git ssb

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#include <libconfig.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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static char* resolve_listen(const char *hostname, const char *port) {
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    /* Need room in the strcat for \0 and :
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     * the format in the socket unit file is hostname:port */
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    char *conn = (char*)malloc(strlen(hostname)+strlen(port)+2);
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    strcpy(conn, hostname);
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    strcat(conn, ":");
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    strcat(conn, port);
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    return conn;
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}
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static int get_listen_from_conf(const char *filename, char **listen[]) {
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    config_t config;
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    config_setting_t *setting, *addr;
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    const char *hostname, *port;
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    int len = 0;
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    /* look up the listen stanzas in the config file so these
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     * can be used in the socket file generated */
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    config_init(&config);
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    if (config_read_file(&config, filename) == CONFIG_FALSE) {
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        /* we don't care if file is missing, skip it */
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        if (config_error_line(&config) != 0) {
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            fprintf(stderr, "%s:%d:%s\n",
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                    filename,
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                    config_error_line(&config),
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                    config_error_text(&config));
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            return -1;
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        }
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    } else {
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        setting = config_lookup(&config, "listen");
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        if (setting) {
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            len = config_setting_length(setting);
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            *listen = malloc(len * sizeof(**listen));
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            for (int i = 0; i < len; i++) {
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                addr = config_setting_get_elem(setting, i);
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                if (! (config_setting_lookup_string(addr, "host", &hostname) &&
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                       config_setting_lookup_string(addr, "port", &port))) {
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                    fprintf(stderr,
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                            "line %d:Incomplete specification (hostname and port required)\n",
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                            config_setting_source_line(addr));
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                    return -1;
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                } else {
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                    (*listen)[i] = malloc(strlen(resolve_listen(hostname, port)));
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                    strcpy((*listen)[i], resolve_listen(hostname, port));
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                }
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            }
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        }
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    }
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    return len;
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}
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static int write_socket_unit(FILE *socket, char *listen[], int num_addr, const char *source) {
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    fprintf(socket,
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            "# Automatically generated by systemd-sslh-generator\n\n"
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            "[Unit]\n"
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            "Before=sslh.service\n"
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            "SourcePath=%s\n"
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            "Documentation=man:sslh(8) man:systemd-sslh-generator(8)\n\n"
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            "[Socket]\n"
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            "FreeBind=true\n",
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            source);
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    for (int i = 0; i < num_addr; i++) {
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        fprintf(socket, "ListenStream=%s\n", listen[i]);
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    }
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    return 0;
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}
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static int gen_sslh_config(char *runtime_unit_dir) {
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    char *sslh_conf;
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    int num_addr;
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    FILE *config;
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    char **listen;
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    FILE *runtime_conf_fd = stdout;
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    const char *unit_file;
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    /* There are two default locations so check both with first given preference */
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    sslh_conf = "/etc/sslh.cfg";
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    config = fopen(sslh_conf, "r");
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    if (config  == NULL) {
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        sslh_conf="/etc/sslh/sslh.cfg";
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        config = fopen(sslh_conf, "r");
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        if (config == NULL) {
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            return -1;
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        }
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    }
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    fclose(config);
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    num_addr = get_listen_from_conf(sslh_conf, &listen);
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    if (num_addr < 0)
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        return -1;
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    /* If this is run by systemd directly write to the location told to
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     * otherwise write to standard out so that it's trivial to check what
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     * will be written */
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    if (runtime_unit_dir != "") {
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        unit_file = "/sslh.socket";
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        size_t uf_len = strlen(unit_file);
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        size_t runtime_len = strlen(runtime_unit_dir) + uf_len + 1;
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        char *runtime_conf = malloc(runtime_len);
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        strcpy(runtime_conf, runtime_unit_dir);
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        strcat(runtime_conf, unit_file);
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        runtime_conf_fd = fopen(runtime_conf, "w");
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    }
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    return write_socket_unit(runtime_conf_fd, listen, num_addr, sslh_conf);
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}
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int main(int argc, char *argv[]){
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    int r = 0;
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    int k;
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    char *runtime_unit_dest = "";
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    if (argc > 1 && (argc != 4) ) {
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        printf("This program takes three or no arguments.\n");
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        return -1;
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    }
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    if (argc  > 1)
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        runtime_unit_dest = argv[1];
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    k = gen_sslh_config(runtime_unit_dest);
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    if (k < 0)
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        r = k;
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    return r < 0 ? -1 : 0;
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}
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