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binutils-gdb/libctf/ctf-archive.c
Nick Alcock 688d28f621 libctf, next: introduce new class of easier-to-use iterators 
The libctf machinery currently only provides one way to iterate over its
data structures: ctf_*_iter functions that take a callback and an arg
and repeatedly call it.

This *works*, but if you are doing a lot of iteration it is really quite
inconvenient: you have to package up your local variables into
structures over and over again and spawn lots of little functions even
if it would be clearer in a single run of code.  Look at ctf-string.c
for an extreme example of how unreadable this can get, with
three-line-long functions proliferating wildly.

The deduplicator takes this to the Nth level. It iterates over a whole
bunch of things: if we'd had to use _iter-class iterators for all of
them there would be twenty additional functions in the deduplicator
alone, for no other reason than that the iterator API requires it.

Let's do something better. strtok_r gives us half the design: generators
in a number of other languages give us the other half.

The *_next API allows you to iterate over CTF-like entities in a single
function using a normal while loop. e.g. here we are iterating over all
the types in a dict:

ctf_next_t *i = NULL;
int *hidden;
ctf_id_t id;

while ((id = ctf_type_next (fp, &i, &hidden, 1)) != CTF_ERR)
  {
    /* do something with 'hidden' and 'id' */
  }
if (ctf_errno (fp) != ECTF_NEXT_END)
    /* iteration error */

Here we are walking through the members of a struct with CTF ID
'struct_type':

ctf_next_t *i = NULL;
ssize_t offset;
const char *name;
ctf_id_t membtype;

while ((offset = ctf_member_next (fp, struct_type, &i, &name,
                                  &membtype)) >= 0
  {
    /* do something with offset, name, and membtype */
  }
if (ctf_errno (fp) != ECTF_NEXT_END)
    /* iteration error */

Like every other while loop, this means you have access to all the local
variables outside the loop while inside it, with no need to tiresomely
package things up in structures, move the body of the loop into a
separate function, etc, as you would with an iterator taking a callback.

ctf_*_next allocates 'i' for you on first entry (when it must be NULL),
and frees and NULLs it and returns a _next-dependent flag value when the
iteration is over: the fp errno is set to ECTF_NEXT_END when the
iteartion ends normally.  If you want to exit early, call
ctf_next_destroy on the iterator.  You can copy iterators using
ctf_next_copy, which copies their current iteration position so you can
remember loop positions and go back to them later (or ctf_next_destroy
them if you don't need them after all).

Each _next function returns an always-likely-to-be-useful property of
the thing being iterated over, and takes pointers to parameters for the
others: with very few exceptions all those parameters can be NULLs if
you're not interested in them, so e.g. you can iterate over only the
offsets of members of a structure this way:

while ((offset = ctf_member_next (fp, struct_id, &i, NULL, NULL)) >= 0)

If you pass an iterator in use by one iteration function to another one,
you get the new error ECTF_NEXT_WRONGFUN back; if you try to change
ctf_file_t in mid-iteration, you get ECTF_NEXT_WRONGFP back.

Internally the ctf_next_t remembers the iteration function in use,
various sizes and increments useful for almost all iterations, then
uses unions to overlap the actual entities being iterated over to keep
ctf_next_t size down.

Iterators available in the public API so far (all tested in actual use
in the deduplicator):

/* Iterate over the members of a STRUCT or UNION, returning each member's
   offset and optionally name and member type in turn.  On end-of-iteration,
   returns -1.  */
ssize_t
ctf_member_next (ctf_file_t *fp, ctf_id_t type, ctf_next_t **it,
                 const char **name, ctf_id_t *membtype);

/* Iterate over the members of an enum TYPE, returning each enumerand's
   NAME or NULL at end of iteration or error, and optionally passing
   back the enumerand's integer VALue.  */
const char *
ctf_enum_next (ctf_file_t *fp, ctf_id_t type, ctf_next_t **it,
              int *val);

/* Iterate over every type in the given CTF container (not including
   parents), optionally including non-user-visible types, returning
   each type ID and optionally the hidden flag in turn. Returns CTF_ERR
   on end of iteration or error.  */
ctf_id_t
ctf_type_next (ctf_file_t *fp, ctf_next_t **it, int *flag,
               int want_hidden);

/* Iterate over every variable in the given CTF container, in arbitrary
   order, returning the name and type of each variable in turn.  The
   NAME argument is not optional.  Returns CTF_ERR on end of iteration
   or error.  */
ctf_id_t
ctf_variable_next (ctf_file_t *fp, ctf_next_t **it, const char **name);

