Tighten up libc file io code to avoid EINTR problems

vm/image.cpp

@@ -22,7 +22,7 @@ void factor_vm::load_data_heap(FILE *file, image_header *h, vm_parameters *p)
 		p->aging_size,
 		p->tenured_size);
 
-	fixnum bytes_read = fread((void*)data->tenured->start,1,h->data_size,file);
+	fixnum bytes_read = safe_fread((void*)data->tenured->start,1,h->data_size,file);
 
 	if((cell)bytes_read != h->data_size)
 	{
@@ -43,7 +43,7 @@ void factor_vm::load_code_heap(FILE *file, image_header *h, vm_parameters *p)
 
 	if(h->code_size != 0)
 	{
-		size_t bytes_read = fread(code->allocator->first_block(),1,h->code_size,file);
+		size_t bytes_read = safe_fread(code->allocator->first_block(),1,h->code_size,file);
 		if(bytes_read != h->code_size)
 		{
 			std::cout << "truncated image: " << bytes_read << " bytes read, ";
@@ -241,7 +241,7 @@ void factor_vm::load_image(vm_parameters *p)
 	}
 
 	image_header h;
-	if(fread(&h,sizeof(image_header),1,file) != 1)
+	if(safe_fread(&h,sizeof(image_header),1,file) != 1)
 		fatal_error("Cannot read image header",0);
 
 	if(h.magic != image_magic)
@@ -253,7 +253,7 @@ void factor_vm::load_image(vm_parameters *p)
 	load_data_heap(file,&h,p);
 	load_code_heap(file,&h,p);
 
-	fclose(file);
+	safe_fclose(file);
 
 	init_objects(&h);
 
@@ -298,10 +298,10 @@ bool factor_vm::save_image(const vm_char *filename)
 
 	bool ok = true;
 
-	if(fwrite(&h,sizeof(image_header),1,file) != 1) ok = false;
+	if(safe_fwrite(&h,sizeof(image_header),1,file) != 1) ok = false;
-	if(fwrite((void*)data->tenured->start,h.data_size,1,file) != 1) ok = false;
+	if(safe_fwrite((void*)data->tenured->start,h.data_size,1,file) != 1) ok = false;
-	if(fwrite(code->allocator->first_block(),h.code_size,1,file) != 1) ok = false;
+	if(safe_fwrite(code->allocator->first_block(),h.code_size,1,file) != 1) ok = false;
-	if(fclose(file)) ok = false;
+	if(safe_fclose(file)) ok = false;
 
 	if(!ok)
 		std::cout << "save-image failed: " << strerror(errno) << std::endl;

vm/io.cpp

@@ -31,6 +31,39 @@ void factor_vm::io_error()
 	general_error(ERROR_IO,tag_fixnum(errno),false_object,NULL);
 }
 
+size_t safe_fread(void *ptr, size_t size, size_t nitems, FILE *stream)
+{
+    size_t items_read = 0;
+
+    do {
+        items_read += fread((void*)((int*)ptr+items_read*size),size,nitems-items_read,stream);
+    } while(items_read != nitems && errno == EINTR);
+
+    return items_read;
+}
+
+size_t safe_fwrite(void *ptr, size_t size, size_t nitems, FILE *stream)
+{
+    size_t items_written = 0;
+
+    do {
+        items_written += fwrite((void*)((int*)ptr+items_written*size),size,nitems-items_written,stream);
+    } while(items_written != nitems && errno == EINTR);
+
+    return items_written;
+}
+
+int safe_fclose(FILE *stream)
+{
+    int ret = 0;
+
+    do {
+        ret = fclose(stream);
+    } while(ret != 0 && errno == EINTR);
+
+    return ret;
+}
+
 void factor_vm::primitive_fopen()
 {
 	data_root<byte_array> mode(ctx->pop(),this);
@@ -38,18 +71,15 @@ void factor_vm::primitive_fopen()
 	mode.untag_check(this);
 	path.untag_check(this);
 
-	for(;;)
+	FILE *file;
-	{
+	do {
-		FILE *file = fopen((char *)(path.untagged() + 1),
+		file = fopen((char *)(path.untagged() + 1),
 				   (char *)(mode.untagged() + 1));
 		if(file == NULL)
 			io_error();
-		else
+	} while(errno == EINTR);
-		{
+
-			ctx->push(allot_alien(file));
+	ctx->push(allot_alien(file));
-			break;
-		}
-	}
 }
 
