separate SIGSEGV handler from jkmalloc() so it can be installed without requiring dynamic memory use

9 files changed, 207 insertions, 129 deletions

diff --git a/mk/__jkmalloc.d b/mk/__jkmalloc.d
index 6436cbcf..5d4a1e77 100644
--- a/mk/__jkmalloc.d
+++ b/mk/__jkmalloc.d
@@ -4,7 +4,6 @@ libc.a(__jkmalloc.o): $(OBJDIR)/__jkmalloc.o
 
 $(OBJDIR)/__jkmalloc.o: src/stdlib/__jkmalloc.c
 $(OBJDIR)/__jkmalloc.o: src/_safety.h
-$(OBJDIR)/__jkmalloc.o: src/_forced/sigaction.h
 $(OBJDIR)/__jkmalloc.o: src/_forced/mmap.h
 $(OBJDIR)/__jkmalloc.o: src/_forced/munmap.h
 $(OBJDIR)/__jkmalloc.o: src/_forced/mprotect.h
diff --git a/mk/__segv.d b/mk/__segv.d
new file mode 100644
index 00000000..ac2464a9
--- /dev/null
+++ b/mk/__segv.d
@@ -0,0 +1,11 @@
+libc_C.0: libc.a(__segv.o)
+libc.a(__segv.o): $(OBJDIR)/__segv.o
+	@$(AR) $(ARFLAGS) $@ $(OBJDIR)/$%
+
+$(OBJDIR)/__segv.o: src/signal/__segv.c
+$(OBJDIR)/__segv.o: src/_safety.h
+$(OBJDIR)/__segv.o: src/_forced/sigaction.h
+$(OBJDIR)/__segv.o: src/stdlib/_jkmalloc.h
+$(OBJDIR)/__segv.o:
+	@mkdir -p $(@D)
+	$(CC) -c -o $@ $(CFLAGS) src/signal/__segv.c
diff --git a/mk/all.mk b/mk/all.mk
index 66e9e1e0..dcca93a1 100644
--- a/mk/all.mk
+++ b/mk/all.mk
@@ -372,6 +372,7 @@ include mk/raise.d
 include mk/__signal_handler.d
 include mk/__sigsegv.d
 include mk/__signal_h.d
+include mk/__segv.d
 include mk/frexp.d
 include mk/erfc.d
 include mk/rint.d
diff --git a/mk/deps.mk b/mk/deps.mk
index b32ecabd..a3963021 100644
--- a/mk/deps.mk
+++ b/mk/deps.mk
@@ -1498,6 +1498,10 @@ all: mk/__signal_h.d
 mk/__signal_h.d: src/signal/__signal_h.c
 	sh mk/deps.sh src/signal/__signal_h.c
 
+all: mk/__segv.d
+mk/__segv.d: src/signal/__segv.c
+	sh mk/deps.sh src/signal/__segv.c
+
 all: mk/frexp.d
 mk/frexp.d: src/math/frexp.c
 	sh mk/deps.sh src/math/frexp.c
diff --git a/src/__main.c b/src/__main.c
index a24c24ef..510def1e 100644
--- a/src/__main.c
+++ b/src/__main.c
@@ -3,6 +3,7 @@
 #include <locale.h>
 #include "stdio/_stdio.h"
 #include "stdlib/_stdlib.h"
+#include "signal/_signal.h"
 
 #undef stdin
 #undef stdout
@@ -39,6 +40,8 @@ void __init_libc(void)
 	extern char **environ;
 	__stdlib_h.environ = environ;
 	#endif
+
+	__segv();
 }
 
