mailutils/mail.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * helper routines
   4  *
   5  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this tarball for details.
   8  */
   9 #include "libbb.h"
  10 #include "mail.h"
  11
  12 static void kill_helper(void)
  13 {
  14         // TODO!!!: is there more elegant way to terminate child on program failure?
  15         if (G.helper_pid > 0)
  16                 kill(G.helper_pid, SIGTERM);
  17 }
  18
  19 // generic signal handler
  20 static void signal_handler(int signo)
  21 {
  22 #define err signo
  23         if (SIGALRM == signo) {
  24                 kill_helper();
  25                 bb_error_msg_and_die("timed out");
  26         }
  27
  28         // SIGCHLD. reap zombies
  29         if (safe_waitpid(G.helper_pid, &err, WNOHANG) > 0)
  30                 if (WIFEXITED(err)) {
  31                         G.helper_pid = 0;
  32                         if (WEXITSTATUS(err))
  33                                 bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err));
  34                 }
  35 #undef err
  36 }
  37
  38 void FAST_FUNC launch_helper(const char **argv)
  39 {
  40         // setup vanilla unidirectional pipes interchange
  41         int idx;
  42         int pipes[4];
  43
  44         xpipe(pipes);
  45         xpipe(pipes+2);
  46         G.helper_pid = vfork();
  47         if (G.helper_pid < 0)
  48                 bb_perror_msg_and_die("vfork");
  49         idx = (!G.helper_pid) * 2;
  50         xdup2(pipes[idx], STDIN_FILENO);
  51         xdup2(pipes[3-idx], STDOUT_FILENO);
  52         if (ENABLE_FEATURE_CLEAN_UP)
  53                 for (int i = 4; --i >= 0; )
  54                         if (pipes[i] > STDOUT_FILENO)
  55                                 close(pipes[i]);
  56         if (!G.helper_pid) {
  57                 // child: try to execute connection helper
  58                 BB_EXECVP(*argv, (char **)argv);
  59                 _exit(127);
  60         }
  61         // parent: check whether child is alive
  62         bb_signals(0
  63                 + (1 << SIGCHLD)
  64                 + (1 << SIGALRM)
  65                 , signal_handler);
  66         signal_handler(SIGCHLD);
  67         // child seems OK -> parent goes on
  68         atexit(kill_helper);
  69 }
  70
  71 const FAST_FUNC char *command(const char *fmt, const char *param)
  72 {
  73         const char *msg = fmt;
  74         if (timeout)
  75                 alarm(timeout);
  76         if (msg) {
  77                 msg = xasprintf(fmt, param);
  78                 printf("%s\r\n", msg);
  79         }
  80         fflush(stdout);
  81         return msg;
  82 }
  83
  84 // NB: parse_url can modify url[] (despite const), but only if '@' is there
  85 /*
  86 static char FAST_FUNC *parse_url(char *url, char **user, char **pass)
  87 {
  88         // parse [user[:pass]@]host
  89         // return host
  90         char *s = strchr(url, '@');
  91         *user = *pass = NULL;
  92         if (s) {
  93                 *s++ = '\0';
  94                 *user = url;
  95                 url = s;
  96                 s = strchr(*user, ':');
  97                 if (s) {
  98                         *s++ = '\0';
  99                         *pass = s;
 100                 }
 101         }
 102         return url;
 103 }
 104 */
 105
 106 void FAST_FUNC encode_base64(char *fname, const char *text, const char *eol)
 107 {
 108         enum {
 109                 SRC_BUF_SIZE = 45,  /* This *MUST* be a multiple of 3 */
 110                 DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
 111         };
 112
 113 #define src_buf text
 114         FILE *fp = fp;
 115         ssize_t len = len;
 116         char dst_buf[DST_BUF_SIZE + 1];
 117
 118         if (fname) {
 119                 fp = (NOT_LONE_DASH(fname)) ? xfopen_for_read(fname) : (FILE *)text;
 120                 src_buf = bb_common_bufsiz1;
 121         // N.B. strlen(NULL) segfaults!
