).  */
    788 extern ctf_dict_t *ctf_create (int *);
    789 
    790 /* Add specific types to a dict.  You can add new types to any dict, but you can
    791    only add members to types that have been added since this dict was read in
    792    (you cannot read in a dict, look up a type in it, then add members to
    793    it).  All adding functions take a uint32_t CTF_ADD_ROOT / CTF_ADD_NONROOT
    794    flag to indicate whether this type should be visible to name lookups via
    795    ctf_lookup_by_name et al.  */
    796 
    797 extern ctf_id_t ctf_add_array (ctf_dict_t *, uint32_t,
    798 			       const ctf_arinfo_t *);
    799 extern ctf_id_t ctf_add_const (ctf_dict_t *, uint32_t, ctf_id_t);
    800 extern ctf_id_t ctf_add_enum_encoded (ctf_dict_t *, uint32_t, const char *,
    801 				      const ctf_encoding_t *);
    802 extern ctf_id_t ctf_add_enum (ctf_dict_t *, uint32_t, const char *);
    803 extern ctf_id_t ctf_add_float (ctf_dict_t *, uint32_t,
    804 			       const char *, const ctf_encoding_t *);
    805 extern ctf_id_t ctf_add_forward (ctf_dict_t *, uint32_t, const char *,
    806 				 uint32_t);
    807 extern ctf_id_t ctf_add_function (ctf_dict_t *, uint32_t,
    808 				  const ctf_funcinfo_t *, const ctf_id_t *);
    809 extern ctf_id_t ctf_add_integer (ctf_dict_t *, uint32_t, const char *,
    810 				 const ctf_encoding_t *);
    811 
    812 /* Add a "slice", which wraps some integral type and changes its encoding
    813    (useful for bitfields, etc).  In most respects slices are treated the same
    814    kind as the type they wrap: only ctf_type_reference can see the difference,
    815    returning the wrapped type.  */
    816 
    817 extern ctf_id_t ctf_add_slice (ctf_dict_t *, uint32_t, ctf_id_t, const ctf_encoding_t *);
    818 extern ctf_id_t ctf_add_pointer (ctf_dict_t *, uint32_t, ctf_id_t);
    819 extern ctf_id_t ctf_add_type (ctf_dict_t *, ctf_dict_t *, ctf_id_t);
    820 extern ctf_id_t ctf_add_typedef (ctf_dict_t *, uint32_t, const char *,
    821 				 ctf_id_t);
    822 extern ctf_id_t ctf_add_restrict (ctf_dict_t *, uint32_t, ctf_id_t);
    823 
    824 /* Struct and union addition.  Straight addition uses possibly-confusing rules
    825    to guess the final size of the struct/union given its members: to explicitly
    826    state the size of the struct or union (to report compiler-generated padding,
    827    etc) use the _sized variants.  */
    828 
    829 extern ctf_id_t ctf_add_struct (ctf_dict_t *, uint32_t, const char *);
    830 extern ctf_id_t ctf_add_union (ctf_dict_t *, uint32_t, const char *);
    831 extern ctf_id_t ctf_add_struct_sized (ctf_dict_t *, uint32_t, const char *,
    832 				      size_t);
    833 extern ctf_id_t ctf_add_union_sized (ctf_dict_t *, uint32_t, const char *,
    834 				     size_t);
    835 
    836 /* Note that CTF cannot encode a given type.  This usually returns an
    837    ECTF_NONREPRESENTABLE error when queried.  Mostly useful for struct members,
    838    variables, etc, to point to.  */
    839 
    840 extern ctf_id_t ctf_add_unknown (ctf_dict_t *, uint32_t, const char *);
    841 extern ctf_id_t ctf_add_volatile (ctf_dict_t *, uint32_t, ctf_id_t);
    842 
    843 /* Add an enumerator to an enum.  If the enum is non-root, so are all the
    844    constants added to it by ctf_add_enumerator.  */
    845 
    846 extern int ctf_add_enumerator (ctf_dict_t *, ctf_id_t, const char *, int);
    847 
    848 /* Add a member to a struct or union, either at the next available offset (with
    849    suitable padding for the alignment) or at a specific offset, and possibly
    850    with a specific encoding (creating a slice for you).  Offsets need not be
    851    unique, and need not be added in ascending order.  */
    852 
    853 extern int ctf_add_member (ctf_dict_t *, ctf_id_t, const char *, ctf_id_t);
    854 extern int ctf_add_member_offset (ctf_dict_t *, ctf_id_t, const char *,
    855 				  ctf_id_t, unsigned long);
    856 extern int ctf_add_member_encoded (ctf_dict_t *, ctf_id_t, const char *,
    857 				   ctf_id_t, unsigned long,
    858 				   const ctf_encoding_t);
