lib/xref.c

   1 // SPDX-License-Identifier: ISC
   2 /*
   3  * Copyright (c) 2017-20  David Lamparter, for NetDEF, Inc.
   4  */
   5
   6 #ifdef HAVE_CONFIG_H
   7 #include "config.h"
   8 #endif
   9
  10 #include <stdlib.h>
  11 #include <stdarg.h>
  12 #include <string.h>
  13 #include <pthread.h>
  14 #include <signal.h>
  15 #include <inttypes.h>
  16
  17 #include "xref.h"
  18 #include "vty.h"
  19 #include "jhash.h"
  20 #include "sha256.h"
  21 #include "memory.h"
  22 #include "hash.h"
  23
  24 struct xref_block *xref_blocks;
  25 static struct xref_block **xref_block_last = &xref_blocks;
  26
  27 struct xrefdata_uid_head xrefdata_uid = INIT_RBTREE_UNIQ(xrefdata_uid);
  28
  29 static void base32(uint8_t **inpos, int *bitpos,
  30                    char *out, size_t n_chars)
  31 {
  32         static const char base32ch[] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
  33
  34         char *opos = out;
  35         uint8_t *in = *inpos;
  36         int bp = *bitpos;
  37
  38         while (opos < out + n_chars) {
  39                 uint32_t bits = in[0] | (in[1] << 8);
  40
  41                 if (bp == -1)
  42                         bits |= 0x10;
  43                 else
  44                         bits >>= bp;
  45
  46                 *opos++ = base32ch[bits & 0x1f];
  47
  48                 bp += 5;
  49                 if (bp >= 8)
  50                         in++, bp -= 8;
  51         }
  52         *opos = '\0';
  53         *inpos = in;
  54         *bitpos = bp;
  55 }
  56
  57 static void xref_add_one(const struct xref *xref)
  58 {
  59         SHA256_CTX sha;
  60         struct xrefdata *xrefdata;
  61
  62         const char *filename, *p, *q;
  63         uint8_t hash[32], *h = hash;
  64         uint32_t be_val;
  65         int bitpos;
  66
  67         if (!xref || !xref->xrefdata)
  68                 return;
  69
  70         xrefdata = xref->xrefdata;
  71         xrefdata->xref = xref;
  72
  73         if (!xrefdata->hashstr)
  74                 return;
  75
  76         /* as far as the unique ID is concerned, only use the last
  77          * directory name + filename, e.g. "bgpd/bgp_route.c".  This
  78          * gives a little leeway in moving things and avoids IDs being
  79          * screwed up by out of tree builds or absolute pathnames.
  80          */
  81         filename = xref->file;
  82         p = strrchr(filename, '/');
  83         if (p) {
  84                 q = memrchr(filename, '/', p - filename);
  85                 if (q)
  86                         filename = q + 1;
  87         }
  88
  89         SHA256_Init(&sha);
  90         SHA256_Update(&sha, filename, strlen(filename));
  91         SHA256_Update(&sha, xrefdata->hashstr,
  92                       strlen(xrefdata->hashstr));
  93         be_val = htonl(xrefdata->hashu32[0]);
  94         SHA256_Update(&sha, &be_val, sizeof(be_val));
  95         be_val = htonl(xrefdata->hashu32[1]);
  96         SHA256_Update(&sha, &be_val, sizeof(be_val));
  97         SHA256_Final(hash, &sha);
  98
  99         bitpos = -1;
 100         base32(&h, &bitpos, &xrefdata->uid[0], 5);
 101         xrefdata->uid[5] = '-';
 102         base32(&h, &bitpos, &xrefdata->uid[6], 5);
 103
 104         xrefdata_uid_add(&xrefdata_uid, xrefdata);
 105 }
 106
 107 void xref_gcc_workaround(const struct xref *xref)
 108 {
 109         xref_add_one(xref);
 110 }
 111
 112 void xref_block_add(struct xref_block *block)
 113 {
 114         const struct xref * const *xrefp;
 115
 116         *xref_block_last = block;
 117         xref_block_last = &block->next;
 118
 119         for (xrefp = block->start; xrefp < block->stop; xrefp++)
 120                 xref_add_one(*xrefp);
 121 }