1: /* tilde.c -- Tilde expansion code (~/foo := $HOME/foo). */
2:
3: /* Copyright (C) 1988-2009 Free Software Foundation, Inc.
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)
60: extern struct passwd *getpwuid PARAMS((uid_t));
61: # endif
62: # if defined (HAVE_GETPWNAM)
63: extern struct passwd *getpwnam PARAMS((const char *));
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. */
82: extern char *sh_get_home_dir PARAMS((void));
83: extern char *sh_get_env_value PARAMS((const char *));
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:
119: static int tilde_find_prefix PARAMS((const char *, int *));
120: static int tilde_find_suffix PARAMS((const char *));
121: static char *isolate_tilde_prefix PARAMS((const char *, int *));
122: static char *glue_prefix_and_suffix PARAMS((char *, const char *, int));
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
128: tilde_find_prefix (string, len)
129: const char *string;
130: int *len;
131: {
132: register int i, j, string_len;
133: register char **prefixes;
134:
135: prefixes = tilde_additional_prefixes;
136:
137: string_len = strlen (string);
138: *len = 0;
139:
140: if (*string == '\0' || *string == '~')
141: return (0);
142:
143: if (prefixes)
144: {
145: for (i = 0; i < string_len; i++)
146: {
147: for (j = 0; prefixes[j]; j++)
148: {
149: if (strncmp (string + i, prefixes[j], strlen (prefixes[j])) == 0)
150: {
151: *len = strlen (prefixes[j]) - 1;
152: return (i + *len);
153: }
154: }
155: }
156: }
157: return (string_len);
158: }
159:
160: /* Find the end of a tilde expansion in STRING, and return the index of
161: the character which ends the tilde definition. */
162: static int
163: tilde_find_suffix (string)
164: const char *string;
165: {
166: register int i, j, string_len;
167: register char **suffixes;
168:
169: suffixes = tilde_additional_suffixes;
170: string_len = strlen (string);
171:
172: for (i = 0; i < string_len; i++)
173: {
174: #if defined (__MSDOS__)
175: if (string[i] == '/' || string[i] == '\\' /* || !string[i] */)
176: #else
177: if (string[i] == '/' /* || !string[i] */)
178: #endif
179: break;
180:
181: for (j = 0; suffixes && suffixes[j]; j++)
182: {
183: if (strncmp (string + i, suffixes[j], strlen (suffixes[j])) == 0)
184: return (i);
185: }
186: }
187: return (i);
188: }
189:
190: /* Return a new string which is the result of tilde expanding STRING. */
191: char *
192: tilde_expand (string)
193: const char *string;
194: {
195: char *result;
196: int result_size, result_index;
197:
198: result_index = result_size = 0;
199: if (result = strchr (string, '~'))
200: result = (char *)xmalloc (result_size = (strlen (string) + 16));
201: else
202: result = (char *)xmalloc (result_size = (strlen (string) + 1));
203:
204: /* Scan through STRING expanding tildes as we come to them. */
205: while (1)
206: {
207: register int start, end;
208: char *tilde_word, *expansion;
209: int len;
210:
211: /* Make START point to the tilde which starts the expansion. */
212: start = tilde_find_prefix (string, &len);
213:
214: /* Copy the skipped text into the result. */
215: if ((result_index + start + 1) > result_size)
216: result = (char *)xrealloc (result, 1 + (result_size += (start + 20)));
217:
218: strncpy (result + result_index, string, start);
219: result_index += start;
220:
221: /* Advance STRING to the starting tilde. */
222: string += start;
223:
224: /* Make END be the index of one after the last character of the
225: username. */
226: end = tilde_find_suffix (string);
227:
228: /* If both START and END are zero, we are all done. */
229: if (!start && !end)
230: break;
231:
232: /* Expand the entire tilde word, and copy it into RESULT. */
233: tilde_word = (char *)xmalloc (1 + end);
234: strncpy (tilde_word, string, end);
235: tilde_word[end] = '\0';
236: string += end;
237:
238: expansion = tilde_expand_word (tilde_word);
239: xfree (tilde_word);
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 *
266: isolate_tilde_prefix (fname, lenp)
267: const char *fname;
268: int *lenp;
269: {
270: char *ret;
271: int i;
272:
273: ret = (char *)xmalloc (strlen (fname));
274: #if defined (__MSDOS__)
275: for (i = 1; fname[i] && fname[i] != '/' && fname[i] != '\\'; i++)
276: #else
277: for (i = 1; fname[i] && fname[i] != '/'; i++)
278: #endif
279: ret[i - 1] = fname[i];
280: ret[i - 1] = '\0';
281: if (lenp)
282: *lenp = i;
283: return ret;
284: }
285:
286: #if 0
287: /* Public function to scan a string (FNAME) beginning with a tilde and find
288: the portion of the string that should be passed to the tilde expansion
289: function. Right now, it just calls tilde_find_suffix and allocates new
290: memory, but it can be expanded to do different things later. */
291: char *
292: tilde_find_word (fname, flags, lenp)
293: const char *fname;
294: int flags, *lenp;
295: {
296: int x;
297: char *r;
298:
299: x = tilde_find_suffix (fname);
300: if (x == 0)
301: {
302: r = savestring (fname);
303: if (lenp)
304: *lenp = 0;
305: }
306: else
307: {
308: r = (char *)xmalloc (1 + x);
309: strncpy (r, fname, x);
310: r[x] = '\0';
311: if (lenp)
312: *lenp = x;
313: }
314:
315: return r;
316: }
317: #endif
318:
319: /* Return a string that is PREFIX concatenated with SUFFIX starting at
320: SUFFIND. */
321: static char *
322: glue_prefix_and_suffix (prefix, suffix, suffind)
323: char *prefix;
324: const char *suffix;
325: int suffind;
326: {
327: char *ret;
328: int plen, slen;
329:
330: plen = (prefix && *prefix) ? strlen (prefix) : 0;
331: slen = strlen (suffix + suffind);
332: ret = (char *)xmalloc (plen + slen + 1);
333: if (plen)
334: strcpy (ret, prefix);
335: strcpy (ret + plen, suffix + suffind);
336: return ret;
337: }
338:
339: /* Do the work of tilde expansion on FILENAME. FILENAME starts with a
340: tilde. If there is no expansion, call tilde_expansion_failure_hook.
