3 * Choose and check temporary directories
5 * (c) 1999 Mark Wooding
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of chkpath.
12 * chkpath is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * chkpath is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with chkpath; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
37 #include <sys/types.h>
43 #include <mLib/alloc.h>
44 #include <mLib/dstr.h>
45 #include <mLib/macros.h>
46 #include <mLib/mdwopt.h>
47 #include <mLib/quis.h>
48 #include <mLib/report.h>
50 #include "checkpath.h"
53 /*----- Static variables --------------------------------------------------*/
56 static struct checkpath cp
;
57 static struct passwd
*pw
;
59 /*----- Main code ---------------------------------------------------------*/
63 * Arguments: @const char *p@ = pathname to check
64 * @int *f@ = try-to-create flag
66 * Returns: Nonzero if the directory is OK
68 * Use: Ensures that a directory is OK. If @f@ is a real pointer,
69 * and @*f@ is set, then try to create the directory.
72 static void complain(const char *p
, const char *msg
, int err
)
76 if (!cp
.cp_verbose
) return;
77 dstr_putf(&d
, "Path: %s: %s", p
, msg
);
78 if (err
) dstr_putf(&d
, ": %s", strerror(err
));
83 static int ok(const char *p
, int *f
)
87 /* --- Read the directory status --- */
91 /* --- Maybe create it if it doesn't exist --- */
93 if (errno
!= ENOENT
|| !f
|| !*f
) {
94 complain(p
, "can't stat", errno
);
98 complain(p
, "can't create", errno
);
103 /* --- Now read the new status --- *
105 * This fixes a race condition between the previous @lstat@ call and
110 complain(p
, "can't stat after creating", errno
);
115 /* --- Make sure the directory is good --- *
117 * It must be a genuine directory (not a link); it must be readable
118 * and writable only by its owner, and that owner must be me.
121 if (!S_ISDIR(st
.st_mode
))
122 complain(p
, "not a directory", 0);
123 else if (st
.st_uid
!= me
)
124 complain(p
, "not owner", 0);
125 else if ((st
.st_mode
& 0777) != 0700)
126 complain(p
, "non-owner access permitted", 0);
132 /* --- @trytmp@ --- *
134 * Arguments: @const char *parent@ = parent directory name
135 * @const char *base@ = subdirectory base name
137 * Returns: Pointer to directory name, or null. (String needs freeing.)
139 * Use: Tries to find or create an appropriate temporary directory.
142 static char *trytmp(const char *parent
, const char *base
)
144 static char c
[] = { "0123456789"
145 "abcdefghijklmnopqrstuvwxyz"
146 "ABCDEFGHIJKLMNOPQRSTUVWXYZ" };
152 /* --- Make sure the parent directory is sane --- *
154 * Must make sure that all the lead-up to the temporary directory is safe.
155 * Otherwise other people can play with symlinks or rename directories
156 * after I've done all this careful work to make the endpoint directory
160 if (checkpath(parent
, &cp
))
163 /* --- See whether the trivial version will work --- */
165 dstr_putf(&d
, "%s/%s", parent
, base
);
166 if (ok(d
.buf
, &createflag
))
169 /* --- Now try with various suffixes --- */
175 for (p
= c
; *p
; p
++) {
178 if (ok(d
.buf
, &createflag
))
180 for (q
= c
; *q
; q
++) {
183 if (ok(d
.buf
, &createflag
))
199 /* --- @fullcheck@ --- *
201 * Arguments: @const char *p@ = pointer to path to check
203 * Returns: Zero if it's a bad directory.
205 * Use: Runs a thorough check on a directory.
208 static int fullcheck(const char *p
)
209 { return (checkpath(p
, &cp
) == 0 && ok(p
, 0)); }
211 /* --- @goodtmp@ --- *
215 * Returns: Pointer to a known-good secure temporary directory, or
218 * Use: Finds a good place to store temporary files.
