libctf/ctf-labels.c

   1 /* Labelled ranges of type IDs.
   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 static int
  24 extract_label_info (ctf_file_t *fp, const ctf_lblent_t **ctl,
  25                     uint32_t *num_labels)
  26 {
  27   const ctf_header_t *h;
  28
  29   h = (const ctf_header_t *) fp->ctf_data.cts_data;
  30
  31   *ctl = (const ctf_lblent_t *) (fp->ctf_buf + h->cth_lbloff);
  32   *num_labels = (h->cth_objtoff - h->cth_lbloff) / sizeof (ctf_lblent_t);
  33
  34   return 0;
  35 }
  36
  37 /* Returns the topmost label, or NULL if any errors are encountered.  */
  38
  39 const char *
  40 ctf_label_topmost (ctf_file_t *fp)
  41 {
  42   const ctf_lblent_t *ctlp = NULL;
  43   const char *s;
  44   uint32_t num_labels = 0;
  45
  46   if (extract_label_info (fp, &ctlp, &num_labels) < 0)
  47     return NULL;                                /* errno is set for us.  */
  48
  49   if (num_labels == 0)
  50     {
  51       (void) ctf_set_errno (fp, ECTF_NOLABELDATA);
  52       return NULL;
  53     }
  54
  55   if ((s = ctf_strraw (fp, (ctlp + num_labels - 1)->ctl_label)) == NULL)
  56     (void) ctf_set_errno (fp, ECTF_CORRUPT);
  57
  58   return s;
  59 }
  60
  61 /* Iterate over all labels.  We pass the label string and the lblinfo_t struct
  62    to the specified callback function.  */
  63 int
  64 ctf_label_iter (ctf_file_t *fp, ctf_label_f *func, void *arg)
  65 {
  66   const ctf_lblent_t *ctlp = NULL;
  67   uint32_t i;
  68   uint32_t num_labels = 0;
  69   ctf_lblinfo_t linfo;
  70   const char *lname;
  71   int rc;
  72
  73   if (extract_label_info (fp, &ctlp, &num_labels) < 0)
  74     return -1;                  /* errno is set for us.  */
  75
  76   if (num_labels == 0)
  77     return (ctf_set_errno (fp, ECTF_NOLABELDATA));
  78
  79   for (i = 0; i < num_labels; i++, ctlp++)
  80     {
  81       if ((lname = ctf_strraw (fp, ctlp->ctl_label)) == NULL)
  82         {
  83           ctf_dprintf ("failed to decode label %u with "
  84                        "type %u\n", ctlp->ctl_label, ctlp->ctl_type);
  85           return (ctf_set_errno (fp, ECTF_CORRUPT));
  86         }
  87
  88       linfo.ctb_type = ctlp->ctl_type;
  89       if ((rc = func (lname, &linfo, arg)) != 0)
  90         return rc;
  91     }
  92
  93   return 0;
  94 }
  95
  96 typedef struct linfo_cb_arg
  97 {
  98   const char *lca_name;         /* Label we want to retrieve info for.  */
  99   ctf_lblinfo_t *lca_info;      /* Where to store the info about the label.  */
 100 } linfo_cb_arg_t;
 101
 102 static int
 103 label_info_cb (const char *lname, const ctf_lblinfo_t *linfo, void *arg)
 104 {
 105   /* If lname matches the label we are looking for, copy the
 106     lblinfo_t struct for the caller.  */
 107
 108   if (strcmp (lname, ((linfo_cb_arg_t *) arg)->lca_name) == 0)
 109     {
 110       /* * Allow caller not to allocate storage to test if label exists.  */
 111
 112       if (((linfo_cb_arg_t *) arg)->lca_info != NULL)
 113         memcpy (((linfo_cb_arg_t *) arg)->lca_info, linfo,
 114                sizeof (ctf_lblinfo_t));
 115       return 1;         /* Indicate we found a match.  */
 116     }
 117
 118   return 0;
 119 }
 120
 121 /* Retrieve information about the label with name "lname". */
 122 int
 123 ctf_label_info (ctf_file_t *fp, const char *lname, ctf_lblinfo_t *linfo)
 124 {
 125   linfo_cb_arg_t cb_arg;
 126   int rc;
 127
 128   cb_arg.lca_name = lname;
 129   cb_arg.lca_info = linfo;
 130
 131   if ((rc = ctf_label_iter (fp, label_info_cb, &cb_arg)) < 0)
 132     return rc;
 133
 134   if (rc != 1)
 135     return (ctf_set_errno (fp, ECTF_NOLABEL));
 136
 137   return 0;
 138 }