ELF_AUX_INFO(3)        FreeBSD Library Functions Manual        ELF_AUX_INFO(3)

NAME
     elf_aux_info - extract data from the elf auxiliary vector of the current
     process

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/auxv.h>

     int
     elf_aux_info(int aux, void *buf, int buflen);

DESCRIPTION
     The elf_aux_info() function retrieves the auxiliary info vector requested
     in aux.  The information is stored into the provided buffer if it will
     fit.  The following values, defined in <sys/elf_common.h> can be
     requested (corresponding buffer sizes are specified in parenthesis):

     AT_CANARY     The canary value for SSP (arbitrary sized buffer, as many
                   bytes are returned as it fits into it, rest is zeroed).

     AT_EXECPATH   The path of executed program (MAXPATHLEN). This may not be
                   present if the process was initialized by fexecve(2) and
                   the namecache no longer contains the file's name.

     AT_HWCAP      CPU / hardware feature flags (sizeof(u_long)).

     AT_HWCAP2     CPU / hardware feature flags (sizeof(u_long)).

     AT_NCPUS      Number of CPUs (sizeof(int)).

     AT_OSRELDATE  The OSRELDATE of the kernel or jail the program is running
                   on (sizeof(int)).

     AT_PAGESIZES  Vector of page sizes (arbitrary sized buffer, as many
                   elements of the pagesizes array are returned as it fits).

     AT_PAGESZ     Page size in bytes (sizeof(int)).

     AT_TIMEKEEP   Pointer to VDSO timehands (for library internal use,
                   sizeof(void *)).

RETURN VALUES
     Returns zero on success, or an error number on failure.

ERRORS
     [EINVAL]           An unknown item was requested.

     [EINVAL]           The provided buffer was not the right size for the
                        requested item.

     [ENOENT]           The requested item is not available.

HISTORY
     The elf_aux_info() function appeared in FreeBSD 12.0.

BUGS
     Only a small subset of available auxiliary info vector items are
     accessible with this function.  Some items require a "right-sized" buffer
     while others just require a "big enough" buffer.

FreeBSD 13.1-RELEASE-p6        November 17, 2019       FreeBSD 13.1-RELEASE-p6