Watch applet by Michael Habermann

3 files changed, 119 insertions, 0 deletions

diff --git a/coreutils/watch.c b/coreutils/watch.c
new file mode 100644
index 000000000..78ede4c1c
--- /dev/null
+++ b/coreutils/watch.c
@@ -0,0 +1,104 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Mini watch implementation for busybox
+ *
+ * Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+/* getopt not needed */
+
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include "busybox.h"
+
+extern int watch_main(int argc, char **argv)
+{
+        const char date_argv[2][10] = { "date", "" };
+        const char clrscr[] =
+                "\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
+        const int header_len = 40;
+        char header[header_len + 1];
+        int period = 2;
+        char **cargv;
+        int cargc;
+        pid_t pid;
+        int old_stdout;
+        int i;
+
+        if (argc < 2) {
+                show_usage();
+        } else {
+                cargv = argv + 1;
+                cargc = argc - 1;
+
+                /* don't use getopt, because it permutes the arguments */
+                if (argc >= 3 && !strcmp(argv[1], "-n")) {
+                        period = strtol(argv[2], NULL, 10);
+                        if (period < 1)
+                                show_usage();
+                        cargv += 2;
+                        cargc -= 2;
+                }
+        }
+
+
+        /* create header */
+        snprintf(header, header_len, "Every %ds: ", period);
+        for (i = 0; i < cargc && (strlen(header) + strlen(cargv[i]) < header_len);
+                 i++) {
+                strcat(header, cargv[i]);
+                strcat(header, " ");
+        }
+
+        /* fill with blanks */
+        for (i = strlen(header); i < header_len; i++)
+                header[i] = ' ';
+
+        header[header_len - 1] = '\0';
+
+
+        /* thanks to lye, who showed me how to redirect stdin/stdout */
+        old_stdout = dup(1);
+
+        while (1) {
+                printf("%s%s", clrscr, header);
+                date_main(1, (char **) date_argv);
+                printf("\n");
+
+                pid = vfork();  /* vfork, because of ucLinux */
+                if (pid > 0) {
+                        //parent
+                        wait(0);
+                        sleep(period);
+                } else if (0 == pid) {
+                        //child
+                        close(1);
+                        dup(old_stdout);
+                        if (execvp(*cargv, cargv))
+                                error_msg_and_die("Couldn't run command\n");
+                } else {
+                        error_msg_and_die("Couldn't vfork\n");
+                }
+        }
+
+
+        return EXIT_SUCCESS;
+}
diff --git a/include/applets.h b/include/applets.h
index d5c257052..de07cc960 100644
--- a/include/applets.h
+++ b/include/applets.h
@@ -532,6 +532,9 @@
 #ifdef CONFIG_VLOCK
         APPLET(vlock, vlock_main, _BB_DIR_USR_BIN, _BB_SUID_ALWAYS)
 #endif
+#ifdef CONFIG_WATCH
+        APPLET(watch, watch_main, _BB_DIR_BIN, _BB_SUID_NEVER)
+#endif
 #ifdef CONFIG_WATCHDOG
         APPLET(watchdog, watchdog_main, _BB_DIR_SBIN, _BB_SUID_NEVER)
 #endif
diff --git a/include/usage.h b/include/usage.h
index 968823e54..1cdaa6681 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -2076,6 +2076,18 @@
         "Options:\n" \
         "\t-a\tLock all VTs"
 
+#define watch_trivial_usage \
+        "[-n <seconds>] COMMAND..."
+#define watch_full_usage \
+        "Executes a program periodically.\n" \
+        "Options:\n" \
+        "\t-n\tLoop period in seconds - default is 2." 
+#define watch_example_usage \
+        "$ watch date\n" \
+        "Mon Dec 17 10:31:40 GMT 2000\n" \
+        "Mon Dec 17 10:31:42 GMT 2000\n" \
+        "Mon Dec 17 10:31:44 GMT 2000" 
+
 #define watchdog_trivial_usage \
         "DEV"
 #define watchdog_full_usage \