Move everything into a new repo.

1 files changed, 54 insertions, 0 deletions

diff --git a/userland/minibox/utilities/cat.c b/userland/minibox/utilities/cat.c
new file mode 100644
index 0000000..c528d49
--- /dev/null
+++ b/userland/minibox/utilities/cat.c
@@ -0,0 +1,54 @@
+// cat - concatenate and print files
+// https://pubs.opengroup.org/onlinepubs/9699919799/
+//
+// TODO: Add -u flag "Write bytes from the input file to the standard
+// output without delay as each is read."
+#include "include.h"
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+int fd_to_stdout(int fd) {
+  int rc;
+  for (char buffer[CAT_BUFFER]; (rc = read(fd, &buffer, sizeof(buffer)));) {
+    if (-1 == rc)
+      return 0;
+    if (-1 == write(fd_stdout, buffer, rc))
+      return 0;
+  }
+  return 1;
+}
+
+int cat_main(int argc, char **argv) {
+  int fd = fd_stdin;
+
+  // If no file operands are specified, the standard input shall be
+  // used.
+  if (argc < 2) {
+    return (fd_to_stdout(0)) ? 0 : 1;
+  }
+
+  argv++;
+  for (; *argv; argv++) {
+    // If a file is '-', the cat utility shall read from the standard
+    // input at that point in the sequence.
+    if (0 == strcmp(*argv, "-")) {
+      if (!fd_to_stdout(0))
+        return 1;
+      continue;
+    }
+
+    if (-1 == (fd = open(*argv, O_RDONLY, 0))) {
+      printf("cat: ");
+      //      fflush(stdout);
+      perror(*argv);
+      return 1;
+    }
+    if (!fd_to_stdout(fd))
+      return 1;
+    close(fd);
+  }
+  return 0;
+}