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 /* Convert a 32-bit ELF symbol into Elf64 and return a pointer to it.  */
  92
  93 Elf64_Sym *
  94 ctf_sym_to_elf64 (const Elf32_Sym *src, Elf64_Sym *dst)
  95 {
  96   dst->st_name = src->st_name;
  97   dst->st_value = src->st_value;
  98   dst->st_size = src->st_size;
  99   dst->st_info = src->st_info;
 100   dst->st_other = src->st_other;
 101   dst->st_shndx = src->st_shndx;
 102
 103   return dst;
 104 }
 105
 106 /* A string appender working on dynamic strings.  Returns NULL on OOM.  */
 107
 108 char *
 109 ctf_str_append (char *s, const char *append)
 110 {
 111   size_t s_len = 0;
 112
 113   if (append == NULL)
 114     return s;
 115
 116   if (s != NULL)
 117     s_len = strlen (s);
 118
 119   size_t append_len = strlen (append);
 120
 121   if ((s = realloc (s, s_len + append_len + 1)) == NULL)
 122     return NULL;
 123
 124   memcpy (s + s_len, append, append_len);
 125   s[s_len + append_len] = '\0';
 126
 127   return s;
 128 }
 129
 130 /* A version of ctf_str_append that returns the old string on OOM.  */
 131
 132 char *
 133 ctf_str_append_noerr (char *s, const char *append)
 134 {
 135   char *new_s;
 136
 137   new_s = ctf_str_append (s, append);
 138   if (!new_s)
 139     return s;
 140   return new_s;
 141 }
 142
 143 /* A realloc() that fails noisily if called with any ctf_str_num_users.  */
 144 void *
 145 ctf_realloc (ctf_file_t *fp, void *ptr, size_t size)
 146 {
 147   if (fp->ctf_str_num_refs > 0)
 148     {
 149       ctf_dprintf ("%p: attempt to realloc() string table with %lu active refs\n",
 150                    (void *) fp, (unsigned long) fp->ctf_str_num_refs);
 151       return NULL;
 152     }
 153   return realloc (ptr, size);
 154 }
 155
 156 /* Store the specified error code into errp if it is non-NULL, and then
 157    return NULL for the benefit of the caller.  */
 158
 159 void *
 160 ctf_set_open_errno (int *errp, int error)
 161 {
 162   if (errp != NULL)
 163     *errp = error;
 164   return NULL;
 165 }
 166
 167 /* Store the specified error code into the CTF container, and then return
 168    CTF_ERR / -1 for the benefit of the caller. */
 169
 170 unsigned long
 171 ctf_set_errno (ctf_file_t * fp, int err)
 172 {
 173   fp->ctf_errno = err;
 174   return CTF_ERR;
 175 }