summaryrefslogtreecommitdiffhomepage
path: root/src/object/mdso_objgen_symentry.c
blob: 47167c749d3a8c59b56c510e0c444223397399cc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
/****************************************************************/
/*  mdso: midipix dso scavenger                                 */
/*  Copyright (C) 2015--2017  Z. Gilboa                         */
/*  Released under GPLv2 and GPLv3; see COPYING.MDSO.           */
/****************************************************************/

#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include <mdso/mdso.h>
#include "mdso_object_impl.h"
#include "mdso_errinfo_impl.h"
#include "perk_consts.h"
#include "perk_structs.h"

struct mdso_symfn_references {
	unsigned char 	refs[16];
};

struct mdso_symentry_object {
	struct pe_raw_coff_object_hdr	hdr;
	struct pe_raw_sec_hdr		sec[2];
	struct mdso_symfn_references	ref[1];
	struct pe_raw_coff_reloc	rel[2];
	struct pe_raw_coff_symbol	sym[9];
	struct pe_raw_coff_strtbl	cst;
};

int mdso_objgen_symentry(
	const struct mdso_driver_ctx *	dctx,
	const char *			sym,
	FILE *				fout,
	struct mdso_object *		vobj)
{
	struct mdso_symentry_object *	syment;
	struct pe_raw_coff_symbol *	symrec;
	unsigned char *			mark;
	unsigned char *			mapsym;
	struct pe_raw_aux_rec_section *	aux;
	size_t				buflen;
	size_t				liblen;
	uint32_t			symlen;
	uint32_t			cstlen;
	uint32_t			objlen;
	uint32_t			aattr;
	uint32_t			sattr;
	uint32_t			rattr;
	uint16_t			oattr;
	uint16_t			machine;
	uint16_t			reltype;
	uint32_t			relrva;
	uint32_t			refoff;
	uint32_t			reloff;
	uint32_t			symoff;
	uint32_t			cstoff;
	uint32_t			datoff;
	uint32_t			stroff;
	uint32_t			uscore;

	if ((buflen = strlen(sym)) > 1024*1024)
		return MDSO_CUSTOM_ERROR(dctx,MDSO_ERR_INVALID_DATA);

	if ((liblen = strlen(dctx->cctx->libname)) > 1024*1024)
		return MDSO_CUSTOM_ERROR(dctx,MDSO_ERR_INVALID_DATA);

	symlen = (uint32_t)buflen;
	cstlen = (uint32_t)liblen + (3 * symlen) + 64;
	objlen = sizeof(*syment) + cstlen;
	uscore = !(dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR);

	if (vobj && vobj->addr && (vobj->size < objlen))
		return MDSO_BUFFER_ERROR(dctx);

	if (vobj && !vobj->addr) {
		vobj->size = objlen;
		vobj->mapstrsnum = 1;
		vobj->mapstrslen = 7 + uscore + symlen;
		return 0;
	}

	if (vobj)
		syment = (struct mdso_symentry_object *)vobj->addr;

	else if (!(syment = calloc(1,objlen)))
		return MDSO_SYSTEM_ERROR(dctx);

	if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
		aattr   = PE_IMAGE_SCN_ALIGN_16BYTES;
		machine = PE_IMAGE_FILE_MACHINE_AMD64;
		reltype = PE_IMAGE_REL_AMD64_ADDR64;
		relrva  = 8;
	} else {
		aattr   = PE_IMAGE_SCN_ALIGN_4BYTES;
		machine = PE_IMAGE_FILE_MACHINE_I386;
		reltype = PE_IMAGE_REL_I386_DIR32;
		relrva  = 4;
	}

	sattr  = PE_IMAGE_SCN_ALIGN_1BYTES;
	sattr |= PE_IMAGE_SCN_MEM_READ;
	sattr |= PE_IMAGE_SCN_CNT_INITIALIZED_DATA;

	rattr  = aattr;
	rattr |= PE_IMAGE_SCN_MEM_READ;
	rattr |= PE_IMAGE_SCN_CNT_INITIALIZED_DATA;

	oattr  = PE_IMAGE_FILE_LINE_NUMS_STRIPPED;
	refoff = offsetof(struct mdso_symentry_object,ref);
	reloff = offsetof(struct mdso_symentry_object,rel);
	symoff = offsetof(struct mdso_symentry_object,sym);
	cstoff = offsetof(struct pe_raw_coff_strtbl,cst_data);
	datoff = 0;

	stroff  = objlen - symlen - 16;
	stroff += 0xf;
	stroff |= 0xf;
	stroff ^= 0xf;

	/* coff object header */
	mdso_obj_write_short(syment->hdr.cfh_machine,machine);
	mdso_obj_write_short(syment->hdr.cfh_num_of_sections,2);
	mdso_obj_write_long(syment->hdr.cfh_ptr_to_sym_tbl,symoff);
	mdso_obj_write_long(syment->hdr.cfh_num_of_syms,9);
	mdso_obj_write_short(syment->hdr.cfh_characteristics,oattr);

	/* .dsostrs section header */
	memcpy(syment->sec[0].sh_name,".dsostrs",8);
	mdso_obj_write_long(syment->sec[0].sh_size_of_raw_data,symlen+1);
	mdso_obj_write_long(syment->sec[0].sh_ptr_to_raw_data,stroff);
	mdso_obj_write_long(syment->sec[0].sh_characteristics,sattr);

