/* 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.
 */
#if defined(__linux__)
# include <sys/prctl.h>
# define PRCTL
#elif defined(__FreeBSD__)
# include <sys/procctl.h>
# define PROCCTL
#endif
#include "libbb.h"
#include "mail.h"

// common signal handler
static void signal_handler(int signo)
{
        if (SIGALRM == signo) {
                bb_simple_error_msg_and_die("timed out");
        }

        // SIGCHLD. reap the zombie if we expect one
        if (G.helper_pid == 0)
                return;
#define status signo
        if (safe_waitpid(G.helper_pid, &status, WNOHANG) > 0) {
                G.helper_pid = 0;
                if (WIFSIGNALED(status))
                        bb_error_msg_and_die("helper killed by signal %u", WTERMSIG(status));
                if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
                        bb_error_msg_and_die("helper exited (%u)", WEXITSTATUS(status));
        }
#undef status
}

void FAST_FUNC launch_helper(const char **argv)
{
        pid_t pid;
        struct fd_pair child_out;
        struct fd_pair child_in;

        xpiped_pair(child_out);
        xpiped_pair(child_in);

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

        fflush_all();
        pid = xvfork();
        if (pid == 0) {
                // child
                close(child_in.wr);
                close(child_out.rd);
                xmove_fd(child_in.rd, STDIN_FILENO);
                xmove_fd(child_out.wr, STDOUT_FILENO);
                // if parent dies, get SIGTERM
#if defined(PRCTL)
                prctl(PR_SET_PDEATHSIG, SIGTERM, 0, 0, 0);
#elif defined(PROCCTL)
                {
                        int signum = SIGTERM;
                        procctl(P_PID, 0, PROC_PDEATHSIG_CTL, &signum);
                }
#endif
                // try to execute connection helper
                // NB: SIGCHLD & SIGALRM revert to SIG_DFL on exec
                BB_EXECVP_or_die((char**)argv);
        }
        G.helper_pid = pid;
        close(child_out.wr);
        close(child_in.rd);
        xmove_fd(child_out.rd, STDIN_FILENO);
        xmove_fd(child_in.wr, STDOUT_FILENO);

        // parent goes on
}

void FAST_FUNC send_r_n(const char *s)
{
        if (G.verbose)
                bb_error_msg("send:'%s'", s);
        printf("%s\r\n", s);
}

char* FAST_FUNC send_mail_command(const char *fmt, const char *param)
{
        char *msg;
        if (G.timeout)
                alarm(G.timeout);
        msg = (char*)fmt;
        if (fmt) {
                msg = xasprintf(fmt, param);
                send_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;
}
*/

static void encode_n_base64(const char *fname, const char *text, size_t len)
{
        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;
        char dst_buf[DST_BUF_SIZE + 1];

        if (fname) {
                fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : stdin;
                src_buf = src;
        }

        while (1) {
                size_t size;
                if (fname) {
                        size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
                        if ((ssize_t)size < 0)
                                bb_simple_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("");
                } 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
}

void FAST_FUNC printstr_base64(const char *text)
{
        encode_n_base64(NULL, text, strlen(text));
}

void FAST_FUNC printbuf_base64(const char *text, unsigned len)
{
        encode_n_base64(NULL, text, len);
}

void FAST_FUNC printfile_base64(const char *fname)
{
        encode_n_base64(fname, NULL, 0);
}

/*
 * get username and password from a file descriptor
 */
void FAST_FUNC get_cred_or_die(int fd)
{
        if (isatty(fd)) {
                G.user = bb_ask_noecho(fd, /* timeout: */ 0, "User: ");
                G.pass = bb_ask_noecho(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_simple_error_msg_and_die("no username or password");
}