Annotation of embedaddon/readline/tilde.c, revision 1.1.1.2

1.1       misho       1: /* tilde.c -- Tilde expansion code (~/foo := $HOME/foo). */
                      2: 
1.1.1.2 ! misho       3: /* Copyright (C) 1988-2020 Free Software Foundation, Inc.
1.1       misho       4: 
                      5:    This file is part of the GNU Readline Library (Readline), a library
                      6:    for reading lines of text with interactive input and history editing.
                      7: 
                      8:    Readline is free software: you can redistribute it and/or modify
                      9:    it under the terms of the GNU General Public License as published by
                     10:    the Free Software Foundation, either version 3 of the License, or
                     11:    (at your option) any later version.
                     12: 
                     13:    Readline is distributed in the hope that it will be useful,
                     14:    but WITHOUT ANY WARRANTY; without even the implied warranty of
                     15:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     16:    GNU General Public License for more details.
                     17: 
                     18:    You should have received a copy of the GNU General Public License
                     19:    along with Readline.  If not, see <http://www.gnu.org/licenses/>.
                     20: */
                     21: 
                     22: #if defined (HAVE_CONFIG_H)
                     23: #  include <config.h>
                     24: #endif
                     25: 
                     26: #if defined (HAVE_UNISTD_H)
                     27: #  ifdef _MINIX
                     28: #    include <sys/types.h>
                     29: #  endif
                     30: #  include <unistd.h>
                     31: #endif
                     32: 
                     33: #if defined (HAVE_STRING_H)
                     34: #  include <string.h>
                     35: #else /* !HAVE_STRING_H */
                     36: #  include <strings.h>
                     37: #endif /* !HAVE_STRING_H */  
                     38: 
                     39: #if defined (HAVE_STDLIB_H)
                     40: #  include <stdlib.h>
                     41: #else
                     42: #  include "ansi_stdlib.h"
                     43: #endif /* HAVE_STDLIB_H */
                     44: 
                     45: #include <sys/types.h>
                     46: #if defined (HAVE_PWD_H)
                     47: #include <pwd.h>
                     48: #endif
                     49: 
                     50: #include "tilde.h"
                     51: 
                     52: #if defined (TEST) || defined (STATIC_MALLOC)
                     53: static void *xmalloc (), *xrealloc ();
                     54: #else
                     55: #  include "xmalloc.h"
                     56: #endif /* TEST || STATIC_MALLOC */
                     57: 
                     58: #if !defined (HAVE_GETPW_DECLS)
                     59: #  if defined (HAVE_GETPWUID)
1.1.1.2 ! misho      60: extern struct passwd *getpwuid (uid_t);
1.1       misho      61: #  endif
                     62: #  if defined (HAVE_GETPWNAM)
1.1.1.2 ! misho      63: extern struct passwd *getpwnam (const char *);
1.1       misho      64: #  endif
                     65: #endif /* !HAVE_GETPW_DECLS */
                     66: 
                     67: #if !defined (savestring)
                     68: #define savestring(x) strcpy ((char *)xmalloc (1 + strlen (x)), (x))
                     69: #endif /* !savestring */
                     70: 
                     71: #if !defined (NULL)
                     72: #  if defined (__STDC__)
                     73: #    define NULL ((void *) 0)
                     74: #  else
                     75: #    define NULL 0x0
                     76: #  endif /* !__STDC__ */
                     77: #endif /* !NULL */
                     78: 
                     79: /* If being compiled as part of bash, these will be satisfied from
                     80:    variables.o.  If being compiled as part of readline, they will
                     81:    be satisfied from shell.o. */
1.1.1.2 ! misho      82: extern char *sh_get_home_dir (void);
        !            83: extern char *sh_get_env_value (const char *);
1.1       misho      84: 
                     85: /* The default value of tilde_additional_prefixes.  This is set to
                     86:    whitespace preceding a tilde so that simple programs which do not
                     87:    perform any word separation get desired behaviour. */
                     88: static const char *default_prefixes[] =
                     89:   { " ~", "\t~", (const char *)NULL };
                     90: 
                     91: /* The default value of tilde_additional_suffixes.  This is set to
                     92:    whitespace or newline so that simple programs which do not
                     93:    perform any word separation get desired behaviour. */
                     94: static const char *default_suffixes[] =
