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1 
2 /*--------------------------------------------------------------------*/
3 /*--- An abstraction that provides a file-reading mechanism.       ---*/
4 /*---                                                 priv_image.h ---*/
5 /*--------------------------------------------------------------------*/
6 
7 /*
8    This file is part of Valgrind, a dynamic binary instrumentation
9    framework.
10 
11    Copyright (C) 2013-2013 Mozilla Foundation
12 
13    This program is free software; you can redistribute it and/or
14    modify it under the terms of the GNU General Public License as
15    published by the Free Software Foundation; either version 2 of the
16    License, or (at your option) any later version.
17 
18    This program is distributed in the hope that it will be useful, but
19    WITHOUT ANY WARRANTY; without even the implied warranty of
20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
21    General Public License for more details.
22 
23    You should have received a copy of the GNU General Public License
24    along with this program; if not, write to the Free Software
25    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
26    02111-1307, USA.
27 
28    The GNU General Public License is contained in the file COPYING.
29 */
30 
31 /* Contributed by Julian Seward <jseward@acm.org> */
32 
33 #ifndef __PRIV_IMAGE_H
34 #define __PRIV_IMAGE_H
35 
36 #include "pub_core_basics.h"    // ULong
37 #include "priv_misc.h"          // ML_(dinfo_zalloc)
38 
39 /*------------------------------------------------------------*/
40 /*--- DiImage -- abstract images                           ---*/
41 /*------------------------------------------------------------*/
42 
43 /* The basic type, containing an abstractified memory area that can be
44    read from.  This is an abstract type since there can be more than
45    one implementation of it. */
46 
47 /* abstract */
48 typedef  struct _DiImage  DiImage;
49 
50 /* an offset in the image */
51 typedef  ULong  DiOffT;
52 
53 /* This denotes an invalid DiOffT value.  Except where otherwise
54    noted, you must never pass this to any of the ML_(image_*)
55    functions -- they will assert.  That does mean though that they can
56    be used for signalling other conditions, for example that some
57    expected part of the image is missing. */
58 #define DiOffT_INVALID ((DiOffT)(0xFFFFFFFFFFFFFFFFULL))
59 
60 /* Create an image from a file in the local filesysem.  Returns NULL
61    if it fails, for whatever reason. */
62 DiImage* ML_(img_from_local_file)(const HChar* fullpath);
63 
64 /* Create an image by connecting to a Valgrind debuginfo server
65    (auxprogs/valgrind-di-server.c).  |filename| contains the object
66    name to ask for; it must be a plain filename, not absolute, not a
67    path.  |serverAddr| must be of the form either "d.d.d.d" or
68    "d.d.d.d:d" where d is one or more digits.  These specify the IPv4
69    address and (in the second case) port number for the server.  In
70    the first case, port 1500 is assumed. */
71 DiImage* ML_(img_from_di_server)(const HChar* filename,
72                                  const HChar* serverAddr);
73 
74 /* Destroy an existing image. */
75 void ML_(img_done)(DiImage*);
76 
77 /* How big is the image? */
78 DiOffT ML_(img_size)(DiImage* img);
79 
80 /* Does the section [offset, +size) exist in the image? */
81 Bool ML_(img_valid)(DiImage* img, DiOffT offset, SizeT size);
82 
83 /* Get info out of an image.  If any part of the section denoted by
84    [offset, +size) is invalid, does not return. */
85 void ML_(img_get)(/*OUT*/void* dst,
86                   DiImage* img, DiOffT offset, SizeT size);
87 
88 /* A version of ML_(img_get) that is significantly cheaper when
89    fetching a lot of data, at the cost of being more difficult to use.
90    Fetches between 1 and |size| bytes from |img| at |offset| and
91    places them in |dst|.  |size| must be at least 1.  The number of
92    bytes read is returned, and the caller must be able to deal with
93    any number between 1 and |size|.  |offset| must be a valid offset
94    in the image; if not the function will not return.  This function
95    will not read off the end of the image. */
96 SizeT ML_(img_get_some)(/*OUT*/void* dst,
97                         DiImage* img, DiOffT offset, SizeT size);
98 
99 /* Copy a C string out of the image, into ML_(dinfo_zalloc)'d space.
