String table sections hold null-terminated character sequences, commonly called strings. The object file uses these strings to represent symbol and section names. You reference a string as an index into the string table section.
The first byte, which is index zero, holds a null character. Likewise, a string table's last byte holds a null character, ensuring null termination for all strings. A string whose index is zero specifies either no name or a null name, depending on the context.
An empty string table section is permitted. The section header's sh_size member contains zero. Nonzero indexes are invalid for an empty string table.
A section header's sh_name member holds an index into the section header string table section. The section header string table is designated by the e_shstrndx member of the ELF header. The following figure shows a string table with 25 bytes and the strings associated with various indexes.
Figure 12-7 ELF String Table
The following table shows the strings of the string table that are shown in the preceding figure.
As the example shows, a string table index can refer to any byte in the section. A string can appear more than once. References to substrings can exist. A single string can be referenced multiple times. Unreferenced strings also are allowed.