                     95:   { " ", "\n", (const char *)NULL };
                     96: 
                     97: /* If non-null, this contains the address of a function that the application
                     98:    wants called before trying the standard tilde expansions.  The function
                     99:    is called with the text sans tilde, and returns a malloc()'ed string
                    100:    which is the expansion, or a NULL pointer if the expansion fails. */
                    101: tilde_hook_func_t *tilde_expansion_preexpansion_hook = (tilde_hook_func_t *)NULL;
                    102: 
                    103: /* If non-null, this contains the address of a function to call if the
                    104:    standard meaning for expanding a tilde fails.  The function is called
                    105:    with the text (sans tilde, as in "foo"), and returns a malloc()'ed string
                    106:    which is the expansion, or a NULL pointer if there is no expansion. */
                    107: tilde_hook_func_t *tilde_expansion_failure_hook = (tilde_hook_func_t *)NULL;
                    108: 
                    109: /* When non-null, this is a NULL terminated array of strings which
                    110:    are duplicates for a tilde prefix.  Bash uses this to expand
                    111:    `=~' and `:~'. */
                    112: char **tilde_additional_prefixes = (char **)default_prefixes;
                    113: 
                    114: /* When non-null, this is a NULL terminated array of strings which match
                    115:    the end of a username, instead of just "/".  Bash sets this to
                    116:    `:' and `=~'. */
                    117: char **tilde_additional_suffixes = (char **)default_suffixes;
                    118: 
1.1.1.2 ! misho     119: static int tilde_find_prefix (const char *, int *);
        !           120: static int tilde_find_suffix (const char *);
        !           121: static char *isolate_tilde_prefix (const char *, int *);
        !           122: static char *glue_prefix_and_suffix (char *, const char *, int);
1.1       misho     123: 
                    124: /* Find the start of a tilde expansion in STRING, and return the index of
                    125:    the tilde which starts the expansion.  Place the length of the text
                    126:    which identified this tilde starter in LEN, excluding the tilde itself. */
                    127: static int
1.1.1.2 ! misho     128: tilde_find_prefix (const char *string, int *len)
1.1       misho     129: {
                    130:   register int i, j, string_len;
                    131:   register char **prefixes;
                    132: 
                    133:   prefixes = tilde_additional_prefixes;
                    134: 
                    135:   string_len = strlen (string);
                    136:   *len = 0;
                    137: 
                    138:   if (*string == '\0' || *string == '~')
                    139:     return (0);
                    140: 
                    141:   if (prefixes)
                    142:     {
                    143:       for (i = 0; i < string_len; i++)
                    144:        {
                    145:          for (j = 0; prefixes[j]; j++)
                    146:            {
                    147:              if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
                    148:                {
                    149:                  *len = strlen (prefixes[j]) - 1;
                    150:                  return (i + *len);
                    151:                }
                    152:            }
                    153:        }
                    154:     }
                    155:   return (string_len);
                    156: }
                    157: 
                    158: /* Find the end of a tilde expansion in STRING, and return the index of
                    159:    the character which ends the tilde definition.  */
                    160: static int
1.1.1.2 ! misho     161: tilde_find_suffix (const char *string)
1.1       misho     162: {
                    163:   register int i, j, string_len;
                    164:   register char **suffixes;
                    165: 
                    166:   suffixes = tilde_additional_suffixes;
                    167:   string_len = strlen (string);
                    168: 
                    169:   for (i = 0; i < string_len; i++)
                    170:     {
                    171: #if defined (__MSDOS__)
                    172:       if (string[i] == '/' || string[i] == '\\' /* || !string[i] */)
                    173: #else
                    174:       if (string[i] == '/' /* || !string[i] */)
                    175: #endif
                    176:        break;
                    177: 
                    178:       for (j = 0; suffixes && suffixes[j]; j++)
                    179:        {
                    180:          if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
                    181:            return (i);
