Add kretprobe support (new --function implementation)

Add kretprobe support (new --function implementation)

Also support probe "symbol" (without +offset) by checking first
character with isalpha().

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/include/lttng-kernel.h b/include/lttng-kernel.h
index 2d88012b079c2d4a5070fdf6ec11d79c84ce2e46..9eb207bb2fd4e255cf88bccc8de61f27ce99deec 100644 (file)
--- a/include/lttng-kernel.h
+++ b/include/lttng-kernel.h
@@ -35,6 +35,7 @@ enum lttng_kernel_instrumentation {
        LTTNG_KERNEL_TRACEPOINT    = 0,
        LTTNG_KERNEL_KPROBE        = 1,
        LTTNG_KERNEL_FUNCTION      = 2,
+       LTTNG_KERNEL_KRETPROBE     = 3,
 };
 
 enum lttng_kernel_context_type {
@@ -65,6 +66,13 @@ struct lttng_kernel_context {
        } u;
 };
 
+struct lttng_kernel_kretprobe {
+       uint64_t addr;
+
+       uint64_t offset;
+       char symbol_name[LTTNG_SYM_NAME_LEN];
+};
+
 /*
  * Either addr is used, or symbol_name and offset.
  */
@@ -85,6 +93,7 @@ struct lttng_kernel_event {
        enum lttng_kernel_instrumentation instrumentation;
        /* Per instrumentation type configuration */
        union {
+               struct lttng_kernel_kretprobe kretprobe;
                struct lttng_kernel_kprobe kprobe;
                struct lttng_kernel_function ftrace;
        } u;

diff --git a/include/lttng/lttng.h b/include/lttng/lttng.h
index b5f754082d9405ad9b97b50969c8ecedd7a8a382..2cbb7f7ed38ddcda2f5efb0ac926d89b9e1f9863 100644 (file)
--- a/include/lttng/lttng.h
+++ b/include/lttng/lttng.h
@@ -73,6 +73,7 @@ enum lttng_event_type {
        LTTNG_EVENT_TRACEPOINT,
        LTTNG_EVENT_PROBE,
        LTTNG_EVENT_FUNCTION,
+       LTTNG_EVENT_FUNCTION_ENTRY,
 };
 
 /*

diff --git a/ltt-sessiond/ltt-sessiond.h b/ltt-sessiond/ltt-sessiond.h
index c2ff58ab6ca84088281973a178cf602333bea84d..17c9c32f8fd75c7a5a445f65f6e941e803cf78a6 100644 (file)
--- a/ltt-sessiond/ltt-sessiond.h
+++ b/ltt-sessiond/ltt-sessiond.h
@@ -36,6 +36,7 @@ const char *kernel_modules_list[] = {
        "ltt-ring-buffer-metadata-mmap-client",
        "lttng-ftrace",
        "lttng-kprobes",
+       "lttng-kretprobes",
        "lttng-probe-block",
        "lttng-probe-irq",
        "lttng-probe-kvm",

diff --git a/ltt-sessiond/trace.c b/ltt-sessiond/trace.c
index 41c4355e939fa67e4c8a7f8b2c4d660e4fc0e6ff..c090f21063d60d8e38c3aecf6150e17195c8d45f 100644 (file)
--- a/ltt-sessiond/trace.c
+++ b/ltt-sessiond/trace.c
@@ -185,6 +185,14 @@ struct ltt_kernel_event *trace_create_kernel_event(struct lttng_event *ev)
                                ev->attr.probe.symbol_name, LTTNG_SYM_NAME_LEN);
                break;
        case LTTNG_EVENT_FUNCTION:
+               attr->instrumentation = LTTNG_KERNEL_KRETPROBE;
+               attr->u.kretprobe.addr = ev->attr.probe.addr;
+               attr->u.kretprobe.offset = ev->attr.probe.offset;
+               attr->u.kretprobe.offset = ev->attr.probe.offset;
+               strncpy(attr->u.kretprobe.symbol_name,
+                               ev->attr.probe.symbol_name, LTTNG_SYM_NAME_LEN);
+               break;
+       case LTTNG_EVENT_FUNCTION_ENTRY:
                attr->instrumentation = LTTNG_KERNEL_FUNCTION;
                strncpy(attr->u.ftrace.symbol_name,
                                ev->attr.ftrace.symbol_name, LTTNG_SYM_NAME_LEN);

diff --git a/lttng/commands/enable_events.c b/lttng/commands/enable_events.c
index 5d025e7085cb881393b795c9816f2048bf1c6fd5..b99b7f4c942294784f577ea8465009aa2b0134c0 100644 (file)
--- a/lttng/commands/enable_events.c
+++ b/lttng/commands/enable_events.c
@@ -25,6 +25,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <inttypes.h>
+#include <ctype.h>
 
