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>

/* 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 = ctf_alloc (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);
      ctf_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)
{
  ctf_id_t new_id;
  char *str = NULL, *bit = NULL, *buf = NULL;

  new_id = id;
  do
    {
      ctf_encoding_t enc;

      id = new_id;
      buf = ctf_type_aname (fp, id);
      if (!buf)
	goto oom;

      /* Slices get a different print representation.  */

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

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

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

  return str;

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

/* 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, ENOMEM));

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

  str = ctf_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, ENOMEM));
	}
      else
	{
	  if (asprintf (&str, "%s (%lx) -> ", sym_name, (unsigned long) i) < 0)
	    return (ctf_set_errno (fp, ENOMEM));
	}

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

      str = ctf_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 *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_NOTYPEDAT:
	    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)
	goto err;

      str = ctf_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 = ctf_str_append (str, bit);
      str = ctf_str_append (str, " (");
      free (bit);

      /* Function arguments.  */

      if (ctf_func_args (state->cds_fp, i, fi.ctc_argc, args) < 0)
	goto err;

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

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

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

    oom:
      free (args);
      free (str);
      return (ctf_set_errno (fp, ENOMEM));
    err:
      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, ENOMEM));

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

  str = ctf_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 = ctf_str_append (*state->cdm_str, "    ");

  if ((typestr = ctf_type_aname (state->cdm_fp, id)) == NULL)
    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 = ctf_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 = ctf_str_append (*state->cdm_str, bit);
      free (bit);
      bit = NULL;
    }

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

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

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

static int
ctf_dump_type (ctf_id_t id, void *arg)
{
  char *str;
  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)) == NULL)
    goto err;

  str = ctf_str_append (str, "\n");
  if ((ctf_type_visit (state->cds_fp, id, ctf_dump_member, &membstate)) < 0)
    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:
  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, ENOMEM));
      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 = ctf_alloc (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:
	  /* Nothing doable (yet): entire header is discarded after read-phase.  */
	  str = strdup ("");
	  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 (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 = ctf_str_append (str, ret);
	  str = ctf_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);

  ctf_set_errno (fp, 0);
  return str;

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