341: This always returns a newly-allocated string, never static storage. */
342: char *
343: tilde_expand_word (filename)
344: const char *filename;
345: {
346: char *dirname, *expansion, *username;
347: int user_len;
348: struct passwd *user_entry;
349:
350: if (filename == 0)
351: return ((char *)NULL);
352:
353: if (*filename != '~')
354: return (savestring (filename));
355:
356: /* A leading `~/' or a bare `~' is *always* translated to the value of
357: $HOME or the home directory of the current user, regardless of any
358: preexpansion hook. */
359: if (filename[1] == '\0' || filename[1] == '/')
360: {
361: /* Prefix $HOME to the rest of the string. */
362: expansion = sh_get_env_value ("HOME");
363:
364: /* If there is no HOME variable, look up the directory in
365: the password database. */
366: if (expansion == 0)
367: expansion = sh_get_home_dir ();
368:
369: return (glue_prefix_and_suffix (expansion, filename, 1));
370: }
371:
372: username = isolate_tilde_prefix (filename, &user_len);
373:
374: if (tilde_expansion_preexpansion_hook)
375: {
376: expansion = (*tilde_expansion_preexpansion_hook) (username);
377: if (expansion)
378: {
379: dirname = glue_prefix_and_suffix (expansion, filename, user_len);
380: xfree (username);
381: xfree (expansion);
382: return (dirname);
383: }
384: }
385:
386: /* No preexpansion hook, or the preexpansion hook failed. Look in the
387: password database. */
388: dirname = (char *)NULL;
389: #if defined (HAVE_GETPWNAM)
390: user_entry = getpwnam (username);
391: #else
392: user_entry = 0;
393: #endif
394: if (user_entry == 0)
395: {
396: /* If the calling program has a special syntax for expanding tildes,
397: and we couldn't find a standard expansion, then let them try. */
398: if (tilde_expansion_failure_hook)
399: {
400: expansion = (*tilde_expansion_failure_hook) (username);
401: if (expansion)
402: {
403: dirname = glue_prefix_and_suffix (expansion, filename, user_len);
404: xfree (expansion);
405: }
406: }
407: /* If we don't have a failure hook, or if the failure hook did not
408: expand the tilde, return a copy of what we were passed. */
409: if (dirname == 0)
410: dirname = savestring (filename);
411: }
412: #if defined (HAVE_GETPWENT)
413: else
414: dirname = glue_prefix_and_suffix (user_entry->pw_dir, filename, user_len);
415: #endif
416:
417: xfree (username);
418: #if defined (HAVE_GETPWENT)
419: endpwent ();
420: #endif
421: return (dirname);
422: }
423:
424:
425: #if defined (TEST)
426: #undef NULL
427: #include <stdio.h>
428:
429: main (argc, argv)
430: int argc;
431: char **argv;
432: {
433: char *result, line[512];
434: int done = 0;
435:
436: while (!done)
437: {
438: printf ("~expand: ");
439: fflush (stdout);
440:
441: if (!gets (line))
442: strcpy (line, "done");
443:
444: if ((strcmp (line, "done") == 0) ||
445: (strcmp (line, "quit") == 0) ||
446: (strcmp (line, "exit") == 0))
447: {
448: done = 1;
449: break;
450: }
451:
452: result = tilde_expand (line);
453: printf (" --> %s\n", result);
454: free (result);
455: }
456: exit (0);
457: }
458:
459: static void memory_error_and_abort ();
460:
461: static void *
462: xmalloc (bytes)
463: size_t bytes;
464: {
465: void *temp = (char *)malloc (bytes);
466:
467: if (!temp)
468: memory_error_and_abort ();
469: return (temp);
470: }
471:
472: static void *
473: xrealloc (pointer, bytes)
474: void *pointer;
475: int bytes;
476: {
477: void *temp;
478:
479: if (!pointer)
480: temp = malloc (bytes);
481: else
482: temp = realloc (pointer, bytes);
483:
484: if (!temp)
485: memory_error_and_abort ();
486:
487: return (temp);
488: }
489:
490: static void
491: memory_error_and_abort ()
492: {
493: fprintf (stderr, "readline: out of virtual memory\n");
494: abort ();
495: }
496:
497: /*
498: * Local variables:
499: * compile-command: "gcc -g -DTEST -o tilde tilde.c"
500: * end:
501: */
502: #endif /* TEST */
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