1 
2 /* pngerror.c - stub functions for i/o and memory allocation
3  *
4  * Last changed in libpng 1.2.22 [November 6, 2007]
5  * For conditions of distribution and use, see copyright notice in png.h
6  * Copyright (c) 1998-2007 Glenn Randers-Pehrson
7  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9  *
10  * This file provides a location for all error handling.  Users who
11  * need special error handling are expected to write replacement functions
12  * and use png_set_error_fn() to use those functions.  See the instructions
13  * at each function.
14  */
15 
16 #define PNG_INTERNAL
17 #include "png.h"
18 
19 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
20 static void /* PRIVATE */
21 png_default_error PNGARG((png_structp png_ptr,
22   png_const_charp error_message));
23 #ifndef PNG_NO_WARNINGS
24 static void /* PRIVATE */
25 png_default_warning PNGARG((png_structp png_ptr,
26   png_const_charp warning_message));
27 #endif /* PNG_NO_WARNINGS */
28 
29 /* This function is called whenever there is a fatal error.  This function
30  * should not be changed.  If there is a need to handle errors differently,
31  * you should supply a replacement error function and use png_set_error_fn()
32  * to replace the error function at run-time.
33  */
34 #ifndef PNG_NO_ERROR_TEXT
35 void PNGAPI
png_error(png_structp png_ptr,png_const_charp error_message)36 png_error(png_structp png_ptr, png_const_charp error_message)
37 {
38 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
39    char msg[16];
40    if (png_ptr != NULL)
41    {
42      if (png_ptr->flags&
43        (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
44      {
45        if (*error_message == '#')
46        {
47            int offset;
48            for (offset=1; offset<15; offset++)
49               if (*(error_message+offset) == ' ')
50                   break;
51            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
52            {
53               int i;
54               for (i=0; i<offset-1; i++)
55                  msg[i]=error_message[i+1];
56               msg[i]='\0';
57               error_message=msg;
58            }
59            else
60               error_message+=offset;
61        }
62        else
63        {
64            if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
65            {
66               msg[0]='0';
67               msg[1]='\0';
68               error_message=msg;
69            }
70        }
71      }
72    }
73 #endif
74    if (png_ptr != NULL && png_ptr->error_fn != NULL)
75       (*(png_ptr->error_fn))(png_ptr, error_message);
76 
77    /* If the custom handler doesn't exist, or if it returns,
78       use the default handler, which will not return. */
79    png_default_error(png_ptr, error_message);
80 }
81 #else
82 void PNGAPI
png_err(png_structp png_ptr)83 png_err(png_structp png_ptr)
84 {
85    if (png_ptr != NULL && png_ptr->error_fn != NULL)
86       (*(png_ptr->error_fn))(png_ptr, '\0');
87 
88    /* If the custom handler doesn't exist, or if it returns,
89       use the default handler, which will not return. */
90    png_default_error(png_ptr, '\0');
91 }
92 #endif /* PNG_NO_ERROR_TEXT */
93 
94 #ifndef PNG_NO_WARNINGS
95 /* This function is called whenever there is a non-fatal error.  This function
96  * should not be changed.  If there is a need to handle warnings differently,
97  * you should supply a replacement warning function and use
98  * png_set_error_fn() to replace the warning function at run-time.
99  */
100 void PNGAPI
png_warning(png_structp png_ptr,png_const_charp warning_message)101 png_warning(png_structp png_ptr, png_const_charp warning_message)
102 {
103    int offset = 0;
104    if (png_ptr != NULL)
105    {
106 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
107    if (png_ptr->flags&
108      (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
109 #endif
110      {
111        if (*warning_message == '#')
112        {
113            for (offset=1; offset<15; offset++)
114               if (*(warning_message+offset) == ' ')
115                   break;
116        }
117      }
118      if (png_ptr != NULL && png_ptr->warning_fn != NULL)
119         (*(png_ptr->warning_fn))(png_ptr, warning_message+offset);
120    }
121    else
122       png_default_warning(png_ptr, warning_message+offset);
123 }
124 #endif /* PNG_NO_WARNINGS */
125 
126 
127 /* These utilities are used internally to build an error message that relates
128  * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
129  * this is used to prefix the message.  The message is limited in length
130  * to 63 bytes, the name characters are output as hex digits wrapped in []
131  * if the character is invalid.