/* Iterate over all CTF files in an archive, returning each dict in turn as a
   ctf_file_t, and NULL on error or end of iteration.  It is the caller's
   responsibility to close it.  Parent dicts may be skipped.  Regardless of
   whether they are skipped or not, the caller must ctf_import the parent if
   need be.  */
ctf_file_t *
ctf_archive_next (const ctf_archive_t *wrapper, ctf_next_t **it,
                  const char **name, int skip_parent, int *errp);

ctf_label_next is prototyped but not implemented yet.

include/
	* ctf-api.h (ECTF_NEXT_END): New error.
	(ECTF_NEXT_WRONGFUN): Likewise.
	(ECTF_NEXT_WRONGFP): Likewise.
	(ECTF_NERR): Adjust.
	(ctf_next_t): New.
	(ctf_next_create): New prototype.
	(ctf_next_destroy): Likewise.
	(ctf_next_copy): Likewise.
	(ctf_member_next): Likewise.
	(ctf_enum_next): Likewise.
	(ctf_type_next): Likewise.
	(ctf_label_next): Likewise.
	(ctf_variable_next): Likewise.

libctf/
	* ctf-impl.h (ctf_next): New.
	(ctf_get_dict): New prototype.
	* ctf-lookup.c (ctf_get_dict): New, split out of...
	(ctf_lookup_by_id): ... here.
	* ctf-util.c (ctf_next_create): New.
	(ctf_next_destroy): New.
	(ctf_next_copy): New.
	* ctf-types.c (includes): Add <assert.h>.
	(ctf_member_next): New.
	(ctf_enum_next): New.
	(ctf_type_iter): Document the lack of iteration over parent
	types.
	(ctf_type_next): New.
	(ctf_variable_next): New.
	* ctf-archive.c (ctf_archive_next): New.
	* libctf.ver: Add new public functions.
2020-07-22 17:57:50 +01:00

