aboutsummaryrefslogtreecommitdiffstats
path: root/tools/bpf/bpftool/tracelog.c (follow)
AgeCommit message (Collapse)AuthorFilesLines
2025-09-15bpftool: Search for tracefs at /sys/kernel/tracing firstQuentin Monnet1-9/+2
With "bpftool prog tracelog", bpftool prints messages from the trace pipe. To do so, it first needs to find the tracefs mount point to open the pipe. Bpftool looks at a few "default" locations, including /sys/kernel/debug/tracing and /sys/kernel/tracing. Some of these locations, namely /tracing and /trace, are not standard. They are in the list because some users used to hardcode the tracing directory to short names; but we have no compelling reason to look at these locations. If we fail to find the tracefs at the default locations, we have an additional step to find it by parsing /proc/mounts anyway, so it's safe to remove these entries from the list of default locations to check. Additionally, Alexei reports that looking for the tracefs at /sys/kernel/debug/tracing may automatically mount the file system under that location, and generate a kernel log message telling that auto-mounting there is deprecated. To avoid this message, let's swap the order for checking the potential mount points: try /sys/kernel/tracing first, which should be the standard location nowadays. The kernel log message may still appear if the tracefs is not mounted on /sys/kernel/tracing when we run bpftool. Reported-by: Alexei Starovoitov <ast@kernel.org> Closes: https://lore.kernel.org/r/CAADnVQLcMi5YQhZKsU4z3S2uVUAGu_62C33G2Zx_ruG3uXa-Ug@mail.gmail.com/ Signed-off-by: Quentin Monnet <qmo@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/r/20250915134209.36568-1-qmo@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-03-17bpftool: Using the right format specifiersJiayuan Chen1-1/+1
Fixed some formatting specifiers errors, such as using %d for int and %u for unsigned int, as well as other byte-length types. Perform type cast using the type derived from the data type itself, for example, if it's originally an int, it will be cast to unsigned int if forced to unsigned. Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250311112809.81901-3-jiayuan.chen@linux.dev
2022-04-25bpftool, musl compat: Replace sys/fcntl.h by fcntl.hDominique Martinet1-1/+1
musl does not like including sys/fcntl.h directly: [...] 1 | #warning redirecting incorrect #include <sys/fcntl.h> to <fcntl.h> [...] Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/bpf/20220424051022.2619648-5-asmadeus@codewreck.org
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>