- Store the symbol table contents in an anonymous swap-backed object. Have
mmap(/dev/ksyms) map that object, and stop mapping the symbol table into
the calling process in ksyms_open(). Previously we would cache a pointer
to the pmap of the opening process, and mmap(/dev/ksyms) would create a
mapping using the physical address found by a pmap lookup at the initial
mapping address. However, this assumes that the cached pmap is valid,
which may not be the case. [1]
- Remove the ksyms ioctl interface. It appears to have been added to work
around a limitation in libelf that no longer exists; see r321842.
Moreover, the interface is difficult to support and isn't present in
illumos. Since ksyms was added specifically to support lockstat(1), it
is expected that this removal won't have any real impact.
- Simplify ksyms_read() to avoid unnecessary copying.
- Don't call the device handle destructor if we fail to capture a snapshot
of the kernel's symbol table. devfs will do that for us.
Reported by: Ilja van Sprundel <ivansprundel@ioactive.com> [1]
Reviewed by: kib (previous revision)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11789
bottom of the manpages and order them consistently.
GNU groff doesn't care about the ordering, and doesn't even mention
CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put
them.
Found by: mdocml lint run
Reviewed by: ru
get a quick snapshot of the kernel's symbol table including the symbols
from any loaded modules (the symbols are all merged into one symbol
table). Unlike like other implementations, this ksyms driver maps
memory in the process memory space to store the snapshot at the time
/dev/ksyms is opened. It also checks to see if the process has already
a snapshot open and won't allow it to open /dev/ksyms it again until it
closes first. This prevents kernel and process memory from being
exhausted. Note that /dev/ksyms is used by the lockstat(1) command.
Reviewed by: gallatin kib (freebsd-arch)
Approved by: gnn (mentor)
