lib/util/util_paths.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba utility functions
   4    Copyright (C) Andrew Tridgell 1992-1998
   5    Copyright (C) Jeremy Allison 2001-2007
   6    Copyright (C) Simo Sorce 2001
   7    Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2003
   8    Copyright (C) James Peach 2006
   9    Copyright (c) 2020      Andreas Schneider <asn@samba.org>
  10
  11    This program is free software; you can redistribute it and/or modify
  12    it under the terms of the GNU General Public License as published by
  13    the Free Software Foundation; either version 3 of the License, or
  14    (at your option) any later version.
  15
  16    This program is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "replace.h"
  26 #include "dynconfig/dynconfig.h"
  27 #include "lib/util/util_paths.h"
  28 #include "system/passwd.h"
  29 #include "system/filesys.h"
  30
  31 /**
  32  * @brief Returns an absolute path to a file in the Samba modules directory.
  33  *
  34  * @param name File to find, relative to MODULESDIR.
  35  *
  36  * @retval Pointer to a string containing the full path.
  37  **/
  38
  39 char *modules_path(TALLOC_CTX *mem_ctx, const char *name)
  40 {
  41         return talloc_asprintf(mem_ctx, "%s/%s", get_dyn_MODULESDIR(), name);
  42 }
  43
  44 /**
  45  * @brief Returns an absolute path to a file in the Samba data directory.
  46  *
  47  * @param name File to find, relative to CODEPAGEDIR.
  48  *
  49  * @retval Pointer to a talloc'ed string containing the full path.
  50  **/
  51
  52 char *data_path(TALLOC_CTX *mem_ctx, const char *name)
  53 {
  54         return talloc_asprintf(mem_ctx, "%s/%s", get_dyn_CODEPAGEDIR(), name);
  55 }
  56
  57 /**
  58  * @brief Returns the platform specific shared library extension.
  59  *
  60  * @retval Pointer to a const char * containing the extension.
  61  **/
  62
  63 const char *shlib_ext(void)
  64 {
  65         return get_dyn_SHLIBEXT();
  66 }
  67
  68 static char *get_user_home_dir(TALLOC_CTX *mem_ctx)
  69 {
  70         struct passwd pwd = {0};
  71         struct passwd *pwdbuf = NULL;
  72         char *buf = NULL;
  73         char *out = NULL;
  74         long int initlen;
  75         size_t len;
  76         int rc;
  77
  78         initlen = sysconf(_SC_GETPW_R_SIZE_MAX);
  79         if (initlen == -1) {
  80                 len = 1024;
  81         } else {
  82                 len = (size_t)initlen;
  83         }
  84         buf = talloc_size(mem_ctx, len);
  85         if (buf == NULL) {
  86                 return NULL;
  87         }
  88
  89         rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);
  90         while (rc == ERANGE) {
  91                 size_t newlen = 2 * len;
  92                 char *tmp = NULL;
  93                 if (newlen < len) {
  94                         /* Overflow */
  95                         goto done;
  96                 }
  97                 len = newlen;
  98                 tmp = talloc_realloc_size(mem_ctx, buf, len);
  99                 if (tmp == NULL) {
 100                         goto done;
 101                 }
 102                 buf = tmp;
 103                 rc = getpwuid_r(getuid(), &pwd, buf, len, &pwdbuf);
 104         }
 105         if (rc != 0 || pwdbuf == NULL ) {
 106                 const char *szPath = getenv("HOME");
 107                 if (szPath == NULL) {
 108                         goto done;
 109                 }
 110                 len = strnlen(szPath, PATH_MAX);
 111                 if (len >= PATH_MAX) {
 112                         goto done;
 113                 }
 114                 out = talloc_strdup(mem_ctx, szPath);
 115                 goto done;
 116         }
 117
 118         out = talloc_strdup(mem_ctx, pwd.pw_dir);
 119 done:
 120         TALLOC_FREE(buf);
 121         return out;
 122 }
 123
 124 char *path_expand_tilde(TALLOC_CTX *mem_ctx, const char *d)
 125 {
 126         char *h = NULL, *r = NULL;
 127         const char *p = NULL;
 128         struct stat sb = {0};
 129         int rc;
 130
 131         if (d[0] != '~') {
 132                 return talloc_strdup(mem_ctx, d);
 133         }
 134         d++;
 135
 136         /* handle ~user/path */
 137         p = strchr(d, '/');
 138         if (p != NULL && p > d) {
 139                 struct passwd *pw;
 140                 size_t s = p - d;
 141                 char u[128];
 142
 143                 if (s >= sizeof(u)) {
 144                         return NULL;
 145                 }
 146                 memcpy(u, d, s);
 147                 u[s] = '\0';
 148
 149                 pw = getpwnam(u);
 150                 if (pw == NULL) {
 151                         return NULL;
 152                 }
 153                 h = talloc_strdup(mem_ctx, pw->pw_dir);
 154         } else {
 155                 p = d;
 156                 h = get_user_home_dir(mem_ctx);
 157         }
 158         if (h == NULL) {
 159                 return NULL;
 160         }
 161
 162         rc = stat(h, &sb);
 163         if (rc != 0) {
 164                 TALLOC_FREE(h);
 165                 return NULL;
 166         }
 167
 168         r = talloc_asprintf(mem_ctx, "%s%s", h, p);
 169         TALLOC_FREE(h);
 170
 171         return r;
 172 }