adding stack limits dynamic check

9 files changed, 148 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 9a7a4dd..e8a6c12 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2010-09-07 Jiri Olsa <olsajiri@gmail.com>
+	* adding stack limits dynamic check
+		- based on proposal from Akos Pasztory
+		- enabled by default, disable by new '-Y' option
+
 2010-08-05  Jiri Olsa <olsajiri@gmail.com>
 	* changed config file magic defines
 	* separate arguments display code, so it could be
diff --git a/TODO b/TODO
index 47d02ac..0aef70a 100644
--- a/TODO
+++ b/TODO
@@ -6,6 +6,7 @@ olsajiri@gmail.com
 
 for 0.5.10
 	- testing/fixing bugs
+	- make automated tests
 
 for 0.6
 	- config - arrays in structures
diff --git a/doc/latrace.txt b/doc/latrace.txt
index 492561b..20be159 100644
--- a/doc/latrace.txt
+++ b/doc/latrace.txt
@@ -78,6 +78,9 @@ OPTIONS
 *-y, --framesize number*::
 	framesize for storing the stack before pltexit (default 100)
 
+*-Y, --not-framesize-check*::
+	disable framesize check
+
 *-I, --no-indent-sym*::
 	do no indent symbols based on the their stack depth
 
diff --git a/src/Makefile b/src/Makefile
index cada828..796028a 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -27,7 +27,8 @@ AUDIT_OBJS=\
 	src/audit-init.o \
 	src/fifo.o \
 	src/output.o \
-	src/objsearch.o
+	src/objsearch.o \
+	src/stack.o
 
 ifeq ($(CONFIG_ARCH_HAVE_ARGS),y)
 AUDIT_OBJS+=\
diff --git a/src/audit.c b/src/audit.c
index bba7e9f..2a97b75 100644
--- a/src/audit.c
+++ b/src/audit.c
@@ -294,7 +294,8 @@ pltenter(ElfW(Sym) *sym, unsigned int ndx, uintptr_t *refcook,
 
 	} while(0);
 
-	*framesizep = lt_sh(&cfg, framesize);
+	*framesizep = lt_stack_framesize(&cfg, regs);
+
 	return sym->st_value;
 }
 
diff --git a/src/audit.h b/src/audit.h
index 1b7d20f..2633944 100644
--- a/src/audit.h
+++ b/src/audit.h
@@ -29,18 +29,21 @@
 # define pltenter la_i86_gnu_pltenter
 # define pltexit la_i86_gnu_pltexit
 # define La_regs La_i86_regs
+# define sp_reg lr_esp
 # define La_retval La_i86_retval
 # define int_retval lrv_eax
 #elif defined __x86_64__
 # define pltenter la_x86_64_gnu_pltenter
 # define pltexit la_x86_64_gnu_pltexit
 # define La_regs La_x86_64_regs
+# define sp_reg lr_rsp
 # define La_retval La_x86_64_retval
 # define int_retval lrv_rax
 #elif defined __arm__
 # define pltenter la_arm_gnu_pltenter
 # define pltexit la_arm_gnu_pltexit
 # define La_regs La_arm_regs
+# define sp_reg lr_sp
 # define La_retval La_arm_retval
 # define int_retval lrv_reg[0]
 #elif defined __powerpc__ && __WORDSIZE == 32
diff --git a/src/config.c b/src/config.c
index 4b92b5b..18c07ba 100644
--- a/src/config.c
+++ b/src/config.c
@@ -51,6 +51,7 @@ static void usage()
 #endif
 	printf("\n");
 	printf("    -y, --framesize number          framesize for storing the stack before pltexit (default 1000)\n");
+	printf("    -Y, --not-framesize-check       disable framesize check\n");
 	printf("    -F, --not-follow-fork           dont follow fork calls - childs\n");
 	printf("    -E, --not-follow-exec           dont follow exec calls\n");
 	printf("\n");
@@ -111,12 +112,13 @@ int lt_config(struct lt_config_app *cfg, int argc, char **argv)
 	cfg->sh = &cfg->sh_storage;
 
 	/* default values settings */
-	lt_sh(cfg, magic)       = LT_CONFIG_MAGIC;
-	lt_sh(cfg, framesize)   = 1000;
-	lt_sh(cfg, fout)        = stdout;
-	lt_sh(cfg, indent_sym)  = 1;
-	lt_sh(cfg, indent_size) = 2;
-	lt_sh(cfg, args_maxlen) = LR_ARGS_MAXLEN;
+	lt_sh(cfg, magic)           = LT_CONFIG_MAGIC;
+	lt_sh(cfg, framesize)       = 1000;
+	lt_sh(cfg, framesize_check) = 1;
+	lt_sh(cfg, fout)            = stdout;
+	lt_sh(cfg, indent_sym)      = 1;
+	lt_sh(cfg, indent_size)     = 2;
+	lt_sh(cfg, args_maxlen)     = LR_ARGS_MAXLEN;
 	lt_sh(cfg, args_detail_maxlen) = LR_ARGS_DETAIL_MAXLEN;
 	cfg->csort = LT_CSORT_CALL;
 
