Syminfo Table Section
The syminfo section contains multiple entries of the type
Elf32_Syminfo
or Elf64_Syminfo
. The
.SUNW_syminfo
section contains one entry for every entry in the
associated symbol table (sh_link
).
If this section is present in an object, additional symbol information is to be found by
taking the symbol index from the associated symbol table and using that to find the
corresponding Elf32_Syminfo
entry or Elf64_Syminfo
entry
in this section. The associated symbol table and the Syminfo
table will
always have the same number of entries.
Index 0
is used to store the current version of the
Syminfo
table, which is SYMINFO_CURRENT
. Since symbol
table entry 0
is always reserved for the UNDEF
symbol
table entry, this usage does not pose any conflicts.
An Syminfo
entry has the following format. See
sys/link.h
.
typedef struct { Elf32_Half si_boundto; Elf32_Half si_flags; } Elf32_Syminfo; typedef struct { Elf64_Half si_boundto; Elf64_Half si_flags; } Elf64_Syminfo;
-
si_boundto
-
An index to an entry in the
.dynamic
section, identified by thesh_info
field, which augments theSyminfo
flags. For example, aDT_NEEDED
entry identifies a dynamic object associated with theSyminfo
entry. The entries that follow are reserved values forsi_boundto
.Name Value Meaning SYMINFO_BT_SELF
0xffff
Symbol bound to self.
SYMINFO_BT_PARENT
0xfffe
Symbol bound to parent. The parent is the first object to cause this dynamic object to be loaded.
SYMINFO_BT_NONE
0xfffd
Symbol has no special symbol binding.
SYMINFO_BT_EXTERN
0
xfffc
Symbol definition is external.
-
si_flags
-
This bit-field can have flags set, as shown in the following table.
Name Value Meaning SYMINFO_FLG_DEPEND
0x01
Symbol reference has an association to the object containing the definition.
SYMINFO_FLG_FILTER
0x02
Symbol definition acts as a standard filter.
SYMINFO_FLG_COPY
0x04
Symbol definition is the result of a copy-relocation.
SYMINFO_FLG_LAZYLOAD
0x08
Symbol reference is to an object that should be lazily loaded.
SYMINFO_FLG_DIRECTBIND
0x10
Symbol reference should be bound directly to the definition.
SYMINFO_FLG_NOEXTDIRECT
0x20
Do not allow an external reference to directly bind to this symbol definition.
SYMINFO_FLG_AUXILIARY
0x40
Symbol definition acts as an auxiliary filter.
SYMINFO_FLG_INTERPOSE
0x80
Symbol definition acts as an interposer. This attribute is only applicable for executables.
SYMINFO_FLG_CAP
0x100
Symbol is associated with capabilities.
SYMINFO_FLG_DEFERRED
0x200
Symbol is associated with a deferred reference, and should not be included in
BIND_NOW
relocations.SYMINFO_FLG_WEAKFILTER
0x400
Set in conjunction with
SYMINFO_FLG_FILTER
to specify a weak standard filter. At runtime, the behavior is identical toSYMINFO_FLG_FILTER
. At link-edit time, if unused dependency processing is active, a weak filter symbol can be ignored in favor of the same symbol from the target filtee. See Generating Weak Filters