Fix some unused DT_ warnings
* DT_PLTGOT - ignored for non-mips
* DT_RELCOUNT/RELACOUNT - ignored
* DT_RELENT/RELAENT - sanity checks
* DT_SYMENT - sanity check
* DT_SONAME - ignore for now.
Bug: 18186310
(cherry picked from commit 4a6e9a835a84aca965f0170f604381dae7f130be)
Change-Id: Ib40095f0770d65628fc7abac5a471378de35ebe7
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 246475b..875335f 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -1875,6 +1875,10 @@
DEBUG("d = %p, d[0](tag) = %p d[1](val) = %p",
d, reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
switch (d->d_tag) {
+ case DT_SONAME:
+ // TODO: glibc dynamic linker uses this name for
+ // initial library lookup; consider doing the same here.
+ break;
case DT_HASH:
nbucket = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr)[0];
nchain = reinterpret_cast<uint32_t*>(load_bias + d->d_un.d_ptr)[1];
@@ -1887,6 +1891,12 @@
case DT_SYMTAB:
symtab = reinterpret_cast<ElfW(Sym)*>(load_bias + d->d_un.d_ptr);
break;
+ case DT_SYMENT:
+ if (d->d_un.d_val != sizeof(ElfW(Sym))) {
+ DL_ERR("invalid DT_SYMENT: %d", d->d_un.d_val);
+ return false;
+ }
+ break;
#if !defined(__LP64__)
case DT_PLTREL:
if (d->d_un.d_val != DT_REL) {
@@ -1909,12 +1919,13 @@
plt_rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
#endif
break;
-#if defined(__mips__)
case DT_PLTGOT:
+#if defined(__mips__)
// Used by mips and mips64.
plt_got = reinterpret_cast<ElfW(Addr)**>(load_bias + d->d_un.d_ptr);
- break;
#endif
+ // Ignore for other platforms... (because RTLD_LAZY is not supported)
+ break;
case DT_DEBUG:
// Set the DT_DEBUG entry to the address of _r_debug for GDB
// if the dynamic table is writable
@@ -1935,6 +1946,15 @@
case DT_RELASZ:
rela_count = d->d_un.d_val / sizeof(ElfW(Rela));
break;
+ case DT_RELAENT:
+ if (d->d_un.d_val != sizeof(ElfW(Rela))) {
+ DL_ERR("invalid DT_RELAENT: %d", d->d_un.d_val);
+ return false;
+ }
+ break;
+ case DT_RELACOUNT:
+ // ignored (see DT_RELCOUNT comments for details)
+ break;
case DT_REL:
DL_ERR("unsupported DT_REL in \"%s\"", name);
return false;
@@ -1948,6 +1968,19 @@
case DT_RELSZ:
rel_count = d->d_un.d_val / sizeof(ElfW(Rel));
break;
+ case DT_RELENT:
+ if (d->d_un.d_val != sizeof(ElfW(Rel))) {
+ DL_ERR("invalid DT_RELENT: %d", d->d_un.d_val);
+ return false;
+ }
+ break;
+ case DT_RELCOUNT:
+ // "Indicates that all RELATIVE relocations have been concatenated together,
+ // and specifies the RELATIVE relocation count."
+ //
+ // TODO: Spec also mentions that this can be used to optimize relocation process;
+ // Not currently used by bionic linker - ignored.
+ break;
case DT_RELA:
DL_ERR("unsupported DT_RELA in \"%s\"", name);
return false;
@@ -2007,8 +2040,6 @@
break;
#if defined(__mips__)
case DT_STRSZ:
- case DT_SYMENT:
- case DT_RELENT:
break;
case DT_MIPS_RLD_MAP:
// Set the DT_MIPS_RLD_MAP entry to the address of _r_debug for GDB.
