Bug 716295 part 1 - Fail more gracefully when .dynamic section can't be grown. r=nfroyd

build/unix/elfhack/elf.cpp

@@ -642,34 +642,25 @@ ElfSection *ElfDynamic_Section::getSectionForType(unsigned int tag)
     return value ? value->getSection() : NULL;
 }
 
-void ElfDynamic_Section::setValueForType(unsigned int tag, ElfValue *val)
+bool ElfDynamic_Section::setValueForType(unsigned int tag, ElfValue *val)
 {
     unsigned int i;
-    for (i = 0; (i < shdr.sh_size / shdr.sh_entsize) && (dyns[i].tag != DT_NULL); i++)
+    unsigned int shnum = shdr.sh_size / shdr.sh_entsize;
+    for (i = 0; (i < shnum) && (dyns[i].tag != DT_NULL); i++)
         if (dyns[i].tag == tag) {
             delete dyns[i].value;
             dyns[i].value = val;
-            return;
+            return true;
         }
-    // This should never happen, as the last entry is always tagged DT_NULL
-    assert(i < shdr.sh_size / shdr.sh_entsize);
     // If we get here, this means we didn't match for the given tag
+    // Most of the time, there are a few DT_NULL entries, that we can
+    // use to add our value, but if we are on the last entry, we can't.
+    if (i >= shnum - 1)
+        return false;
+
     dyns[i].tag = tag;
-    dyns[i++].value = val;
-
-    // If we were on the last entry, we need to grow the section.
-    // Most of the time, though, there are a few DT_NULL entries.
-    if (i < shdr.sh_size / shdr.sh_entsize)
-        return;
-
-    Elf_DynValue value;
-    value.tag = DT_NULL;
-    value.value = NULL;
-    dyns.push_back(value);
-    // Resize the section accordingly
-    shdr.sh_size += shdr.sh_entsize;
-    if (getNext() != NULL)
-        getNext()->markDirty();
+    dyns[i].value = val;
+    return true;
 }
 
 ElfDynamic_Section::ElfDynamic_Section(Elf_Shdr &s, std::ifstream *file, Elf *parent)

build/unix/elfhack/elfhack.cpp

@@ -450,7 +450,10 @@ int do_relocation_section(Elf *elf, unsigned int rel_type, unsigned int rel_type
     section->rels.assign(new_rels.begin(), new_rels.end());
     section->shrink(new_rels.size() * section->getEntSize());
     ElfLocation *init = new ElfLocation(relhackcode, relhackcode->getEntryPoint());
-    dyn->setValueForType(DT_INIT, init);
+    if (!dyn->setValueForType(DT_INIT, init)) {
+        fprintf(stderr, "Can't grow .dynamic section to set DT_INIT. Skipping\n");
+        return -1;
+    }
     // TODO: adjust the value according to the remaining number of relative relocations
     if (dyn->getValueForType(Rel_Type::d_tag_count))
         dyn->setValueForType(Rel_Type::d_tag_count, new ElfPlainValue(0));

build/unix/elfhack/elfxx.h

@@ -505,7 +505,7 @@ public:
 
     ElfValue *getValueForType(unsigned int tag);
     ElfSection *getSectionForType(unsigned int tag);
-    void setValueForType(unsigned int tag, ElfValue *val);
+    bool setValueForType(unsigned int tag, ElfValue *val);
 private:
     std::vector<Elf_DynValue> dyns;
 };