shell/cmdedit.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Termios command line History and Editting for NetBSD sh (ash)
   4  * Copyright (c) 1999
   5  *      Main code:            Adam Rogoyski <rogoyski@cs.utexas.edu>
   6  *      Etc:                  Dave Cinege <dcinege@psychosis.com>
   7  *      Adjusted for busybox: Erik Andersen <andersee@debian.org>
   8  *
   9  * You may use this code as you wish, so long as the original author(s)
  10  * are attributed in any redistributions of the source code.
  11  * This code is 'as is' with no warranty.
  12  * This code may safely be consumed by a BSD or GPL license.
  13  *
  14  * v 0.5  19990328      Initial release
  15  *
  16  * Future plans: Simple file and path name completion. (like BASH)
  17  *
  18  */
  19
  20 /*
  21    Usage and Known bugs:
  22    Terminal key codes are not extensive, and more will probably
  23    need to be added. This version was created on Debian GNU/Linux 2.x.
  24    Delete, Backspace, Home, End, and the arrow keys were tested
  25    to work in an Xterm and console. Ctrl-A also works as Home.
  26    Ctrl-E also works as End. The binary size increase is <3K.
  27
  28    Editting will not display correctly for lines greater then the
  29    terminal width. (more then one line.) However, history will.
  30  */
  31
  32 #include "internal.h"
  33 #ifdef BB_FEATURE_SH_COMMAND_EDITING
  34
  35 #include <stdio.h>
  36 #include <errno.h>
  37 #include <unistd.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <termio.h>
  41 #include <ctype.h>
  42 #include <signal.h>
  43
  44
  45 #define  MAX_HISTORY   15               /* Maximum length of the linked list for the command line history */
  46
  47 #define ESC     27
  48 #define DEL     127
  49 #define member(c, s) ((c) ? ((char *)strchr ((s), (c)) != (char *)NULL) : 0)
  50 #define whitespace(c) (((c) == ' ') || ((c) == '\t'))
  51
  52 static struct history *his_front = NULL;        /* First element in command line list */
  53 static struct history *his_end = NULL;  /* Last element in command line list */
  54 static struct termio old_term, new_term;        /* Current termio and the previous termio before starting ash */
  55
  56 static int history_counter = 0; /* Number of commands in history list */
  57 static int reset_term = 0;              /* Set to true if the terminal needs to be reset upon exit */
  58 char *parsenextc;                               /* copy of parsefile->nextc */
  59
  60 struct history {
  61         char *s;
  62         struct history *p;
  63         struct history *n;
  64 };
  65
  66
  67 /* Version of write which resumes after a signal is caught.  */
  68 int xwrite(int fd, char *buf, int nbytes)
  69 {
  70         int ntry;
  71         int i;
  72         int n;
  73
  74         n = nbytes;
  75         ntry = 0;
  76         for (;;) {
  77                 i = write(fd, buf, n);
  78                 if (i > 0) {
  79                         if ((n -= i) <= 0)
  80                                 return nbytes;
  81                         buf += i;
  82                         ntry = 0;
  83                 } else if (i == 0) {
  84                         if (++ntry > 10)
  85                                 return nbytes - n;
  86                 } else if (errno != EINTR) {
  87                         return -1;
  88                 }
  89         }
  90 }
  91
  92
  93 /* Version of ioctl that retries after a signal is caught.  */
  94 int xioctl(int fd, unsigned long request, char *arg)
  95 {
  96         int i;
  97
  98         while ((i = ioctl(fd, request, arg)) == -1 && errno == EINTR);
  99         return i;
 100 }
 101
 102
 103 void cmdedit_reset_term(void)
 104 {
 105         if (reset_term)
 106                 xioctl(fileno(stdin), TCSETA, (void *) &old_term);
 107 }
 108
 109 void prepareToDie(int sig)
 110 {
 111         cmdedit_reset_term();
 112         fprintf(stdout, "\n");
 113         exit(TRUE);
 114 }
 115
 116 void input_home(int outputFd, int *cursor)
 117 {                                                               /* Command line input routines */
 118         while (*cursor > 0) {
 119                 xwrite(outputFd, "\b", 1);
 120                 --*cursor;
 121         }
 122 }
 123
 124
 125 void input_delete(int outputFd, int cursor)
 126 {
 127         int j = 0;
 128
 129         memmove(parsenextc + cursor, parsenextc + cursor + 1,
 130                         BUFSIZ - cursor - 1);
 131         for (j = cursor; j < (BUFSIZ - 1); j++) {
 132                 if (!*(parsenextc + j))
 133                         break;
 134                 else
 135                         xwrite(outputFd, (parsenextc + j), 1);
