From 8e427c293860576df43ead3639bac807e2a43b03 Mon Sep 17 00:00:00 2001 From: David Lamparter Date: Thu, 9 Aug 2018 22:50:19 +0200 Subject: lib: "xref" identifier infrastructure This adds the machinery for cross reference points (hence "xref") for things to be annotated with source code location or other metadata and/or to be uniquely identified and found at runtime or by dissecting executable files. The extraction tool to walk down an ELF file is done and working but needs some more cleanup and will be added in a separate commit. Signed-off-by: David Lamparter --- lib/xref.c | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 lib/xref.c (limited to 'lib/xref.c') diff --git a/lib/xref.c b/lib/xref.c new file mode 100644 index 0000000000..eb5e8ed2c2 --- /dev/null +++ b/lib/xref.c @@ -0,0 +1,122 @@ +/* + * Copyright (c) 2017-20 David Lamparter, for NetDEF, Inc. + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include +#include +#include +#include +#include +#include + +#include "xref.h" +#include "vty.h" +#include "jhash.h" +#include "sha256.h" +#include "memory.h" +#include "hash.h" + +struct xref_block *xref_blocks; +static struct xref_block **xref_block_last = &xref_blocks; + +static void base32(uint8_t **inpos, int *bitpos, + char *out, size_t n_chars) +{ + static const char base32ch[] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ"; + + char *opos = out; + uint8_t *in = *inpos; + int bp = *bitpos; + + while (opos < out + n_chars) { + uint32_t bits = in[0] | (in[1] << 8); + + if (bp == -1) + bits |= 0x10; + else + bits >>= bp; + + *opos++ = base32ch[bits & 0x1f]; + + bp += 5; + if (bp >= 8) + in++, bp -= 8; + } + *opos = '\0'; + *inpos = in; + *bitpos = bp; +} + +void xref_block_add(struct xref_block *block) +{ + const struct xref * const *xrefp; + SHA256_CTX sha; + + *xref_block_last = block; + xref_block_last = &block->next; + + for (xrefp = block->start; xrefp < block->stop; xrefp++) { + const struct xref *xref = *xrefp; + struct xrefdata *xrefdata; + + const char *filename, *p, *q; + uint8_t hash[32], *h = hash; + uint32_t be_val; + int bitpos; + + if (!xref || !xref->xrefdata) + continue; + + xrefdata = xref->xrefdata; + xrefdata->xref = xref; + + if (!xrefdata->hashstr) + continue; + + /* as far as the unique ID is concerned, only use the last + * directory name + filename, e.g. "bgpd/bgp_route.c". This + * gives a little leeway in moving things and avoids IDs being + * screwed up by out of tree builds or absolute pathnames. + */ + filename = xref->file; + p = strrchr(filename, '/'); + if (p) { + q = memrchr(filename, '/', p - filename); + if (q) + filename = q + 1; + else + filename = p + 1; + } + + SHA256_Init(&sha); + SHA256_Update(&sha, filename, strlen(filename)); + SHA256_Update(&sha, xrefdata->hashstr, + strlen(xrefdata->hashstr)); + be_val = htonl(xrefdata->hashu32[0]); + SHA256_Update(&sha, &be_val, sizeof(be_val)); + be_val = htonl(xrefdata->hashu32[1]); + SHA256_Update(&sha, &be_val, sizeof(be_val)); + SHA256_Final(hash, &sha); + + bitpos = -1; + base32(&h, &bitpos, &xrefdata->uid[0], 5); + xrefdata->uid[5] = '-'; + base32(&h, &bitpos, &xrefdata->uid[6], 5); + } +} -- cgit v1.2.3