libctf/ctf-util.c

   1 /* Miscellaneous utilities.
   2    Copyright (C) 2019 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 /* Convert a 32-bit ELF symbol into Elf64 and return a pointer to it.  */
  84
  85 Elf64_Sym *
  86 ctf_sym_to_elf64 (const Elf32_Sym *src, Elf64_Sym *dst)
  87 {
  88   dst->st_name = src->st_name;
  89   dst->st_value = src->st_value;
  90   dst->st_size = src->st_size;
  91   dst->st_info = src->st_info;
  92   dst->st_other = src->st_other;
  93   dst->st_shndx = src->st_shndx;
  94
  95   return dst;
  96 }
  97
  98 /* Convert an encoded CTF string name into a pointer to a C string by looking
  99   up the appropriate string table buffer and then adding the offset.  */
 100
 101 const char *
 102 ctf_strraw (ctf_file_t *fp, uint32_t name)
 103 {
 104   ctf_strs_t *ctsp = &fp->ctf_str[CTF_NAME_STID (name)];
 105
 106   if (ctsp->cts_strs != NULL && CTF_NAME_OFFSET (name) < ctsp->cts_len)
 107     return (ctsp->cts_strs + CTF_NAME_OFFSET (name));
 108
 109   /* String table not loaded or corrupt offset.  */
 110   return NULL;
 111 }
 112
 113 const char *
 114 ctf_strptr (ctf_file_t *fp, uint32_t name)
 115 {
 116   const char *s = ctf_strraw (fp, name);
 117   return (s != NULL ? s : "(?)");
 118 }
 119
 120 /* Same as strdup(3C), but use ctf_alloc() to do the memory allocation. */
 121
 122 _libctf_malloc_ char *
 123 ctf_strdup (const char *s1)
 124 {
 125   char *s2 = ctf_alloc (strlen (s1) + 1);
 126
 127   if (s2 != NULL)
 128     (void) strcpy (s2, s1);
 129
 130   return s2;
 131 }
 132
 133 /* A string appender working on dynamic strings.  */
 134
 135 char *
 136 ctf_str_append (char *s, const char *append)
 137 {
 138   size_t s_len = 0;
 139
 140   if (append == NULL)
 141     return s;
 142
 143   if (s != NULL)
 144     s_len = strlen (s);
 145
 146   size_t append_len = strlen (append);
 147
 148   if ((s = realloc (s, s_len + append_len + 1)) == NULL)
 149     return NULL;
 150
 151   memcpy (s + s_len, append, append_len);
 152   s[s_len + append_len] = '\0';
 153
 154   return s;
 155 }
 156
 157 /* Store the specified error code into errp if it is non-NULL, and then
 158    return NULL for the benefit of the caller.  */
 159
 160 void *
 161 ctf_set_open_errno (int *errp, int error)
 162 {
 163   if (errp != NULL)
 164     *errp = error;
 165   return NULL;
 166 }
 167
 168 /* Store the specified error code into the CTF container, and then return
 169    CTF_ERR / -1 for the benefit of the caller. */
 170
 171 unsigned long
 172 ctf_set_errno (ctf_file_t * fp, int err)
 173 {
 174   fp->ctf_errno = err;
 175   return CTF_ERR;
 176 }