 136         }
 137
 138         xwrite(outputFd, " \b", 2);
 139
 140         while (j-- > cursor)
 141                 xwrite(outputFd, "\b", 1);
 142 }
 143
 144
 145 void input_end(int outputFd, int *cursor, int len)
 146 {
 147         while (*cursor < len) {
 148                 xwrite(outputFd, "\033[C", 3);
 149                 ++*cursor;
 150         }
 151 }
 152
 153
 154 void input_backspace(int outputFd, int *cursor, int *len)
 155 {
 156         int j = 0;
 157
 158         if (*cursor > 0) {
 159                 xwrite(outputFd, "\b \b", 3);
 160                 --*cursor;
 161                 memmove(parsenextc + *cursor, parsenextc + *cursor + 1,
 162                                 BUFSIZ - *cursor + 1);
 163
 164                 for (j = *cursor; j < (BUFSIZ - 1); j++) {
 165                         if (!*(parsenextc + j))
 166                                 break;
 167                         else
 168                                 xwrite(outputFd, (parsenextc + j), 1);
 169                 }
 170
 171                 xwrite(outputFd, " \b", 2);
 172
 173                 while (j-- > *cursor)
 174                         xwrite(outputFd, "\b", 1);
 175
 176                 --*len;
 177         }
 178 }
 179
 180 char** username_completion_matches(char* command, int *num_matches)
 181 {
 182         char **matches = (char **) NULL;
 183         *num_matches=0;
 184         fprintf(stderr, "\nin username_completion_matches\n");
 185         return (matches);
 186 }
 187 char** find_path_executable_n_cwd_matches(char* command, int *num_matches)
 188 {
 189         char **matches = (char **) NULL;
 190         matches = malloc(sizeof(char*)*100);
 191
 192         matches[0] = malloc(sizeof(char)*50);
 193         matches[1] = malloc(sizeof(char)*50);
 194
 195         sprintf(matches[0], "Hello");
 196         sprintf(matches[1], "Howdy");
 197         *num_matches=2;
 198
 199 //      fprintf(stderr, "\nin find_path_executable_n_cwd_matches\n");
 200         return (matches);
 201 }
 202
 203 /*
 204  * This function is used to grab a character buffer
 205  * from the input file descriptor and allows you to
 206  * a string with full command editing (sortof like
 207  * a mini readline).
 208  *
 209  * The following standard commands are not implemented:
 210  * ESC-b -- Move back one word
 211  * ESC-f -- Move forward one word
 212  * ESC-d -- Delete back one word
 213  * ESC-h -- Delete forward one word
 214  * CTL-t -- Transpose two characters
 215  *
 216  * Furthermore, the "vi" command editing keys are not implemented.
 217  *
 218  * TODO: implement TAB command completion. :)
 219  *
 220  */
 221 extern int cmdedit_read_input(char* prompt, int inputFd, int outputFd,
 222                                                           char command[BUFSIZ])
 223 {
 224
 225         int nr = 0;
 226         int len = 0;
 227         int j = 0;
 228         int cursor = 0;
 229         int break_out = 0;
 230         int ret = 0;
 231         int lastWasTab = FALSE;
 232         char c = 0;
 233         struct history *hp = his_end;
 234
 235         memset(command, 0, sizeof(command));
 236         parsenextc = command;
 237         if (!reset_term) {
 238                 xioctl(inputFd, TCGETA, (void *) &old_term);
 239                 memcpy(&new_term, &old_term, sizeof(struct termio));
 240
 241                 new_term.c_cc[VMIN] = 1;
 242                 new_term.c_cc[VTIME] = 0;
 243                 new_term.c_lflag &= ~ICANON;    /* unbuffered input */
 244                 new_term.c_lflag &= ~ECHO;
 245                 xioctl(inputFd, TCSETA, (void *) &new_term);
 246                 reset_term = 1;
 247         } else {
 248                 xioctl(inputFd, TCSETA, (void *) &new_term);
 249         }
 250
 251         memset(parsenextc, 0, BUFSIZ);
 252
 253         while (1) {
 254
 255                 if ((ret = read(inputFd, &c, 1)) < 1)
 256                         return ret;
 257
 258                 switch (c) {
 259                 case 1:
 260                         /* Control-a -- Beginning of line */
 261                         input_home(outputFd, &cursor);
 262                 case 5:
 263                         /* Control-e -- End of line */
 264                         input_end(outputFd, &cursor, len);
 265                         break;
 266                 case 2:
 267                         /* Control-b -- Move back one character */
 268                         if (cursor > 0) {
 269                                 xwrite(outputFd, "\033[D", 3);
 270                                 cursor--;
 271                         }
 272                         break;
