Merge pull request #37 from Eike-Flath/main

Implementation of sleep

Makefile

@@ -24,6 +24,7 @@ BINS += ln
 BINS += mv
 BINS += chmod
 BINS += sh
+BINS += sleep
 
 BINARIES := $(foreach b, $(BINS), src/$b/$b)
 BINS-COPY := $(foreach b, $(BINS), bin/$b)

src/sleep/sleep.c

@@ -1,6 +1,44 @@
+#include <limits.h>
+#include <signal.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
-int main(void) {
-  printf("Hello, World!\n");
-  return 0;
-}
+#define NAME "sleep (canoutils)"
+#define VERSION "1.0.0"
+#define AUTHOR "Eike Flath"
+
+#include "version_info.h"
+
+static void handle_sigalrm(int sig) {
+  (void)sig;
+  exit(EXIT_SUCCESS);
+}
+
+int main(int argc, char **argv) {
+  if (argc != 2) {
+    fprintf(stderr, "sleep: expected exactly one operand, got %d\n", argc - 1);
+    return EXIT_FAILURE;
+  }
+  if (!strcmp(argv[1], "--version")) {
+    print_version();
+    return EXIT_SUCCESS;
+  }
+  char *endptr = NULL;
+  long n = strtol(argv[1], &endptr, 10);
+  if (argv[1][0] == '\0' || *endptr != '\0') {
+    fprintf(stderr, "sleep: invalid time interval '%s'\n", argv[1]);
+    return EXIT_FAILURE;
+  }
+  if (n < 0) {
+    fprintf(stderr, "sleep: please provide a non-negative time interval\n");
+    return EXIT_FAILURE;
+  }
+  if (n > UINT_MAX) {
+    fprintf(stderr, "sleep: time interval '%s' is too big\n", argv[1]);
+    return EXIT_FAILURE;
+  }
+  signal(SIGALRM, handle_sigalrm);
+  return sleep((unsigned int)n) == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
+}