/* vi: set sw=4 ts=4: */
/*
 * helper routines
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include "libbb.h"
#include "mail.h"

static void kill_helper(void)
{
        if (G.helper_pid > 0) {
                kill(G.helper_pid, SIGTERM);
                G.helper_pid = 0;
        }
}

// generic signal handler
static void signal_handler(int signo)
{
#define err signo
        if (SIGALRM == signo) {
                kill_helper();
                bb_error_msg_and_die("timed out");
        }

        // SIGCHLD. reap zombies
        if (safe_waitpid(G.helper_pid, &err, WNOHANG) > 0) {
                if (WIFSIGNALED(err))
                        bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(err));
                if (WIFEXITED(err)) {
                        G.helper_pid = 0;
                        if (WEXITSTATUS(err))
                                bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(err));
                }
        }
#undef err
}

void FAST_FUNC launch_helper(const char **argv)
{
        // setup vanilla unidirectional pipes interchange
        int i;
        int pipes[4];

        xpipe(pipes);
        xpipe(pipes + 2);

        // NB: handler must be installed before vfork
        bb_signals(0
                + (1 << SIGCHLD)
                + (1 << SIGALRM)
                , signal_handler);

        G.helper_pid = xvfork();

        i = (!G.helper_pid) * 2; // for parent:0, for child:2
        close(pipes[i + 1]);     // 1 or 3 - closing one write end
        close(pipes[2 - i]);     // 2 or 0 - closing one read end
        xmove_fd(pipes[i], STDIN_FILENO);      // 0 or 2 - using other read end
        xmove_fd(pipes[3 - i], STDOUT_FILENO); // 3 or 1 - using other write end
        // End result:
        // parent stdout [3] -> child stdin [2]
        // child stdout [1] -> parent stdin [0]

        if (!G.helper_pid) {
                // child: try to execute connection helper
                // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
                BB_EXECVP_or_die((char**)argv);
        }

        // parent
        // check whether child is alive
        //redundant:signal_handler(SIGCHLD);
        // child seems OK -> parent goes on
        atexit(kill_helper);
}

char* FAST_FUNC send_mail_command(const char *fmt, const char *param)
{
        char *msg;
        if (timeout)
                alarm(timeout);
        msg = (char*)fmt;
        if (fmt) {
                msg = xasprintf(fmt, param);
                if (verbose)
                        bb_error_msg("send:'%s'", msg);
                printf("%s\r\n", msg);
        }
        fflush_all();
        return msg;
}

// NB: parse_url can modify url[] (despite const), but only if '@' is there
/*
static char* FAST_FUNC parse_url(char *url, char **user, char **pass)
{
        // parse [user[:pass]@]host
        // return host
        char *s = strchr(url, '@');
        *user = *pass = NULL;
        if (s) {
                *s++ = '\0';
                *user = url;
                url = s;
                s = strchr(*user, ':');
                if (s) {
                        *s++ = '\0';
                        *pass = s;
                }
        }
        return url;
}
*/

void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
{
        enum {
                SRC_BUF_SIZE = 57,  /* This *MUST* be a multiple of 3 */
                DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
        };
#define src_buf text
        char src[SRC_BUF_SIZE];
        FILE *fp = fp;
        ssize_t len = len;
        char dst_buf[DST_BUF_SIZE + 1];

        if (fname) {
                fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
                src_buf = src;
        } else if (text) {
                // though we do not call uuencode(NULL, NULL) explicitly
                // still we do not want to break things suddenly
                len = strlen(text);
        } else
                return;

        while (1) {
                size_t size;
                if (fname) {
                        size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
                        if ((ssize_t)size < 0)
                                bb_perror_msg_and_die(bb_msg_read_error);
                } else {
                        size = len;
                        if (len > SRC_BUF_SIZE)
                                size = SRC_BUF_SIZE;
                }
                if (!size)
                        break;
                // encode the buffer we just read in
                bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
                if (fname) {
                        puts(eol);
                } else {
                        src_buf += size;
                        len -= size;
                }
                fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
        }
        if (fname && NOT_LONE_DASH(fname))
                fclose(fp);
#undef src_buf
}

/*
 * get username and password from a file descriptor
 */
void FAST_FUNC get_cred_or_die(int fd)
{
        if (isatty(fd)) {
                G.user = xstrdup(bb_ask(fd, /* timeout: */ 0, "User: "));
                G.pass = xstrdup(bb_ask(fd, /* timeout: */ 0, "Password: "));
        } else {
                G.user = xmalloc_reads(fd, /* maxsize: */ NULL);
                G.pass = xmalloc_reads(fd, /* maxsize: */ NULL);
        }
        if (!G.user || !*G.user || !G.pass)
                bb_error_msg_and_die("no username or password");
}