add message argument to xabort()

src/disasm_wrapper.c

@@ -91,15 +91,15 @@ intercept_disasm_init(const unsigned char *begin, const unsigned char *end)
 	 * The handle here must be passed to capstone each time it is used.
 	 */
 	if (cs_open(CS_ARCH_X86, CS_MODE_64, &context->handle) != CS_ERR_OK)
-		xabort();
+		xabort("cs_open");
 
 	/*
 	 * Kindly ask capstone to return some details about the instruction.
 	 * Without this, it only prints the instruction, and we would need
 	 * to parse the resulting string.
 	 */
 	if (cs_option(context->handle, CS_OPT_DETAIL, CS_OPT_ON) != 0)
-		xabort();
+		xabort("cs_option - CS_OPT_DETAIL");
 
 	/*
 	 * Overriding the printing routine used by capstone,
@@ -112,10 +112,10 @@ intercept_disasm_init(const unsigned char *begin, const unsigned char *end)
 		.realloc = realloc,
 		.vsnprintf = nop_vsnprintf};
 	if (cs_option(context->handle, CS_OPT_MEM, (size_t)&x) != 0)
-		xabort();
+		xabort("cs_option - CS_OPT_MEM");
 
 	if ((context->insn = cs_malloc(context->handle)) == NULL)
-		xabort();
+		xabort("cs_malloc");
 
 	return context;
 }

src/intercept.c

@@ -442,11 +442,13 @@ log_header(void)
  * by libc.
  */
 void
-xabort(void)
+xabort(const char *msg)
 {
-	static const char msg[] = "libsyscall_intercept error\n";
+	static const char main_msg[] = " libsyscall_intercept error\n";
 
-	syscall_no_intercept(SYS_write, 2, msg, sizeof(msg));
+	if (msg != NULL)
+		syscall_no_intercept(SYS_write, 2, msg, strlen(msg));
+	syscall_no_intercept(SYS_write, 2, main_msg, sizeof(main_msg));
 	syscall_no_intercept(SYS_exit_group, 1);
 
 	__builtin_trap();

src/intercept.h

@@ -62,7 +62,7 @@ void intercept_patch_with_postfix(unsigned char *syscall_addr,
 
 #define INTERCEPTOR_EXIT_CODE 111
 
-__attribute__((noreturn)) void xabort(void);
+__attribute__((noreturn)) void xabort(const char *);
 
 struct range {
 	unsigned char *address;

src/intercept_desc.c

@@ -64,8 +64,11 @@ open_orig_file(const struct intercept_desc *desc)
 
 	fd = syscall_no_intercept(SYS_open, desc->path, O_RDONLY);
 
-	if (fd < 0)
-		xabort();
+	if (fd < 0) {
+		syscall_no_intercept(SYS_write, 2,
+		    desc->path, strlen(desc->path));
+		xabort(" open_orig_file");
+	}
 
 	return fd;
 }
@@ -143,7 +146,7 @@ find_sections(struct intercept_desc *desc, long fd)
 	}
 
 	if (!text_section_found)
-		xabort();
+		xabort("text section not found");
 }
 
 /*
@@ -715,14 +718,14 @@ allocate_trampoline_table(struct intercept_desc *desc)
 	size = 64 * 0x1000; /* XXX: don't just guess */
 
 	if ((maps = fopen("/proc/self/maps", "r")) == NULL)
-		xabort();
+		xabort("fopen /proc/self/maps");
 
 	while ((fgets(line, sizeof(line), maps)) != NULL) {
 		unsigned char *start;
 		unsigned char *end;
 
 		if (sscanf(line, "%p-%p", (void **)&start, (void **)&end) != 2)
-			xabort();
+			xabort("sscanf from /proc/self/maps");
 
 		/*
 		 * Let's see if an existing mapping overlaps
@@ -744,7 +747,7 @@ allocate_trampoline_table(struct intercept_desc *desc)
 
 		if (guess + size >= desc->text_start + INT32_MAX) {
 			/* Too far away */
-			xabort();
+			xabort("unable to find place for trampoline table");
 		}
 	}
 
@@ -756,7 +759,7 @@ allocate_trampoline_table(struct intercept_desc *desc)
 					-1, 0);
 
 	if (desc->trampoline_table == MAP_FAILED)
-		xabort();
+		xabort("unable to allocate space for trampoline table");
 
 	desc->trampoline_table_size = size;
 

src/intercept_util.c

@@ -59,7 +59,7 @@ xmmap_anon(size_t size)
 				MAP_PRIVATE | MAP_ANON, -1, 0);
 
 	if (addr == MAP_FAILED)
-		xabort();
+		xabort("xmmap_anon");
 
 	return addr;
 }
@@ -71,7 +71,7 @@ xmremap(void *addr, size_t old, size_t new)
 				old, new, MREMAP_MAYMOVE);
 
 	if (addr == MAP_FAILED)
-		xabort();
+		xabort("xmremap");
 