132  */
133 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
134 static PNG_CONST char png_digit[16] = {
135    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
136    'A', 'B', 'C', 'D', 'E', 'F'
137 };
138 
139 #define PNG_MAX_ERROR_TEXT 64
140 
141 #if !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT)
142 static void /* PRIVATE */
png_format_buffer(png_structp png_ptr,png_charp buffer,png_const_charp error_message)143 png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
144    error_message)
145 {
146    int iout = 0, iin = 0;
147 
148    while (iin < 4)
149    {
150       int c = png_ptr->chunk_name[iin++];
151       if (isnonalpha(c))
152       {
153          buffer[iout++] = '[';
154          buffer[iout++] = png_digit[(c & 0xf0) >> 4];
155          buffer[iout++] = png_digit[c & 0x0f];
156          buffer[iout++] = ']';
157       }
158       else
159       {
160          buffer[iout++] = (png_byte)c;
161       }
162    }
163 
164    if (error_message == NULL)
165       buffer[iout] = '\0';
166    else
167    {
168       buffer[iout++] = ':';
169       buffer[iout++] = ' ';
170       png_memcpy(buffer+iout, error_message, PNG_MAX_ERROR_TEXT);
171       buffer[iout+PNG_MAX_ERROR_TEXT-1] = '\0';
172    }
173 }
174 
175 #ifdef PNG_READ_SUPPORTED
176 void PNGAPI
png_chunk_error(png_structp png_ptr,png_const_charp error_message)177 png_chunk_error(png_structp png_ptr, png_const_charp error_message)
178 {
179    char msg[18+PNG_MAX_ERROR_TEXT];
180    if (png_ptr == NULL)
181      png_error(png_ptr, error_message);
182    else
183    {
184      png_format_buffer(png_ptr, msg, error_message);
185      png_error(png_ptr, msg);
186    }
187 }
188 #endif /* PNG_READ_SUPPORTED */
189 #endif /* !defined(PNG_NO_WARNINGS) || !defined(PNG_NO_ERROR_TEXT) */
190 
191 #ifndef PNG_NO_WARNINGS
192 void PNGAPI
png_chunk_warning(png_structp png_ptr,png_const_charp warning_message)193 png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
194 {
195    char msg[18+PNG_MAX_ERROR_TEXT];
196    if (png_ptr == NULL)
197      png_warning(png_ptr, warning_message);
198    else
199    {
200      png_format_buffer(png_ptr, msg, warning_message);
201      png_warning(png_ptr, msg);
202    }
203 }
204 #endif /* PNG_NO_WARNINGS */
205 
206 
207 /* This is the default error handling function.  Note that replacements for
208  * this function MUST NOT RETURN, or the program will likely crash.  This
209  * function is used by default, or if the program supplies NULL for the
210  * error function pointer in png_set_error_fn().
