libctf/ctf-dump.c

/* Textual dumping of CTF data.
   Copyright (C) 2019 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 <string.h>

#define str_append(s, a) ctf_str_append_noerr (s, a)

/* One item to be dumped, in string form.  */

typedef struct ctf_dump_item
{
  ctf_list_t cdi_list;
  char *cdi_item;
} ctf_dump_item_t;

/* Cross-call state for dumping.  Basically just enough to track the section in
   use and a list of return strings.  */

struct ctf_dump_state
{
  ctf_sect_names_t cds_sect;
  ctf_file_t *cds_fp;
  ctf_dump_item_t *cds_current;
  ctf_list_t cds_items;
};

/* Cross-call state for ctf_dump_member. */

typedef struct ctf_dump_membstate
{
  char **cdm_str;
  ctf_file_t *cdm_fp;
} ctf_dump_membstate_t;

static int
ctf_dump_append (ctf_dump_state_t *state, char *str)
{
  ctf_dump_item_t *cdi;

  if ((cdi = malloc (sizeof (struct ctf_dump_item))) == NULL)
    return (ctf_set_errno (state->cds_fp, ENOMEM));

  cdi->cdi_item = str;
  ctf_list_append (&state->cds_items, cdi);
  return 0;
}

static void
ctf_dump_free (ctf_dump_state_t *state)
{
  ctf_dump_item_t *cdi, *next_cdi;

  if (state == NULL)
    return;

  for (cdi = ctf_list_next (&state->cds_items); cdi != NULL;
       cdi = next_cdi)
    {
      free (cdi->cdi_item);
      next_cdi = ctf_list_next (cdi);
      free (cdi);
    }
}

/* Slices need special handling to distinguish them from their referenced
   type.  */

static int
ctf_is_slice (ctf_file_t *fp, ctf_id_t id, ctf_encoding_t *enc)
{
  int kind = ctf_type_kind (fp, id);

  return (((kind == CTF_K_INTEGER) || (kind == CTF_K_ENUM)
	   || (kind == CTF_K_FLOAT))
	  && ctf_type_reference (fp, id) != CTF_ERR
	  && ctf_type_encoding (fp, id, enc) == 0);
}

/* Return a dump for a single type, without member info: but do show the
   type's references.  */

static char *
ctf_dump_format_type (ctf_file_t *fp, ctf_id_t id, int flag)
{
  ctf_id_t new_id;
  char *str = NULL, *bit = NULL, *buf = NULL;

  new_id = id;
  do
    {
      ctf_encoding_t enc;
      const char *nonroot_leader = "";
      const char *nonroot_trailer = "";

      id = new_id;
      if (flag == CTF_ADD_NONROOT)
	{
	  nonroot_leader = "{";
	  nonroot_trailer = "}";
	}

      buf = ctf_type_aname (fp, id);
      if (!buf)
	{
	  if (id == 0 || ctf_errno (fp) == ECTF_NONREPRESENTABLE)
	    {
	      str = str_append (str, " (type not represented in CTF)");
	      ctf_set_errno (fp, ECTF_NOTREF);
	      break;
	    }

	  goto err;
	}

      /* Slices get a different print representation.  */

      if (ctf_is_slice (fp, id, &enc))
	{
	  ctf_type_encoding (fp, id, &enc);
	  if (asprintf (&bit, " %s%lx: [slice 0x%x:0x%x]%s",
			nonroot_leader, id, enc.cte_offset, enc.cte_bits,
			nonroot_trailer) < 0)
	    goto oom;
	}
      else
	{
	  if (asprintf (&bit, " %s%lx: %s (size 0x%lx)%s", nonroot_leader,
			id, buf[0] == '\0' ? "(nameless)" : buf,
			(unsigned long) ctf_type_size (fp, id),
			nonroot_trailer) < 0)
	    goto oom;
	}
      free (buf);
      buf = NULL;
      str = str_append (str, bit);
      free (bit);
      bit = NULL;

      new_id = ctf_type_reference (fp, id);
      if (new_id != CTF_ERR)
	str = str_append (str, " ->");
    } while (new_id != CTF_ERR);

  if (ctf_errno (fp) != ECTF_NOTREF)
    {
      free (str);
      return NULL;
    }

  return str;

 oom:
  ctf_set_errno (fp, errno);
 err:
  free (buf);
  free (str);
  free (bit);
  return NULL;
}

