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Diffstat (limited to 'lib/libsys/auxv.3')
| -rw-r--r-- | lib/libsys/auxv.3 | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/lib/libsys/auxv.3 b/lib/libsys/auxv.3 new file mode 100644 index 000000000000..b3b741937ac7 --- /dev/null +++ b/lib/libsys/auxv.3 @@ -0,0 +1,111 @@ +.\" +.\" Copyright (c) 2019 Ian Lepore <ian@freebsd.org> +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.Dd June 24, 2025 +.Dt ELF_AUX_INFO 3 +.Os +.Sh NAME +.Nm elf_aux_info +.Nd extract data from the elf auxiliary vector of the current process +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/auxv.h +.Ft int +.Fn elf_aux_info "int aux" "void *buf" "int buflen" +.Sh DESCRIPTION +The +.Fn elf_aux_info +function retrieves the auxiliary info vector requested in +.Va aux . +The information is stored into the provided buffer if it will fit. +The following values, defined in +.In sys/elf_common.h +can be requested (corresponding buffer sizes are specified in parenthesis): +.Bl -tag -width AT_OSRELDATE +.It AT_CANARY +The canary value for SSP (arbitrary sized buffer, as many bytes are +returned as it fits into it, rest is zeroed). +.It AT_EXECPATH +The path of executed program +.Dv (MAXPATHLEN). +This may not be present if the process was initialized by +.Xr fexecve 2 +and the namecache no longer contains the file's name. +.It AT_HWCAP +CPU / hardware feature flags +.Dv (sizeof(u_long)). +.It AT_HWCAP2 +CPU / hardware feature flags +.Dv (sizeof(u_long)). +.It AT_HWCAP3 +CPU / hardware feature flags +.Dv (sizeof(u_long)). +.It AT_HWCAP4 +CPU / hardware feature flags +.Dv (sizeof(u_long)). +.It AT_NCPUS +Number of CPUs +.Dv (sizeof(int)). +.It AT_OSRELDATE +The +.Dv OSRELDATE +of the kernel or jail the program is running on +.Dv (sizeof(int)). +.It AT_PAGESIZES +Vector of page sizes (arbitrary sized buffer, as many elements of the +.Dv pagesizes +array are returned as it fits). +.It AT_PAGESZ +Page size in bytes +.Dv (sizeof(int)). +.It AT_TIMEKEEP +Pointer to VDSO timehands (for library internal use, +.Dv sizeof(void *)). +.It AT_USRSTACKBASE +Top of the user stack for main thread. +.It AT_USRSTACKLIM +Limit for grow of the user stack for main thread. +.El +.Sh RETURN VALUES +Returns zero on success, or an error number on failure. +.Sh ERRORS +.Bl -tag -width Er +.It Bq Er EINVAL +An unknown item was requested. +.It Bq Er EINVAL +The provided buffer was not the right size for the requested item. +.It Bq Er ENOENT +The requested item is not available. +.El +.Sh HISTORY +The +.Fn elf_aux_info +function appeared in +.Fx 12.0 . +.Sh 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. |