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/* CTF archive files.
Copyright (C) 2019-2020 Free Software Foundation, Inc.
This file is part of libctf.
libctf is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; see the file COPYING. If not see
<http://www.gnu.org/licenses/>. */
#include <ctf-impl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <elf.h>
#include "ctf-endian.h"
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#ifdef HAVE_MMAP
#include <sys/mman.h>
#endif
static off_t arc_write_one_ctf (ctf_file_t * f, int fd, size_t threshold);
static ctf_file_t *ctf_arc_open_by_offset (const struct ctf_archive *arc,
const ctf_sect_t *symsect,
const ctf_sect_t *strsect,
size_t offset, int *errp);
static int sort_modent_by_name (const void *one, const void *two, void *n);
static void *arc_mmap_header (int fd, size_t headersz);
static void *arc_mmap_file (int fd, size_t size);
static int arc_mmap_writeout (int fd, void *header, size_t headersz,
const char **errmsg);
static int arc_mmap_unmap (void *header, size_t headersz, const char **errmsg);
/* Write out a CTF archive to the start of the file referenced by the passed-in
fd. The entries in CTF_FILES are referenced by name: the names are passed in
the names array, which must have CTF_FILES entries.
Returns 0 on success, or an errno, or an ECTF_* value. */
int
ctf_arc_write_fd (int fd, ctf_file_t **ctf_files, size_t ctf_file_cnt,
const char **names, size_t threshold)
{
const char *errmsg;
struct ctf_archive *archdr;
size_t i;
char dummy = 0;
size_t headersz;
ssize_t namesz;
size_t ctf_startoffs; /* Start of the section we are working over. */
char *nametbl = NULL; /* The name table. */
char *np;
off_t nameoffs;
struct ctf_archive_modent *modent;
ctf_dprintf ("Writing CTF archive with %lu files\n",
(unsigned long) ctf_file_cnt);
/* Figure out the size of the mmap()ed header, including the
ctf_archive_modent array. We assume that all of this needs no
padding: a likely assumption, given that it's all made up of
uint64_t's. */
headersz = sizeof (struct ctf_archive)
+ (ctf_file_cnt * sizeof (uint64_t) * 2);
ctf_dprintf ("headersz is %lu\n", (unsigned long) headersz);
/* From now on we work in two pieces: an mmap()ed region from zero up to the
headersz, and a region updated via write() starting after that, containing
all the tables. Platforms that do not support mmap() just use write(). */
ctf_startoffs = headersz;
if (lseek (fd, ctf_startoffs - 1, SEEK_SET) < 0)
{
errmsg = "ctf_arc_write(): cannot extend file while writing: %s\n";
goto err;
}
if (write (fd, &dummy, 1) < 0)
{
errmsg = "ctf_arc_write(): cannot extend file while writing: %s\n";
goto err;
}
if ((archdr = arc_mmap_header (fd, headersz)) == NULL)
{
errmsg = "ctf_arc_write(): Cannot mmap(): %s\n";
goto err;
}
/* Fill in everything we can, which is everything other than the name
table offset. */
archdr->ctfa_magic = htole64 (CTFA_MAGIC);
archdr->ctfa_nfiles = htole64 (ctf_file_cnt);
archdr->ctfa_ctfs = htole64 (ctf_startoffs);
/* We could validate that all CTF files have the same data model, but
since any reasonable construction process will be building things of
only one bitness anyway, this is pretty pointless, so just use the
model of the first CTF file for all of them. (It *is* valid to
create an empty archive: the value of ctfa_model is irrelevant in
this case, but we must be sure not to dereference uninitialized
memory.) */
if (ctf_file_cnt > 0)
archdr->ctfa_model = htole64 (ctf_getmodel (ctf_files[0]));
/* Now write out the CTFs: ctf_archive_modent array via the mapping,
ctfs via write(). The names themselves have not been written yet: we
track them in a local strtab until the time is right, and sort the
modents array after construction.
The name table is not sorted. */
for (i = 0, namesz = 0; i < le64toh (archdr->ctfa_nfiles); i++)
namesz += strlen (names[i]) + 1;
nametbl = malloc (namesz);
if (nametbl == NULL)
{
errmsg = "Error writing named CTF to archive: %s\n";
