GDB show’s Auxiliary Vector
(gdb) info auxv
33 AT_SYSINFO_EHDR System-supplied DSO's ELF header 0x7fff68bdf000
16 AT_HWCAP Machine-dependent CPU capability hints 0x78bfbff
6 AT_PAGESZ System page size 4096
17 AT_CLKTCK Frequency of times() 100
3 AT_PHDR Program headers for program 0x400040
4 AT_PHENT Size of program header entry 56
5 AT_PHNUM Number of program headers 8
7 AT_BASE Base address of interpreter 0x7f936f757000
8 AT_FLAGS Flags 0x0
9 AT_ENTRY Entry point of program 0x401850
11 AT_UID Real user ID 1000
12 AT_EUID Effective user ID 1000
13 AT_GID Real group ID 1000
14 AT_EGID Effective group ID 1000
23 AT_SECURE Boolean, was exec setuid-like? 0
25 AT_RANDOM Address of 16 random bytes 0x7fff68a94c69
31 AT_EXECFN File name of executable 0x7fff68a95fef "/bin/cat"
15 AT_PLATFORM String identifying platform 0x7fff68a94c79 "x86_64"
0 AT_NULL End of vector 0x0
(gdb)
Process Involved
/bin/cat .
concatenate files and print on the standard output.
Explanation
Display the auxiliary vector of the inferior, which can be either a
live process or a core dump file. GDB prints each tag value
numerically, and also shows names and text descriptions for
recognized tags. Some values in the vector are numbers, some bit
masks, and some pointers to strings or other data. GDB displays
each value in the most appropriate form for a recognized tag, and
in hexadecimal for an unrecognized tag.
source : http://www.slac.stanford.edu/comp/unix/package/
rtems/doc/html/gdb/gdb.info.Auxiliary_Vector.html
A Screen Shot from /usr/include/elf.h in Debian
/* Legal values for a_type (entry type). */
#define AT_NULL 0 /* End of vector */
#define AT_IGNORE 1 /* Entry should be ignored */
#define AT_EXECFD 2 /* File descriptor of program */
#define AT_PHDR 3 /* Program headers for program */
#define AT_PHENT 4 /* Size of program header entry */
#define AT_PHNUM 5 /* Number of program headers */
#define AT_PAGESZ 6 /* System page size */
#define AT_BASE 7 /* Base address of interpreter */
#define AT_FLAGS 8 /* Flags */
#define AT_ENTRY 9 /* Entry point of program */
#define AT_NOTELF 10 /* Program is not ELF */
#define AT_UID 11 /* Real uid */
#define AT_EUID 12 /* Effective uid */
#define AT_GID 13 /* Real gid */
#define AT_EGID 14 /* Effective gid */
#define AT_CLKTCK 17 /* Frequency of times() */
valavil.in 