100    The caller owns the string and must free it with ML_(dinfo_free).
101    |offset| may be DiOffT_INVALID, in which case this returns NULL. */
102 HChar* ML_(img_strdup)(DiImage* img, const HChar* cc, DiOffT offset);
103 
104 /* Do strcmp on two C strings in the image.  Chars are cast to HChar
105    before comparison. */
106 Int ML_(img_strcmp)(DiImage* img, DiOffT off1, DiOffT off2);
107 
108 /* Do strcmp of a C string in the image vs a normal one.  Chars are
109    cast to HChar before comparison. */
110 Int ML_(img_strcmp_c)(DiImage* img, DiOffT off1, const HChar* str2);
111 
112 /* Do strlen of a C string in the image. */
113 SizeT ML_(img_strlen)(DiImage* img, DiOffT off);
114 
115 /* Fetch various sized primitive types from the image.  These operate
116    at the endianness and word size of the host. */
117 UChar  ML_(img_get_UChar) (DiImage* img, DiOffT offset);
118 UShort ML_(img_get_UShort)(DiImage* img, DiOffT offset);
119 UInt   ML_(img_get_UInt)  (DiImage* img, DiOffT offset);
120 ULong  ML_(img_get_ULong) (DiImage* img, DiOffT offset);
121 
122 /* Calculate the "GNU Debuglink CRC" for the image.  This
123    unfortunately has to be done as part of the DiImage implementation
124    because it involves reading the entire image, and is therefore
125    something that needs to be handed off to the remote server -- since
126    to do it otherwise would imply pulling the entire image across the
127    connection, making the client/server split pointless. */
128 UInt ML_(img_calc_gnu_debuglink_crc32)(DiImage* img);
129 
130 
131 /*------------------------------------------------------------*/
132 /*--- DiCursor -- cursors for reading images               ---*/
133 /*------------------------------------------------------------*/
134 
135 /* A type built on DiImage.  It contains a DiImage and a 'current
136    offset' in the image, and is useful for building low level readers
137    of images.  In the functions section below, "read" means "read data
138    at the cursor without moving it along", and "step" means "read data
139    at the cursor and move it along by the size of the item read". */
140 typedef
141    struct { DiImage* img; DiOffT ioff; }
142    DiCursor;
143 
144 /* An invalid cursor.  You can't use it for anything. */
145 #define DiCursor_INVALID ((DiCursor){NULL,DiOffT_INVALID})
146 
mk_DiCursor(DiImage * img,DiOffT ioff)147 static inline DiCursor mk_DiCursor ( DiImage* img, DiOffT ioff ) {
148    return (DiCursor){img, ioff};
149 }
150 
ML_(cur_is_valid)151 static inline Bool ML_(cur_is_valid)(DiCursor c) {
152    return c.img != NULL;
153 }
154 
155 
156 /*------------------------------------------------------------*/
157 /*--- DiSlice -- subranges within DiImages                 ---*/
158 /*------------------------------------------------------------*/
159 
160 /* Another type built on top of DiImage.  It denotes a subrange of an
161    image and is useful for representing (eg) exactly the part of an
162    image that is a specific ELF section. */
163 typedef
164    struct { DiImage* img; DiOffT ioff; DiOffT szB; }
165    DiSlice;
166 
167 /* A DiSlice can also be INVALID, meaning it does not refer to any
168    part of any image. */
169 #define DiSlice_INVALID ((DiSlice){NULL,DiOffT_INVALID,0})
170 
mk_DiSlice(DiImage * img,DiOffT ioff,DiOffT szB)171 static inline DiSlice mk_DiSlice ( DiImage* img, DiOffT ioff, DiOffT szB ) {