    859 
    860 extern int ctf_add_variable (ctf_dict_t *, const char *, ctf_id_t);
    861 
    862 /* Set the size and member and index types of an array.  */
    863 
    864 extern int ctf_set_array (ctf_dict_t *, ctf_id_t, const ctf_arinfo_t *);
    865 
    866 /* Add a function oor object symbol type with a particular name, without saying
    867    anything about the actual symbol index.  (The linker will then associate them
    868    with actual symbol indexes using the ctf_link functions below.)  */
    869 
    870 extern int ctf_add_objt_sym (ctf_dict_t *, const char *, ctf_id_t);
    871 extern int ctf_add_func_sym (ctf_dict_t *, const char *, ctf_id_t);
    872 
    873 /* Snapshot/rollback.  Call ctf_update to snapshot the state of a dict:
    874   a later call to ctf_discard then deletes all types added since (but not new
    875   members, enumerands etc).  Call ctf_snapshot to return a snapshot ID: pass
    876   one of these IDs to ctf_rollback to discard all types added since the
    877   corresponding call to ctf_snapshot.  */
    878 
    879 extern int ctf_update (ctf_dict_t *);
    880 extern ctf_snapshot_id_t ctf_snapshot (ctf_dict_t *);
    881 extern int ctf_rollback (ctf_dict_t *, ctf_snapshot_id_t);
    882 extern int ctf_discard (ctf_dict_t *);
    883 
    884 /* Dict writeout.
    885 
    886    ctf_write: write out an uncompressed dict to an fd.
    887    ctf_compress_write: write out a compressed dict to an fd (currently always
    888    gzip, but this may change in future).
    889    ctf_write_mem: write out a dict to a buffer and return it and its size,
    890    compressing it if its uncompressed size is over THRESHOLD.  */
    891 
    892 extern int ctf_write (ctf_dict_t *, int);
    893 extern int ctf_compress_write (ctf_dict_t * fp, int fd);
    894 extern unsigned char *ctf_write_mem (ctf_dict_t *, size_t *, size_t threshold);
    895 
    896 /* Create a CTF archive named FILE from CTF_DICTS inputs with NAMES (or write it
    897    to the passed-in fd).  */
    898 
    899 extern int ctf_arc_write (const char *file, ctf_dict_t **ctf_dicts, size_t,
    900 			  const char **names, size_t);
    901 extern int ctf_arc_write_fd (int, ctf_dict_t **, size_t, const char **,
    902 			     size_t);
    903 
    904 /* Linking.  These functions are used by ld to link .ctf sections in input
    905    object files into a single .ctf section which is an archive possibly
    906    containing members containing types whose names collide across multiple
    907    compilation units, but they are usable by other programs as well and are not
    908    private to the linker.  */
    909 
    910 /* Add a CTF archive to the link with a given NAME (usually the name of the
    911    containing object file).  The dict added to is usually a new dict created
    912    with ctf_create which will be filled with types corresponding to the shared
    913    dict in the output (conflicting types in child dicts in the output archive
    914    are stored in internal space inside this dict, but are not easily visible
    915    until after ctf_link_write below).
    916 
    917    The NAME need not be unique (but usually is).  */
    918 
    919 extern int ctf_link_add_ctf (ctf_dict_t *, ctf_archive_t *, const char *name);
    920 
    921 /* Do the deduplicating link, filling the dict with types.  The FLAGS are the
    922    CTF_LINK_* flags above.  */
    923 
    924 extern int ctf_link (ctf_dict_t *, int flags);
    925 
    926 /* Symtab linker handling, called after ctf_link to set up the symbol type
    927    information used by ctf_*_lookup_symbol.  */
    928 
    929 /* Add strings to the link from the ELF string table, repeatedly calling
    930    ADD_STRING to add each string and its corresponding offset in turn.  */
    931 
    932 typedef const char *ctf_link_strtab_string_f (uint32_t *offset, void *arg);
    933 extern int ctf_link_add_strtab (ctf_dict_t *,
    934 				ctf_link_strtab_string_f *add_string, void *);
    935 
    936 /* Note that a given symbol will be public with a given set of properties.