 void __main(int (*main)(int, char*[]), int argc, char **argv)
diff --git a/src/signal/__segv.c b/src/signal/__segv.c
new file mode 100644
index 00000000..7a4a2656
--- /dev/null
+++ b/src/signal/__segv.c
@@ -0,0 +1,147 @@
+#include <errno.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "_safety.h"
+
+#ifdef _XOPEN_SOURCE
+#else
+#include "_forced/sigaction.h"
+#include "_forced/mprotect.h"
+
+#define sysconf(__n) 4096
+#define psiginfo(x, y)	fprintf(stderr, "%s (%p)\n", (char*)(y), (void*)(x))
+#define sigemptyset(x) memset(x, 0, sizeof(*x))
+#endif
+
+#include "stdlib/_jkmalloc.h"
+
+static void __jk_undef(void)
+{
+	static int printed = 0;
+	if (printed == 0) {
+		printed = 1;
+		fprintf(stderr, "Undefined Behavior: ");
+	}
+}
+
+static void __jk_error(const char *s, void *addr, struct jk_source *src)
+{
+	__jk_undef();
+
+	if (s && *s) {
+		fputs(s, stderr);
+		if (addr != NULL) {
+			fprintf(stderr, " %p", addr);
+		}
+		fputs("\n", stderr);
+	}
+
+	if (src && src->bucket && src->bucket->trace[0] != '\0') {
+		fwrite(src->bucket->trace, src->bucket->tlen, 1, stderr);
+		fputs("\n", stderr);
+	}
+
+	if (src && src->file) {
+		fprintf(stderr, "!!! %s() (%s:%ju)\n", src->func, src->file, src->line);
+	}
+
+	_Exit(JKMALLOC_EXIT_VALUE);
+}
+
+static void __jk_sigaction(int sig, siginfo_t *si, void *addr)
+{
+	__signal_h.current = 0;
+
+	(void)sig; (void)addr;
+
+	__jk_undef();
+
+	if (__dangerous[0].func) {
+		fprintf(stderr, "In call to %s, attempting to read parameter %s (%p)\n", __dangerous[0].func, __dangerous[0].param, __dangerous[0].addr);
+	}
+
+	if (__dangerous[1].func) {
+		fprintf(stderr, "In call to %s, attempting to write parameter %s (%p)\n", __dangerous[1].func, __dangerous[1].param, __dangerous[1].addr);
+	}
+
+	if (!si) {
+		__jk_error("No signal information provided", NULL, NULL);
+	}
+
+	if (si->si_addr == NULL) {
+		psiginfo(si, "NULL pointer dereference");
+		__jk_error(NULL, NULL, NULL);
+	}
+
+	struct jk_bucket *bucket = jk_pageof(si->si_addr);
+	if (mprotect(bucket, __jk_pagesize, PROT_READ) != 0) {
+		psiginfo(si, NULL);
+		__jk_error(NULL, NULL, NULL);
+	}
+
+	MAGIC_CHECK:
+	switch (bucket->magic) {
+	case JK_UNDER_MAGIC:
+		if (bucket->size == 0) {
+			psiginfo(si, "Attempt to use 0-byte allocation");
+		} else {
+			psiginfo(si, "Heap underflow detected");
+		}
+		break;
+
+	case JK_OVER_MAGIC:
+		if (bucket->size == 0) {
+			psiginfo(si, "Attempt to use 0-byte allocation");
+		} else {
+			psiginfo(si, "Heap overflow detected");
+			fprintf(stderr, "Allocation of size %zu at %p, overflow at %p (offset %zu)\n", bucket->size, (void*)bucket->start, si->si_addr, (size_t)((char*)si->si_addr - (char*)bucket->start));
+			fprintf(stderr, "Buffer begins with %4s\n", (char*)bucket->start);
+		}
+		break;
+
+	case JK_FREE_MAGIC:
+		psiginfo(si, "Use after free() detected");
+		break;
+
+	case JK_RONLY_MAGIC:
+		psiginfo(si, "Attempt to modify read-only memory detected");
+		break;
+
+	default:
+		/* try to find the actual error */
+		bucket = (void*)((char*)bucket - __jk_pagesize);
+		if (mprotect(bucket, __jk_pagesize, PROT_READ) != 0) {
+			psiginfo(si, NULL);
+			__jk_error(NULL, NULL, NULL);
+		}
+		goto MAGIC_CHECK;
+	}
+
+	struct jk_source src = { .bucket = bucket };
+	__jk_error(NULL, NULL, &src);
+}
+
+GCC_SSE_HACK
+void __segv(void)
+{
+	static int sa_set = 0;
+	if (!sa_set) {
+		struct sigaction sa = {
+			.sa_flags = SA_SIGINFO,
+			.sa_sigaction = __jk_sigaction,
+		};
+		sigemptyset(&sa.sa_mask);
+		sigaction(SIGSEGV, &sa, NULL);
+		sa_set = 1;
+	}
+}
+
+/*
+SIGNAL_SAFE(0)
+STDC(0)
+*/
diff --git a/src/signal/_signal.h b/src/signal/_signal.h
index 1e484f83..f0d038f5 100644
--- a/src/signal/_signal.h
+++ b/src/signal/_signal.h
@@ -13,6 +13,7 @@ extern struct __signal_h {
 } __signal_h;
 
 void __signal_handler(int);
+void __segv(void);
 
