1 files changed, 104 insertions, 0 deletions
diff --git a/memory.c b/memory.c
new file mode 100644
index 0000000..37b9983
--- /dev/null
+++ b/memory.c
@@ -0,0 +1,104 @@
+// low-level stuff for reading/writing the memory of another process
+
+static void close_process(State *state, char const *reason) {
+	GtkBuilder *builder = state->builder;
+	free(state->maps); state->maps = NULL;
+	state->nmaps = 0;
+	state->pid = 0;
+	{
+		GtkListStore *store = GTK_LIST_STORE(gtk_builder_get_object(builder, "memory"));
+		gtk_list_store_clear(store);
+	}
+	if (reason)
+		display_info(state, "Can't access process anymore: %s", reason);
+	else
+		display_info_nofmt(state, "Can't access process anymore.");
+}
+
+// don't use this function; use one of the ones below
+static int memory_open(State *state, int flags) {
+	if (state->pid) {
+		if (state->stop_while_accessing_memory) {
+			if (kill(state->pid, SIGSTOP) == -1) {
+				close_process(state, strerror(errno));
+				return 0;
+			}
+		}
+		char name[64];
+		sprintf(name, "/proc/%lld/mem", (long long)state->pid);
+		int fd = open(name, flags);
+		if (fd == -1) {
+			close_process(state, strerror(errno));
+			return 0;
+		}
+		return fd;
+	}
+	return 0;
+}
+
+static void memory_close(State *state, int fd) {
+	if (state->stop_while_accessing_memory) {
+		kill(state->pid, SIGCONT);
+	}
+	if (fd) close(fd);
+}
+
+	
+// get a file descriptor for reading memory from the process
+// returns 0 on failure
+static int memory_reader_open(State *state) {
+	return memory_open(state, O_RDONLY);
+}
+
+static void memory_reader_close(State *state, int reader) {
+	memory_close(state, reader);
+}
+
+// like memory_reader_open, but for writing to memory
+static int memory_writer_open(State *state) {
+	return memory_open(state, O_WRONLY);
+}
+
+static void memory_writer_close(State *state, int writer) {
+	memory_close(state, writer);
+}
+
+static uint8_t memory_read_byte(int reader, Address addr) {
+	lseek(reader, (off_t)addr, SEEK_SET);
+	uint8_t byte = 0;
+	read(reader, &byte, 1);
+	return byte;
+}
+
+// returns number of bytes successfully read
+static Address memory_read_bytes(int reader, Address addr, uint8_t *memory, Address nbytes) {
+	lseek(reader, (off_t)addr, SEEK_SET);
+	Address idx = 0;
+	while (idx < nbytes) {
+		ssize_t n = read(reader, &memory[idx], (size_t)(nbytes - idx));
+		if (n <= 0) break;
+		idx += (Address)n;
+	}
+	return idx;
+}
+
+// returns # of bytes written (so either 0 or 1)
+static Address memory_write_byte(int writer, Address addr, uint8_t byte) {
+	lseek(writer, (off_t)addr, SEEK_SET);
+	if (write(writer, &byte, 1) == 1)
+		return 1;
+	else
+		return 0;
+}
+
+// returns # of bytes written
+static Address memory_write_bytes(int writer, Address addr, uint8_t const *bytes, Address nbytes) {
+	lseek(writer, (off_t)addr, SEEK_SET);
+	Address idx = 0;
+	while (idx < nbytes) {
+		ssize_t n = write(writer, &bytes[idx], (size_t)(nbytes - idx));
+		if (n < 0) break;
+		idx += (Address)n;
+	}
+	return idx;
+}