perf trace: Support using -f to override perf.data file ownership

Enable perf trace to use perf.data when it is not owned by current user
or root.

Example:

 # perf trace record ls
 # chown Yunlong.Song:Yunlong.Song perf.data
 # ls -al perf.data
 -rw------- 1 Yunlong.Song Yunlong.Song 4153101 Apr  2 15:28 perf.data
 # id
 uid=0(root) gid=0(root) groups=0(root),64(pkcs11)

Before this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
   Error: unknown switch `f'

  usage: perf trace [<options>] [<command>]
     or: perf trace [<options>] -- <command> [<options>]
     or: perf trace record [<options>] [<command>]
     or: perf trace record [<options>] -- <command> [<options>]

         --event <event>   event selector. use 'perf list' to list
 						  available events
         --comm            show the thread COMM next to its id
         --tool_stats      show tool stats
     -e, --expr <expr>     list of events to trace
     -o, --output <file>   output file name
     -i, --input <file>    Analyze events in file
     -p, --pid <pid>       trace events on existing process id
     -t, --tid <tid>       trace events on existing thread id
         --filter-pids <float>
  ...

As shown above, the -f option does not work at all.

After this patch:

 # perf trace -i perf.data
 File perf.data not owned by current user or root (use -f to override)
 # perf trace -i perf.data -f
 0.056 ( 0.002 ms): ls/47325 brk(                                 ...
 0.108 ( 0.018 ms): ls/47325 mmap(len: 4096, prot: READ|WRITE,    ...
 0.145 ( 0.013 ms): ls/47325 access(filename: 0x7f31259a0eb0,     ...
 0.172 ( 0.008 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.180 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.185 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.189 ( 0.003 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.195 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.199 ( 0.002 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.205 ( 0.004 ms): ls/47325 open(filename: 0x7fffeb9a0d00,       ...
 0.211 ( 0.004 ms): ls/47325 stat(filename: 0x7fffeb9a0d00,       ...
 0.220 ( 0.007 ms): ls/47325 open(filename: 0x7f312599e8ff,       ...
 ...
 ...

As shown above, the -f option really works now.

Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1427982439-27388-10-git-send-email-yunlong.song@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index bcc98ce3e5b8fc2bdb72e1550e00b15418a2903e..e124741be187ee729a77b088d30f843ee24eefa4 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -1254,6 +1254,7 @@ struct trace {
        bool                    show_comm;
        bool                    show_tool_stats;
        bool                    trace_syscalls;
+       bool                    force;
        int                     trace_pgfaults;
 };
 
@@ -2345,6 +2346,7 @@ static int trace__replay(struct trace *trace)
        struct perf_data_file file = {
                .path  = input_name,
                .mode  = PERF_DATA_MODE_READ,
+               .force = trace->force,
        };
        struct perf_session *session;
        struct perf_evsel *evsel;
@@ -2693,6 +2695,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
        OPT_CALLBACK_DEFAULT('F', "pf", &trace.trace_pgfaults, "all|maj|min",
                     "Trace pagefaults", parse_pagefaults, "maj"),
        OPT_BOOLEAN(0, "syscalls", &trace.trace_syscalls, "Trace syscalls"),
+       OPT_BOOLEAN('f', "force", &trace.force, "don't complain, do it"),
        OPT_END()
        };
        const char * const trace_subcommands[] = { "record", NULL };