# $OpenBSD: parse_structinfo.awk,v 1.1 2009/08/09 23:04:49 miod Exp $ # # Copyright (c) 2009 Miodrag Vallat. # # 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. # # This ugly script parses the output of objdump -g in order to extract # structure layout information, to be used by ddb. # # The output of this script is the following static data: # - for each struct: # - its name # - its size (individual element size if an array) # - the number of elements in the array (1 if not) # - its first and last field indexes # - for each field: # - its name # - its offset and size # - the index of the struct it is member of # This allows fast struct -> field information retrieval. # # To retrieve information from a field size or offset, we also output # the following reverse arrays: # - for each offset, in ascending order, a variable length list of field # indexes. # - for each size, in ascending order, a variable length list of field # indexes. # # The compromise here is that I want to minimize linear searches. Memory # use is considered secondary, hence the back `pointer' to the struct in the # fields array. # # No attempt is made to share name pointers when multiple fields share # the same name. Rewriting this script in perl, or any other language # with hash data structures, would be a good time to add this. BEGIN { depth = 0; ignore = 0; scnt = 0; # current struct count sidx = -1; # current struct index # field index #0 is used as a sentinel. fcnt = 1; # current field count fidx = 0; # current field index ocnt = 0; # current offset count zcnt = 0; # current size count } /^struct / { depth = 1; sidx = scnt; sname[sidx] = $2; ssize[sidx] = $6; sfieldmin[sidx] = fcnt; scnt++; #printf("struct %d %s (size %d)\n", sidx, $2, $6); next; } /^};/ { if (depth != 0) { depth = 0; if (fcnt == sfieldmin[sidx]) # empty struct, ignore it scnt--; else sfieldmax[sidx] = fidx; } else ignore--; next; } /{.*}/ { # single line enum next; } /{/ { # subcomponent if (depth != 0) { depth++; } else { ignore++; } next; } /}/ { if (ignore != 0) { ignore--; next; } else { depth--; } if (depth != 1) next; # FALLTHROUGH } /bitsize/ { if (ignore != 0) next; if (depth != 1) next; # Bitfields are a PITA... From a ddb point of view, we can't really # access storage units smaller than a byte. # So we'll report all bitfields as having size 0, and the # rounded down byte position where they start. cursize = int($(NF - 3)); curoffs = int($(NF - 1) / 8); if ((cursize % 8) != 0) cursize = 0; else cursize /= 8; # try and gather the field name. field = $(NF - 6); if (field == "};") { # anonymous union. discard it. next; } if (field == "*/);") { field = $(NF - 9); # function pointer # remove enclosing braces field = substr(field, 2, length(field) - 2); } colon = index(field, ":"); if (colon != 0) field = substr(field, 1, colon - 1); else if (substr(field, length(field), 1) == ";") field = substr(field, 1, length(field) - 1); while (index(field, "*") == 1) field = substr(field, 2); # This could be an array. If it is, we need to trim the field # name and update its size to a single member size. obracket = index(field, "["); cbracket = index(field, "]"); if (obracket != 0) { obracket++; nitems = substr(field, obracket, cbracket - obracket); field = substr(field, 1, obracket - 2); cursize /= nitems; } else nitems = 1; fidx = fcnt; fname[fidx] = field; foffs[fidx] = curoffs; fsize[fidx] = cursize; fitems[fidx] = nitems; fstruct[fidx] = sidx; fcnt++; #printf(" %s at %d len %d\n", field, curoffs, cursize); # Remember size and offset if not found yet for (i = 0; i < ocnt; i++) if (offs[i] == curoffs) break; if (i == ocnt) { # keep array sorted for (i = 0; i < ocnt; i++) if (offs[i] > curoffs) break; if (i < ocnt) { for (j = ocnt + 1; j > i; j--) offs[j] = offs[j - 1]; } offs[i] = curoffs; ocnt++; } for (i = 0; i < zcnt; i++) if (sizes[i] == cursize) break; if (i == zcnt) { # keep array sorted for (i = 0; i < zcnt; i++) if (sizes[i] > cursize) break; if (i < zcnt) { for (j = zcnt + 1; j > i; j--) sizes[j] = sizes[j - 1]; } sizes[i] = cursize; zcnt++; } } END { printf("/*\n"); printf(" * THIS IS A GENERATED FILE. DO NOT EDIT!\n"); printf(" */\n\n"); printf("#include <sys/param.h>\n"); printf("#include <sys/types.h>\n"); printf("\n"); # structure definitions printf("struct ddb_struct_info {\n"); printf("\tconst char *name;\n"); printf("\tsize_t size;\n"); printf("\tuint fmin, fmax;\n"); printf("};\n"); printf("struct ddb_field_info {\n"); printf("\tconst char *name;\n"); printf("\tuint sidx;\n"); printf("\tsize_t offs;\n"); printf("\tsize_t size;\n"); printf("\tuint nitems;\n"); printf("};\n"); printf("struct ddb_field_offsets {\n"); printf("\tsize_t offs;\n"); printf("\tconst uint *list;\n"); printf("};\n"); printf("struct ddb_field_sizes {\n"); printf("\tsize_t size;\n"); printf("\tconst uint *list;\n"); printf("};\n"); # forward arrays printf("#define NSTRUCT %d\n", scnt); printf("static const struct ddb_struct_info ddb_struct_info[NSTRUCT] = {\n"); for (i = 0; i < scnt; i++) { printf("\t{ \"%s\", %d, %d, %d },\n", sname[i], ssize[i], sfieldmin[i], sfieldmax[i]); } printf("};\n\n"); printf("#define NFIELD %d\n", fcnt); printf("static const struct ddb_field_info ddb_field_info[NFIELD] = {\n"); printf("\t{ NULL, 0, 0, 0 },\n"); for (i = 1; i < fcnt; i++) { printf("\t{ \"%s\", %d, %d, %d, %d },\n", fname[i], fstruct[i], foffs[i], fsize[i], fitems[i]); } printf("};\n\n"); # reverse arrays printf("static const uint ddb_fields_by_offset[] = {\n"); w = 0; for (i = 0; i < ocnt; i++) { cmp = offs[i]; ohead[i] = w; for (f = 1; f < fcnt; f++) if (foffs[f] == cmp) { if ((w % 10) == 0) printf("\t"); printf("%d, ", f); w++; if ((w % 10) == 0) printf("\n"); } if ((w % 10) == 0) printf("\t"); printf("0, "); w++; if ((w % 10) == 0) printf("\n"); } if ((w % 10) != 0) printf("\n"); printf("};\n\n"); printf("#define NOFFS %d\n", ocnt); printf("static const struct ddb_field_offsets ddb_field_offsets[NOFFS] = {\n"); for (i = 0; i < ocnt; i++) { printf("\t{ %d, ddb_fields_by_offset + %d },\n", offs[i], ohead[i]); } printf("};\n\n"); printf("static const uint ddb_fields_by_size[] = {\n"); w = 0; for (i = 0; i < zcnt; i++) { cmp = sizes[i]; zhead[i] = w; for (f = 1; f < fcnt; f++) if (fsize[f] == cmp) { if ((w % 10) == 0) printf("\t"); printf("%d, ", f); w++; if ((w % 10) == 0) printf("\n"); } if ((w % 10) == 0) printf("\t"); printf("0, "); w++; if ((w % 10) == 0) printf("\n"); } if ((w % 10) != 0) printf("\n"); printf("};\n\n"); printf("#define NSIZES %d\n", zcnt); printf("static const struct ddb_field_sizes ddb_field_sizes[NSIZES] = {\n"); for (i = 0; i < zcnt; i++) { printf("\t{ %d, ddb_fields_by_size + %d },\n", sizes[i], zhead[i]); } printf("};\n"); }