xref: /freebsd/lib/libkvm/kvm_nlist.3 (revision dc36d6f9bb1753f3808552f3afd30eda9a7b206a)

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.Dd November 27, 2015
.Dt KVM_NLIST 3
.Os
.Sh NAME
.Nm kvm_nlist ,
.Nm kvm_nlist2
.Nd retrieve symbol table names from a kernel image
.Sh LIBRARY
.Lb libkvm
.Sh SYNOPSIS
.In kvm.h
.In nlist.h
.Ft int
.Fn kvm_nlist "kvm_t *kd" "struct nlist *nl"
.Ft int
.Fn kvm_nlist2 "kvm_t *kd" "struct kvm_nlist *nl"
.Sh DESCRIPTION
The
.Fn kvm_nlist
function retrieves the symbol table entries indicated by the name list argument
.Fa \&nl .
This argument points to an array of nlist structures, terminated by
an entry whose
.Fa n_name
field is
.Dv NULL
(see
.Xr nlist 3 ) .
Each symbol is looked up using the
.Fa n_name
field, and if found, the
corresponding
.Fa n_type
and
.Fa n_value
fields are filled in.
These fields are set
to 0 if the symbol is not found.
.Pp
The
.Xr kldsym 2
system call is used to locate symbols in live kernels.
This is a less than perfect
emulation of the nlist values but has the advantage of being aware of kernel
modules and is reasonably fast.
.Pp
The
.Fn kvm_nlist2
function retrieves the symbol table entries indicated by the name list argument
.Fa nl .
This argument points to an array of
.Vt "struct kvm_nlist"
structures,
terminated by an entry whose
.Fa n_name
field is
.Dv NULL
These structures are similar to the nlist structures used by
.Fn kvm_nlist
except that the
.Fa n_value
field uses a different type
.Pq Vt kvaddr_t
to avoid truncation when examining non-native kernel images.
.Sh RETURN VALUES
The
.Fn kvm_nlist
and
.Fn kvm_nlist2
functions return the number of invalid entries found.
If the kernel symbol table was unreadable, -1 is returned.
.Sh SEE ALSO
.Xr kldsym 2 ,
.Xr kvm 3 ,
.Xr kvm_close 3 ,
.Xr kvm_getargv 3 ,
.Xr kvm_getenvv 3 ,
.Xr kvm_geterr 3 ,
.Xr kvm_getprocs 3 ,
.Xr kvm_native 3 ,
.Xr kvm_open 3 ,
.Xr kvm_openfiles 3 ,
.Xr kvm_read 3 ,
.Xr kvm_write 3
.Sh HISTORY
The
.Fn kvm_nlist2
function first appeared in
.Fx 11.0 .