                    182:        }
                    183:     }
                    184:   return (i);
                    185: }
                    186: 
                    187: /* Return a new string which is the result of tilde expanding STRING. */
                    188: char *
1.1.1.2 ! misho     189: tilde_expand (const char *string)
1.1       misho     190: {
                    191:   char *result;
                    192:   int result_size, result_index;
                    193: 
                    194:   result_index = result_size = 0;
                    195:   if (result = strchr (string, '~'))
                    196:     result = (char *)xmalloc (result_size = (strlen (string) + 16));
                    197:   else
                    198:     result = (char *)xmalloc (result_size = (strlen (string) + 1));
                    199: 
                    200:   /* Scan through STRING expanding tildes as we come to them. */
                    201:   while (1)
                    202:     {
                    203:       register int start, end;
                    204:       char *tilde_word, *expansion;
                    205:       int len;
                    206: 
                    207:       /* Make START point to the tilde which starts the expansion. */
                    208:       start = tilde_find_prefix (string, &len);
                    209: 
                    210:       /* Copy the skipped text into the result. */
                    211:       if ((result_index + start + 1) > result_size)
                    212:        result = (char *)xrealloc (result, 1 + (result_size += (start + 20)));
                    213: 
                    214:       strncpy (result + result_index, string, start);
                    215:       result_index += start;
                    216: 
                    217:       /* Advance STRING to the starting tilde. */
                    218:       string += start;
                    219: 
                    220:       /* Make END be the index of one after the last character of the
                    221:         username. */
                    222:       end = tilde_find_suffix (string);
                    223: 
                    224:       /* If both START and END are zero, we are all done. */
                    225:       if (!start && !end)
                    226:        break;
                    227: 
                    228:       /* Expand the entire tilde word, and copy it into RESULT. */
                    229:       tilde_word = (char *)xmalloc (1 + end);
                    230:       strncpy (tilde_word, string, end);
                    231:       tilde_word[end] = '\0';
                    232:       string += end;
                    233: 
                    234:       expansion = tilde_expand_word (tilde_word);
1.1.1.2 ! misho     235: 
        !           236:       if (expansion == 0)
        !           237:        expansion = tilde_word;
        !           238:       else
        !           239:        xfree (tilde_word);     
1.1       misho     240: 
                    241:       len = strlen (expansion);
                    242: #ifdef __CYGWIN__
                    243:       /* Fix for Cygwin to prevent ~user/xxx from expanding to //xxx when
                    244:         $HOME for `user' is /.  On cygwin, // denotes a network drive. */
                    245:       if (len > 1 || *expansion != '/' || *string != '/')
                    246: #endif
                    247:        {
                    248:          if ((result_index + len + 1) > result_size)
                    249:            result = (char *)xrealloc (result, 1 + (result_size += (len + 20)));
                    250: 
                    251:          strcpy (result + result_index, expansion);
                    252:          result_index += len;
                    253:        }
                    254:       xfree (expansion);
                    255:     }
                    256: 
                    257:   result[result_index] = '\0';
                    258: 
                    259:   return (result);
                    260: }
                    261: 
                    262: /* Take FNAME and return the tilde prefix we want expanded.  If LENP is
                    263:    non-null, the index of the end of the prefix into FNAME is returned in
                    264:    the location it points to. */
                    265: static char *
1.1.1.2 ! misho     266: isolate_tilde_prefix (const char *fname, int *lenp)
1.1       misho     267: {
                    268:   char *ret;
                    269:   int i;
                    270: 
                    271:   ret = (char *)xmalloc (strlen (fname));
                    272: #if defined (__MSDOS__)
                    273:   for (i = 1; fname[i] && fname[i] != '/' && fname[i] != '\\'; i++)
                    274: #else
                    275:   for (i = 1; fname[i] && fname[i] != '/'; i++)
                    276: #endif
                    277:     ret[i - 1] = fname[i];
                    278:   ret[i - 1] = '\0';
                    279:   if (lenp)
