/* Miscellaneous utilities.

   Copyright (C) 2019-2023 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>

#include "ctf-endian.h"

/* Simple doubly-linked list append routine.  This implementation assumes that

   each list element contains an embedded ctf_list_t as the first member.

   An additional ctf_list_t is used to store the head (l_next) and tail

   (l_prev) pointers.  The current head and tail list elements have their

   previous and next pointers set to NULL, respectively.  */

void

ctf_list_append (ctf_list_t *lp, void *newp)

{

  ctf_list_t *p = lp->l_prev; /* p = tail list element.  */

  ctf_list_t *q = newp;   /* q = new list element.  */

  lp->l_prev = q;

  q->l_prev = p;

  q->l_next = NULL;

  if (p != NULL)

    p->l_next = q;

  else

    lp->l_next = q;

}

/* Prepend the specified existing element to the given ctf_list_t.  The

   existing pointer should be pointing at a struct with embedded ctf_list_t.  */

void

ctf_list_prepend (ctf_list_t * lp, void *newp)

{

  ctf_list_t *p = newp;   /* p = new list element.  */

  ctf_list_t *q = lp->l_next; /* q = head list element.  */

  lp->l_next = p;

  p->l_prev = NULL;

  p->l_next = q;

  if (q != NULL)

    q->l_prev = p;

  else

    lp->l_prev = p;

}

/* Delete the specified existing element from the given ctf_list_t.  The

   existing pointer should be pointing at a struct with embedded ctf_list_t.  */

void

ctf_list_delete (ctf_list_t *lp, void *existing)

{

  ctf_list_t *p = existing;

  if (p->l_prev != NULL)

    p->l_prev->l_next = p->l_next;

  else

    lp->l_next = p->l_next;

  if (p->l_next != NULL)

    p->l_next->l_prev = p->l_prev;

  else

    lp->l_prev = p->l_prev;

}

/* Return 1 if the list is empty.  */

int

ctf_list_empty_p (ctf_list_t *lp)

{

  return (lp->l_next == NULL && lp->l_prev == NULL);

}

/* Splice one entire list onto the end of another one.  The existing list is

   emptied.  */

void

ctf_list_splice (ctf_list_t *lp, ctf_list_t *append)

{

  if (ctf_list_empty_p (append))

    return;

  if (lp->l_prev != NULL)

    lp->l_prev->l_next = append->l_next;

  else

    lp->l_next = append->l_next;

  append->l_next->l_prev = lp->l_prev;

  lp->l_prev = append->l_prev;

  append->l_next = NULL;

  append->l_prev = NULL;

}

/* Convert a 32-bit ELF symbol to a ctf_link_sym_t.  */

ctf_link_sym_t *

ctf_elf32_to_link_sym (ctf_dict_t *fp, ctf_link_sym_t *dst, const Elf32_Sym *src,

           uint32_t symidx)

{

  Elf32_Sym tmp;

  int needs_flipping = 0;

#ifdef WORDS_BIGENDIAN

  if (fp->ctf_symsect_little_endian)

    needs_flipping = 1;

#else

  if (!fp->ctf_symsect_little_endian)

    needs_flipping = 1;

#endif

  memcpy (&tmp, src, sizeof (Elf32_Sym));

  if (needs_flipping)

    {

      swap_thing (tmp.st_name);

      swap_thing (tmp.st_size);

      swap_thing (tmp.st_shndx);

      swap_thing (tmp.st_value);

    }

  /* The name must be in the external string table.  */

  if (tmp.st_name < fp->ctf_str[CTF_STRTAB_1].cts_len)

    dst->st_name = (const char *) fp->ctf_str[CTF_STRTAB_1].cts_strs + tmp.st_name;

  else

    dst->st_name = _CTF_NULLSTR;

  dst->st_nameidx_set = 0;

  dst->st_symidx = symidx;

  dst->st_shndx = tmp.st_shndx;

  dst->st_type = ELF32_ST_TYPE (tmp.st_info);

  dst->st_value = tmp.st_value;

  return dst;

}

/* Convert a 64-bit ELF symbol to a ctf_link_sym_t.  */

ctf_link_sym_t *

ctf_elf64_to_link_sym (ctf_dict_t *fp, ctf_link_sym_t *dst, const Elf64_Sym *src,

           uint32_t symidx)

{

  Elf64_Sym tmp;

  int needs_flipping = 0;

