1 files changed, 95 insertions, 9 deletions

diff --git a/tools/lib/api/io.h b/tools/lib/api/io.h
index 777c20f6b604..1731996b2c32 100644
--- a/tools/lib/api/io.h
+++ b/tools/lib/api/io.h
@@ -7,8 +7,12 @@
 #ifndef __API_IO__
 #define __API_IO__
 
+#include <errno.h>
+#include <poll.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
+#include <linux/types.h>
 
 struct io {
 	/* File descriptor being read/ */
@@ -21,6 +25,8 @@ struct io {
 	char *end;
 	/* Currently accessed data pointer. */
 	char *data;
+	/* Read timeout, 0 implies no timeout. */
+	int timeout_ms;
 	/* Set true on when the end of file on read error. */
 	bool eof;
 };
@@ -33,29 +39,59 @@ static inline void io__init(struct io *io, int fd,
 	io->buf = buf;
 	io->end = buf;
 	io->data = buf;
+	io->timeout_ms = 0;
 	io->eof = false;
 }
 
-/* Reads one character from the "io" file with similar semantics to fgetc. */
-static inline int io__get_char(struct io *io)
+/* Read from fd filling the buffer. Called when io->data == io->end. */
+static inline int io__fill_buffer(struct io *io)
 {
-	char *ptr = io->data;
+	ssize_t n;
 
 	if (io->eof)
 		return -1;
 
-	if (ptr == io->end) {
-		ssize_t n = read(io->fd, io->buf, io->buf_len);
+	if (io->timeout_ms != 0) {
+		struct pollfd pfds[] = {
+			{
+				.fd = io->fd,
+				.events = POLLIN,
+			},
+		};
 
+		n = poll(pfds, 1, io->timeout_ms);
+		if (n == 0)
+			errno = ETIMEDOUT;
+		if (n > 0 && !(pfds[0].revents & POLLIN)) {
+			errno = EIO;
+			n = -1;
+		}
 		if (n <= 0) {
 			io->eof = true;
 			return -1;
 		}
-		ptr = &io->buf[0];
-		io->end = &io->buf[n];
 	}
-	io->data = ptr + 1;
-	return *ptr;
+	n = read(io->fd, io->buf, io->buf_len);
+
+	if (n <= 0) {
+		io->eof = true;
+		return -1;
+	}
+	io->data = &io->buf[0];
+	io->end = &io->buf[n];
+	return 0;
+}
+
+/* Reads one character from the "io" file with similar semantics to fgetc. */
+static inline int io__get_char(struct io *io)
+{
+	if (io->data == io->end) {
+		int ret = io__fill_buffer(io);
+
+		if (ret)
+			return ret;
+	}
+	return *io->data++;
 }
 
 /* Read a hexadecimal value with no 0x prefix into the out argument hex. If the
@@ -112,4 +148,54 @@ static inline int io__get_dec(struct io *io, __u64 *dec)
 	}
 }
 
+/* Read up to and including the first delim. */
+static inline ssize_t io__getdelim(struct io *io, char **line_out, size_t *line_len_out, int delim)
+{
+	char buf[128];
+	int buf_pos = 0;
+	char *line = NULL, *temp;
+	size_t line_len = 0;
+	int ch = 0;
+
+	/* TODO: reuse previously allocated memory. */
+	free(*line_out);
+	while (ch != delim) {
+		ch = io__get_char(io);
+
+		if (ch < 0)
+			break;
+
+		if (buf_pos == sizeof(buf)) {
+			temp = realloc(line, line_len + sizeof(buf));
+			if (!temp)
+				goto err_out;
+			line = temp;
+			memcpy(&line[line_len], buf, sizeof(buf));
+			line_len += sizeof(buf);
+			buf_pos = 0;
+		}
+		buf[buf_pos++] = (char)ch;
+	}
+	temp = realloc(line, line_len + buf_pos + 1);
+	if (!temp)
+		goto err_out;
+	line = temp;
+	memcpy(&line[line_len], buf, buf_pos);
+	line[line_len + buf_pos] = '\0';
+	line_len += buf_pos;
+	*line_out = line;
+	*line_len_out = line_len;
+	return line_len;
+err_out:
+	free(line);
+	*line_out = NULL;
+	*line_len_out = 0;
+	return -ENOMEM;
+}
+
+static inline ssize_t io__getline(struct io *io, char **line_out, size_t *line_len_out)
+{
+	return io__getdelim(io, line_out, line_len_out, /*delim=*/'\n');
+}
+
 #endif /* __API_IO__ */