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    Subject[RFC] [PATCH 2/2] perf/probe: Detect probe target when m/x options are absent
    From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

    Options -m and -x explicitly allow tracing of modules / user space
    binaries. In absense of these options, check if the first argument
    can be used as a target.

    perf probe /bin/zsh zfree is equivalent to perf probe -x /bin/zsh
    zfree.

    Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
    ---
    tools/perf/Documentation/perf-probe.txt | 8 ++++--
    tools/perf/builtin-probe.c | 43 +++++++++++++++++++++++++++++--
    2 files changed, 46 insertions(+), 5 deletions(-)

    diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
    index fb673be..51205f0 100644
    --- a/tools/perf/Documentation/perf-probe.txt
    +++ b/tools/perf/Documentation/perf-probe.txt
    @@ -104,6 +104,10 @@ OPTIONS
    Specify path to the executable or shared library file for user
    space tracing. Can also be used with --funcs option.

    +In absence of -m/-x options, perf probe checks if the first argument after
    +the options is an absolute path name. If its an absolute path, perf probe
    +uses it as a target module/target user space binary to probe.
    +
    PROBE SYNTAX
    ------------
    Probe points are defined by following syntax.
    @@ -190,11 +194,11 @@ Delete all probes on schedule().

    Add probes at zfree() function on /bin/zsh

    - ./perf probe -x /bin/zsh zfree
    + ./perf probe -x /bin/zsh zfree or ./perf probe /bin/zsh zfree

    Add probes at malloc() function on libc

    - ./perf probe -x /lib/libc.so.6 malloc
    + ./perf probe -x /lib/libc.so.6 malloc or ./perf probe /lib/libc.so.6 malloc

    SEE ALSO
    --------
    diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
    index ee3d84a..e215ae6 100644
    --- a/tools/perf/builtin-probe.c
    +++ b/tools/perf/builtin-probe.c
    @@ -85,21 +85,58 @@ static int parse_probe_event(const char *str)
    return ret;
    }

    +static int set_target(const char *ptr)
    +{
    + int found = 0;
    + const char *buf;
    +
    + /*
    + * The first argument after options can be an absolute path
    + * to an executable / library or kernel module.
    + *
    + * TODO: Support relative path, and $PATH, $LD_LIBRARY_PATH,
    + * short module name.
    + */
    + if (!params.target && ptr && *ptr == '/') {
    + params.target = ptr;
    + found = 1;
    + buf = ptr + (strlen(ptr) - 3);
    +
    + if (strcmp(buf, ".ko"))
    + params.uprobes = true;
    +
    + }
    +
    + return found;
    +}
    +
    static int parse_probe_event_argv(int argc, const char **argv)
    {
    - int i, len, ret;
    + int i, len, ret, found_target;
    char *buf;

    + found_target = set_target(argv[0]);
    + if (found_target && argc == 1)
    + return 0;
    +
    /* Bind up rest arguments */
    len = 0;
    - for (i = 0; i < argc; i++)
    + for (i = 0; i < argc; i++) {
    + if (i == 0 && found_target)
    + continue;
    +
    len += strlen(argv[i]) + 1;
    + }
    buf = zalloc(len + 1);
    if (buf == NULL)
    return -ENOMEM;
    len = 0;
    - for (i = 0; i < argc; i++)
    + for (i = 0; i < argc; i++) {
    + if (i == 0 && found_target)
    + continue;
    +
    len += sprintf(&buf[len], "%s ", argv[i]);
    + }
    params.mod_events = true;
    ret = parse_probe_event(buf);
    free(buf);



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