/* Dump one string field from the file header into the cds_items.  */
static int
ctf_dump_header_strfield (ctf_file_t *fp, ctf_dump_state_t *state,
			  const char *name, uint32_t value)
{
  char *str;
  if (value)
    {
      if (asprintf (&str, "%s: %s\n", name, ctf_strptr (fp, value)) < 0)
	goto err;
      ctf_dump_append (state, str);
    }
  return 0;

 err:
  return (ctf_set_errno (fp, errno));
}

/* Dump one section-offset field from the file header into the cds_items.  */
static int
ctf_dump_header_sectfield (ctf_file_t *fp, ctf_dump_state_t *state,
			   const char *sect, uint32_t off, uint32_t nextoff)
{
  char *str;
  if (nextoff - off)
    {
      if (asprintf (&str, "%s:\t0x%lx -- 0x%lx (0x%lx bytes)\n", sect,
		    (unsigned long) off, (unsigned long) (nextoff - 1),
		    (unsigned long) (nextoff - off)) < 0)
	goto err;
      ctf_dump_append (state, str);
    }
  return 0;

 err:
  return (ctf_set_errno (fp, errno));
}

/* Dump the file header into the cds_items.  */
static int
ctf_dump_header (ctf_file_t *fp, ctf_dump_state_t *state)
{
  char *str;
  const ctf_header_t *hp = fp->ctf_header;
  const char *vertab[] =
    {
     NULL, "CTF_VERSION_1",
     "CTF_VERSION_1_UPGRADED_3 (latest format, version 1 type "
     "boundaries)",
     "CTF_VERSION_2",
     "CTF_VERSION_3", NULL
    };
  const char *verstr = NULL;

  if (asprintf (&str, "Magic number: %x\n", hp->cth_magic) < 0)
      goto err;
  ctf_dump_append (state, str);

  if (hp->cth_version <= CTF_VERSION)
    verstr = vertab[hp->cth_version];

  if (verstr == NULL)
    verstr = "(not a valid version)";

  if (asprintf (&str, "Version: %i (%s)\n", hp->cth_version,
		verstr) < 0)
    goto err;
  ctf_dump_append (state, str);

  /* Everything else is only printed if present.  */

  /* The flags are unusual in that they represent the ctf_file_t *in memory*:
     flags representing compression, etc, are turned off as the file is
     decompressed.  So we store a copy of the flags before they are changed, for
     the dumper.  */

  if (fp->ctf_openflags > 0)
    {
      if (fp->ctf_openflags)
	if (asprintf (&str, "Flags: 0x%x (%s)", fp->ctf_openflags,
		      fp->ctf_openflags & CTF_F_COMPRESS ? "CTF_F_COMPRESS"
							 : "") < 0)
	goto err;
      ctf_dump_append (state, str);
    }

  if (ctf_dump_header_strfield (fp, state, "Parent label",
				hp->cth_parlabel) < 0)
    goto err;

  if (ctf_dump_header_strfield (fp, state, "Parent name", hp->cth_parname) < 0)
    goto err;

  if (ctf_dump_header_strfield (fp, state, "Compilation unit name",
				hp->cth_cuname) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "Label section", hp->cth_lbloff,
				 hp->cth_objtoff) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "Data object section",
				 hp->cth_objtoff, hp->cth_funcoff) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "Function info section",
				 hp->cth_funcoff, hp->cth_varoff) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "Variable section",
				 hp->cth_varoff, hp->cth_typeoff) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "Type section",
				 hp->cth_typeoff, hp->cth_stroff) < 0)
    goto err;

  if (ctf_dump_header_sectfield (fp, state, "String section", hp->cth_stroff,
				 hp->cth_stroff + hp->cth_strlen + 1) < 0)
    goto err;

  return 0;
 err:
  return (ctf_set_errno (fp, errno));
}

/* Dump a single label into the cds_items.  */

static int
ctf_dump_label (const char *name, const ctf_lblinfo_t *info,
		void *arg)
{
  char *str;
  char *typestr;
  ctf_dump_state_t *state = arg;

  if (asprintf (&str, "%s -> ", name) < 0)
    return (ctf_set_errno (state->cds_fp, errno));

  if ((typestr = ctf_dump_format_type (state->cds_fp, info->ctb_type,
				       CTF_ADD_ROOT)) == NULL)
    {
      free (str);
      return -1;			/* errno is set for us.  */
    }

  str = str_append (str, typestr);
  free (typestr);

  ctf_dump_append (state, str);
  return 0;
}

/* Dump all the object entries into the cds_items.  (There is no iterator for
   this section, so we just do it in a loop, and this function handles all of
   them, rather than only one.  */

static int
ctf_dump_objts (ctf_file_t *fp, ctf_dump_state_t *state)
{
  size_t i;

  for (i = 0; i < fp->ctf_nsyms; i++)
    {
      char *str;
      char *typestr;
      const char *sym_name;
      ctf_id_t type;

      if ((type = ctf_lookup_by_symbol (state->cds_fp, i)) == CTF_ERR)
	switch (ctf_errno (state->cds_fp))
	  {
	    /* Most errors are just an indication that this symbol is not a data
	       symbol, but this one indicates that we were called wrong, on a
	       CTF file with no associated symbol table.  */
	  case ECTF_NOSYMTAB:
	    return -1;
	  case ECTF_NOTDATA:
	  case ECTF_NOTYPEDAT:
	    continue;
	  }