172    return (DiSlice){img, ioff, szB};
173 }
174 
ML_(sli_is_valid)175 static inline Bool ML_(sli_is_valid)( DiSlice sli ) {
176    return sli.img != NULL;
177 }
178 
179 /* Create a slice from a combination of a cursor and a length.  The
180    maximum implied offset must not exceed the size of the underlying
181    image; this is asserted for. */
ML_(sli_from_cur)182 static inline DiSlice ML_(sli_from_cur)( DiCursor cur, DiOffT size ) {
183    if (ML_(cur_is_valid)(cur)) {
184       vg_assert(size != DiOffT_INVALID);
185       vg_assert(cur.ioff + size <= ML_(img_size)(cur.img));
186       return mk_DiSlice(cur.img, cur.ioff, size);
187    } else {
188       return DiSlice_INVALID;
189    }
190 }
191 
192 /* Create a slice which exactly covers the given image. */
ML_(sli_from_img)193 static inline DiSlice ML_(sli_from_img)( DiImage* img ) {
194    if (img) {
195       return mk_DiSlice(img, 0, ML_(img_size)(img));
196    } else {
197       return DiSlice_INVALID;
198    }
199 }
200 
201 
202 /*------------------------------------------------------------*/
203 /*--- Functions that operate on DiCursors                  ---*/
204 /*------------------------------------------------------------*/
205 
206 /* Create a cursor from a slice, referring to the first byte of the
207    slice. */
ML_(cur_from_sli)208 static inline DiCursor ML_(cur_from_sli)( DiSlice sl ) {
209    if (ML_(sli_is_valid)(sl)) {
210       DiCursor c;
211       c.img  = sl.img;
212       c.ioff = sl.ioff;
213       return c;
214    } else {
215       return DiCursor_INVALID;
216    }
217 }
218 
ML_(cur_cmpLT)219 static inline Bool ML_(cur_cmpLT)( DiCursor c1, DiCursor c2 ) {
220    vg_assert(c1.img == c2.img);
221    return c1.ioff < c2.ioff;
222 }
ML_(cur_cmpEQ)223 static inline Bool ML_(cur_cmpEQ)( DiCursor c1, DiCursor c2 ) {
224    vg_assert(c1.img == c2.img);
225    return c1.ioff == c2.ioff;
226 }
ML_(cur_cmpGT)227 static inline Bool ML_(cur_cmpGT)( DiCursor c1, DiCursor c2 ) {
228    vg_assert(c1.img == c2.img);
229    return c1.ioff > c2.ioff;
230 }
231 
ML_(cur_plus)232 static inline DiCursor ML_(cur_plus)( DiCursor c, Long n ) {
233    c.ioff += (DiOffT)n;
234    return c;
235 }
236 
237 /* Asserts that c1 and c2 refer to the same image.  Returns the difference
238    in offsets (c1.ioff - c2.ioff). */
ML_(cur_minus)239 static inline Long ML_(cur_minus)( DiCursor c1, DiCursor c2 ) {
240    vg_assert(c1.img == c2.img);
241    return (Long)(c1.ioff) - (Long)(c2.ioff);
242 }
243 
ML_(cur_strlen)244 static inline SizeT ML_(cur_strlen)( DiCursor c ) {
245    return ML_(img_strlen)( c.img, c.ioff );
246 }
247 
248 // strdup from the given cursor.  Caller must ML_(dinfo_free) the
249 // resulting string.
ML_(cur_read_strdup)250 static inline HChar* ML_(cur_read_strdup)( DiCursor c, const HChar* cc ) {
251    vg_assert(c.ioff != DiOffT_INVALID);
252    HChar* res = ML_(img_strdup)(c.img, cc, c.ioff);
253    return res;
254 }
255 // strdup from the given cursor and advance it.  Caller must
256 // ML_(dinfo_free) the resulting string.
ML_(cur_step_strdup)257 static inline HChar* ML_(cur_step_strdup)( DiCursor* c, const HChar* cc ) {
258    vg_assert(c->ioff != DiOffT_INVALID);
259    HChar* res = ML_(img_strdup)(c->img, cc, c->ioff);
260    c->ioff += VG_(strlen)(res) + 1;
261    return res;
262 }
263 
264 // Fetch an arbitrary number of bytes from the cursor.