 122         } else if (text) {
 123                 // though we do not call uuencode(NULL, NULL) explicitly
 124                 // still we do not want to break things suddenly
 125                 len = strlen(text);
 126         } else
 127                 return;
 128
 129         while (1) {
 130                 size_t size;
 131                 if (fname) {
 132                         size = fread((char *)src_buf, 1, SRC_BUF_SIZE, fp);
 133                         if ((ssize_t)size < 0)
 134                                 bb_perror_msg_and_die(bb_msg_read_error);
 135                 } else {
 136                         size = len;
 137                         if (len > SRC_BUF_SIZE)
 138                                 size = SRC_BUF_SIZE;
 139                 }
 140                 if (!size)
 141                         break;
 142                 // encode the buffer we just read in
 143                 bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
 144                 if (fname) {
 145                         printf("%s\n", eol);
 146                 } else {
 147                         src_buf += size;
 148                         len -= size;
 149                 }
 150                 fwrite(dst_buf, 1, 4 * ((size + 2) / 3), stdout);
 151         }
 152         if (fname && NOT_LONE_DASH(fname))
 153                 fclose(fp);
 154 #undef src_buf
 155 }
 156
 157 void FAST_FUNC decode_base64(FILE *src_stream, FILE *dst_stream)
 158 {
 159         int term_count = 1;
 160
 161         while (1) {
 162                 char translated[4];
 163                 int count = 0;
 164
 165                 while (count < 4) {
 166                         char *table_ptr;
 167                         int ch;
 168
 169                         /* Get next _valid_ character.
 170                          * global vector bb_uuenc_tbl_base64[] contains this string:
 171                          * "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=\n"
 172                          */
 173                         do {
 174                                 ch = fgetc(src_stream);
 175                                 if (ch == EOF) {
 176                                         bb_error_msg_and_die(bb_msg_read_error);
 177                                 }
 178                                 // - means end of MIME section
 179                                 if ('-' == ch) {
 180                                         // push it back
 181                                         ungetc(ch, src_stream);
 182                                         return;
 183                                 }
 184                                 table_ptr = strchr(bb_uuenc_tbl_base64, ch);
 185                         } while (table_ptr == NULL);
 186
 187                         /* Convert encoded character to decimal */
 188                         ch = table_ptr - bb_uuenc_tbl_base64;
 189
 190                         if (*table_ptr == '=') {
 191                                 if (term_count == 0) {
 192                                         translated[count] = '\0';
 193                                         break;
 194                                 }
 195                                 term_count++;
 196                         } else if (*table_ptr == '\n') {
 197                                 /* Check for terminating line */
 198                                 if (term_count == 5) {
 199                                         return;
 200                                 }
 201                                 term_count = 1;
 202                                 continue;
 203                         } else {
 204                                 translated[count] = ch;
 205                                 count++;
 206                                 term_count = 0;
 207                         }
 208                 }
 209
 210                 /* Merge 6 bit chars to 8 bit */
 211                 if (count > 1) {
 212                         fputc(translated[0] << 2 | translated[1] >> 4, dst_stream);
 213                 }
 214                 if (count > 2) {
 215                         fputc(translated[1] << 4 | translated[2] >> 2, dst_stream);
 216                 }
 217                 if (count > 3) {
 218                         fputc(translated[2] << 6 | translated[3], dst_stream);
 219                 }
 220         }
 221 }
 222
 223
 224 /*
 225  * get username and password from a file descriptor
 226  */
 227 void FAST_FUNC get_cred_or_die(int fd)
 228 {
 229         // either from TTY
 230         if (isatty(fd)) {
 231                 G.user = xstrdup(bb_ask_stdin("User: "));
 232                 G.pass = xstrdup(bb_ask_stdin("Password: "));
 233         // or from STDIN
 234         } else {
 235                 FILE *fp = fdopen(fd, "r");
 236                 G.user = xmalloc_fgetline(fp);
 237                 G.pass = xmalloc_fgetline(fp);
 238                 fclose(fp);
 239         }
 240         if (!G.user || !*G.user || !G.pass || !*G.pass)
 241                 bb_error_msg_and_die("no username or password");
 242 }