      /* Variable name.  */
      sym_name = ctf_lookup_symbol_name (fp, i);
      if (sym_name[0] == '\0')
	{
	  if (asprintf (&str, "%lx -> ", (unsigned long) i) < 0)
	    return (ctf_set_errno (fp, errno));
	}
      else
	{
	  if (asprintf (&str, "%s (%lx) -> ", sym_name, (unsigned long) i) < 0)
	    return (ctf_set_errno (fp, errno));
	}

      /* Variable type.  */
      if ((typestr = ctf_dump_format_type (state->cds_fp, type,
					   CTF_ADD_ROOT)) == NULL)
	{
	  free (str);
	  return -1;			/* errno is set for us.  */
	}

      str = str_append (str, typestr);
      free (typestr);

      ctf_dump_append (state, str);
    }
  return 0;
}

/* Dump all the function entries into the cds_items.  (As above, there is no
   iterator for this section.)  */

static int
ctf_dump_funcs (ctf_file_t *fp, ctf_dump_state_t *state)
{
  size_t i;

  for (i = 0; i < fp->ctf_nsyms; i++)
    {
      char *str;
      char *bit;
      const char *err;
      const char *sym_name;
      ctf_funcinfo_t fi;
      ctf_id_t type;
      size_t j;
      ctf_id_t *args;

      if ((type = ctf_func_info (state->cds_fp, i, &fi)) == CTF_ERR)
	switch (ctf_errno (state->cds_fp))
	  {
	    /* Most errors are just an indication that this symbol is not a data
	       symbol, but this one indicates that we were called wrong, on a
	       CTF file with no associated symbol table.  */
	  case ECTF_NOSYMTAB:
	    return -1;
	  case ECTF_NOTDATA:
	  case ECTF_NOTFUNC:
	  case ECTF_NOFUNCDAT:
	    continue;
	  }
      if ((args = calloc (fi.ctc_argc, sizeof (ctf_id_t))) == NULL)
	return (ctf_set_errno (fp, ENOMEM));

      /* Return type.  */
      if ((str = ctf_type_aname (state->cds_fp, type)) == NULL)
	{
	  err = "look up return type";
	  goto err;
	}

      str = str_append (str, " ");

      /* Function name.  */

      sym_name = ctf_lookup_symbol_name (fp, i);
      if (sym_name[0] == '\0')
	{
	  if (asprintf (&bit, "0x%lx ", (unsigned long) i) < 0)
	    goto oom;
	}
      else
	{
	  if (asprintf (&bit, "%s (0x%lx) ", sym_name, (unsigned long) i) < 0)
	    goto oom;
	}
      str = str_append (str, bit);
      str = str_append (str, " (");
      free (bit);

      /* Function arguments.  */

      if (ctf_func_args (state->cds_fp, i, fi.ctc_argc, args) < 0)
	{
	  err = "look up argument type";
	  goto err;
	}

      for (j = 0; j < fi.ctc_argc; j++)
	{
	  if ((bit = ctf_type_aname (state->cds_fp, args[j])) == NULL)
	    {
	      err = "look up argument type name";
	      goto err;
	    }
	  str = str_append (str, bit);
	  if ((j < fi.ctc_argc - 1) || (fi.ctc_flags & CTF_FUNC_VARARG))
	    str = str_append (str, ", ");
	  free (bit);
	}

      if (fi.ctc_flags & CTF_FUNC_VARARG)
	str = str_append (str, "...");
      str = str_append (str, ")");

      free (args);
      ctf_dump_append (state, str);
      continue;

    oom:
      free (args);
      free (str);
      return (ctf_set_errno (fp, errno));
    err:
      ctf_dprintf ("Cannot %s dumping function type for symbol 0x%li: %s\n",
		   err, (unsigned long) i,
		   ctf_errmsg (ctf_errno (state->cds_fp)));
      free (args);
      free (str);
      return -1;		/* errno is set for us.  */
    }
  return 0;
}