                    280:     *lenp = i;
                    281:   return ret;
                    282: }
                    283: 
                    284: #if 0
                    285: /* Public function to scan a string (FNAME) beginning with a tilde and find
                    286:    the portion of the string that should be passed to the tilde expansion
                    287:    function.  Right now, it just calls tilde_find_suffix and allocates new
                    288:    memory, but it can be expanded to do different things later. */
                    289: char *
1.1.1.2 ! misho     290: tilde_find_word (const char *fname, int flags, int *lenp)
1.1       misho     291: {
                    292:   int x;
                    293:   char *r;
                    294: 
                    295:   x = tilde_find_suffix (fname);
                    296:   if (x == 0)
                    297:     {
                    298:       r = savestring (fname);
                    299:       if (lenp)
                    300:        *lenp = 0;
                    301:     }
                    302:   else
                    303:     {
                    304:       r = (char *)xmalloc (1 + x);
                    305:       strncpy (r, fname, x);
                    306:       r[x] = '\0';
                    307:       if (lenp)
                    308:        *lenp = x;
                    309:     }
                    310: 
                    311:   return r;
                    312: }
                    313: #endif
                    314: 
                    315: /* Return a string that is PREFIX concatenated with SUFFIX starting at
                    316:    SUFFIND. */
                    317: static char *
1.1.1.2 ! misho     318: glue_prefix_and_suffix (char *prefix, const char *suffix, int suffind)
1.1       misho     319: {
                    320:   char *ret;
                    321:   int plen, slen;
                    322: 
                    323:   plen = (prefix && *prefix) ? strlen (prefix) : 0;
                    324:   slen = strlen (suffix + suffind);
                    325:   ret = (char *)xmalloc (plen + slen + 1);
                    326:   if (plen)
                    327:     strcpy (ret, prefix);
                    328:   strcpy (ret + plen, suffix + suffind);
                    329:   return ret;
                    330: }
                    331: 
                    332: /* Do the work of tilde expansion on FILENAME.  FILENAME starts with a
                    333:    tilde.  If there is no expansion, call tilde_expansion_failure_hook.
                    334:    This always returns a newly-allocated string, never static storage. */
                    335: char *
1.1.1.2 ! misho     336: tilde_expand_word (const char *filename)
1.1       misho     337: {
                    338:   char *dirname, *expansion, *username;
                    339:   int user_len;
                    340:   struct passwd *user_entry;
                    341: 
                    342:   if (filename == 0)
                    343:     return ((char *)NULL);
                    344: 
                    345:   if (*filename != '~')
                    346:     return (savestring (filename));
                    347: 
                    348:   /* A leading `~/' or a bare `~' is *always* translated to the value of
                    349:      $HOME or the home directory of the current user, regardless of any
                    350:      preexpansion hook. */
                    351:   if (filename[1] == '\0' || filename[1] == '/')
                    352:     {
                    353:       /* Prefix $HOME to the rest of the string. */
                    354:       expansion = sh_get_env_value ("HOME");
1.1.1.2 ! misho     355: #if defined (_WIN32)
        !           356:       if (expansion == 0)
        !           357:        expansion = sh_get_env_value ("APPDATA");
        !           358: #endif
1.1       misho     359: 
                    360:       /* If there is no HOME variable, look up the directory in
                    361:         the password database. */
                    362:       if (expansion == 0)
                    363:        expansion = sh_get_home_dir ();
                    364: 
                    365:       return (glue_prefix_and_suffix (expansion, filename, 1));
                    366:     }
                    367: 
                    368:   username = isolate_tilde_prefix (filename, &user_len);
                    369: 
                    370:   if (tilde_expansion_preexpansion_hook)
                    371:     {
                    372:       expansion = (*tilde_expansion_preexpansion_hook) (username);
                    373:       if (expansion)
                    374:        {
                    375:          dirname = glue_prefix_and_suffix (expansion, filename, user_len);
                    376:          xfree (username);
                    377:          xfree (expansion);
                    378:          return (dirname);
                    379:        }
                    380:     }