211  */
212 static void /* PRIVATE */
png_default_error(png_structp png_ptr,png_const_charp error_message)213 png_default_error(png_structp png_ptr, png_const_charp error_message)
214 {
215 #ifndef PNG_NO_CONSOLE_IO
216 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
217    if (*error_message == '#')
218    {
219      int offset;
220      char error_number[16];
221      for (offset=0; offset<15; offset++)
222      {
223          error_number[offset] = *(error_message+offset+1);
224          if (*(error_message+offset) == ' ')
225              break;
226      }
227      if((offset > 1) && (offset < 15))
228      {
229        error_number[offset-1]='\0';
230        fprintf(stderr, "libpng error no. %s: %s\n", error_number,
231           error_message+offset);
232      }
233      else
234        fprintf(stderr, "libpng error: %s, offset=%d\n", error_message,offset);
235    }
236    else
237 #endif
238    fprintf(stderr, "libpng error: %s\n", error_message);
239 #endif
240 
241 #ifdef PNG_SETJMP_SUPPORTED
242    if (png_ptr)
243    {
244 #  ifdef USE_FAR_KEYWORD
245    {
246       jmp_buf jmpbuf;
247       png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));
248       longjmp(jmpbuf, 1);
249    }
250 #  else
251    longjmp(png_ptr->jmpbuf, 1);
252 #  endif
253    }
254 #else
255    PNG_ABORT();
256 #endif
257 #ifdef PNG_NO_CONSOLE_IO
258    error_message = error_message; /* make compiler happy */
259 #endif
260 }
261 
262 #ifndef PNG_NO_WARNINGS
263 /* This function is called when there is a warning, but the library thinks
264  * it can continue anyway.  Replacement functions don't have to do anything
265  * here if you don't want them to.  In the default configuration, png_ptr is
266  * not used, but it is passed in case it may be useful.
267  */
268 static void /* PRIVATE */
png_default_warning(png_structp png_ptr,png_const_charp warning_message)269 png_default_warning(png_structp png_ptr, png_const_charp warning_message)
270 {
271 #ifndef PNG_NO_CONSOLE_IO
272 #  ifdef PNG_ERROR_NUMBERS_SUPPORTED
273    if (*warning_message == '#')
274    {
275      int offset;
276      char warning_number[16];
277      for (offset=0; offset<15; offset++)
278      {
279         warning_number[offset]=*(warning_message+offset+1);
280         if (*(warning_message+offset) == ' ')
281             break;
282      }
283      if((offset > 1) && (offset < 15))
284      {
285        warning_number[offset-1]='\0';
286        fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
287           warning_message+offset);
288      }
289      else
290        fprintf(stderr, "libpng warning: %s\n", warning_message);
291    }
292    else
293 #  endif
294      fprintf(stderr, "libpng warning: %s\n", warning_message);
295 #else
296    warning_message = warning_message; /* make compiler happy */
297 #endif
298    png_ptr = png_ptr; /* make compiler happy */
299 }
300 #endif /* PNG_NO_WARNINGS */
301 
302 /* This function is called when the application wants to use another method
303  * of handling errors and warnings.  Note that the error function MUST NOT
304  * return to the calling routine or serious problems will occur.  The return
305  * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
306  */
307 void PNGAPI
png_set_error_fn(png_structp png_ptr,png_voidp error_ptr,png_error_ptr error_fn,png_error_ptr warning_fn)308 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
309    png_error_ptr error_fn, png_error_ptr warning_fn)
310 {
311    if (png_ptr == NULL)
312       return;
313    png_ptr->error_ptr = error_ptr;
314    png_ptr->error_fn = error_fn;
315    png_ptr->warning_fn = warning_fn;
316 }
317 
318 
319 /* This function returns a pointer to the error_ptr associated with the user
320  * functions.  The application should free any memory associated with this
321  * pointer before png_write_destroy and png_read_destroy are called.
322  */
323 png_voidp PNGAPI
png_get_error_ptr(png_structp png_ptr)324 png_get_error_ptr(png_structp png_ptr)
325 {
326    if (png_ptr == NULL)
327       return NULL;
328    return ((png_voidp)png_ptr->error_ptr);
329 }
330 
331 
332 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
333 void PNGAPI
png_set_strip_error_numbers(png_structp png_ptr,png_uint_32 strip_mode)334 png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
335 {
336    if(png_ptr != NULL)
337    {
338      png_ptr->flags &=
339        ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
340    }
341 }
342 #endif
343 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
344