libctf/ctf-util.c

   1 /* Miscellaneous utilities.
   2    Copyright (C) 2019-2020 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 #include <ctf-impl.h>
  21 #include <string.h>
  22
  23 /* Simple doubly-linked list append routine.  This implementation assumes that
  24    each list element contains an embedded ctf_list_t as the first member.
  25    An additional ctf_list_t is used to store the head (l_next) and tail
  26    (l_prev) pointers.  The current head and tail list elements have their
  27    previous and next pointers set to NULL, respectively.  */
  28
  29 void
  30 ctf_list_append (ctf_list_t *lp, void *newp)
  31 {
  32   ctf_list_t *p = lp->l_prev;   /* p = tail list element.  */
  33   ctf_list_t *q = newp;         /* q = new list element.  */
  34
  35   lp->l_prev = q;
  36   q->l_prev = p;
  37   q->l_next = NULL;
  38
  39   if (p != NULL)
  40     p->l_next = q;
  41   else
  42     lp->l_next = q;
  43 }
  44
  45 /* Prepend the specified existing element to the given ctf_list_t.  The
  46    existing pointer should be pointing at a struct with embedded ctf_list_t.  */
  47
  48 void
  49 ctf_list_prepend (ctf_list_t * lp, void *newp)
  50 {
  51   ctf_list_t *p = newp;         /* p = new list element.  */
  52   ctf_list_t *q = lp->l_next;   /* q = head list element.  */
  53
  54   lp->l_next = p;
  55   p->l_prev = NULL;
  56   p->l_next = q;
  57
  58   if (q != NULL)
  59     q->l_prev = p;
  60   else
  61     lp->l_prev = p;
  62 }
  63
  64 /* Delete the specified existing element from the given ctf_list_t.  The
  65    existing pointer should be pointing at a struct with embedded ctf_list_t.  */
  66
  67 void
  68 ctf_list_delete (ctf_list_t *lp, void *existing)
  69 {
  70   ctf_list_t *p = existing;
  71
  72   if (p->l_prev != NULL)
  73     p->l_prev->l_next = p->l_next;
  74   else
  75     lp->l_next = p->l_next;
  76
  77   if (p->l_next != NULL)
  78     p->l_next->l_prev = p->l_prev;
  79   else
  80     lp->l_prev = p->l_prev;
  81 }
  82
  83 /* Return 1 if the list is empty.  */
  84
  85 int
  86 ctf_list_empty_p (ctf_list_t *lp)
  87 {
  88   return (lp->l_next == NULL && lp->l_prev == NULL);
  89 }
  90
  91 /* Splice one entire list onto the end of another one.  The existing list is
  92    emptied.  */
  93
  94 void
  95 ctf_list_splice (ctf_list_t *lp, ctf_list_t *append)
  96 {
  97   if (ctf_list_empty_p (append))
  98     return;
  99
 100   if (lp->l_prev != NULL)
 101     lp->l_prev->l_next = append->l_next;
 102   else
 103     lp->l_next = append->l_next;
 104
 105   append->l_next->l_prev = lp->l_prev;
 106   lp->l_prev = append->l_prev;
 107   append->l_next = NULL;
 108   append->l_prev = NULL;
 109 }
 110
 111 /* Convert a 32-bit ELF symbol to a ctf_link_sym_t.  */
 112
 113 ctf_link_sym_t *
 114 ctf_elf32_to_link_sym (ctf_dict_t *fp, ctf_link_sym_t *dst, const Elf32_Sym *src,
 115                        uint32_t symidx)
 116 {
 117   /* The name must be in the external string table.  */
 118   if (src->st_name < fp->ctf_str[CTF_STRTAB_1].cts_len)
 119     dst->st_name = (const char *) fp->ctf_str[CTF_STRTAB_1].cts_strs + src->st_name;
 120   else
 121     dst->st_name = _CTF_NULLSTR;
 122   dst->st_nameidx_set = 0;
 123   dst->st_symidx = symidx;
 124   dst->st_shndx = src->st_shndx;
 125   dst->st_type = ELF32_ST_TYPE (src->st_info);
 126   dst->st_value = src->st_value;
 127
 128   return dst;
 129 }
 130
 131 /* Convert a 64-bit ELF symbol to a ctf_link_sym_t.  */
 132
 133 ctf_link_sym_t *
 134 ctf_elf64_to_link_sym (ctf_dict_t *fp, ctf_link_sym_t *dst, const Elf64_Sym *src,
 135                        uint32_t symidx)
 136 {
 137   /* The name must be in the external string table.  */
 138   if (src->st_name < fp->ctf_str[CTF_STRTAB_1].cts_len)