goto err_unmap;
}
for (i = 0, namesz = 0,
modent = (ctf_archive_modent_t *) ((char *) archdr
+ sizeof (struct ctf_archive));
i < le64toh (archdr->ctfa_nfiles); i++)
{
off_t off;
strcpy (&nametbl[namesz], names[i]);
off = arc_write_one_ctf (ctf_files[i], fd, threshold);
if ((off < 0) && (off > -ECTF_BASE))
{
errmsg = "ctf_arc_write(): Cannot determine file "
"position while writing to archive: %s";
goto err_free;
}
if (off < 0)
{
errmsg = "ctf_arc_write(): Cannot write CTF file to archive: %s\n";
errno = off * -1;
goto err_free;
}
modent->name_offset = htole64 (namesz);
modent->ctf_offset = htole64 (off - ctf_startoffs);
namesz += strlen (names[i]) + 1;
modent++;
}
ctf_qsort_r ((ctf_archive_modent_t *) ((char *) archdr
+ sizeof (struct ctf_archive)),
le64toh (archdr->ctfa_nfiles),
sizeof (struct ctf_archive_modent), sort_modent_by_name,
nametbl);
/* Now the name table. */
if ((nameoffs = lseek (fd, 0, SEEK_CUR)) < 0)
{
errmsg = "ctf_arc_write(): Cannot get current file position "
"in archive: %s\n";
goto err_free;
}
archdr->ctfa_names = htole64 (nameoffs);
np = nametbl;
while (namesz > 0)
{
ssize_t len;
if ((len = write (fd, np, namesz)) < 0)
{
errmsg = "ctf_arc_write(): Cannot write name table to archive: %s\n";
goto err_free;
}
namesz -= len;
np += len;
}
free (nametbl);
if (arc_mmap_writeout (fd, archdr, headersz, &errmsg) < 0)
goto err_unmap;
if (arc_mmap_unmap (archdr, headersz, &errmsg) < 0)
goto err;
return 0;
err_free:
free (nametbl);
err_unmap:
arc_mmap_unmap (archdr, headersz, NULL);
err:
ctf_dprintf (errmsg, errno < ECTF_BASE ? strerror (errno) :
ctf_errmsg (errno));
return errno;
}
/* Write out a CTF archive. The entries in CTF_FILES are referenced by name:
the names are passed in the names array, which must have CTF_FILES entries.
If the filename is NULL, create a temporary file and return a pointer to it.
Returns 0 on success, or an errno, or an ECTF_* value. */
int
ctf_arc_write (const char *file, ctf_file_t ** ctf_files, size_t ctf_file_cnt,
const char **names, size_t threshold)
{
int err;
int fd;
if ((fd = open (file, O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0666)) < 0)
{
ctf_dprintf ("ctf_arc_write(): cannot create %s: %s\n", file,
strerror (errno));
return errno;
}
err = ctf_arc_write_fd (fd, ctf_files, ctf_file_cnt, names, threshold);
if (err)
goto err_close;
if ((err = close (fd)) < 0)
ctf_dprintf ("ctf_arc_write(): Cannot close after writing to archive: "
"%s\n", strerror (errno));
goto err;
err_close:
(void) close (fd);
err:
if (err < 0)
unlink (file);
return err;
}
/* Write one CTF file out. Return the file position of the written file (or
rather, of the file-size uint64_t that precedes it): negative return is a
negative errno or ctf_errno value. On error, the file position may no longer
be at the end of the file. */
static off_t
arc_write_one_ctf (ctf_file_t * f, int fd, size_t threshold)
{
off_t off, end_off;
uint64_t ctfsz = 0;
char *ctfszp;
size_t ctfsz_len;
int (*writefn) (ctf_file_t * fp, int fd);
if (ctf_serialize (f) < 0)
return f->ctf_errno * -1;
if ((off = lseek (fd, 0, SEEK_CUR)) < 0)
return errno * -1;
if (f->ctf_size > threshold)
writefn = ctf_compress_write;
else
writefn = ctf_write;
/* This zero-write turns into the size in a moment. */
ctfsz_len = sizeof (ctfsz);
ctfszp = (char *) &ctfsz;
while (ctfsz_len > 0)
{
ssize_t writelen = write (fd, ctfszp, ctfsz_len);
if (writelen < 0)
return errno * -1;
ctfsz_len -= writelen;
ctfszp += writelen;
}
if (writefn (f, fd) != 0)
return f->ctf_errno * -1;
if ((end_off = lseek (fd, 0, SEEK_CUR)) < 0)
return errno * -1;
ctfsz = htole64 (end_off - off);
if ((lseek (fd, off, SEEK_SET)) < 0)
return errno * -1;
/* ... here. */
ctfsz_len = sizeof (ctfsz);
ctfszp = (char *) &ctfsz;
while (ctfsz_len > 0)
{
ssize_t writelen = write (fd, ctfszp, ctfsz_len);
if (writelen < 0)
return errno * -1;
ctfsz_len -= writelen;
ctfszp += writelen;
}
end_off = LCTF_ALIGN_OFFS (end_off, 8);
