lttng-sessiond/utils.c

   1 /*
   2  * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; only version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  16  * Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <errno.h>
  21 #include <limits.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <unistd.h>
  28
  29 #include <lttngerr.h>
  30
  31 #include "utils.h"
  32
  33 /*
  34  * Write to writable pipe used to notify a thread.
  35  */
  36 int notify_thread_pipe(int wpipe)
  37 {
  38         int ret;
  39
  40         ret = write(wpipe, "!", 1);
  41         if (ret < 0) {
  42                 PERROR("write poll pipe");
  43         }
  44
  45         return ret;
  46 }
  47
  48 /*
  49  * Return pointer to home directory path using the env variable HOME.
  50  *
  51  * No home, NULL is returned.
  52  */
  53 const char *get_home_dir(void)
  54 {
  55         return ((const char *) getenv("HOME"));
  56 }
  57
  58 /*
  59  * Create recursively directory using the FULL path.
  60  */
  61 int mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid)
  62 {
  63         int ret;
  64         char *p, tmp[PATH_MAX];
  65         size_t len;
  66         mode_t old_umask;
  67
  68         DBG3("mkdir() recursive %s with mode %d for uid %d and gid %d", path, mode,
  69                         uid, gid);
  70
  71         ret = snprintf(tmp, sizeof(tmp), "%s", path);
  72         if (ret < 0) {
  73                 PERROR("snprintf mkdir");
  74                 goto error;
  75         }
  76
  77         len = ret;
  78         if (tmp[len - 1] == '/') {
  79                 tmp[len - 1] = 0;
  80         }
  81
  82         old_umask = umask(0);
  83         for (p = tmp + 1; *p; p++) {
  84                 if (*p == '/') {
  85                         *p = 0;
  86                         ret = mkdir(tmp, mode);
  87                         if (ret < 0) {
  88                                 if (!(errno == EEXIST)) {
  89                                         PERROR("mkdir recursive");
  90                                         ret = -errno;
  91                                         goto umask_error;
  92                                 }
  93                         } else if (ret == 0) {
  94                                 /*
  95                                  * We created the directory. Set its ownership to the
  96                                  * user/group specified.
  97                                  */
  98                                 ret = chown(tmp, uid, gid);
  99                                 if (ret < 0) {
 100                                         PERROR("chown in mkdir recursive");
 101                                         ret = -errno;
 102                                         goto umask_error;
 103                                 }
 104                         }
 105                         *p = '/';
 106                 }
 107         }
 108
 109         ret = mkdir(tmp, mode);
 110         if (ret < 0) {
 111                 if (!(errno == EEXIST)) {
 112                         PERROR("mkdir recursive last piece");
 113                         ret = -errno;
 114                 } else {
 115                         ret = 0;
 116                 }
 117         } else if (ret == 0) {
 118                 /*
 119                  * We created the directory. Set its ownership to the user/group
 120                  * specified.
 121                  */
 122                 ret = chown(tmp, uid, gid);
 123                 if (ret < 0) {
 124                         PERROR("chown in mkdir recursive");
 125                         ret = -errno;
 126                         goto umask_error;
 127                 }
 128         }
 129
 130 umask_error:
 131         umask(old_umask);
 132 error:
 133         return ret;
 134 }