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path: root/tools/bpf/bpftool/tracelog.c
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2018-12-18tools: bpftool: add an option to prevent auto-mount of bpffs, tracefsQuentin Monnet1-0/+3
In order to make life easier for users, bpftool automatically attempts to mount the BPF virtual file system, if it is not mounted already, before trying to pin objects in it. Similarly, it attempts to mount tracefs if necessary before trying to dump the trace pipe to the console. While mounting file systems on-the-fly can improve user experience, some administrators might prefer to avoid that. Let's add an option to block these mount attempts. Note that it does not prevent automatic mounting of tracefs by debugfs for the "bpftool prog tracelog" command. Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-18tools: bpftool: attempt to mount tracefs if required for tracelog cmdQuentin Monnet1-7/+13
As a follow-up to commit 30da46b5dc3a ("tools: bpftool: add a command to dump the trace pipe"), attempt to mount the tracefs virtual file system if it is not detected on the system before trying to dump content of the tracing pipe on an invocation of "bpftool prog tracelog". Usually, tracefs in automatically mounted by debugfs when the user tries to access it (e.g. "ls /sys/kernel/debug/tracing" mounts the tracefs). So if we failed to find it, it is probably that debugfs is not here either. Therefore, we just attempt a single mount, at a location that does not involve debugfs: /sys/kernel/tracing. Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-12-05tools: bpftool: add a command to dump the trace pipeQuentin Monnet1-0/+157
BPF programs can use the bpf_trace_printk() helper to print debug information into the trace pipe. Add a subcommand "bpftool prog tracelog" to simply dump this pipe to the console. This is for a good part copied from iproute2, where the feature is available with "tc exec bpf dbg". Changes include dumping pipe content to stdout instead of stderr and adding JSON support (content is dumped as an array of strings, one per line read from the pipe). This version is dual-licensed, with Daniel's permission. Cc: Daniel Borkmann <daniel@iogearbox.net> Suggested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>