debug: Add option to log to Linux tracing

Add the option (-T) to wpa_supplicant to log all debug messages into the
kernel tracing, allowing to aggregate kernel debugging with
wpa_supplicant debugging and recording all with trace-cmd.

Since tracing has relatively low overhead and can be filtered
afterwards, record all messages regardless of log level. However, it
will honor the -K option and not record key material by default.

Signed-hostap: Johannes Berg <johannes.berg@intel.com>

diff --git a/src/utils/wpa_debug.c b/src/utils/wpa_debug.c
index 858a97c..3b71d10 100644 (file)
--- a/src/utils/wpa_debug.c
+++ b/src/utils/wpa_debug.c
@@ -16,6 +16,18 @@
 static int wpa_debug_syslog = 0;
 #endif /* CONFIG_DEBUG_SYSLOG */
 
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdio.h>
+
+static FILE *wpa_debug_tracing_file = NULL;
+
+#define WPAS_TRACE_PFX "wpas <%d>: "
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
+
 
 int wpa_debug_level = MSG_INFO;
 int wpa_debug_show_keys = 0;
@@ -107,6 +119,77 @@ static int syslog_priority(int level)
 #endif /* CONFIG_DEBUG_SYSLOG */
 
 
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+
+int wpa_debug_open_linux_tracing(void)
+{
+       int mounts, trace_fd;
+       char buf[4096] = {};
+       ssize_t buflen;
+       char *line, *tmp1, *path = NULL;
+
+       mounts = open("/proc/mounts", O_RDONLY);
+       if (mounts < 0) {
+               printf("no /proc/mounts\n");
+               return -1;
+       }
+
+       buflen = read(mounts, buf, sizeof(buf) - 1);
+       close(mounts);
+       if (buflen < 0) {
+               printf("failed to read /proc/mounts\n");
+               return -1;
+       }
+
+       line = strtok_r(buf, "\n", &tmp1);
+       while (line) {
+               char *tmp2, *tmp_path, *fstype;
+               /* "<dev> <mountpoint> <fs type> ..." */
+               strtok_r(line, " ", &tmp2);
+               tmp_path = strtok_r(NULL, " ", &tmp2);
+               fstype = strtok_r(NULL, " ", &tmp2);
+               if (strcmp(fstype, "debugfs") == 0) {
+                       path = tmp_path;
+                       break;
+               }
+
+               line = strtok_r(NULL, "\n", &tmp1);
+       }
+
+       if (path == NULL) {
+               printf("debugfs mountpoint not found\n");
+               return -1;
+       }
+
+       snprintf(buf, sizeof(buf) - 1, "%s/tracing/trace_marker", path);
+
+       trace_fd = open(buf, O_WRONLY);
+       if (trace_fd < 0) {
+               printf("failed to open trace_marker file\n");
+               return -1;
+       }
+       wpa_debug_tracing_file = fdopen(trace_fd, "w");
+       if (wpa_debug_tracing_file == NULL) {
+               close(trace_fd);
+               printf("failed to fdopen()\n");
+               return -1;
+       }
+
+       return 0;
+}
+
+
+void wpa_debug_close_linux_tracing(void)
+{
+       if (wpa_debug_tracing_file == NULL)
+               return;
+       fclose(wpa_debug_tracing_file);
+       wpa_debug_tracing_file = NULL;
+}
+
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
+
+
 /**
  * wpa_printf - conditional printf
  * @level: priority level (MSG_*) of the message
@@ -151,6 +234,17 @@ void wpa_printf(int level, const char *fmt, ...)
 #endif /* CONFIG_ANDROID_LOG */
        }
        va_end(ap);
+
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+       if (wpa_debug_tracing_file != NULL) {
+               va_start(ap, fmt);
+               fprintf(wpa_debug_tracing_file, WPAS_TRACE_PFX, level);
+               vfprintf(wpa_debug_tracing_file, fmt, ap);
+               fprintf(wpa_debug_tracing_file, "\n");
+               fflush(wpa_debug_tracing_file);
+               va_end(ap);
+       }
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
 }
 
