/* Copyright (C) 2010-2018 David Anderson. All Rights Reserved. Portions Copyright 2012 SN Systems Ltd. All rights reserved. This program is free software; you can redistribute it and/or modify it under the terms of version 2.1 of the GNU Lesser General Public License as published by the Free Software Foundation. This program is distributed in the hope that it would be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Further, this software is distributed without any warranty that it is free of the rightful claim of any third person regarding infringement or the like. Any license provided herein, whether implied or otherwise, applies only to this software file. Patent licenses, if any, provided herein do not apply to combinations of this program with other software, or any other product whatsoever. You should have received a copy of the GNU Lesser General Public License along with this program; if not, write the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston MA 02110-1301, USA. */ /* This implements _dwarf_insert_harmless_error and related helper functions for recording compiler errors that need not make the input unusable. Applications can use dwarf_get_harmless_error_list to find (and possibly print) a warning about such errors. The initial error reported here is DW_DLE_DEBUG_FRAME_LENGTH_NOT_MULTIPLE which was a bug in a specific compiler. It is a fixed length circular list to constrain the space used for errors. The assumption is that these errors are exceedingly rare, and indicate a broken compiler (the one that produced the object getting the error(s)). dh_maxcount is recorded internally as 1 greater than requested. Hiding the fact we always leave one slot unused (at least). So a user request for N slots really gives the user N usable slots. */ #include "config.h" #include "dwarf_incl.h" #include #ifdef HAVE_STDLIB_H #include #endif /* HAVE_STDLIB_H */ #ifdef HAVE_MALLOC_H /* Useful include for some Windows compilers. */ #include #endif /* HAVE_MALLOC_H */ #include "dwarf_frame.h" #include "dwarf_harmless.h" /* The pointers returned here through errmsg_ptrs_array become invalidated by any call to libdwarf. Any call. */ int dwarf_get_harmless_error_list(Dwarf_Debug dbg, unsigned count, const char ** errmsg_ptrs_array, unsigned * errs_count) { struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; if (!dhp->dh_errors) { dhp->dh_errs_count = 0; return DW_DLV_NO_ENTRY; } if (dhp->dh_errs_count == 0) { return DW_DLV_NO_ENTRY; } if (errs_count) { *errs_count = dhp->dh_errs_count; } if (count) { /* NULL terminate the array of pointers */ --count; errmsg_ptrs_array[count] = 0; if (dhp->dh_next_to_use != dhp->dh_first) { unsigned i = 0; unsigned cur = dhp->dh_first; for (i = 0; cur != dhp->dh_next_to_use; ++i) { if (i >= count ) { /* All output spaces are used. */ break; } errmsg_ptrs_array[i] = dhp->dh_errors[cur]; cur = (cur +1) % dhp->dh_maxcount; } errmsg_ptrs_array[i] = 0; } } dhp->dh_next_to_use = 0; dhp->dh_first = 0; dhp->dh_errs_count = 0; return DW_DLV_OK; } /* strncpy does not null-terminate, this does it. */ static void safe_strncpy(char *targ, char *src, unsigned spaceavail) { unsigned goodcount = spaceavail-1; if (spaceavail < 1) { return; /* impossible */ } strncpy(targ,src,goodcount); targ[goodcount] = 0; } /* Insertion made public is only for testing the harmless error code, it is not necessarily useful for libdwarf client code aside from code testing libdwarf. */ void dwarf_insert_harmless_error(Dwarf_Debug dbg, char *newerror) { struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; unsigned next = 0; unsigned cur = dhp->dh_next_to_use; char *msgspace; if (!dhp->dh_errors) { dhp->dh_errs_count++; return; } msgspace = dhp->dh_errors[cur]; safe_strncpy(msgspace, newerror,DW_HARMLESS_ERROR_MSG_STRING_SIZE); next = (cur+1) % dhp->dh_maxcount; dhp->dh_errs_count++; dhp->dh_next_to_use = next; if (dhp->dh_next_to_use == dhp->dh_first) { /* Array is full set full invariant. */ dhp->dh_first = (dhp->dh_first+1) % dhp->dh_maxcount; } } /* The size of the circular list of strings may be set and reset as desired. Returns the previous size of the list. If the list is shortened excess error entries are simply dropped. If the reallocation fails the list size is left unchanged. Do not make this a long list! Remember the maxcount we record is 1 > the user count, so we adjust it so it looks like the user count. */ unsigned dwarf_set_harmless_error_list_size(Dwarf_Debug dbg, unsigned maxcount ) { struct Dwarf_Harmless_s *dhp = &dbg->de_harmless_errors; unsigned prevcount = dhp->dh_maxcount; if (maxcount != 0) { ++maxcount; if (maxcount != dhp->dh_maxcount) { /* Assign transfers 'ownership' of the malloc areas to oldarray. */ struct Dwarf_Harmless_s oldarray = *dhp; /* Do not double increment the max, the init() func increments it too. */ dwarf_harmless_init(dhp,maxcount-1); if (oldarray.dh_next_to_use != oldarray.dh_first) { unsigned i = 0; for (i = oldarray.dh_first; i != oldarray.dh_next_to_use; i = (i+1)%oldarray.dh_maxcount) { dwarf_insert_harmless_error(dbg,oldarray.dh_errors[i]); } if (oldarray.dh_errs_count > dhp->dh_errs_count) { dhp->dh_errs_count = oldarray.dh_errs_count; } } dwarf_harmless_cleanout(&oldarray); } } return prevcount-1; } /* Only callable from within libdwarf (as a practical matter) */ void dwarf_harmless_init(struct Dwarf_Harmless_s *dhp,unsigned size) { unsigned i = 0; memset(dhp,0,sizeof(*dhp)); dhp->dh_maxcount = size +1; dhp->dh_errors = (char **)malloc(sizeof( char *) *dhp->dh_maxcount); if (!dhp->dh_errors) { dhp->dh_maxcount = 0; return; } for (i = 0; i < dhp->dh_maxcount; ++i) { char *newstr = (char *)malloc(DW_HARMLESS_ERROR_MSG_STRING_SIZE); dhp->dh_errors[i] = newstr; if (!newstr) { dhp->dh_maxcount = 0; /* Let it leak, the leak is a constrained amount. */ dhp->dh_errors = 0; return; } /* We make the string content well-defined by an initial NUL byte, but this is not really necessary. */ newstr[0] = 0; } } void dwarf_harmless_cleanout(struct Dwarf_Harmless_s *dhp) { unsigned i = 0; if (!dhp->dh_errors) { return; } for (i = 0; i < dhp->dh_maxcount; ++i) { free(dhp->dh_errors[i]); dhp->dh_errors[i] = 0; } free(dhp->dh_errors); dhp->dh_errors = 0; dhp->dh_maxcount = 0; }