 273                 case 6:
 274                         /* Control-f -- Move forward one character */
 275                         if (cursor < len) {
 276                                 xwrite(outputFd, "\033[C", 3);
 277                                 cursor++;
 278                         }
 279                         break;
 280                 case 4:
 281                         /* Control-d -- Delete one character */
 282                         if (cursor != len) {
 283                                 input_delete(outputFd, cursor);
 284                                 len--;
 285                         } else if (len == 0) {
 286                                 prepareToDie(0);
 287                                 exit(0);
 288                         }
 289                         break;
 290                 case 14:
 291                         /* Control-n -- Get next command */
 292                         if (hp && hp->n && hp->n->s) {
 293                                 free(hp->s);
 294                                 hp->s = strdup(parsenextc);
 295                                 hp = hp->n;
 296                                 goto hop;
 297                         }
 298                         break;
 299                 case 16:
 300                         /* Control-p -- Get previous command */
 301                         if (hp && hp->p) {
 302                                 free(hp->s);
 303                                 hp->s = strdup(parsenextc);
 304                                 hp = hp->p;
 305                                 goto hop;
 306                         }
 307                         break;
 308                 case '\t':
 309                         {
 310                                 /* Do TAB completion */
 311                                 static int num_matches=0;
 312                                 static char **matches = (char **) NULL;
 313                                 int pos = cursor;
 314
 315
 316                                 if (lastWasTab == FALSE) {
 317                                         char *tmp, *tmp1, *matchBuf;
 318
 319                                         /* For now, we will not bother with trying to distinguish
 320                                          * whether the cursor is in/at a command extression -- we
 321                                          * will always try all possable matches.  If you don't like
 322                                          * that, feel free to fix it.
 323                                          */
 324
 325                                         /* Make a local copy of the string -- up
 326                                          * to the the position of the cursor */
 327                                         matchBuf = (char *) calloc(BUFSIZ, sizeof(char));
 328                                         strncpy(matchBuf, parsenextc, cursor);
 329                                         tmp=matchBuf;
 330
 331                                         /* skip past any command seperator tokens */
 332                                         while (*tmp && (tmp1=strpbrk(tmp, ";|&{(`")) != NULL) {
 333                                                 tmp=++tmp1;
 334                                                 /* skip any leading white space */
 335                                                 while (*tmp && isspace(*tmp))
 336                                                         ++tmp;
 337                                         }
 338
 339                                         /* skip any leading white space */
 340                                         while (*tmp && isspace(*tmp))
 341                                                 ++tmp;
 342
 343                                         /* Free up any memory already allocated */
 344                                         if (matches) {
 345                                                 free(matches);
 346                                                 matches = (char **) NULL;
 347                                         }
 348
 349                                         /* If the word starts in `~', and there is no slash in the word,
 350                                          * then try completing this word as a username. */
 351                                         if (*tmp == '~' && !strchr(tmp, '/'))
 352                                                 matches = username_completion_matches(tmp, &num_matches);
 353
 354                                         /* Try to match any executable in our patch, and everything
 355                                          * in the current working directory that matches.
