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

diff --git a/coregrind/m_debuginfo/readelf.c b/coregrind/m_debuginfo/readelf.c
index 9e239b0f20257db6c18f47705a5e830db155583f..086172505392fb76e429fff24db64a8067f15d31 100644 (file)
--- 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: */