if ((lseek (fd, end_off, SEEK_SET)) < 0)
return errno * -1;
return off;
}
/* qsort() function to sort the array of struct ctf_archive_modents into
ascending name order. */
static int
sort_modent_by_name (const void *one, const void *two, void *n)
{
const struct ctf_archive_modent *a = one;
const struct ctf_archive_modent *b = two;
char *nametbl = n;
return strcmp (&nametbl[le64toh (a->name_offset)],
&nametbl[le64toh (b->name_offset)]);
}
/* bsearch_r() function to search for a given name in the sorted array of struct
ctf_archive_modents. */
static int
search_modent_by_name (const void *key, const void *ent, void *arg)
{
const char *k = key;
const struct ctf_archive_modent *v = ent;
const char *search_nametbl = arg;
return strcmp (k, &search_nametbl[le64toh (v->name_offset)]);
}
/* Make a new struct ctf_archive_internal wrapper for a ctf_archive or a
ctf_file. Closes ARC and/or FP on error. Arrange to free the SYMSECT or
STRSECT, as needed, on close. Possibly do not unmap on close. */
struct ctf_archive_internal *
ctf_new_archive_internal (int is_archive, int unmap_on_close,
struct ctf_archive *arc,
ctf_file_t *fp, const ctf_sect_t *symsect,
const ctf_sect_t *strsect,
int *errp)
{
struct ctf_archive_internal *arci;
if ((arci = calloc (1, sizeof (struct ctf_archive_internal))) == NULL)
{
if (is_archive)
{
if (unmap_on_close)
ctf_arc_close_internal (arc);
}
else
ctf_file_close (fp);
return (ctf_set_open_errno (errp, errno));
}
arci->ctfi_is_archive = is_archive;
if (is_archive)
arci->ctfi_archive = arc;
else
arci->ctfi_file = fp;
if (symsect)
memcpy (&arci->ctfi_symsect, symsect, sizeof (struct ctf_sect));
if (strsect)
memcpy (&arci->ctfi_strsect, strsect, sizeof (struct ctf_sect));
arci->ctfi_free_symsect = 0;
arci->ctfi_unmap_on_close = unmap_on_close;
return arci;
}
/* Open a CTF archive or dictionary from data in a buffer (which the caller must
preserve until ctf_arc_close() time). Returns the archive, or NULL and an
error in *err (if not NULL). */
ctf_archive_t *
ctf_arc_bufopen (const ctf_sect_t *ctfsect, const ctf_sect_t *symsect,
const ctf_sect_t *strsect, int *errp)
{
struct ctf_archive *arc = NULL;
int is_archive;
ctf_file_t *fp = NULL;
if (ctfsect->cts_size > sizeof (uint64_t) &&
((*(uint64_t *) ctfsect->cts_data) == CTFA_MAGIC))
{
/* The archive is mmappable, so this operation is trivial.
This buffer is nonmodifiable, so the trick involving mmapping only part
of it and storing the length in the magic number is not applicable: so
record this fact in the archive-wrapper header. (We cannot record it
in the archive, because the archive may very well be a read-only
mapping.) */
is_archive = 1;
arc = (struct ctf_archive *) ctfsect->cts_data;
}
else
{
is_archive = 0;
if ((fp = ctf_bufopen (ctfsect, symsect, strsect, errp)) == NULL)
{
ctf_dprintf ("ctf_internal_open(): cannot open CTF: %s\n",
ctf_errmsg (*errp));
return NULL;
}
}
return ctf_new_archive_internal (is_archive, 0, arc, fp, symsect, strsect,
errp);
}
/* Open a CTF archive. Returns the archive, or NULL and an error in *err (if
not NULL). */
struct ctf_archive *
ctf_arc_open_internal (const char *filename, int *errp)
{
const char *errmsg;
int fd;
struct stat s;
struct ctf_archive *arc; /* (Actually the whole file.) */
libctf_init_debug();
if ((fd = open (filename, O_RDONLY)) < 0)
{
errmsg = "ctf_arc_open(): cannot open %s: %s\n";
goto err;
}
if (fstat (fd, &s) < 0)
{
errmsg = "ctf_arc_open(): cannot stat %s: %s\n";
goto err_close;
}
if ((arc = arc_mmap_file (fd, s.st_size)) == NULL)
{
errmsg = "ctf_arc_open(): Cannot read in %s: %s\n";
goto err_close;
}
if (le64toh (arc->ctfa_magic) != CTFA_MAGIC)
{
errmsg = "ctf_arc_open(): Invalid magic number";
errno = ECTF_FMT;
goto err_unmap;
}
/* This horrible hack lets us know how much to unmap when the file is
closed. (We no longer need the magic number, and the mapping
is private.) */
arc->ctfa_magic = s.st_size;
close (fd);
return arc;
err_unmap:
arc_mmap_unmap (arc, s.st_size, NULL);