 
@@ -158,6 +252,25 @@ static void _wpa_hexdump(int level, const char *title, const u8 *buf,
                         size_t len, int show)
 {
        size_t i;
+
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+       if (wpa_debug_tracing_file != NULL) {
+               fprintf(wpa_debug_tracing_file,
+                       WPAS_TRACE_PFX "%s - hexdump(len=%lu):",
+                       level, title, (unsigned long) len);
+               if (buf == NULL) {
+                       fprintf(wpa_debug_tracing_file, " [NULL]\n");
+               } else if (!show) {
+                       fprintf(wpa_debug_tracing_file, " [REMOVED]\n");
+               } else {
+                       for (i = 0; i < len; i++)
+                               fprintf(wpa_debug_tracing_file,
+                                       " %02x", buf[i]);
+               }
+               fflush(wpa_debug_tracing_file);
+       }
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
+
        if (level < wpa_debug_level)
                return;
 #ifdef CONFIG_ANDROID_LOG
@@ -281,6 +394,25 @@ static void _wpa_hexdump_ascii(int level, const char *title, const u8 *buf,
        const u8 *pos = buf;
        const size_t line_len = 16;
 
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+       if (wpa_debug_tracing_file != NULL) {
+               fprintf(wpa_debug_tracing_file,
+                       WPAS_TRACE_PFX "%s - hexdump_ascii(len=%lu):",
+                       level, title, (unsigned long) len);
+               if (buf == NULL) {
+                       fprintf(wpa_debug_tracing_file, " [NULL]\n");
+               } else if (!show) {
+                       fprintf(wpa_debug_tracing_file, " [REMOVED]\n");
+               } else {
+                       /* can do ascii processing in userspace */
+                       for (i = 0; i < len; i++)
+                               fprintf(wpa_debug_tracing_file,
+                                       " %02x", buf[i]);
+               }
+               fflush(wpa_debug_tracing_file);
+       }
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
+
        if (level < wpa_debug_level)
                return;
 #ifdef CONFIG_ANDROID_LOG

diff --git a/src/utils/wpa_debug.h b/src/utils/wpa_debug.h
index c79907a..339c749 100644 (file)
--- a/src/utils/wpa_debug.h
+++ b/src/utils/wpa_debug.h
@@ -255,6 +255,24 @@ static inline void wpa_debug_close_syslog(void)
 
 #endif /* CONFIG_DEBUG_SYSLOG */
 
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+
+int wpa_debug_open_linux_tracing(void);
+void wpa_debug_close_linux_tracing(void);
+
+#else /* CONFIG_DEBUG_LINUX_TRACING */
+
+static inline int wpa_debug_open_linux_tracing(void)
+{
+       return 0;
+}
+
+static inline void wpa_debug_close_linux_tracing(void)
+{
+}
+
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
+
 
 #ifdef EAPOL_TEST
 #define WPA_ASSERT(a)                                                 \

diff --git a/wpa_supplicant/Makefile b/wpa_supplicant/Makefile
index a976098..b3a9d55 100644 (file)
--- a/wpa_supplicant/Makefile
+++ b/wpa_supplicant/Makefile
@@ -1273,6 +1273,10 @@ CFLAGS += -DLOG_HOSTAPD="$(CONFIG_DEBUG_SYSLOG_FACILITY)"
 endif
 endif
 
+ifdef CONFIG_DEBUG_LINUX_TRACING
+CFLAGS += -DCONFIG_DEBUG_LINUX_TRACING
+endif
+
 ifdef CONFIG_DEBUG_FILE
 CFLAGS += -DCONFIG_DEBUG_FILE
 endif

diff --git a/wpa_supplicant/defconfig b/wpa_supplicant/defconfig
index 480bc64..4aea570 100644 (file)
--- a/wpa_supplicant/defconfig
+++ b/wpa_supplicant/defconfig
@@ -413,6 +413,12 @@ CONFIG_PEERKEY=y
 # Set syslog facility for debug messages
 #CONFIG_DEBUG_SYSLOG_FACILITY=LOG_DAEMON
 