 	return addr;
 }
@@ -80,7 +80,7 @@ void
 xmunmap(void *addr, size_t len)
 {
 	if (syscall_no_intercept(SYS_munmap, addr, len) != 0)
-		xabort();
+		xabort("xmunmap");
 }
 
 long
@@ -89,7 +89,7 @@ xlseek(long fd, unsigned long off, int whence)
 	long result = syscall_no_intercept(SYS_lseek, fd, off, whence);
 
 	if (result < 0)
-		xabort();
+		xabort("xlseek");
 
 	return result;
 }
@@ -99,7 +99,7 @@ xread(long fd, void *buffer, size_t size)
 {
 	if (syscall_no_intercept(SYS_read, fd,
 	    (long)buffer, (long)size) != (long)size)
-		xabort();
+		xabort("xread");
 }
 
 /*
@@ -133,7 +133,7 @@ intercept_setup_log(const char *path_base, const char *trunc)
 	log_fd = syscall_no_intercept(SYS_open, path, flags, 0700);
 
 	if (log_fd < 0)
-		xabort();
+		xabort("setup_log");
 }
 
 /*

src/patcher.c

@@ -148,7 +148,7 @@ create_jump(unsigned char opcode, unsigned char *from, void *to)
 	ptrdiff_t delta = ((unsigned char *)to) - (from + JUMP_INS_SIZE);
 
 	if (delta > ((ptrdiff_t)INT32_MAX) || delta < ((ptrdiff_t)INT32_MIN))
-		xabort();
+		xabort("create_jump distance check");
 
 	int32_t delta32 = (int32_t)delta;
 	unsigned char *d = (unsigned char *)&delta32;
@@ -181,7 +181,7 @@ check_trampoline_usage(const struct intercept_desc *desc)
 	size_t used = (size_t)(desc->next_trampoline - desc->trampoline_table);
 
 	if (used + TRAMPOLINE_SIZE >= desc->trampoline_table_size)
-		xabort();
+		xabort("trampoline space not enough");
 }
 
 /*
@@ -490,7 +490,8 @@ create_patch_wrappers(struct intercept_desc *desc)
 					patch->syscall_offset);
 
 				intercept_log(buffer, (size_t)l);
-				xabort();
+				xabort("not enough space for patching"
+				    " around syscal");
 			}
 		}
 
@@ -719,7 +720,8 @@ create_wrapper(struct patch_desc *patch,
 	}
 
 	if (patch->syscall_offset > UINT32_MAX)
-		xabort(); /* libc larger than 2 gigabytes? wow */
+		xabort("patch->syscall_offset > UINT32_MAX");
+		/* libc larger than 2 gigabytes? wow */
 
 	/* the instruction pushing the syscall's address to the stack */
 	create_push_imm(begin + o_push_origin, (uint32_t)patch->syscall_offset);
@@ -790,7 +792,7 @@ create_short_jump(unsigned char *from, unsigned char *to)
 	ptrdiff_t d = to - (from + 2);
 
 	if (d < - 128 || d > 127)
-		xabort();
+		xabort("create_short_jump distance check");
 
 	from[0] = SHORT_JMP_OPCODE;
 	from[1] = (unsigned char)((char)d);
@@ -824,14 +826,14 @@ activate_patches(struct intercept_desc *desc)
 
 	if (syscall_no_intercept(SYS_mprotect, first_page, size,
 	    PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
-		xabort();
+		xabort("mprotect PROT_READ | PROT_WRITE | PROT_EXEC");
 
 	for (unsigned i = 0; i < desc->count; ++i) {
 		const struct patch_desc *patch = desc->items + i;
 
 		if (patch->dst_jmp_patch < desc->text_start ||
 		    patch->dst_jmp_patch > desc->text_end)
-			xabort();
+			xabort("dst_jmp_patch outside text");
 
 		/*
 		 * The dst_jmp_patch pointer contains the address where
@@ -902,7 +904,7 @@ activate_patches(struct intercept_desc *desc)
 
 	if (syscall_no_intercept(SYS_mprotect, first_page, size,
 	    PROT_READ | PROT_EXEC) != 0)
-		xabort();
+		xabort("mprotect PROT_READ | PROT_EXEC");
 }
 
 /*
@@ -920,7 +922,7 @@ next_asm_wrapper_space(void)
 	unsigned char *result;
 
 	if (next + tmpl_size + PAGE_SIZE > sizeof(asm_wrapper_space))
-		xabort();
+		xabort("not enough space in asm_wrapper_space");
 
 	result = asm_wrapper_space + next;
 
@@ -943,5 +945,5 @@ mprotect_asm_wrappers(void)
 	    round_down_address(asm_wrapper_space + PAGE_SIZE),
 	    sizeof(asm_wrapper_space) - PAGE_SIZE,
 	    PROT_READ | PROT_EXEC) != 0)
-		xabort();
+		xabort("mprotect_asm_wrappers PROT_READ | PROT_EXEC");
 }