From 1cc06c7e14e047ba9781c40030ed031d3ca4ce15 Mon Sep 17 00:00:00 2001 From: Ivo Raisr Date: Thu, 29 Oct 2015 07:28:58 +0000 Subject: [PATCH] ELF debug info reader was confused with multiple .rodata sections on Solaris The ELF debug info reader on Solaris now performs a quick pre-scan of section headers for .rodata sections. If there are multiple .rodata sections present then symbols from .symtab are scanned which section they point to. The "true" .rodata section is thus determined. Fixes BZ#353802. git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15719 --- coregrind/m_debuginfo/readelf.c | 101 ++++++++++++++++++++++++++++++-- 1 file changed, 97 insertions(+), 4 deletions(-) diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c index 9e239b0f2..086172505 100644 --- a/coregrind/m_debuginfo/readelf.c +++ b/coregrind/m_debuginfo/readelf.c @@ -1506,6 +1506,11 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) XArray* /* of RangeAndBias */ svma_ranges = NULL; +# if defined(VGO_solaris) + Word *rodata_sects = NULL; + Word rodata_shndx = -1; +# endif /* VGO_solaris */ + vg_assert(di); vg_assert(di->fsm.have_rx_map == True); vg_assert(di->fsm.have_rw_map == True); @@ -1835,6 +1840,81 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) reg->svma_base, reg->svma_limit - 1, (UWord)reg->bias ); } + /* TOPLEVEL */ +# if defined(VGO_solaris) + /* Quick pre-scan of sections headers. Check if multiple .rodata sections + are present. See https://bugs.kde.org/show_bug.cgi?id=353802 */ + rodata_sects = ML_(dinfo_zalloc)("di.redi_name.1", + shdr_mnent * sizeof(Word)); + Word rodata_nsects = 0; + Word symtab_shndx = -1; + DiOffT symtab_sz = DiOffT_INVALID; + DiOffT symtab_ioff = DiOffT_INVALID; + for (i = 0; i < shdr_mnent; i++) { + ElfXX_Shdr a_shdr; + ML_(img_get)(&a_shdr, mimg, + INDEX_BIS(shdr_mioff, i, shdr_ment_szB), sizeof(a_shdr)); + DiOffT name_mioff = shdr_strtab_mioff + a_shdr.sh_name; + if (ML_(img_strcmp_c)(mimg, name_mioff, ".rodata") == 0) { + rodata_sects[i] = True; + rodata_nsects += 1; + } else if (ML_(img_strcmp_c)(mimg, name_mioff, ".symtab") == 0) { + symtab_shndx = i; + symtab_sz = a_shdr.sh_size; + symtab_ioff = a_shdr.sh_offset; + } + } + + if ((rodata_nsects > 1) && (symtab_shndx != -1)) { + TRACE_SYMTAB("Multiple (%ld) .rodata sections present.\n", rodata_nsects); + + /* Multiple .rodata sections present. Which one the symbols point to? */ + for (i = 1; i < (Word) (symtab_sz/sizeof(ElfXX_Sym)); i++) { + ElfXX_Sym sym; + ML_(img_get)(&sym, mimg, + symtab_ioff + i * sizeof(ElfXX_Sym), sizeof(sym)); + /* Consider only object symbols with size > 0. */ + if ((sym.st_size > 0) && (ELFXX_ST_TYPE(sym.st_info) == STT_OBJECT)) { + HChar buf[100]; // large enough + if (sym.st_shndx >= shdr_mnent) { + VG_(snprintf)(buf, sizeof(buf), "Symbol %ld points to a " + "non-existent section %d.\n", i, sym.st_shndx); + ML_(symerr)(di, True, buf); + goto out; + } + if (rodata_sects[sym.st_shndx] == True) { + if (rodata_shndx == -1) + rodata_shndx = sym.st_shndx; + + if (rodata_shndx != sym.st_shndx) { + VG_(snprintf)(buf, sizeof(buf), "Object symbols point to " + "multiple .rodata sections (%lu and %d). " + "Giving up.\n", rodata_shndx, sym.st_shndx); + ML_(symerr)(di, True, buf); + goto out; + } + } + } + } + } + + if (rodata_shndx == -1) { + if (rodata_nsects >= 1) { + for (i = 0; i < shdr_mnent; i++) { + if (rodata_sects[i] == True) + rodata_shndx = i; + } + } + + if (rodata_nsects > 1) + TRACE_SYMTAB("Symbols do not point to any .rodata section. Section " + "#%ld was chosen.\n", rodata_shndx); + } else { + TRACE_SYMTAB("Symbols point only to .rodata section #%ld. Good.\n", + rodata_shndx); + } +# endif /* VGO_solaris */ + /* TOPLEVEL */ /* Iterate over section headers */ for (i = 0; i < shdr_mnent; i++) { @@ -1842,7 +1922,7 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) ML_(img_get)(&a_shdr, mimg, INDEX_BIS(shdr_mioff, i, shdr_ment_szB), sizeof(a_shdr)); DiOffT name_mioff = shdr_strtab_mioff + a_shdr.sh_name; - HChar* name = ML_(img_strdup)(mimg, "di.redi_name.1", name_mioff); + HChar* name = ML_(img_strdup)(mimg, "di.redi_name.2", name_mioff); Addr svma = a_shdr.sh_addr; OffT foff = a_shdr.sh_offset; UWord size = a_shdr.sh_size; /* Do not change this to be signed. */ @@ -1867,10 +1947,10 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) } } - TRACE_SYMTAB(" [sec %2ld] %s %s al%2u foff %6ld .. %6lu " + TRACE_SYMTAB(" [sec %2ld] %s %s al%4u foff %6ld .. %6lu " " svma %p name \"%s\"\n", i, inrx ? "rx" : " ", inrw ? "rw" : " ", alyn, - foff, foff+size-1, (void*)svma, name); + foff, (size == 0) ? foff : foff+size-1, (void *) svma, name); /* Check for sane-sized segments. SHT_NOBITS sections have zero size in the file and their offsets are just conceptual. */ @@ -1977,7 +2057,11 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) /* Accept .rodata where mapped as rx (data), even if zero-sized */ if (0 == VG_(strcmp)(name, ".rodata")) { - if (inrx && !di->rodata_present) { + if (inrx && !di->rodata_present +# if defined(VGO_solaris) + && i == rodata_shndx +# endif + ) { di->rodata_present = True; di->rodata_svma = svma; di->rodata_avma = svma + inrx->bias; @@ -1994,6 +2078,11 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) di->rodata_avma + di->rodata_size - 1); TRACE_SYMTAB("acquiring .rodata bias = %#lx\n", (UWord)di->rodata_bias); +# if defined(VGO_solaris) + } else if (i != rodata_shndx) { + /* Skip this section. It is of no use to us. + See https://bugs.kde.org/show_bug.cgi?id=353802 */ +# endif } else { BAD(".rodata"); } @@ -3030,6 +3119,10 @@ Bool ML_(read_elf_debug_info) ( struct _DebugInfo* di ) if (svma_ranges) VG_(deleteXA)(svma_ranges); +# if defined(VGO_solaris) + if (rodata_sects != NULL) ML_(dinfo_free)(rodata_sects); +# endif + return res; } /* out: */