Add getopt() options.

Implement a --verbose switch

1 files changed, 50 insertions, 20 deletions

diff --git a/rtwatch.c b/rtwatch.c
index ee34406..7a05dd4 100644
--- a/rtwatch.c
+++ b/rtwatch.c
@@ -16,6 +16,7 @@
 #include <sys/mount.h>
 #include <sys/wait.h>
 #include <inttypes.h>
+#include <getopt.h>
 
 #define TOP_PATH "/var/run/rtwatch"
 #define PERIOD_USEC_FILE
@@ -23,6 +24,8 @@
 #define CPU_LOAD_MAX 50           /* 80% CPU load at max */
 #define RTPRIO_MAX 18
 
+static int verbose = 0;
+
 static int write_long(const char *fn, unsigned long u) {
         int fd;
         ssize_t k;
@@ -184,7 +187,8 @@ static int wait_for_kid(pid_t pid, int timeout, sigset_t *ss, int *ret, int *ret
                 }
 
                 if (WIFSIGNALED(status)) {
-                        fprintf(stderr, "Warning: child process terminated with signal %i.\n", WTERMSIG(status));
+                        if (verbose)
+                                fprintf(stderr, "Warning: child process terminated with signal %i.\n", WTERMSIG(status));
                         *ret_signal = WTERMSIG(status);
                         return 0;
                 }
@@ -197,7 +201,8 @@ static int wait_for_kid(pid_t pid, int timeout, sigset_t *ss, int *ret, int *ret
 static int safe_kill(pid_t pid, sigset_t *ss, int *ret, int *ret_signal) {
         int r;
 
-        fprintf(stderr, "Killing child %lu with signal %i\n", (unsigned long) pid, SIGTERM);
+        if (verbose)
+                fprintf(stderr, "Killing child %lu with signal %i\n", (unsigned long) pid, SIGTERM);
 
         if (kill(pid, SIGTERM) < 0) {
                 if (errno == ESRCH)
@@ -210,7 +215,8 @@ static int safe_kill(pid_t pid, sigset_t *ss, int *ret, int *ret_signal) {
         if ((r = wait_for_kid(pid, 1, ss, ret, ret_signal)) <= 0)
                 return r;
 
-        fprintf(stderr, "Killing child %lu with signal %i\n", (unsigned long) pid, SIGKILL);
+        if (verbose)
+                fprintf(stderr, "Killing child %lu with signal %i\n", (unsigned long) pid, SIGKILL);
 
         if (kill(pid, SIGKILL) < 0) {
                 if (errno == ESRCH)
@@ -223,18 +229,21 @@ static int safe_kill(pid_t pid, sigset_t *ss, int *ret, int *ret_signal) {
         if ((r = wait_for_kid(pid, 1, ss, ret, ret_signal)) <= 0)
                 return r;
 
-        fprintf(stderr, "Client didn't react.\n");
+        fprintf(stderr, "Client didn't react on termination signals.\n");
         return -1;
 }
 
 static void help(const char *argv0, FILE *f) {
 
         fprintf(f,
-                "%s <percentage> <program> [arguments...]\n\n"
-                "\truntime: available runtime in percent.\n"
-                "\tprogram: the program to run\n\n"
-                "Example:\n"
-                "\t%s 1.5 foobar\n",
+                "%s <percentage> -- <program> [arguments...]\n\n"
+                "\t-v\tVerbose\n"
+                "\t-h\tHelp\n\n"
+                "\t<percentage>: CPU time to assign in percent.\n"
+                "\t<program>: the program to run\n\n"
+                "Example:\n\n"
+                "\t%s 1.5 -- foobar\n\n"
+                "\tRuns 'foobar' and assigns it 1.5%% of the available CPU time.\n",
                 argv0, argv0);
 }
 
@@ -247,6 +256,12 @@ int main(int argc, char *argv[]) {
         float cpu_percentage;
         unsigned long runtime_usec, period_usec, u;
         int ret_signal = -1;
+        int o;
+        static const struct option long_options[] = {
+                { "help",           no_argument,       NULL, 'h' },
+                { "verbose",        no_argument,       NULL, 'v' },
+                { NULL, 0, NULL, 0 }
+        };
 
         if (argc < 0)
                 argv0 = "rtwatch";
@@ -255,18 +270,29 @@ int main(int argc, char *argv[]) {
         else
                 argv0 = argv[0];
 
-        if (argc == 1) {
-                help(argv0, stdout);
-                ret = 0;
-                goto finish;
+        while ((o = getopt_long(argc, argv, "hv", long_options, NULL)) >= 0) {
+
+                switch (o) {
+
+                        case 'h':
+                                help(argv0, stdout);
+                                break;
+
+                        case 'v':
+                                verbose = 1;
+                                break;
+
+                        default:
+                                goto finish;
+                }
         }
 
-        if (argc < 3) {
+        if (optind+2 > argc) {
                 help(argv0, stderr);
                 goto finish;
         }
 
-        cpu_percentage = atof(argv[1]);
+        cpu_percentage = atof(argv[optind]);
 
         if (cpu_percentage <= 0 || cpu_percentage > 100) {
                 fprintf(stderr, "Failed to parse period argument: %s\n", argv[1]);
@@ -287,10 +313,11 @@ int main(int argc, char *argv[]) {
                 goto finish;
         }
 
-        fprintf(stderr, "period=%0.2fms runtime=%0.2fms max_cpu_load=%0.1f%%\n",
-                (double) period_usec / 1000,
-                (double) runtime_usec / 1000,
-                (double) (runtime_usec*100/period_usec));
+        if (verbose)
+                fprintf(stderr, "period=%0.2fms runtime=%0.2fms max_cpu_load=%0.1f%%\n",
+                        (double) period_usec / 1000,
+                        (double) runtime_usec / 1000,
+                        (double) (runtime_usec*100/period_usec));
 
         if (geteuid() != 0) {
                 fprintf(stderr, "%s needs to be run as root.\n", argv0);
@@ -369,7 +396,10 @@ int main(int argc, char *argv[]) {
                 fprintf(stderr, "fork(): %s\n", strerror(errno));
                 goto finish_remove_cgroup_path;
         } else if (!pid)
-                _exit(child(runtime_usec, cgroup_path, argv + 2));
+                _exit(child(runtime_usec, cgroup_path, argv + optind + 1));
+
+        if (verbose)
+                fprintf(stderr, "Child process has PID %lu.\n", (unsigned long) pid);
 
         if (wait_for_kid(pid, 0, &ss, &ret, &ret_signal) < 0)
                 goto finish_kill;