1 /*
2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
5 *
6 * As far as I am concerned, the code I have written for this software
7 * can be used freely for any purpose. Any derived versions of this
8 * software must be clearly marked as such, and if the derived work is
9 * incompatible with the protocol description in the RFC file, it must be
10 * called by a name other than "ssh" or "Secure Shell".
11 */
12 /*
13 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
14 * Use is subject to license terms.
15 */
16
17 #include "includes.h"
18 RCSID("$OpenBSD: tildexpand.c,v 1.13 2002/06/23 03:25:50 deraadt Exp $");
19
20 #include <libgen.h>
21
22 #include "xmalloc.h"
23 #include "log.h"
24 #include "tildexpand.h"
25
26 /*
27 * Expands tildes in the file name. Returns data allocated by xmalloc.
28 * Warning: this calls getpw*.
29 */
30 char *
tilde_expand_filename(const char * filename,uid_t my_uid)31 tilde_expand_filename(const char *filename, uid_t my_uid)
32 {
33 const char *cp;
34 uint_t userlen;
35 char *expanded;
36 struct passwd *pw;
37 char *pw_dir;
38 char user[100];
39 int len;
40
41 /* Return immediately if no tilde. */
42 if (filename[0] != '~')
43 return (xstrdup(filename));
44
45 /* Skip the tilde. */
46 filename++;
47
48 /* Find where the username ends. */
49 cp = strchr(filename, '/');
50 if (cp)
51 userlen = cp - filename; /* Something after username. */
52 else
53 userlen = strlen(filename); /* Nothing after username. */
54
55 /* This is the ~/xyz case with no ~username specification. */
56 if (userlen == 0)
57 pw = getpwuid(my_uid);
58 else {
59 /* Tilde refers to someone elses home directory. */
60 if (userlen > sizeof (user) - 1)
61 fatal("User name after tilde too long.");
62 memcpy(user, filename, userlen);
63 user[userlen] = 0;
64 pw = getpwnam(user);
65 }
66
67 /* Use the HOME variable now. */
68 if (pw == NULL) {
69 debug("User account's password entry not found, trying to use "
70 "the HOME variable.");
71 if ((pw_dir = getenv("HOME")) == NULL) {
72 fatal("User account's password entry not found and "
73 "the HOME variable not set.");
74 }
75 } else {
76 pw_dir = pw->pw_dir;
77 }
78
79 /* If referring to someones home directory, return it now. */
80 if (cp == NULL) {
81 /* Only home directory specified */
82 return (xstrdup(pw_dir));
83 }
84
85 /* Build a path combining the specified directory and path. */
86 len = strlen(pw_dir) + strlen(cp + 1) + 2;
87 if (len > MAXPATHLEN)
88 fatal("Home directory too long (%d > %d)", len - 1,
89 MAXPATHLEN - 1);
90
91 expanded = xmalloc(len);
92 snprintf(expanded, len, "%s%s%s", pw_dir,
93 strcmp(pw_dir, "/") ? "/" : "", cp + 1);
94 return (expanded);
95 }
96