221 static char *goodtmp(void)
225 /* --- First of all, try the user's current choice --- */
227 if ((p
= getenv("TMPDIR")) != 0 && fullcheck(p
))
230 /* --- Try making a directory in `/tmp' --- */
232 if ((q
= trytmp("/tmp", pw
->pw_name
)) != 0)
235 /* --- That failed: try a directory in the user's home --- */
237 if ((q
= trytmp(pw
->pw_dir
, "tmp")) != 0)
240 /* --- Still no joy: give up --- *
242 * To be fair, if the user can't find a safe place in his own home
243 * directory then he's pretty stuffed.
249 /* --- @report@ --- */
251 static void report(unsigned what
, int verbose
,
252 const char *p
, const char *msg
,
256 /* --- @usage@ --- */
258 static void usage(FILE *fp
)
259 { fprintf(fp
, "Usage: %s [-bcv] [-g NAME] [-C PATH]\n", QUIS
); }
261 /* --- @version@ --- */
263 static void version(FILE *fp
)
264 { fprintf(fp
, "%s version %s\n", QUIS
, VERSION
); }
268 static void help(FILE *fp
)
274 Sets a suitable and secure temporary directory, or checks that a given\n\
275 directory is suitable for use with temporary files. A directory is\n\
276 considered good for a particular user if it's readable and writable only\n\
277 by that user, and if all its parents are modifiable only by the user or\n\
280 Options supported:\n\
282 -h, --help Display this help text.\n\
283 -V, --version Display the program's version number.\n\
284 -u, --usage Display a terse usage summary.\n\
286 -b, --bourne Output a `TMPDIR' setting for Bourne shell users.\n\
287 -c, --cshell Output a `TMPDIR' setting for C shell users.\n\
288 -v, --verbose Report problems to standard error.\n\
289 -g, --group NAME Trust group NAME to be honest and true.\n\
290 -C, --check PATH Check whether PATH is good, setting exit status.\n\
292 The default action is to examine the caller's shell and output a suitable\n\
293 setting for that shell type.\n\
300 * Arguments: @int argc@ = number of command line arguments
301 * @char *argv[]@ = the actual argument strings
303 * Returns: Zero if all went well, else nonzero.
305 * Use: Performs helpful operations on temporary directories.
308 int main(int argc
, char *argv
[])
320 /* --- Initialize variables --- */
323 me
= cp
.cp_uid
= geteuid();
324 cp
.cp_what
= (CP_WRWORLD
| CP_WROTHGRP
| CP_WROTHUSR
|
325 CP_STICKYOK
| CP_REPORT
| CP_ERROR
);
327 cp
.cp_report
= report
;
328 cp
.cp_gids
= 0; /* ignore group membership */
331 die(1, "you don't exist");
333 /* --- Parse arguments --- */
336 static struct option opts
[] = {
337 { "help", 0, 0, 'h' },
338 { "version", 0, 0, 'V' },
339 { "usage", 0, 0, 'u' },
340 { "bourne", 0, 0, 'b' },
341 { "cshell", 0, 0, 'c' },
342 { "check", OPTF_ARGREQ
, 0, 'C' },
343 { "verify", OPTF_ARGREQ
, 0, 'C' },
344 { "verbose", 0, 0, 'v' },
345 { "trust-groups", 0, 0, 't' },
346 { "group", OPTF_ARGREQ
, 0, 'g' },
349 int i
= mdwopt(argc
, argv
, "hVu" "bcvtg:C:", opts
, 0, 0, 0);
370 return (!fullcheck(optarg
));
373 allowgroup(&cp
, optarg
);
384 if (duff
|| optind
!= argc
) {
389 /* --- Choose a shell --- */
392 if (!(p
= getenv("SHELL")))
394 if (strstr(p
, "csh"))
400 /* --- Start the checking --- */
402 if ((p
= goodtmp()) == 0)
403 die(1, "no good tmp directory");
406 printf("TMPDIR=\"%s\"; export TMPDIR\n", p
);
409 printf("setenv TMPDIR \"%s\"\n", p
);
416 /*----- That's all, folks -------------------------------------------------*/