    937    If the symbol has been added with that name via ctf_add_{func,objt}_sym,
    938    this symbol type will end up in the symtypetabs and can be looked up via
    939    ctf_*_lookup_symbol after the dict is read back in.  */
    940 
    941 extern int ctf_link_add_linker_symbol (ctf_dict_t *, ctf_link_sym_t *);
    942 
    943 /* Impose an ordering on symbols, as defined by the strtab and symbol
    944    added by earlier calls to the above two functions.  */
    945 
    946 extern int ctf_link_shuffle_syms (ctf_dict_t *);
    947 
    948 /* Return the serialized form of this ctf_linked dict as a new
    949    dynamically-allocated string, compressed if size over THRESHOLD.
    950 
    951    May be a CTF dict or a CTF archive (this library mostly papers over the
    952    differences so you can open both the same way, treat both as ctf_archive_t
    953    and so on).  */
    954 
    955 extern unsigned char *ctf_link_write (ctf_dict_t *, size_t *size,
    956 				      size_t threshold);
    957 
    958 /* Specialist linker functions.  These functions are not used by ld, but can be
    959    used by other programs making use of the linker machinery for other purposes
    960    to customize its output.  Must be called befoore ctf_link. */
    961 
    962 /* Add an entry to rename a given compilation unit to some other name.  This
    963    is only used if conflicting types are found in that compilation unit: they
    964    will instead be placed in the child dict named TO. Many FROMs can map to one
    965    TO: all the types are placed together in that dict, with any whose names
    966    collide as a result being marked as non-root types.  */
    967 
    968 extern int ctf_link_add_cu_mapping (ctf_dict_t *, const char *from,
    969 				    const char *to);
    970 
    971 /* Allow CTF archive names to be tweaked at the last minute before writeout.
    972    Unlike cu-mappings, this cannot transform names so that they collide: it's
    973    meant for unusual use cases that use names for archive members that are not
    974    exactly the same as CU names but are modified in some systematic way.  */
    975 typedef char *ctf_link_memb_name_changer_f (ctf_dict_t *,
    976 					    const char *, void *);
    977 extern void ctf_link_set_memb_name_changer
    978   (ctf_dict_t *, ctf_link_memb_name_changer_f *, void *);
    979 
    980 /* Filter out unwanted variables, which can be very voluminous, and (unlike
    981    symbols) cause the CTF string table to grow to hold their names.  The
    982    variable filter should return nonzero if a variable should not appear in the
    983    output.  */
    984 typedef int ctf_link_variable_filter_f (ctf_dict_t *, const char *, ctf_id_t,
    985 					void *);
    986 extern int ctf_link_set_variable_filter (ctf_dict_t *,
    987 					 ctf_link_variable_filter_f *, void *);
    988 
    989 /* Turn debugging off and on, and get its value.  This is the same as setting
    990    LIBCTF_DEBUG in the environment.  */
    991 extern void ctf_setdebug (int debug);
    992 extern int ctf_getdebug (void);
    993 
    994 /* Deprecated aliases for existing functions and types.  */
    995 
    996 struct ctf_file;
    997 typedef struct ctf_dict ctf_file_t;
    998 extern void ctf_file_close (ctf_file_t *);
    999 extern ctf_dict_t *ctf_parent_file (ctf_dict_t *);
   1000 extern ctf_dict_t *ctf_arc_open_by_name (const ctf_archive_t *,
   1001 					 const char *, int *);
   1002 extern ctf_dict_t *ctf_arc_open_by_name_sections (const ctf_archive_t *arc,
   1003 						  const ctf_sect_t *symsect,
   1004 						  const ctf_sect_t *strsect,
   1005 						  const char *name, int *errp);
   1006 
   1007 /* Deprecated witeout function to write out a gzip-compressed dict.  Unlike all
   1008    the other writeout functions, this even compresses the header (it has to,
   1009    since it's passed a gzFile), so the caller must also decompress it, since
   1010    ctf_open() etc cannot tell it is a CTF dict or how large it is before
   1011    decompression.  */
   1012 
   1013 extern int ctf_gzwrite (ctf_dict_t *fp, gzFile fd);
   1014 
   1015 /* Deprecated functions with no current use.  */
   1016 
   1017 extern const char *ctf_label_topmost (ctf_dict_t *);
   1018 extern int ctf_label_info (ctf_dict_t *, const char *, ctf_lblinfo_t *);
   1019 extern int ctf_label_iter (ctf_dict_t *, ctf_label_f *, void *);
   1020 extern int ctf_label_next (ctf_dict_t *, ctf_next_t **, const char **); /* TBD */
   1021 
   1022 #ifdef	__cplusplus
   1023 }
   1024 #endif
   1025 
   1026 #endif				/* _CTF_API_H */
   1027