Add getopt for options management

This patch also introduce the usage function.

Signed-off-by: David Goulet <david.goulet@polymtl.ca>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/lttng/lttngtrace.c b/lttng/lttngtrace.c
index 9b0bb40a6f68bbaa35a4b9080d21f604d5b4a697..f43c097b93f79d612deea487571c25e3a2eb24be 100644 (file)
--- a/lttng/lttngtrace.c
+++ b/lttng/lttngtrace.c
@@ -53,6 +53,16 @@ static int autotrace;        /*
                         * we unlink if needed ?
                         */
 static int sigfwd_pid;
+static char *progname = NULL;
+
+void usage(void) {
+       fprintf(stderr, "usage : %s [-o trace_name] command\n", progname);
+       fprintf(stderr, "\nTracing tool for LTTng and UST\n\
+\n\
+Options:\n\
+       -o trace_name\t\tOutput file of the trace\n\
+");
+}
 
 static int recunlink(const char *dirname)
 {
@@ -152,7 +162,7 @@ static int write_child_pid(pid_t pid, uid_t uid, gid_t gid)
                perror("Error writing child pid");
                return -errno;
        }
-       
+
        fprintf(fp, "%u", (unsigned int) pid);
        ret = fclose(fp);
        if (ret)
@@ -164,32 +174,38 @@ static int write_child_pid(pid_t pid, uid_t uid, gid_t gid)
        return ret;
 }
 
-static int parse_options(int argc, char *argv[], int *arg)
+static int parse_options(int argc, char **argv, int *arg)
 {
-       int ret = 0;
-
-       for (;;) {
-               if (*arg >= argc
-                   || argv[*arg][0] != '-'
-                   || argv[*arg][0] == '\0'
-                   || argv[*arg][1] == '\0'
-                   || !strcmp(argv[*arg], "--"))
-                       break;
-               switch (argv[*arg][1]) {
-               case 'o':       if (*arg + 1 >= argc) {
-                                       printf("Missing -o trace name\n");
-                                       ret = -EINVAL;
-                                       break;
-                               }
-                               trace_path = argv[*arg + 1];
-                               (*arg) += 2;
+       int i, c;
+
+       while ((c = getopt(argc, argv, "ho:")) != -1) {
+               switch (c) {
+                       case 'o':
+                               trace_path = strdup(optarg);
                                break;
-               default:        printf("Unknown option -%c\n", argv[*arg][1]);
-                               ret = -EINVAL;
-                               return ret;
+                       case 'h':
+                               usage();
+                               exit(EXIT_SUCCESS);
+                       case '?':
+                               usage();
+                               exit(EXIT_FAILURE);
+                       default:
+                               exit(EXIT_FAILURE);
                }
        }
-       return ret;
+
+       if (argc - optind > 0) {
+               for (i = optind + 1; i < argc; i++) {
+                       printf ("Non-option argument %s\n", argv[i]);
+               }
+       } else {
+               usage();
+               exit(EXIT_FAILURE);
+       }
+
+       *arg = optind;
+
+       return 0;
 }
 
 static int init_trace_path(void)
@@ -264,8 +280,12 @@ int main(int argc, char *argv[])
        int arg = 1;
        sigset_t saved_mask;
 
-       if (argc < 2)
+       progname = argv[0];
+
+       if (argc < 2) {
+               usage();
                return -ENOENT;
+       }
 
        euid = geteuid();
        uid = getuid();
@@ -273,7 +293,7 @@ int main(int argc, char *argv[])
        gid = geteuid();
 
        if (euid != 0 && uid != 0) {
-               printf("%s must be setuid root\n", argv[0]);
+               printf("%s must be setuid root\n", progname);
                return -EPERM;
        }
 
@@ -282,11 +302,9 @@ int main(int argc, char *argv[])
        printf_dbg("egid: %d\n", egid);
        printf_dbg("gid: %d\n", gid);
 
-       if (arg < argc) {
-               ret = parse_options(argc, argv, &arg);
-               if (ret)
-                       return ret;
-       }
+       ret = parse_options(argc, argv, &arg);
+       if (ret)
+               return ret;
 
        ret = init_trace_path();
        gret = (gret == 0) ? ret : gret;