seq: slurp the file instead of mmap

mmap is not robust when there are writes possible.

1 files changed, 56 insertions, 0 deletions

diff --git a/slurp.c b/slurp.c
new file mode 100644
index 0000000..6366e6f
--- /dev/null
+++ b/slurp.c
@@ -0,0 +1,56 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+slurp(char *filename, char **bufo, off_t *leno)
+{
+	int fd;
+	struct stat st;
+	ssize_t nread = 0;
+	ssize_t n;
+	int r = 0;
+	
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		r = errno;
+		goto out;
+	}
+	if (fstat(fd, &st) < 0) {
+		r = errno;
+		goto out;
+	}
+	if (st.st_size == 0) {
+		*bufo = "";
+		*leno = 0;
+		return 0;
+	}
+	*bufo = malloc(st.st_size);
+	if (!*bufo) {
+		r = ENOMEM;
+		goto out;
+	}
+
+	do {
+		if ((n = read(fd, *bufo + nread, st.st_size - nread)) < 0) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				r = errno;
+				goto out;
+			}
+		}
+		if (!n)
+			break;
+		nread += n;
+	} while (nread < st.st_size);
+	*leno = nread;
+
+out:
+	close(fd);
+	return r;
+}