err_close:
close (fd);
err:
if (errp)
*errp = errno;
ctf_dprintf (errmsg, filename, errno < ECTF_BASE ? strerror (errno) :
ctf_errmsg (errno));
return NULL;
}
/* Close an archive. */
void
ctf_arc_close_internal (struct ctf_archive *arc)
{
if (arc == NULL)
return;
/* See the comment in ctf_arc_open(). */
arc_mmap_unmap (arc, arc->ctfa_magic, NULL);
}
/* Public entry point: close an archive, or CTF file. */
void
ctf_arc_close (ctf_archive_t *arc)
{
if (arc == NULL)
return;
if (arc->ctfi_is_archive)
{
if (arc->ctfi_unmap_on_close)
ctf_arc_close_internal (arc->ctfi_archive);
}
else
ctf_file_close (arc->ctfi_file);
if (arc->ctfi_free_symsect)
free ((void *) arc->ctfi_symsect.cts_data);
free (arc->ctfi_data);
if (arc->ctfi_bfd_close)
arc->ctfi_bfd_close (arc);
free (arc);
}
/* Return the ctf_file_t with the given name, or NULL if none, setting 'err' if
non-NULL. A name of NULL means to open the default file. */
static ctf_file_t *
ctf_arc_open_by_name_internal (const struct ctf_archive *arc,
const ctf_sect_t *symsect,
const ctf_sect_t *strsect,
const char *name, int *errp)
{
struct ctf_archive_modent *modent;
const char *search_nametbl;
if (name == NULL)
name = _CTF_SECTION; /* The default name. */
ctf_dprintf ("ctf_arc_open_by_name(%s): opening\n", name);
modent = (ctf_archive_modent_t *) ((char *) arc
+ sizeof (struct ctf_archive));
search_nametbl = (const char *) arc + le64toh (arc->ctfa_names);
modent = bsearch_r (name, modent, le64toh (arc->ctfa_nfiles),
sizeof (struct ctf_archive_modent),
search_modent_by_name, (void *) search_nametbl);
/* This is actually a common case and normal operation: no error
debug output. */
if (modent == NULL)
{
if (errp)
*errp = ECTF_ARNNAME;
return NULL;
}
return ctf_arc_open_by_offset (arc, symsect, strsect,
le64toh (modent->ctf_offset), errp);
}
/* Return the ctf_file_t with the given name, or NULL if none, setting 'err' if
non-NULL. A name of NULL means to open the default file.
Use the specified string and symbol table sections.
Public entry point. */
ctf_file_t *
ctf_arc_open_by_name_sections (const ctf_archive_t *arc,
const ctf_sect_t *symsect,
const ctf_sect_t *strsect,
const char *name,
int *errp)
{
if (arc->ctfi_is_archive)
{
ctf_file_t *ret;
ret = ctf_arc_open_by_name_internal (arc->ctfi_archive, symsect, strsect,
name, errp);
if (ret)
ret->ctf_archive = (ctf_archive_t *) arc;
return ret;
}
if ((name != NULL) && (strcmp (name, _CTF_SECTION) != 0))
{
if (errp)
*errp = ECTF_ARNNAME;
return NULL;
}
arc->ctfi_file->ctf_archive = (ctf_archive_t *) arc;
/* Bump the refcount so that the user can ctf_file_close() it. */
arc->ctfi_file->ctf_refcnt++;
return arc->ctfi_file;
}
/* Return the ctf_file_t with the given name, or NULL if none, setting 'err' if
non-NULL. A name of NULL means to open the default file.
Public entry point. */
ctf_file_t *
ctf_arc_open_by_name (const ctf_archive_t *arc, const char *name, int *errp)
{
const ctf_sect_t *symsect = &arc->ctfi_symsect;
const ctf_sect_t *strsect = &arc->ctfi_strsect;
if (symsect->cts_name == NULL)
symsect = NULL;
if (strsect->cts_name == NULL)
strsect = NULL;
return ctf_arc_open_by_name_sections (arc, symsect, strsect, name, errp);
}
/* Return the ctf_file_t at the given ctfa_ctfs-relative offset, or NULL if
none, setting 'err' if non-NULL. */
static ctf_file_t *
ctf_arc_open_by_offset (const struct ctf_archive *arc,
const ctf_sect_t *symsect,
const ctf_sect_t *strsect, size_t offset,
int *errp)
{
ctf_sect_t ctfsect;
ctf_file_t *fp;
ctf_dprintf ("ctf_arc_open_by_offset(%lu): opening\n", (unsigned long) offset);
memset (&ctfsect, 0, sizeof (ctf_sect_t));
offset += le64toh (arc->ctfa_ctfs);
ctfsect.cts_name = _CTF_SECTION;
ctfsect.cts_size = le64toh (*((uint64_t *) ((char *) arc + offset)));
ctfsect.cts_entsize = 1;
ctfsect.cts_data = (void *) ((char *) arc + offset + sizeof (uint64_t));
fp = ctf_bufopen (&ctfsect, symsect, strsect, errp);
if (fp)
ctf_setmodel (fp, le64toh (arc->ctfa_model));