/* Dump a single variable into the cds_items.  */
static int
ctf_dump_var (const char *name, ctf_id_t type, void *arg)
{
  char *str;
  char *typestr;
  ctf_dump_state_t *state = arg;

  if (asprintf (&str, "%s -> ", name) < 0)
    return (ctf_set_errno (state->cds_fp, errno));

  if ((typestr = ctf_dump_format_type (state->cds_fp, type,
				       CTF_ADD_ROOT)) == NULL)
    {
      free (str);
      return -1;			/* errno is set for us.  */
    }

  str = str_append (str, typestr);
  free (typestr);

  ctf_dump_append (state, str);
  return 0;
}

/* Dump a single member into the string in the membstate.  */
static int
ctf_dump_member (const char *name, ctf_id_t id, unsigned long offset,
		  int depth, void *arg)
{
  ctf_dump_membstate_t *state = arg;
  char *typestr = NULL;
  char *bit = NULL;
  ctf_encoding_t ep;
  ssize_t i;

  for (i = 0; i < depth; i++)
    *state->cdm_str = str_append (*state->cdm_str, "    ");

  if ((typestr = ctf_type_aname (state->cdm_fp, id)) == NULL)
    {
      if (id == 0 || ctf_errno (state->cdm_fp) == ECTF_NONREPRESENTABLE)
	{
	  if (asprintf (&bit, "    [0x%lx] (type not represented in CTF)",
			offset) < 0)
	    goto oom;

	  *state->cdm_str = str_append (*state->cdm_str, bit);
	  free (typestr);
	  free (bit);
	  return 0;
	}

      goto oom;
    }

  if (asprintf (&bit, "    [0x%lx] (ID 0x%lx) (kind %i) %s %s (aligned at 0x%lx",
		offset, id, ctf_type_kind (state->cdm_fp, id), typestr, name,
		(unsigned long) ctf_type_align (state->cdm_fp, id)) < 0)
    goto oom;
  *state->cdm_str = str_append (*state->cdm_str, bit);
  free (typestr);
  free (bit);
  typestr = NULL;
  bit = NULL;

  if ((ctf_type_kind (state->cdm_fp, id) == CTF_K_INTEGER)
      || (ctf_type_kind (state->cdm_fp, id) == CTF_K_FLOAT)
      || (ctf_is_slice (state->cdm_fp, id, &ep) == CTF_K_ENUM))
    {
      ctf_type_encoding (state->cdm_fp, id, &ep);
      if (asprintf (&bit, ", format 0x%x, offset:bits 0x%x:0x%x", ep.cte_format,
		    ep.cte_offset, ep.cte_bits) < 0)
	goto oom;
      *state->cdm_str = str_append (*state->cdm_str, bit);
      free (bit);
      bit = NULL;
    }

  *state->cdm_str = str_append (*state->cdm_str, ")\n");
  return 0;

 oom:
  free (typestr);
  free (bit);
  return (ctf_set_errno (state->cdm_fp, errno));
}

/* Dump a single type into the cds_items.  */
static int
ctf_dump_type (ctf_id_t id, int flag, void *arg)
{
  char *str;
  const char *err;
  ctf_dump_state_t *state = arg;
  ctf_dump_membstate_t membstate = { &str, state->cds_fp };
  size_t len;

  if ((str = ctf_dump_format_type (state->cds_fp, id, flag)) == NULL)
    {
      err = "format type";
      goto err;
    }

  str = str_append (str, "\n");
  if ((ctf_type_visit (state->cds_fp, id, ctf_dump_member, &membstate)) < 0)
    {
      if (id == 0 || ctf_errno (state->cds_fp) == ECTF_NONREPRESENTABLE)
	{
	  ctf_dump_append (state, str);
	  return 0;
	}
      err = "visit members";
      goto err;
    }

  /* Trim off the last linefeed added by ctf_dump_member().  */
  len = strlen (str);
  if (str[len-1] == '\n')
    str[len-1] = '\0';

  ctf_dump_append (state, str);
  return 0;

 err:
  ctf_dprintf ("Cannot %s dumping type 0x%lx: %s\n", err, id,
	       ctf_errmsg (ctf_errno (state->cds_fp)));
  free (str);
  return -1;				/* errno is set for us.  */
}