#ifdef WORDS_BIGENDIAN

  if (fp->ctf_symsect_little_endian)

    needs_flipping = 1;

#else

  if (!fp->ctf_symsect_little_endian)

    needs_flipping = 1;

#endif

  memcpy (&tmp, src, sizeof (Elf64_Sym));

  if (needs_flipping)

    {

      swap_thing (tmp.st_name);

      swap_thing (tmp.st_size);

      swap_thing (tmp.st_shndx);

      swap_thing (tmp.st_value);

    }

  /* The name must be in the external string table.  */

  if (tmp.st_name < fp->ctf_str[CTF_STRTAB_1].cts_len)

    dst->st_name = (const char *) fp->ctf_str[CTF_STRTAB_1].cts_strs + tmp.st_name;

  else

    dst->st_name = _CTF_NULLSTR;

  dst->st_nameidx_set = 0;

  dst->st_symidx = symidx;

  dst->st_shndx = tmp.st_shndx;

  dst->st_type = ELF32_ST_TYPE (tmp.st_info);

  /* We only care if the value is zero, so avoid nonzeroes turning into

     zeroes.  */

  if (_libctf_unlikely_ (tmp.st_value != 0 && ((uint32_t) tmp.st_value == 0)))

    dst->st_value = 1;

  else

    dst->st_value = (uint32_t) tmp.st_value;

  return dst;

}

/* A string appender working on dynamic strings.  Returns NULL on OOM.  */

char *

ctf_str_append (char *s, const char *append)

{

  size_t s_len = 0;

  if (append == NULL)

    return s;

  if (s != NULL)

    s_len = strlen (s);

  size_t append_len = strlen (append);

  if ((s = realloc (s, s_len + append_len + 1)) == NULL)

    return NULL;

  memcpy (s + s_len, append, append_len);

  s[s_len + append_len] = '\0';

  return s;

}

/* A version of ctf_str_append that returns the old string on OOM.  */

char *

ctf_str_append_noerr (char *s, const char *append)

{

  char *new_s;

  new_s = ctf_str_append (s, append);

  if (!new_s)

    return s;

  return new_s;

}

/* A realloc() that fails noisily if called with any ctf_str_num_users.  */

void *

ctf_realloc (ctf_dict_t *fp, void *ptr, size_t size)

{

  if (fp->ctf_str_num_refs > 0)

    {

      ctf_dprintf ("%p: attempt to realloc() string table with %lu active refs\n",

       (void *) fp, (unsigned long) fp->ctf_str_num_refs);

      return NULL;

    }

  return realloc (ptr, size);

}

/* Store the specified error code into errp if it is non-NULL, and then

   return NULL for the benefit of the caller.  */

void *

ctf_set_open_errno (int *errp, int error)

{

  if (errp != NULL)

    *errp = error;

  return NULL;

}

/* Store the specified error code into the CTF dict, and then return CTF_ERR /

   -1 for the benefit of the caller. */

unsigned long

ctf_set_errno (ctf_dict_t *fp, int err)

{

  fp->ctf_errno = err;

  return CTF_ERR;

}

/* Create a ctf_next_t.  */

ctf_next_t *

ctf_next_create (void)

{

  return calloc (1, sizeof (struct ctf_next));

}

/* Destroy a ctf_next_t, for early exit from iterators.  */

void

ctf_next_destroy (ctf_next_t *i)

{

  if (i == NULL)

    return;

  if (i->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)

    free (i->u.ctn_sorted_hkv);

  if (i->ctn_next)

    ctf_next_destroy (i->ctn_next);

  free (i);

}

/* Copy a ctf_next_t.  */

ctf_next_t *

ctf_next_copy (ctf_next_t *i)

{

  ctf_next_t *i2;

  if ((i2 = ctf_next_create()) == NULL)

    return NULL;

  memcpy (i2, i, sizeof (struct ctf_next));

  if (i2->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)

    {

      size_t els = ctf_dynhash_elements ((ctf_dynhash_t *) i->cu.ctn_h);

      if ((i2->u.ctn_sorted_hkv = calloc (els, sizeof (ctf_next_hkv_t))) == NULL)

  {

    free (i2);

    return NULL;

  }

      memcpy (i2->u.ctn_sorted_hkv, i->u.ctn_sorted_hkv,

        els * sizeof (ctf_next_hkv_t));

    }

  return i2;

}