return fp;
}
/* Return the number of members in an archive. */
size_t
ctf_archive_count (const ctf_archive_t *wrapper)
{
if (!wrapper->ctfi_is_archive)
return 1;
return wrapper->ctfi_archive->ctfa_nfiles;
}
/* Raw iteration over all CTF files in an archive. We pass the raw data for all
CTF files in turn to the specified callback function. */
static int
ctf_archive_raw_iter_internal (const struct ctf_archive *arc,
ctf_archive_raw_member_f *func, void *data)
{
int rc;
size_t i;
struct ctf_archive_modent *modent;
const char *nametbl;
modent = (ctf_archive_modent_t *) ((char *) arc
+ sizeof (struct ctf_archive));
nametbl = (((const char *) arc) + le64toh (arc->ctfa_names));
for (i = 0; i < le64toh (arc->ctfa_nfiles); i++)
{
const char *name;
char *fp;
name = &nametbl[le64toh (modent[i].name_offset)];
fp = ((char *) arc + le64toh (arc->ctfa_ctfs)
+ le64toh (modent[i].ctf_offset));
if ((rc = func (name, (void *) (fp + sizeof (uint64_t)),
le64toh (*((uint64_t *) fp)), data)) != 0)
return rc;
}
return 0;
}
/* Raw iteration over all CTF files in an archive: public entry point.
Returns -EINVAL if not supported for this sort of archive. */
int
ctf_archive_raw_iter (const ctf_archive_t *arc,
ctf_archive_raw_member_f * func, void *data)
{
if (arc->ctfi_is_archive)
return ctf_archive_raw_iter_internal (arc->ctfi_archive, func, data);
return -EINVAL; /* Not supported. */
}
/* Iterate over all CTF files in an archive. We pass all CTF files in turn to
the specified callback function. */
static int
ctf_archive_iter_internal (const ctf_archive_t *wrapper,
const struct ctf_archive *arc,
const ctf_sect_t *symsect,
const ctf_sect_t *strsect,
ctf_archive_member_f *func, void *data)
{
int rc;
size_t i;
ctf_file_t *f;
struct ctf_archive_modent *modent;
const char *nametbl;
modent = (ctf_archive_modent_t *) ((char *) arc
+ sizeof (struct ctf_archive));
nametbl = (((const char *) arc) + le64toh (arc->ctfa_names));
for (i = 0; i < le64toh (arc->ctfa_nfiles); i++)
{
const char *name;
name = &nametbl[le64toh (modent[i].name_offset)];
if ((f = ctf_arc_open_by_name_internal (arc, symsect, strsect,
name, &rc)) == NULL)
return rc;
f->ctf_archive = (ctf_archive_t *) wrapper;
if ((rc = func (f, name, data)) != 0)
{
ctf_file_close (f);
return rc;
}
ctf_file_close (f);
}
return 0;
}
/* Iterate over all CTF files in an archive: public entry point. We pass all
CTF files in turn to the specified callback function. */
int
ctf_archive_iter (const ctf_archive_t *arc, ctf_archive_member_f *func,
void *data)
{
const ctf_sect_t *symsect = &arc->ctfi_symsect;
const ctf_sect_t *strsect = &arc->ctfi_strsect;
if (symsect->cts_name == NULL)
symsect = NULL;
if (strsect->cts_name == NULL)
strsect = NULL;
if (arc->ctfi_is_archive)
return ctf_archive_iter_internal (arc, arc->ctfi_archive, symsect, strsect,
func, data);
return func (arc->ctfi_file, _CTF_SECTION, data);
}
/* Iterate over all CTF files in an archive, returning each dict in turn as a
ctf_file_t, and NULL on error or end of iteration. It is the caller's
responsibility to close it. Parent dicts may be skipped. Regardless of
whether they are skipped or not, the caller must ctf_import the parent if
need be.
We identify parents by name rather than by flag value: for now, with the
linker only emitting parents named _CTF_SECTION, this works well enough. */
ctf_file_t *
ctf_archive_next (const ctf_archive_t *wrapper, ctf_next_t **it, const char **name,
int skip_parent, int *errp)
{
ctf_file_t *f;
ctf_next_t *i = *it;
struct ctf_archive *arc;
struct ctf_archive_modent *modent;
const char *nametbl;
const char *name_;
if (!i)
{
if ((i = ctf_next_create()) == NULL)
{
if (errp)
*errp = ENOMEM;
return NULL;
}
i->cu.ctn_arc = wrapper;
i->ctn_iter_fun = (void (*) (void)) ctf_archive_next;
*it = i;
}
if ((void (*) (void)) ctf_archive_next != i->ctn_iter_fun)
{
if (errp)
*errp = ECTF_NEXT_WRONGFUN;
return NULL;
}
if (wrapper != i->cu.ctn_arc)
{
if (errp)
*errp = ECTF_NEXT_WRONGFP;