 #include "../cmd.h"
 #include "../conf.h"
@@ -40,7 +41,8 @@ static int opt_userspace;
 static int opt_enable_all;
 static pid_t opt_pid;
 static char *opt_probe;
-static char *opt_function_symbol;
+static char *opt_function;
+static char *opt_function_entry_symbol;
 static char *opt_channel_name;
 
 enum {
@@ -50,6 +52,7 @@ enum {
        OPT_MARKER,
        OPT_PROBE,
        OPT_FUNCTION,
+       OPT_FUNCTION_ENTRY,
 };
 
 static struct poptOption long_options[] = {
@@ -66,6 +69,7 @@ static struct poptOption long_options[] = {
        {"marker",         0,   POPT_ARG_NONE, 0, OPT_MARKER, 0, 0},
        {"probe",         0,   POPT_ARG_STRING, 0, OPT_PROBE, 0, 0},
        {"function",       0,   POPT_ARG_STRING, 0, OPT_FUNCTION, 0, 0},
+       {"function:entry", 0,   POPT_ARG_STRING, 0, OPT_FUNCTION_ENTRY, 0, 0},
        {0, 0, 0, 0, 0, 0, 0}
 };
 
@@ -87,11 +91,16 @@ static void usage(FILE *ofp)
        fprintf(ofp, "\n");
        fprintf(ofp, "Event options:\n");
        fprintf(ofp, "    --tracepoint           Tracepoint event (default)\n");
-       fprintf(ofp, "    --probe [addr | symbol+offset]\n");
+       fprintf(ofp, "    --probe [addr | symbol | symbol+offset]\n");
        fprintf(ofp, "                           Dynamic probe.\n");
        fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
        fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
-       fprintf(ofp, "    --function SYMBOL      Function tracer event\n");
+       fprintf(ofp, "    --function [addr | symbol | symbol+offset]\n");
+       fprintf(ofp, "                           Dynamic function entry/return probe.\n");
+       fprintf(ofp, "                           Addr and offset can be octal (0NNN...),\n");
+       fprintf(ofp, "                           decimal (NNN...) or hexadecimal (0xNNN...)\n");
+       fprintf(ofp, "    --function:entry symbol\n");
+       fprintf(ofp, "                           Function tracer event\n");
        fprintf(ofp, "    --marker               User-space marker (deprecated)\n");
        fprintf(ofp, "\n");
 }
@@ -109,7 +118,7 @@ static int parse_probe_opts(struct lttng_event *ev, char *opt)
 
        if (opt == NULL) {
                ret = -1;
-               goto error;
+               goto end;
        }
 
        /* Check for symbol+offset */
@@ -120,12 +129,25 @@ static int parse_probe_opts(struct lttng_event *ev, char *opt)
                if (strlen(s_hex) == 0) {
                        ERR("Invalid probe offset %s", s_hex);
                        ret = -1;
-                       goto error;
+                       goto end;
                }
                ev->attr.probe.offset = strtoul(s_hex, NULL, 0);
                DBG("probe offset %" PRIu64, ev->attr.probe.offset);
                ev->attr.probe.addr = 0;
-               goto error;
+               goto end;
+       }
+
+       /* Check for symbol */
+       if (isalpha(name[0])) {
+               ret = sscanf(opt, "%s", name);
+               if (ret == 1) {
+                       strncpy(ev->attr.probe.symbol_name, name, LTTNG_SYMBOL_NAME_LEN);
+                       DBG("probe symbol %s", ev->attr.probe.symbol_name);
+                       ev->attr.probe.offset = 0;
+                       DBG("probe offset %" PRIu64, ev->attr.probe.offset);
+                       ev->attr.probe.addr = 0;
+                       goto end;
+               }
        }
 
        /* Check for address */
@@ -134,19 +156,19 @@ static int parse_probe_opts(struct lttng_event *ev, char *opt)
                if (strlen(s_hex) == 0) {
                        ERR("Invalid probe address %s", s_hex);
                        ret = -1;
-                       goto error;
+                       goto end;
                }
                ev->attr.probe.addr = strtoul(s_hex, NULL, 0);
                DBG("probe addr %" PRIu64, ev->attr.probe.addr);
                ev->attr.probe.offset = 0;
                memset(ev->attr.probe.symbol_name, 0, LTTNG_SYMBOL_NAME_LEN);
-               goto error;
+               goto end;
        }
 
        /* No match */
        ret = -1;
 
-error:
+end:
        return ret;
 }
 
@@ -222,7 +244,17 @@ static int enable_events(void)
                                }
                                break;
                        case LTTNG_EVENT_FUNCTION:
-                               strncpy(ev.attr.ftrace.symbol_name, opt_function_symbol, LTTNG_SYMBOL_NAME_LEN);
+                               ret = parse_probe_opts(&ev, opt_function);
+                               if (ret < 0) {
+                                       ERR("Unable to parse function probe options");
+                                       ret = 0;
+                                       goto error;
+                               }
+                               break;
+                       case LTTNG_EVENT_FUNCTION_ENTRY:
+                               strncpy(ev.attr.ftrace.symbol_name,
+                                       opt_function_entry_symbol,
+                                       LTTNG_SYMBOL_NAME_LEN);
                                break;
                        default:
                                ret = CMD_NOT_IMPLEMENTED;
@@ -296,7 +328,11 @@ int cmd_enable_events(int argc, const char **argv)
                        break;
                case OPT_FUNCTION:
                        opt_event_type = LTTNG_EVENT_FUNCTION;
-                       opt_function_symbol = poptGetOptArg(pc);
+                       opt_function = poptGetOptArg(pc);
+                       break;
+               case OPT_FUNCTION_ENTRY:
+                       opt_event_type = LTTNG_EVENT_FUNCTION_ENTRY;
+                       opt_function_entry_symbol = poptGetOptArg(pc);
                        break;
                default:
                        usage(stderr);