	/* .dsosyms section header */
	memcpy(syment->sec[1].sh_name,".dsosyms",8);
	mdso_obj_write_long(syment->sec[1].sh_size_of_raw_data,2*relrva);
	mdso_obj_write_long(syment->sec[1].sh_ptr_to_raw_data,refoff);
	mdso_obj_write_long(syment->sec[1].sh_ptr_to_relocs,reloff);
	mdso_obj_write_short(syment->sec[1].sh_num_of_relocs,2);
	mdso_obj_write_long(syment->sec[1].sh_characteristics,rattr);

	/* .dsosyms relocation record: .symstr */
	mdso_obj_write_long(syment->rel[0].rel_sym,6);
	mdso_obj_write_long(syment->rel[0].rel_rva,0);
	mdso_obj_write_short(syment->rel[0].rel_type,reltype);

	/* .dsosyms relocation record: .dsometa_libname */
	mdso_obj_write_long(syment->rel[1].rel_sym,8);
	mdso_obj_write_long(syment->rel[1].rel_rva,relrva);
	mdso_obj_write_short(syment->rel[1].rel_type,reltype);

	/* coff string table */
	mdso_obj_write_long(syment->cst.cst_size,cstlen);

	/* coff symbol table */
	symrec = syment->sym;
	mark   = syment->cst.cst_data;

	/* coff symbol: .file */
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_FILE;
	symrec[0].cs_num_of_aux_symbols[0] = 1;

	mdso_obj_write_short(&symrec[0].cs_section_number[0],PE_IMAGE_SYM_DEBUG);
	mdso_obj_write_long(&symrec[1].cs_name[4],cstoff+datoff);

	memcpy(symrec[0].cs_name,".file",5);
	memcpy(&mark[0],".",1);
	memcpy(&mark[1],sym,symlen);
	memcpy(&mark[1+symlen],"_symentry.s",11);

	datoff += 13 + symlen;
	mark   += 13 + symlen;
	symrec += 2;

	/* coff symbol: .dsostrs */
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
	symrec[0].cs_num_of_aux_symbols[0] = 1;

	mdso_obj_write_short(symrec[0].cs_section_number,1);
	memcpy(symrec[0].cs_name,".dsostrs",8);

	aux = (struct pe_raw_aux_rec_section *)&symrec[1];
	mdso_obj_write_long(aux->aux_size,symlen+1);
	mdso_obj_write_short(aux->aux_num_of_relocs,0);

	datoff += 0;
	mark   += 0;
	symrec += 2;

	/* coff symbol: .dsosyms */
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
	symrec[0].cs_num_of_aux_symbols[0] = 1;

	mdso_obj_write_short(symrec[0].cs_section_number,2);
	memcpy(symrec[0].cs_name,".dsosyms",8);

	aux = (struct pe_raw_aux_rec_section *)&symrec[1];
	mdso_obj_write_long(aux->aux_size,2*relrva);
	mdso_obj_write_short(aux->aux_num_of_relocs,2);

	datoff += 0;
	mark   += 0;
	symrec += 2;

	/* coff symbol: .symstr */
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_STATIC;
	symrec[0].cs_num_of_aux_symbols[0] = 0;

	mdso_obj_write_short(symrec[0].cs_section_number,1);
	memcpy(symrec[0].cs_name,".symstr",7);

	datoff += 0;
	mark   += 0;
	symrec += 1;

	/* coff symbol: __imp_sym */
	mapsym = mark;
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_EXTERNAL;
	symrec[0].cs_num_of_aux_symbols[0] = 0;

	mdso_obj_write_short(symrec[0].cs_section_number,2);
	mdso_obj_write_long(&symrec[0].cs_name[4],cstoff+datoff);

	if (dctx->cctx->drvflags & MDSO_DRIVER_QUAD_PTR) {
		memcpy(&mark[0],"__imp_",6);
		memcpy(&mark[6],sym,symlen);
	} else {
		memcpy(&mark[0],"__imp_",6);
		memcpy(&mark[7],sym,symlen);
		mark[6] = '_';
		datoff++;
		mark++;
	}

	datoff += 7 + symlen;
	mark   += 7 + symlen;
	symrec += 1;

	/* archive symbol map */
	if (vobj && vobj->mapstrs)
		memcpy(vobj->mapstrs,mapsym,mark-mapsym);

	/* coff symbol: .dsometa_libname */
	symrec[0].cs_storage_class[0] = PE_IMAGE_SYM_CLASS_EXTERNAL;
	symrec[0].cs_num_of_aux_symbols[0] = 0;

	mdso_obj_write_short(symrec[0].cs_section_number,0);
	mdso_obj_write_long(&symrec[0].cs_name[4],cstoff+datoff);

	memcpy(&mark[0],".dsometa_",9);
	memcpy(&mark[9],dctx->cctx->libname,liblen);

	/* .symstr */
	mark = syment->hdr.cfh_machine;
	memcpy(&mark[stroff],sym,symlen);

	/* tada */
	if (fout)
		if (fwrite(syment,objlen,1,fout) == 0)
			return MDSO_FILE_ERROR(dctx);

	if (!vobj)
		free(syment);

	return 0;
}