 FILE *factor_vm::pop_file_handle()
@@ -61,8 +91,7 @@ void factor_vm::primitive_fgetc()
 {
 	FILE *file = pop_file_handle();
 
-	for(;;)
+	do {
-	{
 		int c = fgetc(file);
 		if(c == EOF)
 		{
@@ -79,7 +108,7 @@ void factor_vm::primitive_fgetc()
 			ctx->push(tag_fixnum(c));
 			break;
 		}
-	}
+	} while(errno == EINTR);
 }
 
 void factor_vm::primitive_fread()
@@ -97,8 +126,8 @@ void factor_vm::primitive_fread()
 
 	for(;;)
 	{
-		int c = fread(buf.untagged() + 1,1,size,file);
+		int c = safe_fread(buf.untagged() + 1,1,size,file);
-		if(c <= 0)
+		if(c == 0)
 		{
 			if(feof(file))
 			{
@@ -110,12 +139,13 @@ void factor_vm::primitive_fread()
 		}
 		else
 		{
-			if(c != size)
+			if(feof(file))
 			{
 				byte_array *new_buf = allot_byte_array(c);
 				memcpy(new_buf + 1, buf.untagged() + 1,c);
 				buf = new_buf;
 			}
+
 			ctx->push(buf.value());
 			break;
 		}
@@ -127,17 +157,12 @@ void factor_vm::primitive_fputc()
 	FILE *file = pop_file_handle();
 	fixnum ch = to_fixnum(ctx->pop());
 
-	for(;;)
+	do {
-	{
 		if(fputc(ch,file) == EOF)
-		{
 			io_error();
-
-			/* Still here? EINTR */
-		}
 		else
 			break;
-	}
+	} while(errno == EINTR);
 }
 
 void factor_vm::primitive_fwrite()
@@ -150,23 +175,9 @@ void factor_vm::primitive_fwrite()
 	if(length == 0)
 		return;
 
-	for(;;)
+	size_t written = safe_fwrite(string,1,length,file);
-	{
+	if(written != length)
-		size_t written = fwrite(string,1,length,file);
+		io_error();
-		if(written == length)
-			break;
-		else
-		{
-			if(feof(file))
-				break;
-			else
-				io_error();
-
-			/* Still here? EINTR */
-			length -= written;
-			string += written;
-		}
-	}
 }
 
 void factor_vm::primitive_ftell()
@@ -174,8 +185,12 @@ void factor_vm::primitive_ftell()
 	FILE *file = pop_file_handle();
 	off_t offset;
 
-	if((offset = FTELL(file)) == -1)
+	do {
-		io_error();
+		if((offset = FTELL(file)) == -1)
+			io_error();
+		else
+			break;
+	} while(errno == EINTR);
 
 	ctx->push(from_signed_8(offset));
 }
@@ -196,37 +211,30 @@ void factor_vm::primitive_fseek()
 		break;
 	}
 
-	if(FSEEK(file,offset,whence) == -1)
+	do {
-	{
+		if(FSEEK(file,offset,whence) == -1)
-		io_error();
+			io_error();
-
+		else
-		/* Still here? EINTR */
+			break;
-		critical_error("Don't know what to do; EINTR from fseek()?",0);
+	} while(errno == EINTR);
-	}
 }
 
 void factor_vm::primitive_fflush()
 {
 	FILE *file = pop_file_handle();
-	for(;;)
+	do {
-	{
 		if(fflush(file) == EOF)
 			io_error();
 		else
 			break;
-	}
+	} while(errno == EINTR);
 }
 
 void factor_vm::primitive_fclose()
 {
 	FILE *file = pop_file_handle();
-	for(;;)
+	if(safe_fclose(file) == EOF)
-	{
+		io_error();
-		if(fclose(file) == EOF)
-			io_error();
-		else
-			break;
-	}
 }
 
 /* This function is used by FFI I/O. Accessing the errno global directly is

vm/io.hpp

@@ -1,6 +1,10 @@
 namespace factor
 {
 
+size_t safe_fread(void *ptr, size_t size, size_t nitems, FILE *stream);
+size_t safe_fwrite(void *ptr, size_t size, size_t nitems, FILE *stream);
+int safe_fclose(FILE *stream);
+
 /* Platform specific primitives */
 
 VM_C_API int err_no();