1 /* 2 Copyright (C) 2010-2018 David Anderson. All Rights Reserved. 3 Portions Copyright 2012 SN Systems Ltd. All rights reserved. 4 5 This program is free software; you can redistribute it and/or modify it 6 under the terms of version 2.1 of the GNU Lesser General Public License 7 as published by the Free Software Foundation. 8 9 This program is distributed in the hope that it would be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 12 13 Further, this software is distributed without any warranty that it is 14 free of the rightful claim of any third person regarding infringement 15 or the like. Any license provided herein, whether implied or 16 otherwise, applies only to this software file. Patent licenses, if 17 any, provided herein do not apply to combinations of this program with 18 other software, or any other product whatsoever. 19 20 You should have received a copy of the GNU Lesser General Public 21 License along with this program; if not, write the Free Software 22 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301, 23 USA. 24 25 */ 26 27 /* This implements _dwarf_insert_harmless_error 28 and related helper functions for recording 29 compiler errors that need not make the input 30 unusable. 31 32 Applications can use dwarf_get_harmless_error_list to 33 find (and possibly print) a warning about such errors. 34 35 The initial error reported here is 36 DW_DLE_DEBUG_FRAME_LENGTH_NOT_MULTIPLE which was a 37 bug in a specific compiler. 38 39 It is a fixed length circular list to constrain 40 the space used for errors. 41 42 The assumption is that these errors are exceedingly 43 rare, and indicate a broken compiler (the one that 44 produced the object getting the error(s)). 45 46 dh_maxcount is recorded internally as 1 greater than 47 requested. Hiding the fact we always leave one 48 slot unused (at least). So a user request for 49 N slots really gives the user N usable slots. */ 50 51 52 53 #include "config.h" 54 #include "dwarf_incl.h" 55 #include <stdio.h> 56 #ifdef HAVE_STDLIB_H 57 #include <stdlib.h> 58 #endif /* HAVE_STDLIB_H */ 59 #ifdef HAVE_MALLOC_H 60 /* Useful include for some Windows compilers. */ 61 #include <malloc.h> 62 #endif /* HAVE_MALLOC_H */ 63 #include "dwarf_frame.h" 64 #include "dwarf_harmless.h" 65 66 67 /* The pointers returned here through errmsg_ptrs_array 68 become invalidated by any call to libdwarf. Any call. 69 */ 70 int dwarf_get_harmless_error_list(Dwarf_Debug dbg, 71 unsigned count, 72 const char ** errmsg_ptrs_array, 73 unsigned * errs_count) 74 { 75 struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; 76 if (!dhp->dh_errors) { 77 dhp->dh_errs_count = 0; 78 return DW_DLV_NO_ENTRY; 79 } 80 if (dhp->dh_errs_count == 0) { 81 return DW_DLV_NO_ENTRY; 82 } 83 if (errs_count) { 84 *errs_count = dhp->dh_errs_count; 85 } 86 if (count) { 87 /* NULL terminate the array of pointers */ 88 --count; 89 errmsg_ptrs_array[count] = 0; 90 91 if (dhp->dh_next_to_use != dhp->dh_first) { 92 unsigned i = 0; 93 unsigned cur = dhp->dh_first; 94 for (i = 0; cur != dhp->dh_next_to_use; ++i) { 95 if (i >= count ) { 96 /* All output spaces are used. */ 97 break; 98 } 99 errmsg_ptrs_array[i] = dhp->dh_errors[cur]; 100 cur = (cur +1) % dhp->dh_maxcount; 101 } 102 errmsg_ptrs_array[i] = 0; 103 } 104 } 105 dhp->dh_next_to_use = 0; 106 dhp->dh_first = 0; 107 dhp->dh_errs_count = 0; 108 return DW_DLV_OK; 109 } 110 111 /* strncpy does not null-terminate, this does it. */ 112 static void 113 safe_strncpy(char *targ, char *src, unsigned spaceavail) 114 { 115 unsigned