Add needstack, get_stack_direction, get_stack_limit, and get_stack_space

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 71 insertions, 0 deletions

diff --git a/get_stack_space.c b/get_stack_space.c
new file mode 100644
index 0000000..7f1fdd3
--- /dev/null
+++ b/get_stack_space.c
@@ -0,0 +1,71 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+
+int
+libsimple_get_stack_space(uintptr_t *restrict low, uintptr_t *restrict high)
+{
+	char buf[4096], *line;
+	int fd;
+	ssize_t r;
+	size_t off = 0;
+	size_t lineoff, linelen;
+
+	fd = open("/proc/self/maps", O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	for (;;) {
+	read_again:
+		r = read(fd, &buf[off], sizeof(buf) - off);
+		if (r <= 0) {
+			if (r && errno == EINTR)
+				continue;
+			close(fd);
+			if (!r)
+				errno = EIO;
+			return -1;
+		}
+		off += (size_t)r;
+
+		for (lineoff = 0; lineoff < off; lineoff += linelen) {
+			char *lf = strchr(&buf[lineoff], '\n');
+			if (!lf) {
+				memmove(&buf[0], &buf[lineoff], off -= lineoff);
+				goto read_again;
+			}
+			line = &buf[lineoff];
+			linelen = (size_t)(&lf[1] - line);
+			if (linelen > sizeof(" [stack]\n") - 1U)
+				if (!strcmp(&line[linelen - (sizeof(" [stack]\n") - 1U)], " [stack]\n"))
+					goto line_found;
+		}
+		
+	}
+	
+line_found:
+	close(fd);
+
+	*low = (uintptr_t)strtoumax(line, &line, 16);
+	*high = (uintptr_t)strtoumax(&line[1], &line, 16);
+	if (*low > *high) {
+		*low ^= *high;
+		*high ^= *low;
+		*low ^= *high;
+	}
+
+	return 0;
+}
+
+
+#else
+#include "test.h"
+
+int
+main(void)
+{
+	return 0;
+}
+
+#endif