                    381: 
                    382:   /* No preexpansion hook, or the preexpansion hook failed.  Look in the
                    383:      password database. */
                    384:   dirname = (char *)NULL;
                    385: #if defined (HAVE_GETPWNAM)
                    386:   user_entry = getpwnam (username);
                    387: #else
                    388:   user_entry = 0;
                    389: #endif
                    390:   if (user_entry == 0)
                    391:     {
                    392:       /* If the calling program has a special syntax for expanding tildes,
                    393:         and we couldn't find a standard expansion, then let them try. */
                    394:       if (tilde_expansion_failure_hook)
                    395:        {
                    396:          expansion = (*tilde_expansion_failure_hook) (username);
                    397:          if (expansion)
                    398:            {
                    399:              dirname = glue_prefix_and_suffix (expansion, filename, user_len);
                    400:              xfree (expansion);
                    401:            }
                    402:        }
                    403:       /* If we don't have a failure hook, or if the failure hook did not
                    404:         expand the tilde, return a copy of what we were passed. */
                    405:       if (dirname == 0)
                    406:        dirname = savestring (filename);
                    407:     }
                    408: #if defined (HAVE_GETPWENT)
                    409:   else
                    410:     dirname = glue_prefix_and_suffix (user_entry->pw_dir, filename, user_len);
                    411: #endif
                    412: 
                    413:   xfree (username);
                    414: #if defined (HAVE_GETPWENT)
                    415:   endpwent ();
                    416: #endif
                    417:   return (dirname);
                    418: }
                    419: 
                    420: 
                    421: #if defined (TEST)
                    422: #undef NULL
                    423: #include <stdio.h>
                    424: 
1.1.1.2 ! misho     425: main (int argc, char **argv)
1.1       misho     426: {
                    427:   char *result, line[512];
                    428:   int done = 0;
                    429: 
                    430:   while (!done)
                    431:     {
                    432:       printf ("~expand: ");
                    433:       fflush (stdout);
                    434: 
                    435:       if (!gets (line))
                    436:        strcpy (line, "done");
                    437: 
                    438:       if ((strcmp (line, "done") == 0) ||
                    439:          (strcmp (line, "quit") == 0) ||
                    440:          (strcmp (line, "exit") == 0))
                    441:        {
                    442:          done = 1;
                    443:          break;
                    444:        }
                    445: 
                    446:       result = tilde_expand (line);
                    447:       printf ("  --> %s\n", result);
                    448:       free (result);
                    449:     }
                    450:   exit (0);
                    451: }
                    452: 
1.1.1.2 ! misho     453: static void memory_error_and_abort (void);
1.1       misho     454: 
                    455: static void *
1.1.1.2 ! misho     456: xmalloc (size_t bytes)
1.1       misho     457: {
                    458:   void *temp = (char *)malloc (bytes);
                    459: 
                    460:   if (!temp)
                    461:     memory_error_and_abort ();
                    462:   return (temp);
                    463: }
                    464: 
                    465: static void *
1.1.1.2 ! misho     466: xrealloc (void *pointer, int bytes)
1.1       misho     467: {
                    468:   void *temp;
                    469: 
                    470:   if (!pointer)
                    471:     temp = malloc (bytes);
                    472:   else
                    473:     temp = realloc (pointer, bytes);
                    474: 
                    475:   if (!temp)
                    476:     memory_error_and_abort ();
                    477: 
                    478:   return (temp);
                    479: }
                    480: 
                    481: static void
1.1.1.2 ! misho     482: memory_error_and_abort (void)
1.1       misho     483: {
                    484:   fprintf (stderr, "readline: out of virtual memory\n");
                    485:   abort ();
                    486: }
                    487: 
                    488: /*
                    489:  * Local variables:
                    490:  * compile-command: "gcc -g -DTEST -o tilde tilde.c"
                    491:  * end:
                    492:  */
                    493: #endif /* TEST */

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