source: tools/repeat.c @ bab2917

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <stdbool.h>
#include <string.h>

#include <getopt.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/wait.h>

int repetitions = 0;
bool stop_on_error = false;
char * this_cmd = NULL;
bool print_iterations = false;

void parse_args(int argc, char * argv[]);
void setup();
int run();

int main(int argc, char * argv[]) {
        parse_args(argc, argv);
        setup();
        for(int i = 0; i < repetitions; i++) {
                if(print_iterations) {
                        printf("\r%d / %d", i, repetitions);
                        fflush(stdout);
                }
                int retcode = run();
                if( !WIFEXITED(retcode) ) {
                        printf("FAILURE: %d @ %d\n", retcode, i + 1);
                }
                if( !WIFEXITED(retcode) && stop_on_error ) {
                        return retcode;
                }
        }

        if(print_iterations) {
                printf("\r%d / %d\n", repetitions, repetitions);
        }

        return 0;
}

void usage( FILE * out, int code ) {
        fprintf(out, "%s [OPTION] [--] N CMD\n", this_cmd);
        fprintf(out, "Repeat CMD N times\n\n");
        fprintf(out, "\t-h,--help\tprint this usage message\n");
        fprintf(out, "\t-s\t\tstop on error\n");
        fprintf(out, "\t-i\t\toutput iterations instead of CMD stdout\n");
        fprintf(out, "\t-x\t\tprint CMD before running it\n");
        fprintf(out, "\t-a FILE\t\tredirect output of command to append to FILE\n");
        fprintf(out, "\t-r FILE\t\tredirect output of command to FILE\n");
        exit(code);
}

char ** cmd_to_run = NULL;
bool print_cmd = false;
bool redirect = false;
bool redirect_append = false;
char * redirect_to = "/dev/null";
pid_t child_pid = 0;

void error() {
        fprintf(stderr,"\n");
        usage(stderr, 1);
}

void parse_args(int argc, char * argv[]) {
        this_cmd = argv[0];

        enum { Help, };
        static struct option long_opts[] = {
                { "help", no_argument, 0, Help },
                { 0, 0, 0, 0 }
        }; // long_opts
        int long_index;

        int c;
        while ( (c = getopt_long( argc, argv, "ahirsx", long_opts, &long_index)) != -1 ) {
                switch ( c ) {
                        case Help:
                        case 'h':
                                usage(stdout, 0);
                                break;
                        case 's':
                                stop_on_error = true;
                                break;
                        case 'x':
                                print_cmd = true;
                                break;
                        case 'i':
                                print_iterations = true;
                                break;
                        case 'a':
                                if(redirect) { fprintf(stderr, "Cannot have -a and -r\n"); error(); }
                                redirect_append = true;
                                redirect_to = argv[optind];
                                optind++;
                                break;
                        case 'r':
                                if(redirect_append) { fprintf(stderr, "Cannot have -a and -r\n"); error(); }
                                redirect = true;
                                redirect_to = argv[optind];
                                optind++;
                                break;
                        default:
                                error("");
                                break;
                } // switch
        } // while

        if( argc < optind + 2 ) {
                fprintf(stderr, "Too few arguments\n");
                error();
        }

        char * pEnd;
        char * repeats_c = argv[optind];
        repetitions = strtol(repeats_c, &pEnd, 10);

        bool is_number = (size_t)(pEnd - repeats_c) == strlen(repeats_c);
        bool in_range  = repetitions > 0;
        if( !is_number || !in_range ) {
                fprintf(
                        stderr,
                        "repetitions option : %s not an number greater than 0\n",
                        repeats_c
                );
                error();
        }

        cmd_to_run = argv + optind + 1;
}

void setup() {

}

int run() {
        /* Duplicate this process. */
        child_pid = fork();
        if (child_pid != 0) {

                /* This is the parent process. */
                int status;
                waitpid(child_pid, &status, 0);
                child_pid = 0;
                return status;
        }
        else {
                /* Now execute PROGRAM, searching for it in the path.  */
                if( print_cmd ) {
                        char ** cmd = cmd_to_run;
                        while (*cmd) {
                                printf("%s ", *cmd);
                                cmd++;
                        }
                        printf("\n");
                }
                if(print_iterations || redirect || redirect_append) {
                        __attribute__((unused)) FILE * ignore =
                                freopen(redirect_to, redirect_append ? "a" : "w" , stdout);
                }
                execvp ( *cmd_to_run, cmd_to_run);
                /* The execvp  function returns only if an error occurs.  */
                fprintf(stderr, "an error occurred in execvp\n");
                abort ();
        }

        return 0;
}