 356                                          */
 357                                         if (!matches)
 358                                                 matches = find_path_executable_n_cwd_matches(tmp, &num_matches);
 359                                 } else {
 360                                         if ( matches && num_matches>0 ) {
 361                                                 int i, col;
 362
 363                                                 fprintf(stderr, "\nTabbing...\n");
 364
 365                                                 /* Make a list of the matches */
 366                                                 col += xwrite(outputFd, "\n", 1);
 367                                                 for (i=0,col=0; i<num_matches; i++) {
 368                                                         col += xwrite(outputFd, prompt, strlen(matches[i]));
 369                                                         if (col > 60 && matches[i+1] != NULL) {
 370                                                                 xwrite(outputFd, "\n", 1);
 371                                                                 col = 0;
 372                                                         }
 373                                                 }
 374                                                 xwrite(outputFd, "\n", 1);
 375
 376                                                 len+=strlen(prompt);
 377                                                 fprintf(stderr, "len=%d\n", len);
 378
 379                                                 /* Move to the beginning of the line */
 380                                                 input_home(outputFd, &len);
 381
 382                                                 /* erase everything */
 383                                                 for (j = 0; j < len; j++)
 384                                                         xwrite(outputFd, " ", 1);
 385
 386                                                 /* return to begining of line */
 387                                                 input_home(outputFd, &cursor);
 388
 389                                                 /* Rewrite the prompt) */
 390                                                 xwrite(outputFd, prompt, strlen(prompt));
 391
 392                                                 /* Rewrite the command */
 393                                                 len = strlen(parsenextc);
 394                                                 xwrite(outputFd, parsenextc, len);
 395
 396                                                 /* Move back to where the cursor used to be */
 397                                                 for (cursor=pos; cursor > 0; cursor--)
 398                                                         xwrite(outputFd, "\b", 1);
 399                                                 cursor = pos;
 400
 401                                                 //fprintf(stderr, "\nprompt='%s'\n", prompt);
 402                                         }
 403                                 }
 404                                 break;
 405                         }
 406                 case '\b':
 407                 case DEL:
 408                         /* Backspace */
 409                         input_backspace(outputFd, &cursor, &len);
 410                         break;
 411                 case '\n':
 412                         /* Enter */
 413                         *(parsenextc + len++ + 1) = c;
 414                         xwrite(outputFd, &c, 1);
 415                         break_out = 1;
 416                         break;
 417                 case ESC:{
 418                                 /* escape sequence follows */
 419                                 if ((ret = read(inputFd, &c, 1)) < 1)
 420                                         return ret;
 421
 422                                 if (c == '[') { /* 91 */
 423                                         if ((ret = read(inputFd, &c, 1)) < 1)
 424                                                 return ret;
 425
 426                                         switch (c) {
 427                                         case 'A':
 428                                                 /* Up Arrow -- Get previous command */
 429                                                 if (hp && hp->p) {
 430                                                         free(hp->s);
 431                                                         hp->s = strdup(parsenextc);
 432                                                         hp = hp->p;
 433                                                         goto hop;
 434                                                 }
 435                                                 break;
 436                                         case 'B':
 437                                                 /* Down Arrow -- Get next command */
 438                                                 if (hp && hp->n && hp->n->s) {
 439                                                         free(hp->s);
 440                                                         hp->s = strdup(parsenextc);
 441                                                         hp = hp->n;
 442                                                         goto hop;
 443                                                 }
 444                                                 break;
 445
 446                                                 /* This is where we rewrite the line
 447                                                  * using the selected history item */
 448                                           hop:
 449                                                 len = strlen(parsenextc);
 450
 451                                                 /* return to begining of line */
 452                                                 for (; cursor > 0; cursor--)
 453                                                         xwrite(outputFd, "\b", 1);
 454                                                 xwrite(outputFd, parsenextc, len);
 455
 456                                                 /* erase old command */
 457                                                 for (j = 0; j < len; j++)
 458                                                         xwrite(outputFd, " ", 1);
 459
 460                                                 /* return to begining of line */
 461                                                 for (j = len; j > 0; j--)
 462                                                         xwrite(outputFd, "\b", 1);
 463
 464                                                 memset(parsenextc, 0, BUFSIZ);
 465                                                 /* write new command */
 466                                                 strcpy(parsenextc, hp->s);
 467                                                 len = strlen(hp->s);
 468                                                 xwrite(outputFd, parsenextc, len);
 469                                                 cursor = len;
 470                                                 break;
 471                                         case 'C':