 /*
 STDC(-1)
diff --git a/src/stdlib/__jkmalloc.c b/src/stdlib/__jkmalloc.c
index 34b34fbc..2f9bc3a3 100644
--- a/src/stdlib/__jkmalloc.c
+++ b/src/stdlib/__jkmalloc.c
@@ -1,7 +1,6 @@
 #include <errno.h>
 #include <limits.h>
 #include <stdlib.h>
-#include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
@@ -13,66 +12,22 @@
 #include <sys/mman.h>
 #include <unistd.h>
 #else
-#include "_forced/sigaction.h"
 #include "_forced/mmap.h"
 #include "_forced/munmap.h"
 #include "_forced/mprotect.h"
 
 #define sysconf(__n) 4096
-#define psiginfo(x, y)	fprintf(stderr, "%s (%p)\n", (char*)(y), (void*)(x))
-#define sigemptyset(x) memset(x, 0, sizeof(*x))
 #endif
 
 #include "_jkmalloc.h"
 
-#define PTR_BITS	(CHAR_BIT * sizeof(uintptr_t))
-
-#define JKMALLOC_EXIT_VALUE	(127 + SIGSEGV)
-#define JK_FREE_LIST_SIZE	(8)
-
-/* magic numbers derived from CRC-32 of jk_foo_block */
-#define JK_FREE_MAGIC		(0x551a51dc)
-#define JK_UNDER_MAGIC		(0xcb2873ac)
-#define JK_OVER_MAGIC		(0x18a12c17)
-#define JK_RONLY_MAGIC		(0x902faf31)
-
-#define jk_pages(bytes)		(((bytes + __jk_pagesize - 1) / __jk_pagesize) + 2)
-#define jk_pageof(addr)		((void*)((uintptr_t)addr - ((uintptr_t)addr % __jk_pagesize)))
-#define jk_bucketof(addr)	((void*)((uintptr_t)jk_pageof(addr) - __jk_pagesize))
-
-struct jk_bucket {
-	uint32_t magic;
-	uintptr_t start;
-	size_t size;
-	size_t align;
-	size_t pages;
-	size_t tlen;
-	char trace[];
-};
-
-struct jk_source {
-	const char *file;
-	const char *func;
-	uintmax_t line;
-	struct jk_bucket *bucket;
-};
-
 static struct jk_bucket *__jk_free_list[JK_FREE_LIST_SIZE];
 static size_t __jk_free_buckets = 0;
-static size_t __jk_pagesize = 0;
-
-static void __jk_undef(void)
-{
-	static int printed = 0;
-	if (printed == 0) {
-		printed = 1;
-		fprintf(stderr, "Undefined Behavior: ");
-	}
-}
+//static size_t __jk_pagesize = 0;
 
 static void __jk_error(const char *s, void *addr, struct jk_source *src)
 {
-	__jk_undef();
+	fprintf(stderr, "Undefined Behavior: ");
 
 	if (s && *s) {
 		fputs(s, stderr);
@@ -117,91 +72,11 @@ static void *__jk_page_alloc(size_t npages)
 	return pages;
 }
 