+# Add support for sending all debug messages (regardless of debug verbosity)
+# to the Linux kernel tracing facility. This helps debug the entire stack by
+# making it easy to record everything happening from the driver up into the
+# same file, e.g., using trace-cmd.
+#CONFIG_DEBUG_LINUX_TRACING=y
+
 # Enable privilege separation (see README 'Privilege separation' for details)
 #CONFIG_PRIVSEP=y
 

diff --git a/wpa_supplicant/main.c b/wpa_supplicant/main.c
index c124ca2..bde956e 100644 (file)
--- a/wpa_supplicant/main.c
+++ b/wpa_supplicant/main.c
@@ -61,6 +61,10 @@ static void usage(void)
 #ifdef CONFIG_DEBUG_SYSLOG
        printf("  -s = log output to syslog instead of stdout\n");
 #endif /* CONFIG_DEBUG_SYSLOG */
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+       printf("  -T = record to Linux tracing in addition to logging\n");
+       printf("       (records all messages regardless of debug verbosity)\n");
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
        printf("  -t = include timestamp in debug messages\n"
               "  -h = show this help text\n"
               "  -L = show license (BSD)\n"
@@ -139,7 +143,8 @@ int main(int argc, char *argv[])
        wpa_supplicant_fd_workaround();
 
        for (;;) {
-               c = getopt(argc, argv, "b:Bc:C:D:de:f:g:hi:KLNo:O:p:P:qstuvW");
+               c = getopt(argc, argv,
+                          "b:Bc:C:D:de:f:g:hi:KLNo:O:p:P:qsTtuvW");
                if (c < 0)
                        break;
                switch (c) {
@@ -214,6 +219,11 @@ int main(int argc, char *argv[])
                        params.wpa_debug_syslog++;
                        break;
 #endif /* CONFIG_DEBUG_SYSLOG */
+#ifdef CONFIG_DEBUG_LINUX_TRACING
+               case 'T':
+                       params.wpa_debug_tracing++;
+                       break;
+#endif /* CONFIG_DEBUG_LINUX_TRACING */
                case 't':
                        params.wpa_debug_timestamp++;
                        break;

diff --git a/wpa_supplicant/wpa_supplicant.c b/wpa_supplicant/wpa_supplicant.c
index 71542f0..e9c42d3 100644 (file)
--- a/wpa_supplicant/wpa_supplicant.c
+++ b/wpa_supplicant/wpa_supplicant.c
@@ -2875,6 +2875,14 @@ struct wpa_global * wpa_supplicant_init(struct wpa_params *params)
        wpa_debug_open_file(params->wpa_debug_file_path);
        if (params->wpa_debug_syslog)
                wpa_debug_open_syslog();
+       if (params->wpa_debug_tracing) {
+               ret = wpa_debug_open_linux_tracing();
+               if (ret) {
+                       wpa_printf(MSG_ERROR,
+                                  "Failed to enable trace logging");
+                       return NULL;
+               }
+       }
 
        ret = eap_register_methods();
        if (ret) {
@@ -3037,6 +3045,7 @@ void wpa_supplicant_deinit(struct wpa_global *global)
        os_free(global);
        wpa_debug_close_syslog();
        wpa_debug_close_file();
+       wpa_debug_close_linux_tracing();
 }
 
 

diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
index 0ba1935..e2e0aed 100644 (file)
--- a/wpa_supplicant/wpa_supplicant_i.h
+++ b/wpa_supplicant/wpa_supplicant_i.h
@@ -161,6 +161,11 @@ struct wpa_params {
        int wpa_debug_syslog;
 
        /**
+        * wpa_debug_tracing - Enable log output through Linux tracing
+        */
+       int wpa_debug_tracing;
+
+       /**
         * override_driver - Optional driver parameter override
         *
         * This parameter can be used to override the driver parameter in