goodcount = spaceavail-1; 116 if (spaceavail < 1) { 117 return; /* impossible */ 118 } 119 strncpy(targ,src,goodcount); 120 targ[goodcount] = 0; 121 } 122 123 /* Insertion made public is only for testing the harmless error code, 124 it is not necessarily useful for libdwarf client code aside 125 from code testing libdwarf. */ 126 void dwarf_insert_harmless_error(Dwarf_Debug dbg, 127 char *newerror) 128 { 129 struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; 130 unsigned next = 0; 131 unsigned cur = dhp->dh_next_to_use; 132 char *msgspace; 133 if (!dhp->dh_errors) { 134 dhp->dh_errs_count++; 135 return; 136 } 137 msgspace = dhp->dh_errors[cur]; 138 safe_strncpy(msgspace, newerror,DW_HARMLESS_ERROR_MSG_STRING_SIZE); 139 next = (cur+1) % dhp->dh_maxcount; 140 dhp->dh_errs_count++; 141 dhp->dh_next_to_use = next; 142 if (dhp->dh_next_to_use == dhp->dh_first) { 143 /* Array is full set full invariant. */ 144 dhp->dh_first = (dhp->dh_first+1) % dhp->dh_maxcount; 145 } 146 } 147 148 /* The size of the circular list of strings may be set 149 and reset as desired. Returns the previous size of 150 the list. If the list is shortened excess error entries 151 are simply dropped. 152 If the reallocation fails the list size is left unchanged. 153 Do not make this a long list! 154 155 Remember the maxcount we record is 1 > the user count, 156 so we adjust it so it looks like the user count. 157 */ 158 unsigned dwarf_set_harmless_error_list_size(Dwarf_Debug dbg, 159 unsigned maxcount ) 160 { 161 struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; 162 unsigned prevcount = dhp->dh_maxcount; 163 if (maxcount != 0) { 164 ++maxcount; 165 if (maxcount != dhp->dh_maxcount) { 166 /* Assign transfers 'ownership' of the malloc areas 167 to oldarray. */ 168 struct Dwarf_Harmless_s oldarray = *dhp; 169 /* Do not double increment the max, the init() func 170 increments it too. */ 171 dwarf_harmless_init(dhp,maxcount-1); 172 if (oldarray.dh_next_to_use != oldarray.dh_first) { 173 unsigned i = 0; 174 for (i = oldarray.dh_first; i != oldarray.dh_next_to_use; 175 i = (i+1)%oldarray.dh_maxcount) { 176 dwarf_insert_harmless_error(dbg,oldarray.dh_errors[i]); 177 } 178 if (oldarray.dh_errs_count > dhp->dh_errs_count) { 179 dhp->dh_errs_count = oldarray.dh_errs_count; 180 } 181 } 182 dwarf_harmless_cleanout(&oldarray); 183 } 184 } 185 return prevcount-1; 186 } 187 188 /* Only callable from within libdwarf (as a practical matter) 189 */ 190 void 191 dwarf_harmless_init(struct Dwarf_Harmless_s *dhp,unsigned size) 192 { 193 unsigned i = 0; 194 memset(dhp,0,sizeof(*dhp)); 195 dhp->dh_maxcount = size +1; 196 dhp->dh_errors = (char **)malloc(sizeof( char *) *dhp->dh_maxcount); 197 if (!dhp->dh_errors) { 198 dhp->dh_maxcount = 0; 199 return; 200 } 201 202 for (i = 0; i < dhp->dh_maxcount; ++i) { 203 char *newstr = 204 (char *)malloc(DW_HARMLESS_ERROR_MSG_STRING_SIZE); 205 dhp->dh_errors[i] = newstr; 206 if (!newstr) { 207 dhp->dh_maxcount = 0; 208 /* Let it leak, the leak is a constrained amount. */ 209 dhp->dh_errors = 0; 210 return; 211 } 212 /* We make the string content well-defined by an initial 213 NUL byte, but this is not really necessary. */ 214 newstr[0] = 0; 215 } 216 } 217 218 void 219 dwarf_harmless_cleanout(struct Dwarf_Harmless_s *dhp) 220 { 221 unsigned i = 0; 222 if (!dhp->dh_errors) { 223 return; 224 } 225 for (i = 0; i < dhp->dh_maxcount; ++i) { 226 free(dhp->dh_errors[i]); 227 dhp->dh_errors[i] = 0; 228 } 229 free(dhp->dh_errors); 230 dhp->dh_errors = 0; 231 dhp->dh_maxcount = 0; 232 } 233