ML_(cur_read_get)265 static inline void ML_(cur_read_get) ( /*OUT*/void* dst,
266                                        DiCursor c, SizeT size) {
267    ML_(img_get)(dst, c.img, c.ioff, size);
268 }
269 
270 // Fetch an arbitrary number of bytes from the cursor, and advance it.
ML_(cur_step_get)271 static inline void ML_(cur_step_get) ( /*OUT*/void* dst,
272                                        DiCursor* c, SizeT size) {
273    ML_(img_get)(dst, c->img, c->ioff, size);
274    c->ioff += size;
275 }
276 
277 // memdup from the given cursor.  Caller must ML_(dinfo_free) the
278 // resulting block.
ML_(cur_read_memdup)279 static inline UChar* ML_(cur_read_memdup)( DiCursor c, SizeT size,
280                                            const HChar* cc )
281 {
282    UChar* dst = ML_(dinfo_zalloc)(cc, size);
283    if (size > 0)
284       ML_(cur_read_get)(dst, c, size);
285    return dst;
286 }
287 
ML_(cur_read_UChar)288 static inline UChar ML_(cur_read_UChar) ( DiCursor c ) {
289    UChar r = ML_(img_get_UChar)( c.img, c.ioff );
290    return r;
291 }
ML_(cur_step_UChar)292 static inline UChar ML_(cur_step_UChar)( DiCursor* c ) {
293    UChar r = ML_(img_get_UChar)( c->img, c->ioff );
294    c->ioff += sizeof(UChar);
295    return r;
296 }
297 
ML_(cur_read_UShort)298 static inline UShort ML_(cur_read_UShort) ( DiCursor c ) {
299    UShort r = ML_(img_get_UShort)( c.img, c.ioff );
300    return r;
301 }
ML_(cur_step_UShort)302 static inline UShort ML_(cur_step_UShort) ( DiCursor* c ) {
303    UShort r = ML_(img_get_UShort)( c->img, c->ioff );
304    c->ioff += sizeof(UShort);
305    return r;
306 }
ML_(cur_step_Short)307 static inline Short ML_(cur_step_Short) ( DiCursor* c ) {
308    return (Short)ML_(cur_step_UShort)( c );
309 }
310 
ML_(cur_read_UInt)311 static inline UInt ML_(cur_read_UInt) ( DiCursor c ) {
312    UInt r = ML_(img_get_UInt)( c.img, c.ioff );
313    return r;
314 }
ML_(cur_step_UInt)315 static inline UInt ML_(cur_step_UInt) ( DiCursor* c ) {
316    UInt r = ML_(img_get_UInt)( c->img, c->ioff );
317    c->ioff += sizeof(UInt);
318    return r;
319 }
ML_(cur_step_Int)320 static inline Int ML_(cur_step_Int) ( DiCursor* c ) {
321    return (Int)ML_(cur_step_UInt)( c );
322 }
323 
ML_(cur_read_ULong)324 static inline ULong ML_(cur_read_ULong) ( DiCursor c ) {
325    ULong r = ML_(img_get_ULong)( c.img, c.ioff );
326    return r;
327 }
ML_(cur_step_ULong)328 static inline ULong ML_(cur_step_ULong) ( DiCursor* c ) {
329    ULong r = ML_(img_get_ULong)( c->img, c->ioff );
330    c->ioff += sizeof(ULong);
331    return r;
332 }
ML_(cur_step_Long)333 static inline Long ML_(cur_step_Long) ( DiCursor* c ) {
334    return (Long)ML_(cur_step_ULong)( c );
335 }
336 
ML_(cur_step_Addr)337 static inline Addr ML_(cur_step_Addr) ( DiCursor* c ) {
338    if (sizeof(Addr) == sizeof(UInt)) {
339       return ML_(cur_step_UInt)(c);
340    } else if  (sizeof(Addr) == sizeof(ULong)) {
341       return ML_(cur_step_ULong)(c);
342    } else {
343       vg_assert(0);
344    }
345 }
346 
347 #endif /* ndef __PRIV_IMAGE_H */
348 
349 /*--------------------------------------------------------------------*/
350 /*--- end                                             priv_image.h ---*/
351 /*--------------------------------------------------------------------*/
352