-static void __jk_sigaction(int sig, siginfo_t *si, void *addr)
-{
-	__signal_h.current = 0;
-
-	(void)sig; (void)addr;
-
-	__jk_undef();
-
-	if (__dangerous.func) {
-		fprintf(stderr, "In call to %s, accessing parameter %s (%p)\n", __dangerous.func, __dangerous.param, __dangerous.addr);
-	}
-
-	if (!si) {
-		__jk_error("No signal information provided", NULL, NULL);
-	}
-
-	if (si->si_addr == NULL) {
-		psiginfo(si, "NULL pointer dereference");
-		__jk_error(NULL, NULL, NULL);
-	}
-
-	struct jk_bucket *bucket = jk_pageof(si->si_addr);
-	if (mprotect(bucket, __jk_pagesize, PROT_READ) != 0) {
-		psiginfo(si, NULL);
-		__jk_error(NULL, NULL, NULL);
-	}
-
-	MAGIC_CHECK:
-	switch (bucket->magic) {
-	case JK_UNDER_MAGIC:
-		if (bucket->size == 0) {
-			psiginfo(si, "Attempt to use 0-byte allocation");
-		} else {
-			psiginfo(si, "Heap underflow detected");
-		}
-		break;
-
-	case JK_OVER_MAGIC:
-		if (bucket->size == 0) {
-			psiginfo(si, "Attempt to use 0-byte allocation");
-		} else {
-			psiginfo(si, "Heap overflow detected");
-			fprintf(stderr, "Allocation of size %zu at %p, overflow at %p (offset %zu)\n", bucket->size, (void*)bucket->start, si->si_addr, (size_t)((char*)si->si_addr - (char*)bucket->start));
-			fprintf(stderr, "Buffer begins with %4s\n", (char*)bucket->start);
-		}
-		break;
-
-	case JK_FREE_MAGIC:
-		psiginfo(si, "Use after free() detected");
-		break;
-
-	case JK_RONLY_MAGIC:
-		psiginfo(si, "Attempt to modify read-only memory detected");
-		break;
-
-	default:
-		/* try to find the actual error */
-		bucket = (void*)((char*)bucket - __jk_pagesize);
-		if (mprotect(bucket, __jk_pagesize, PROT_READ) != 0) {
-			psiginfo(si, NULL);
-			__jk_error(NULL, NULL, NULL);
-		}
-		goto MAGIC_CHECK;
-	}
-
-	struct jk_source src = { .bucket = bucket };
-	__jk_error(NULL, NULL, &src);
-}
-
 GCC_SSE_HACK
 void* __jkmalloc(void *ptr, size_t alignment, size_t size1, size_t size2, const char *user)
 {
-	static int sa_set = 0;
-	if (!sa_set) {
-		struct sigaction sa = {
-			.sa_flags = SA_SIGINFO,
-			.sa_sigaction = __jk_sigaction,
-		};
-		sigemptyset(&sa.sa_mask);
-		sigaction(SIGSEGV, &sa, NULL);
-		sa_set = 1;
-	}
-
 	if (__jk_pagesize == 0) {
-		__jk_pagesize = sysconf(_SC_PAGESIZE);
+		//__jk_pagesize = sysconf(_SC_PAGESIZE);
 	}
 
 	struct jk_source src = {
diff --git a/src/stdlib/_jkmalloc.h b/src/stdlib/_jkmalloc.h
index cab5cfcb..107bf904 100644
--- a/src/stdlib/_jkmalloc.h
+++ b/src/stdlib/_jkmalloc.h
@@ -3,6 +3,43 @@
 
 #include <inttypes.h>
 
+#define PTR_BITS        (CHAR_BIT * sizeof(uintptr_t))
+
+#define JKMALLOC_EXIT_VALUE     (127 + SIGSEGV)
+#define JK_FREE_LIST_SIZE       (8)
+
+#define __jk_pagesize		(4096)
+
+/* magic numbers derived from CRC-32 of jk_foo_block */
+#define JK_FREE_MAGIC           (0x551a51dc)
+#define JK_UNDER_MAGIC          (0xcb2873ac)
+#define JK_OVER_MAGIC           (0x18a12c17)
+#define JK_RONLY_MAGIC          (0x902faf31)
+
+#define jk_pages(bytes)         (((bytes + __jk_pagesize - 1) / __jk_pagesize) + 2)
+#define jk_pageof(addr)         ((void*)((uintptr_t)addr - ((uintptr_t)addr % __jk_pagesize)))
+#define jk_bucketof(addr)       ((void*)((uintptr_t)jk_pageof(addr) - __jk_pagesize))
+
+
+struct jk_bucket {
+        uint32_t magic;
+        uintptr_t start;
+        size_t size;
+        size_t align;
+        size_t pages;
+        size_t tlen;
+        char trace[];
+};
+
+
+struct jk_source {
+        const char *file;
+        const char *func;
+        uintmax_t line;
+        struct jk_bucket *bucket;
+};
+
+
 void* __jkmalloc(void *ptr, size_t alignment, size_t size1 , size_t size2, const char *user);
 
 #endif