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+/* vi: set sw=4 ts=4: */
+/*
+ * Mini watch implementation for busybox
+ *
+ * Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
+ * Copyrigjt (C) Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ */
+
+/* BB_AUDIT SUSv3 N/A */
+/* BB_AUDIT GNU defects -- only option -n is supported. */
+
+#include "libbb.h"
+
+// procps 2.0.18:
+// watch [-d] [-n seconds]
+// [--differences[=cumulative]] [--interval=seconds] command
+//
+// procps-3.2.3:
+// watch [-dt] [-n seconds]
+// [--differences[=cumulative]] [--interval=seconds] [--no-title] command
+//
+// (procps 3.x and procps 2.x are forks, not newer/older versions of the same)
+
+int watch_main(int argc, char **argv);
+int watch_main(int argc, char **argv)
+{
+ unsigned opt;
+ unsigned period = 2;
+ unsigned cmdlen = 1; // 1 for terminal NUL
+ char *header = NULL;
+ char *cmd;
+ char *tmp;
+ char **p;
+
+ opt_complementary = "-1"; // at least one param please
+ opt = getopt32(argc, argv, "+dtn:", &tmp);
+ //if (opt & 0x1) // -d (ignore)
+ //if (opt & 0x2) // -t
+ if (opt & 0x4) period = xatou(tmp);
+ argv += optind;
+
+ p = argv;
+ while (*p)
+ cmdlen += strlen(*p++) + 1;
+ tmp = cmd = xmalloc(cmdlen);
+ while (*argv) {
+ tmp += sprintf(tmp, " %s", *argv);
+ argv++;
+ }
+ cmd++; // skip initial space
+
+ while (1) {
+ printf("\033[H\033[J");
+ if (!(opt & 0x2)) { // no -t
+ int width, len;
+ char *thyme;
+ time_t t;
+
+ get_terminal_width_height(STDOUT_FILENO, &width, 0);
+ header = xrealloc(header, width--);
+ // '%-*s' pads header with spaces to the full width
+ snprintf(header, width, "Every %ds: %-*s", period, width, cmd);
+ time(&t);
+ thyme = ctime(&t);
+ len = strlen(thyme);
+ if (len < width)
+ strcpy(header + width - len, thyme);
+ puts(header);
+ }
+ fflush(stdout);
+ // TODO: 'real' watch pipes cmd's output to itself
+ // and does not allow it to overflow the screen
+ // (taking into account linewrap!)
+ system(cmd);
+ sleep(period);
+ }
+ return 0; // gcc thinks we can reach this :)
+}