return NULL;
}
/* Iteration is made a bit more complex by the need to handle ctf_file_t's
transparently wrapped in a single-member archive. These are parents: if
skip_parent is on, they are skipped and the iterator terminates
immediately. */
if (!wrapper->ctfi_is_archive && i->ctn_n == 0)
{
i->ctn_n++;
if (!skip_parent)
{
wrapper->ctfi_file->ctf_refcnt++;
return wrapper->ctfi_file;
}
}
arc = wrapper->ctfi_archive;
/* The loop keeps going when skip_parent is on as long as the member we find
is the parent (i.e. at most two iterations, but possibly an early return if
*all* we have is a parent). */
const ctf_sect_t *symsect;
const ctf_sect_t *strsect;
do
{
if ((!wrapper->ctfi_is_archive) || (i->ctn_n >= le64toh (arc->ctfa_nfiles)))
{
ctf_next_destroy (i);
*it = NULL;
if (errp)
*errp = ECTF_NEXT_END;
return NULL;
}
symsect = &wrapper->ctfi_symsect;
strsect = &wrapper->ctfi_strsect;
if (symsect->cts_name == NULL)
symsect = NULL;
if (strsect->cts_name == NULL)
strsect = NULL;
modent = (ctf_archive_modent_t *) ((char *) arc
+ sizeof (struct ctf_archive));
nametbl = (((const char *) arc) + le64toh (arc->ctfa_names));
name_ = &nametbl[le64toh (modent[i->ctn_n].name_offset)];
i->ctn_n++;
} while (skip_parent && strcmp (name_, _CTF_SECTION) == 0);
if (name)
*name = name_;
f = ctf_arc_open_by_name_internal (arc, symsect, strsect,
name_, errp);
f->ctf_archive = (ctf_archive_t *) wrapper;
return f;
}
#ifdef HAVE_MMAP
/* Map the header in. Only used on new, empty files. */
static void *arc_mmap_header (int fd, size_t headersz)
{
void *hdr;
if ((hdr = mmap (NULL, headersz, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
0)) == MAP_FAILED)
return NULL;
return hdr;
}
/* mmap() the whole file, for reading only. (Map it writably, but privately: we
need to modify the region, but don't need anyone else to see the
modifications.) */
static void *arc_mmap_file (int fd, size_t size)
{
void *arc;
if ((arc = mmap (NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
fd, 0)) == MAP_FAILED)
return NULL;
return arc;
}
/* Persist the header to disk. */
static int arc_mmap_writeout (int fd _libctf_unused_, void *header,
size_t headersz, const char **errmsg)
{
if (msync (header, headersz, MS_ASYNC) < 0)
{
if (errmsg)
*errmsg = "arc_mmap_writeout(): Cannot sync after writing to %s: %s\n";
return -1;
}
return 0;
}
/* Unmap the region. */
static int arc_mmap_unmap (void *header, size_t headersz, const char **errmsg)
{
if (munmap (header, headersz) < 0)
{
if (errmsg)
*errmsg = "arc_mmap_munmap(): Cannot unmap after writing to %s: %s\n";
return -1;
}
return 0;
}
#else
/* Map the header in. Only used on new, empty files. */
static void *arc_mmap_header (int fd _libctf_unused_, size_t headersz)
{
void *hdr;
if ((hdr = malloc (headersz)) == NULL)
return NULL;
return hdr;
}
/* Pull in the whole file, for reading only. We assume the current file
position is at the start of the file. */
static void *arc_mmap_file (int fd, size_t size)
{
char *data;
if ((data = malloc (size)) == NULL)
return NULL;
if (ctf_pread (fd, data, size, 0) < 0)
{
free (data);
return NULL;
}
return data;
}
/* Persist the header to disk. */
static int arc_mmap_writeout (int fd, void *header, size_t headersz,
const char **errmsg)
{
ssize_t len;
size_t acc = 0;
char *data = (char *) header;
ssize_t count = headersz;
if ((lseek (fd, 0, SEEK_SET)) < 0)
{
if (errmsg)
*errmsg = "arc_mmap_writeout(): Cannot seek while writing header to "
"%s: %s\n";
return -1;
}
while (headersz > 0)
{
if ((len = write (fd, data, count)) < 0)
{
if (errmsg)
*errmsg = "arc_mmap_writeout(): Cannot write header to %s: %s\n";
return len;
}
if (len == EINTR)
continue;
acc += len;
if (len == 0) /* EOF. */
break;
count -= len;
data += len;
}
return 0;
}
/* Unmap the region. */
static int arc_mmap_unmap (void *header, size_t headersz _libctf_unused_,
const char **errmsg _libctf_unused_)
{
free (header);
return 0;
}
#endif
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