lib/xref.c

   1 /*
   2  * Copyright (c) 2017-20  David Lamparter, for NetDEF, Inc.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #ifdef HAVE_CONFIG_H
  18 #include "config.h"
  19 #endif
  20
  21 #include <stdlib.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #include <pthread.h>
  25 #include <signal.h>
  26 #include <inttypes.h>
  27
  28 #include "xref.h"
  29 #include "vty.h"
  30 #include "jhash.h"
  31 #include "sha256.h"
  32 #include "memory.h"
  33 #include "hash.h"
  34
  35 struct xref_block *xref_blocks;
  36 static struct xref_block **xref_block_last = &xref_blocks;
  37
  38 static void base32(uint8_t **inpos, int *bitpos,
  39                    char *out, size_t n_chars)
  40 {
  41         static const char base32ch[] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
  42
  43         char *opos = out;
  44         uint8_t *in = *inpos;
  45         int bp = *bitpos;
  46
  47         while (opos < out + n_chars) {
  48                 uint32_t bits = in[0] | (in[1] << 8);
  49
  50                 if (bp == -1)
  51                         bits |= 0x10;
  52                 else
  53                         bits >>= bp;
  54
  55                 *opos++ = base32ch[bits & 0x1f];
  56
  57                 bp += 5;
  58                 if (bp >= 8)
  59                         in++, bp -= 8;
  60         }
  61         *opos = '\0';
  62         *inpos = in;
  63         *bitpos = bp;
  64 }
  65
  66 static void xref_add_one(const struct xref *xref)
  67 {
  68         SHA256_CTX sha;
  69         struct xrefdata *xrefdata;
  70
  71         const char *filename, *p, *q;
  72         uint8_t hash[32], *h = hash;
  73         uint32_t be_val;
  74         int bitpos;
  75
  76         if (!xref || !xref->xrefdata)
  77                 return;
  78
  79         xrefdata = xref->xrefdata;
  80         xrefdata->xref = xref;
  81
  82         if (!xrefdata->hashstr)
  83                 return;
  84
  85         /* as far as the unique ID is concerned, only use the last
  86          * directory name + filename, e.g. "bgpd/bgp_route.c".  This
  87          * gives a little leeway in moving things and avoids IDs being
  88          * screwed up by out of tree builds or absolute pathnames.
  89          */
  90         filename = xref->file;
  91         p = strrchr(filename, '/');
  92         if (p) {
  93                 q = memrchr(filename, '/', p - filename);
  94                 if (q)
  95                         filename = q + 1;
  96         }
  97
  98         SHA256_Init(&sha);
  99         SHA256_Update(&sha, filename, strlen(filename));
 100         SHA256_Update(&sha, xrefdata->hashstr,
 101                       strlen(xrefdata->hashstr));
 102         be_val = htonl(xrefdata->hashu32[0]);
 103         SHA256_Update(&sha, &be_val, sizeof(be_val));
 104         be_val = htonl(xrefdata->hashu32[1]);
 105         SHA256_Update(&sha, &be_val, sizeof(be_val));
 106         SHA256_Final(hash, &sha);
 107
 108         bitpos = -1;
 109         base32(&h, &bitpos, &xrefdata->uid[0], 5);
 110         xrefdata->uid[5] = '-';
 111         base32(&h, &bitpos, &xrefdata->uid[6], 5);
 112 }
 113
 114 void xref_gcc_workaround(const struct xref *xref)
 115 {
 116         xref_add_one(xref);
 117 }
 118
 119 void xref_block_add(struct xref_block *block)
 120 {
 121         const struct xref * const *xrefp;
 122
 123         *xref_block_last = block;
 124         xref_block_last = &block->next;
 125
 126         for (xrefp = block->start; xrefp < block->stop; xrefp++)
 127                 xref_add_one(*xrefp);
 128 }