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 into Elf64 and return a pointer to it.  */
 112
 113 Elf64_Sym *
 114 ctf_sym_to_elf64 (const Elf32_Sym *src, Elf64_Sym *dst)
 115 {
 116   dst->st_name = src->st_name;
 117   dst->st_value = src->st_value;
 118   dst->st_size = src->st_size;
 119   dst->st_info = src->st_info;
 120   dst->st_other = src->st_other;
 121   dst->st_shndx = src->st_shndx;
 122
 123   return dst;
 124 }
 125
 126 /* A string appender working on dynamic strings.  Returns NULL on OOM.  */
 127
 128 char *
 129 ctf_str_append (char *s, const char *append)
 130 {
 131   size_t s_len = 0;
 132
 133   if (append == NULL)
 134     return s;
 135
 136   if (s != NULL)
 137     s_len = strlen (s);
 138
 139   size_t append_len = strlen (append);
 140
 141   if ((s = realloc (s, s_len + append_len + 1)) == NULL)
 142     return NULL;
 143
 144   memcpy (s + s_len, append, append_len);
 145   s[s_len + append_len] = '\0';
 146
 147   return s;
 148 }
 149
 150 /* A version of ctf_str_append that returns the old string on OOM.  */
 151
 152 char *
 153 ctf_str_append_noerr (char *s, const char *append)
 154 {
 155   char *new_s;
 156
 157   new_s = ctf_str_append (s, append);
 158   if (!new_s)
 159     return s;
 160   return new_s;
 161 }
 162
 163 /* A realloc() that fails noisily if called with any ctf_str_num_users.  */
 164 void *
 165 ctf_realloc (ctf_file_t *fp, void *ptr, size_t size)
 166 {
 167   if (fp->ctf_str_num_refs > 0)
 168     {
 169       ctf_dprintf ("%p: attempt to realloc() string table with %lu active refs\n",
 170                    (void *) fp, (unsigned long) fp->ctf_str_num_refs);
 171       return NULL;
 172     }
 173   return realloc (ptr, size);
 174 }
 175
 176 /* Store the specified error code into errp if it is non-NULL, and then
 177    return NULL for the benefit of the caller.  */
 178
 179 void *
 180 ctf_set_open_errno (int *errp, int error)
 181 {
 182   if (errp != NULL)
 183     *errp = error;
 184   return NULL;
 185 }
 186
 187 /* Store the specified error code into the CTF container, and then return
 188    CTF_ERR / -1 for the benefit of the caller. */
 189
 190 unsigned long
 191 ctf_set_errno (ctf_file_t * fp, int err)
 192 {
 193   fp->ctf_errno = err;
 194   return CTF_ERR;
 195 }
 196
 197 /* Create a ctf_next_t.  */
 198
 199 ctf_next_t *
 200 ctf_next_create (void)
 201 {
 202   return calloc (1, sizeof (struct ctf_next));
 203 }
 204
 205 /* Destroy a ctf_next_t, for early exit from iterators.  */
 206
 207 void
 208 ctf_next_destroy (ctf_next_t *i)
 209 {
 210   if (i == NULL)
 211     return;
 212
 213   if (i->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)
 214     free (i->u.ctn_sorted_hkv);
 215   free (i);
 216 }
 217
 218 /* Copy a ctf_next_t.  */
 219
 220 ctf_next_t *
 221 ctf_next_copy (ctf_next_t *i)
 222 {
 223   ctf_next_t *i2;
 224
 225   if ((i2 = ctf_next_create()) == NULL)
 226     return NULL;
 227   memcpy (i2, i, sizeof (struct ctf_next));
 228
 229   if (i2->ctn_iter_fun == (void (*) (void)) ctf_dynhash_next_sorted)
 230     {
 231       size_t els = ctf_dynhash_elements ((ctf_dynhash_t *) i->cu.ctn_h);
 232       if ((i2->u.ctn_sorted_hkv = calloc (els, sizeof (ctf_next_hkv_t))) == NULL)
 233         {
 234           free (i2);
 235           return NULL;
 236         }
 237       memcpy (i2->u.ctn_sorted_hkv, i->u.ctn_sorted_hkv,
 238               els * sizeof (ctf_next_hkv_t));
 239     }
 240   return i2;
 241 }