1 files changed, 71 insertions, 0 deletions
diff --git a/src/logtee/logtee.c b/src/logtee/logtee.c
new file mode 100644
index 0000000..55520db
--- /dev/null
+++ b/src/logtee/logtee.c
@@ -0,0 +1,71 @@
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <limits.h>
+
+#define BUFLEN 4096
+
+int main(int argc, char *argv[])
+{
+        int fd;
+        int len, slen;
+        int ret;
+        int timeout;
+        char *timeout_env;
+        struct pollfd fds[] = { {
+                        .fd = STDIN_FILENO,
+                        .events = POLLIN | POLLERR,
+                }
+        };
+
+        timeout_env = getenv("LOGTEE_TIMEOUT_MS");
+        if (timeout_env)
+                timeout = atoi(timeout_env);
+        else
+                timeout = -1;
+
+        if (argc != 2) {
+                fprintf(stderr, "Usage: %s <file>\n", argv[0]);
+                exit(EXIT_FAILURE);
+        }
+
+        fd = open(argv[1], O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, 0644);
+        if (fd == -1) {
+                perror("open");
+                exit(EXIT_FAILURE);
+        }
+
+        fprintf(stderr, "Logging to %s: ", argv[1]);
+
+        slen = 0;
+
+        do {
+                ret = poll(fds, sizeof(fds) / sizeof(fds[0]), timeout);
+                if (ret == 0) {
+                        fprintf(stderr, "Timed out after %d milliseconds of no output.\n", timeout);
+                        exit(EXIT_FAILURE);
+                }
+                len = splice(STDIN_FILENO, NULL, fd, NULL, BUFLEN, SPLICE_F_MOVE | SPLICE_F_NONBLOCK);
+
+                if (len < 0) {
+                        if (errno == EAGAIN)
+                                continue;
+                        perror("tee");
+                        exit(EXIT_FAILURE);
+                } else if (len == 0)
+                        break;
+                slen += len;
+                if ((slen / BUFLEN) > 0) {
+                        fprintf(stderr, ".");
+                }
+                slen = slen % BUFLEN;
+
+        } while (1);
+        close(fd);
+        fprintf(stderr, "\n");
+        exit(EXIT_SUCCESS);
+}