 472                                                 /* Right Arrow -- Move forward one character */
 473                                                 if (cursor < len) {
 474                                                         xwrite(outputFd, "\033[C", 3);
 475                                                         cursor++;
 476                                                 }
 477                                                 break;
 478                                         case 'D':
 479                                                 /* Left Arrow -- Move back one character */
 480                                                 if (cursor > 0) {
 481                                                         xwrite(outputFd, "\033[D", 3);
 482                                                         cursor--;
 483                                                 }
 484                                                 break;
 485                                         case '3':
 486                                                 /* Delete */
 487                                                 if (cursor != len) {
 488                                                         input_delete(outputFd, cursor);
 489                                                         len--;
 490                                                 }
 491                                                 break;
 492                                         case '1':
 493                                                 /* Home (Ctrl-A) */
 494                                                 input_home(outputFd, &cursor);
 495                                                 break;
 496                                         case '4':
 497                                                 /* End (Ctrl-E) */
 498                                                 input_end(outputFd, &cursor, len);
 499                                                 break;
 500                                         }
 501                                         if (c == '1' || c == '3' || c == '4')
 502                                                 if ((ret = read(inputFd, &c, 1)) < 1)
 503                                                         return ret;     /* read 126 (~) */
 504                                 }
 505                                 if (c == 'O') {
 506                                         /* 79 */
 507                                         if ((ret = read(inputFd, &c, 1)) < 1)
 508                                                 return ret;
 509                                         switch (c) {
 510                                         case 'H':
 511                                                 /* Home (xterm) */
 512                                                 input_home(outputFd, &cursor);
 513                                                 break;
 514                                         case 'F':
 515                                                 /* End (xterm) */
 516                                                 input_end(outputFd, &cursor, len);
 517                                                 break;
 518                                         }
 519                                 }
 520                                 c = 0;
 521                                 break;
 522                         }
 523
 524                 default:                                /* If it's regular input, do the normal thing */
 525
 526                         if (!isprint(c))        /* Skip non-printable characters */
 527                                 break;
 528
 529                         if (len >= (BUFSIZ - 2))        /* Need to leave space for enter */
 530                                 break;
 531
 532                         len++;
 533
 534                         if (cursor == (len - 1)) {      /* Append if at the end of the line */
 535                                 *(parsenextc + cursor) = c;
 536                         } else {                        /* Insert otherwise */
 537                                 memmove(parsenextc + cursor + 1, parsenextc + cursor,
 538                                                 len - cursor - 1);
 539
 540                                 *(parsenextc + cursor) = c;
 541
 542                                 for (j = cursor; j < len; j++)
 543                                         xwrite(outputFd, parsenextc + j, 1);
 544                                 for (; j > cursor; j--)
 545                                         xwrite(outputFd, "\033[D", 3);
 546                         }
 547
 548                         cursor++;
 549                         xwrite(outputFd, &c, 1);
 550                         break;
 551                 }
 552                 if (c == '\t')
 553                         lastWasTab = TRUE;
 554                 else
 555                         lastWasTab = FALSE;
 556
 557                 if (break_out)                  /* Enter is the command terminator, no more input. */
 558                         break;
 559         }
 560
 561         nr = len + 1;
 562         xioctl(inputFd, TCSETA, (void *) &old_term);
 563         reset_term = 0;
 564
 565
 566         /* Handle command history log */
 567         if (*(parsenextc)) {
 568
 569                 struct history *h = his_end;
 570
 571                 if (!h) {
 572                         /* No previous history */
 573                         h = his_front = malloc(sizeof(struct history));
 574                         h->n = malloc(sizeof(struct history));
 575
 576                         h->p = NULL;
 577                         h->s = strdup(parsenextc);
 578                         h->n->p = h;
 579                         h->n->n = NULL;
 580                         h->n->s = NULL;
 581                         his_end = h->n;
 582                         history_counter++;
 583                 } else {
 584                         /* Add a new history command */
 585                         h->n = malloc(sizeof(struct history));
 586
 587                         h->n->p = h;
 588                         h->n->n = NULL;
 589                         h->n->s = NULL;
 590                         h->s = strdup(parsenextc);
 591                         his_end = h->n;
 592
 593                         /* After max history, remove the oldest command */
 594                         if (history_counter >= MAX_HISTORY) {
 595
 596                                 struct history *p = his_front->n;
 597
 598                                 p->p = NULL;
 599                                 free(his_front->s);
 600                                 free(his_front);
 601                                 his_front = p;
 602                         } else {
 603                                 history_counter++;
 604                         }
 605                 }
 606         }
 607
 608         return nr;
 609 }
 610
 611 extern void cmdedit_init(void)
 612 {
 613         atexit(cmdedit_reset_term);
 614         signal(SIGINT, prepareToDie);
 615         signal(SIGQUIT, prepareToDie);
 616         signal(SIGTERM, prepareToDie);
 617 }
 618 #endif                                                  /* BB_FEATURE_SH_COMMAND_EDITING */