/* Dump the string table into the cds_items.  */

static int
ctf_dump_str (ctf_file_t *fp, ctf_dump_state_t *state)
{
  const char *s = fp->ctf_str[CTF_STRTAB_0].cts_strs;

  for (; s < fp->ctf_str[CTF_STRTAB_0].cts_strs +
	 fp->ctf_str[CTF_STRTAB_0].cts_len;)
    {
      char *str;
      if (asprintf (&str, "%lx: %s",
		    (unsigned long) (s - fp->ctf_str[CTF_STRTAB_0].cts_strs),
		    s) < 0)
	return (ctf_set_errno (fp, errno));
      ctf_dump_append (state, str);
      s += strlen (s) + 1;
    }

  return 0;
}

/* Dump a particular section of a CTF file, in textual form.  Call with a
   pointer to a NULL STATE: each call emits a dynamically allocated string
   containing a description of one entity in the specified section, in order.
   Only the first call (with a NULL state) may vary SECT.  Once the CTF section
   has been entirely dumped, the call returns NULL and frees and annuls the
   STATE, ready for another section to be dumped.  The returned textual content
   may span multiple lines: between each call the FUNC is called with one
   textual line at a time, and should return a suitably decorated line (it can
   allocate a new one and return it if it likes).  */

char *
ctf_dump (ctf_file_t *fp, ctf_dump_state_t **statep, ctf_sect_names_t sect,
	  ctf_dump_decorate_f *func, void *arg)
{
  char *str;
  char *line;
  ctf_dump_state_t *state = NULL;

  if (*statep == NULL)
    {
      /* Data collection.  Transforming a call-at-a-time iterator into a
	 return-at-a-time iterator in a language without call/cc is annoying. It
	 is easiest to simply collect everything at once and then return it bit
	 by bit.  The first call will take (much) longer than otherwise, but the
	 amortized time needed is the same.  */

      if ((*statep = malloc (sizeof (struct ctf_dump_state))) == NULL)
	{
	  ctf_set_errno (fp, ENOMEM);
	  goto end;
	}
      state = *statep;

      memset (state, 0, sizeof (struct ctf_dump_state));
      state->cds_fp = fp;
      state->cds_sect = sect;

      switch (sect)
	{
	case CTF_SECT_HEADER:
	  ctf_dump_header (fp, state);
	  break;
	case CTF_SECT_LABEL:
	  if (ctf_label_iter (fp, ctf_dump_label, state) < 0)
	    {
	      if (ctf_errno (fp) != ECTF_NOLABELDATA)
		goto end;		/* errno is set for us.  */
	      ctf_set_errno (fp, 0);
	    }
	  break;
	case CTF_SECT_OBJT:
	  if (ctf_dump_objts (fp, state) < 0)
	    goto end;			/* errno is set for us.  */
	  break;
	case CTF_SECT_FUNC:
	  if (ctf_dump_funcs (fp, state) < 0)
	    goto end;			/* errno is set for us.  */
	  break;
	case CTF_SECT_VAR:
	  if (ctf_variable_iter (fp, ctf_dump_var, state) < 0)
	    goto end;			/* errno is set for us.  */
	  break;
	case CTF_SECT_TYPE:
	  if (ctf_type_iter_all (fp, ctf_dump_type, state) < 0)
	    goto end;			/* errno is set for us.  */
	  break;
	case CTF_SECT_STR:
	  ctf_dump_str (fp, state);
	  break;
	default:
	  ctf_set_errno (fp, ECTF_DUMPSECTUNKNOWN);
	  goto end;
	}
    }
  else
    {
      state = *statep;

      if (state->cds_sect != sect)
	{
	  ctf_set_errno (fp, ECTF_DUMPSECTCHANGED);
	  goto end;
	}
    }

  if (state->cds_current == NULL)
    state->cds_current = ctf_list_next (&state->cds_items);
  else
    state->cds_current = ctf_list_next (state->cds_current);

  if (state->cds_current == NULL)
    goto end;

  /* Hookery.  There is some extra complexity to preserve linefeeds within each
     item while removing linefeeds at the end.  */
  if (func)
    {
      size_t len;

      str = NULL;
      for (line = state->cds_current->cdi_item; line && *line; )
	{
	  char *nline = line;
	  char *ret;

	  nline = strchr (line, '\n');
	  if (nline)
	    nline[0] = '\0';

	  ret = func (sect, line, arg);
	  str = str_append (str, ret);
	  str = str_append (str, "\n");
	  if (ret != line)
	    free (ret);

	  if (nline)
	    {
	      nline[0] = '\n';
	      nline++;
	    }

	  line = nline;
	}

      len = strlen (str);

      if (str[len-1] == '\n')
	str[len-1] = '\0';
    }
  else
    {
      str = strdup (state->cds_current->cdi_item);
      if (!str)
	{
	  ctf_set_errno (fp, ENOMEM);
	  return str;
	}
    }

  ctf_set_errno (fp, 0);
  return str;

 end:
  ctf_dump_free (state);
  free (state);
  ctf_set_errno (fp, 0);
  *statep = NULL;
  return NULL;
}