error simulation: adding sigsegv handler support

5 files changed, 61 insertions, 3 deletions

diff --git a/src/audit-error.c b/src/audit-error.c
index 428d41e..b313a56 100644
--- a/src/audit-error.c
+++ b/src/audit-error.c
@@ -6,6 +6,7 @@
 #include <sys/syscall.h>
 #include <strings.h>
 #include <string.h>
+#include <signal.h>
 
 #include "config.h"
 #include "backtrace.h"
@@ -73,6 +74,43 @@ static void share_info(struct lt_config_audit *cfg,
 	dump_backtrace(cfg->sh, 0);
 }
 
+static struct lt_config_shared *ss_cfg;
+
+static void sig_segv_handler(int sig)
+{
+	char text[LT_MAXMSG];
+	struct timeval tv;
+
+	gettimeofday(&tv, NULL);
+
+	snprintf(text, LT_MAXMSG, "ERROR SIMULATION got SIGSEGV");
+
+	if (lt_sh(ss_cfg, pipe)) {
+		char buf[LT_FIFO_MSG_MAXLEN];
+		int len;
+
+		len = lt_fifo_mtext_get(ss_cfg, buf, &tv, text);
+		/* TODO erro handling */
+		lt_fifo_send(ss_cfg, pipe_fd, buf, len);
+	} else
+		lt_out_text(ss_cfg->sh, &tv, syscall(SYS_gettid), text);
+
+	dump_backtrace(ss_cfg, 0);
+	exit(-1);
+}
+
+static int install_sigsegv(struct lt_config_shared *cfg)
+{
+	struct sigaction act;
+
+	bzero(&act, sizeof(act));
+	act.sa_handler = sig_segv_handler;
+
+	ss_cfg = cfg;
+
+	return sigaction(SIGSEGV, &act, NULL);
+}
+
 int lt_error_sym_exit(struct lt_config_audit *cfg,
 		      struct lt_symbol *sym,
 		      struct timeval *tv,
@@ -104,6 +142,10 @@ int lt_error_sym_exit(struct lt_config_audit *cfg,
 
 	/* and share some info about the sinner */
 	share_info(cfg, esym, tv, lr, inregs);
+
+	if (esym->handle_sigsegv && install_sigsegv(cfg->sh))
+		PRINT_VERBOSE(cfg, 1, "failed to install SIGSEGV handler\n");
+
 	return 0;
 }
 
@@ -135,6 +177,7 @@ static int symbol_add(struct lt_config_audit *cfg,
 
 	sym->name = strdup(def_sym->symbol);
 	sym->ret = def_sym->ret;
+	sym->handle_sigsegv = def_sym->handle_sigsegv;
 
 	e.key = sym->name;
 	e.data = sym;
diff --git a/src/config-bison.y b/src/config-bison.y
index c93c802..247a270 100644
--- a/src/config-bison.y
+++ b/src/config-bison.y
@@ -74,6 +74,7 @@ static struct lt_list_head ln_names;
 %token ERROR
 %token ERR_DO ERR_DIR ERR_RUN ERR_GO ERR_RETURN ERR_N
 %token ERR_PROG ERR_ARGS ERR_FILTER ERR_SEQ ERR_START
+%token ERR_SIGSEGV
 
 %union
 {
@@ -335,7 +336,13 @@ error_return: ERR_RETURN NAME '{' error_return_def '}'
 error_return_def:
 error_return_def NAME '=' VALUE
 {
-	if (lt_error_return_ass(scfg, &error_app_return, $2, $4))
+	if (lt_error_return_ass(scfg, &error_app_return, $2, $4, 0))
+		ABORT("failed to add symbol to return definition");
+}
+|
+error_return_def NAME '=' VALUE ERR_SIGSEGV
+{
+	if (lt_error_return_ass(scfg, &error_app_return, $2, $4, 1))
 		ABORT("failed to add symbol to return definition");
 }
 |
diff --git a/src/config-flex.l b/src/config-flex.l
index 22855e4..5f86b9f 100644
--- a/src/config-flex.l
+++ b/src/config-flex.l
@@ -129,6 +129,7 @@ ERROR			{ BEGIN(error); return ERROR; }
 <error>START		{ return ERR_START; }
 <error>FILTER		{ return ERR_FILTER; }
 <error>SEQ		{ return ERR_SEQ; }
+<error>SIGSEGV		{ return ERR_SIGSEGV; }
 
 <error>{value}		{ RETURN_LONG(VALUE); }
 <error>{name}		{ RETURN_STR(NAME); }
diff --git a/src/error.c b/src/error.c
index fefa87d..fc13cad 100644
--- a/src/error.c
+++ b/src/error.c
@@ -296,6 +296,7 @@ static int prepare_config_error(struct lt_config_app *cfg,
 			strncpy(sym_def->symbol, sym->name, LT_MAXNAME);
 			sym_def->ret = sym->val;
 			sym_def->filter.type = ret->filter.type;
+			sym_def->handle_sigsegv = sym->handle_sigsegv;
 
 			PRINT_VERBOSE(cfg, 1, "symbol %s, ret %s\n",
 					sym->name, sym->val);
@@ -624,7 +625,8 @@ app_return_get(struct lt_config_app *cfg, struct lt_error_app_return **ret)
 
 int lt_error_return_ass(struct lt_config_app *cfg,
 			struct lt_error_app_return **ret,
-			char *name, unsigned long val)
+			char *name, unsigned long val,
+			int handle_sigsegv)
 {
 	struct lt_error_app_return *app_ret = app_return_get(cfg, ret);
 	struct lt_error_app_return_sym *sym;
@@ -638,6 +640,7 @@ int lt_error_return_ass(struct lt_config_app *cfg,
 
 	sym->name = strdup(name);
 	sym->val = val;
+	sym->handle_sigsegv = handle_sigsegv;
 
 	PRINT_VERBOSE(cfg, 1, "%s = %ld\n", sym->name, val);
 
diff --git a/src/error.h b/src/error.h
index 367e576..2486549 100644
--- a/src/error.h
+++ b/src/error.h
@@ -16,6 +16,7 @@ struct lt_error_def_sym {
 #define LT_MAXNAME 20
 	char symbol[LT_MAXNAME];
 	long ret;
+	int handle_sigsegv;
 	struct lt_error_def_filter filter;
 };
 
@@ -38,6 +39,7 @@ struct lt_error_sym {
 	char *name;
 	unsigned long ret;
 	unsigned long call;
+	int handle_sigsegv;
 	struct lt_error_audit_filter filter;
 
 	struct lt_list_head list;
@@ -46,6 +48,7 @@ struct lt_error_sym {
 struct lt_error_app_return_sym {
 	char *name;
 	long val;
+	int handle_sigsegv;
 
 	struct lt_list_head list;
 };
@@ -112,7 +115,8 @@ int lt_error_run_args(struct lt_config_app *cfg,
 		      struct lt_list_head *args);
 int lt_error_return_ass(struct lt_config_app *cfg,
 			struct lt_error_app_return **ret,
-			char *name, unsigned long val);
+			char *name, unsigned long val,
+			int handle_sigsegv);
 int lt_error_return_filter(struct lt_config_app *cfg,
 			   struct lt_error_app_return **ret,
 			   int type, void *data);