 139     dst->st_name = (const char *) fp->ctf_str[CTF_STRTAB_1].cts_strs + src->st_name;
 140   else
 141     dst->st_name = _CTF_NULLSTR;
 142   dst->st_nameidx_set = 0;
 143   dst->st_symidx = symidx;
 144   dst->st_shndx = src->st_shndx;
 145   dst->st_type = ELF32_ST_TYPE (src->st_info);
 146
 147   /* We only care if the value is zero, so avoid nonzeroes turning into
 148      zeroes.  */
 149   if (_libctf_unlikely_ (src->st_value != 0 && ((uint32_t) src->st_value == 0)))
 150     dst->st_value = 1;
 151   else
 152     dst->st_value = (uint32_t) src->st_value;
 153
 154   return dst;
 155 }
 156
 157 /* A string appender working on dynamic strings.  Returns NULL on OOM.  */
 158
 159 char *
 160 ctf_str_append (char *s, const char *append)
 161 {
 162   size_t s_len = 0;
 163
 164   if (append == NULL)
 165     return s;
 166
 167   if (s != NULL)
 168     s_len = strlen (s);
 169
 170   size_t append_len = strlen (append);
 171
 172   if ((s = realloc (s, s_len + append_len + 1)) == NULL)
 173     return NULL;
 174
 175   memcpy (s + s_len, append, append_len);
 176   s[s_len + append_len] = '\0';
 177
 178   return s;
 179 }
 180
 181 /* A version of ctf_str_append that returns the old string on OOM.  */
 182
 183 char *
 184 ctf_str_append_noerr (char *s, const char *append)
 185 {
 186   char *new_s;
 187
 188   new_s = ctf_str_append (s, append);
 189   if (!new_s)
 190     return s;
 191   return new_s;
 192 }
 193
 194 /* A realloc() that fails noisily if called with any ctf_str_num_users.  */
 195 void *
 196 ctf_realloc (ctf_dict_t *fp, void *ptr, size_t size)
 197 {
 198   if (fp->ctf_str_num_refs > 0)
 199     {
 200       ctf_dprintf ("%p: attempt to realloc() string table with %lu active refs\n",
 201                    (void *) fp, (unsigned long) fp->ctf_str_num_refs);
 202       return NULL;
 203     }
 204   return realloc (ptr, size);
 205 }
 206
 207 /* Store the specified error code into errp if it is non-NULL, and then
 208    return NULL for the benefit of the caller.  */
 209
 210 void *
 211 ctf_set_open_errno (int *errp, int error)
 212 {
 213   if (errp != NULL)
 214     *errp = error;
 215   return NULL;
 216 }
 217
 218 /* Store the specified error code into the CTF dict, and then return CTF_ERR /
 219    -1 for the benefit of the caller. */
 220
 221 unsigned long
 222 ctf_set_errno (ctf_dict_t *fp, int err)
 223 {
 224   fp->ctf_errno = err;
 225   return CTF_ERR;
 226 }
 227
 228 /* Create a ctf_next_t.  */
 229
 230 ctf_next_t *
 231 ctf_next_create (void)
 232 {
 233   return calloc (1, sizeof (struct ctf_next));
 234 }
 235
 236 /* Destroy a ctf_next_t, for early exit from iterators.  */
 237
 238 void
 239 ctf_next_destroy (ctf_next_t *i)
 240 {
 241   if (i == NULL)
 242     return;
 243
 244   if (i->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)
 245     free (i->u.ctn_sorted_hkv);
 246   if (i->ctn_iter_fun == (void (*) (void)) ctf_symbol_next
 247       && i->cu.ctn_fp->ctf_flags & LCTF_RDWR)
 248     ctf_next_destroy (i->u.ctn_next);
 249   free (i);
 250 }
 251
 252 /* Copy a ctf_next_t.  */
 253
 254 ctf_next_t *
 255 ctf_next_copy (ctf_next_t *i)
 256 {
 257   ctf_next_t *i2;
 258
 259   if ((i2 = ctf_next_create()) == NULL)
 260     return NULL;
 261   memcpy (i2, i, sizeof (struct ctf_next));
 262
 263   if (i2->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)
 264     {
 265       size_t els = ctf_dynhash_elements ((ctf_dynhash_t *) i->cu.ctn_h);
 266       if ((i2->u.ctn_sorted_hkv = calloc (els, sizeof (ctf_next_hkv_t))) == NULL)
 267         {
 268           free (i2);
 269           return NULL;
 270         }
 271       memcpy (i2->u.ctn_sorted_hkv, i->u.ctn_sorted_hkv,
 272               els * sizeof (ctf_next_hkv_t));
 273     }
 274   return i2;
 275 }