@@ -142,6 +144,7 @@ int lt_config(struct lt_config_app *cfg, int argc, char **argv)
 			{"enable-args", required_argument, 0, 'A'},
 			{"detail-args", required_argument, 0, 'D'},
 			{"framesize", required_argument, 0, 'y'},
+			{"not-framesize-check ", no_argument, 0, 'Y'},
 			{"lib-subst", required_argument, 0, 'L'},
 			{"verbose", no_argument, 0, 'v'},
 			{"hide-tid", no_argument, 0, 'T'},
@@ -154,7 +157,7 @@ int lt_config(struct lt_config_app *cfg, int argc, char **argv)
 			{0, 0, 0, 0}
 		};
 
-		c = getopt_long(argc, argv, "+s:l:t:f:vhi:BdISb:cC:y:L:po:a:ADVTFERq",
+		c = getopt_long(argc, argv, "+s:l:t:f:vhi:BdISb:cC:y:YL:po:a:ADVTFERq",
 					long_options, &option_index);
 
 		if (c == -1)
@@ -242,6 +245,10 @@ int lt_config(struct lt_config_app *cfg, int argc, char **argv)
 			lt_sh(cfg, framesize) = atoi(optarg);
 			break;
 
+		case 'Y':
+			lt_sh(cfg, framesize_check) = 0;
+			break;
+
 		case 'L':
 			if (strlen(optarg) > LT_SYMBOLS_MAXSIZE)
 				return -1;
diff --git a/src/config.h b/src/config.h
index 6213292..2a36c58 100644
--- a/src/config.h
+++ b/src/config.h
@@ -115,6 +115,7 @@ struct lt_config_shared {
 	int hide_tid;
 	int not_follow_exec;
 	int not_follow_fork;
+	int framesize_check;
 	unsigned int framesize;
 
 	/* for 'not_follow_fork' */
@@ -299,6 +300,9 @@ int lt_objsearch_init(struct lt_config_audit *cfg, char **ptr, int cnt);
 char* lt_objsearch(struct lt_config_audit *cfg, const char *name, 
 		uintptr_t *cookie, unsigned int flag);
 
+/* stack */
+int lt_stack_framesize(struct lt_config_audit *cfg, La_regs *regs);
+
 #define PRINT(fmt, args...) \
 do { \
 	char lpbuf[1024]; \
diff --git a/src/stack.c b/src/stack.c
new file mode 100644
index 0000000..ade5ef9
--- /dev/null
+++ b/src/stack.c
@@ -0,0 +1,114 @@
+
+#include <errno.h>
+#include <string.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+
+#include "config.h"
+
+static __thread void *stack_start = NULL;
+static __thread void *stack_end   = NULL;
+
+static unsigned long get_stack_size(struct lt_config_audit *cfg)
+{
+	static unsigned long stack_size = 0;
+	static struct rlimit rlim;
+
+	if (stack_size)
+		return stack_size;
+
+	if (getrlimit(RLIMIT_STACK, &rlim))
+		return 0;
+
+	PRINT_VERBOSE(cfg, 1, "stack size: %lx\n", rlim.rlim_cur);
+
+	return stack_size = rlim.rlim_cur;
+}
+
+/* find and update current stack boundaries */
+static int load_stack(struct lt_config_audit *cfg, void *sp)
+{
+	FILE *maps;
+	char line[128];
+	int found = 0;
+	void *start, *end;
+
+	maps = fopen("/proc/self/maps", "r");
+	if (!maps) {
+		PRINT_VERBOSE(cfg, 1, "failed to open maps: %s\n",
+				strerror(errno));
+		return -1;
+	}
+
+
+	while (!found && fgets(line, sizeof(line), maps)) {
+
+		if (1 != sscanf(line, "%*p-%p", &end))
+			continue;
+
+		/* FIXME
+		 * what if the new stack is not GROWSDOWN?
+		 * let's get the limit via RLIMIT_STACK,
+		 * which should be ok for most cases now..
+		 *
+		 * it does not feel safe/complete, but probably better
+		 * than nothing
+		 */
+		start = end - get_stack_size(cfg);
+
+		found = ((start < sp) && (sp < end));
+
+		PRINT_VERBOSE(cfg, 1, "start %p, end %p, sp %p, in %d\n",
+				start, end, sp, found);
+	}
+
+	fclose(maps);
+
+	if (found) {
+		stack_start = start;
+		stack_end   = end;
+	}
+
+	return found ? 0 : -1;
+}
+
+/* check the current stack pointer and check its boundaries */
+int lt_stack_framesize(struct lt_config_audit *cfg, La_regs *regs)
+{
+	void *sp_top, *sp_bottom;
+	void *sp = (void*) regs->sp_reg;
+	unsigned int framesize = lt_sh(cfg, framesize);
+
+	if (!lt_sh(cfg, framesize_check))
+		return framesize;
+
+	/* got here first time, or we are out of bounds */
+	if (!stack_start ||
+	    (sp < stack_start || sp > stack_end)) {
+
+		/* we are screeeeeewed */
+		if (load_stack(cfg, sp))
+			return framesize;
+	}
+
+	/* FIXME what about stacks growing up.. arm might */
+	sp_top = sp + framesize;
+
+	if (sp_top > stack_end) {
+		framesize = stack_end - sp - 1;
+		PRINT_VERBOSE(cfg, 1,
+			"top reached, framesize changed to %lu\n",
+			framesize);
+	}
+
+	sp_bottom = sp - framesize;
+
+	if (sp_bottom < stack_start) {
+		framesize = sp - stack_start;
+		PRINT_VERBOSE(cfg, 1,
+			"bottom reached, framesize changed to %lu\n",
+			framesize);
+	}
+
+	return framesize;
+}