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60b6c79c MD |
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/wait.h> | |
26 | #include <sys/types.h> | |
27 | #include <sys/stat.h> | |
28 | #include <unistd.h> | |
29 | #include <fcntl.h> | |
30 | ||
31 | #include <lttngerr.h> | |
32 | ||
33 | struct mkdir_data { | |
34 | const char *path; | |
35 | mode_t mode; | |
36 | }; | |
37 | ||
38 | struct open_data { | |
39 | const char *path; | |
40 | int flags; | |
41 | mode_t mode; | |
42 | }; | |
43 | ||
44 | /* | |
45 | * Create recursively directory using the FULL path. | |
46 | */ | |
47 | static | |
48 | int _mkdir_recursive(void *_data) | |
49 | { | |
50 | struct mkdir_data *data = _data; | |
51 | const char *path; | |
52 | char *p, tmp[PATH_MAX]; | |
53 | struct stat statbuf; | |
54 | mode_t mode; | |
55 | size_t len; | |
56 | int ret; | |
57 | ||
58 | path = data->path; | |
59 | mode = data->mode; | |
60 | ||
61 | ret = snprintf(tmp, sizeof(tmp), "%s", path); | |
62 | if (ret < 0) { | |
63 | PERROR("snprintf mkdir"); | |
64 | goto error; | |
65 | } | |
66 | ||
67 | len = ret; | |
68 | if (tmp[len - 1] == '/') { | |
69 | tmp[len - 1] = 0; | |
70 | } | |
71 | ||
72 | for (p = tmp + 1; *p; p++) { | |
73 | if (*p == '/') { | |
74 | *p = 0; | |
75 | ret = stat(tmp, &statbuf); | |
76 | if (ret < 0) { | |
77 | ret = mkdir(tmp, mode); | |
78 | if (ret < 0) { | |
79 | if (!(errno == EEXIST)) { | |
80 | PERROR("mkdir recursive"); | |
81 | ret = -errno; | |
82 | goto error; | |
83 | } | |
84 | } | |
85 | } | |
86 | *p = '/'; | |
87 | } | |
88 | } | |
89 | ||
90 | ret = mkdir(tmp, mode); | |
91 | if (ret < 0) { | |
92 | if (!(errno == EEXIST)) { | |
93 | PERROR("mkdir recursive last piece"); | |
94 | ret = -errno; | |
95 | } else { | |
96 | ret = 0; | |
97 | } | |
98 | } | |
99 | ||
100 | error: | |
101 | return ret; | |
102 | } | |
103 | ||
104 | static | |
105 | int _mkdir(void *_data) | |
106 | { | |
107 | struct mkdir_data *data = _data; | |
108 | return mkdir(data->path, data->mode); | |
109 | } | |
110 | ||
111 | static | |
112 | int _open(void *_data) | |
113 | { | |
114 | struct open_data *data = _data; | |
115 | return open(data->path, data->flags, data->mode); | |
116 | } | |
117 | ||
118 | static | |
119 | int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid) | |
120 | { | |
121 | int ret = 0; | |
122 | pid_t pid; | |
123 | ||
124 | /* | |
125 | * If we are non-root, we can only deal with our own uid. | |
126 | */ | |
127 | if (geteuid() != 0) { | |
128 | if (uid != geteuid()) { | |
129 | ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)", | |
130 | uid, geteuid()); | |
131 | return -EPERM; | |
132 | } | |
133 | return (*cmd)(data); | |
134 | } | |
135 | ||
136 | pid = fork(); | |
137 | if (pid > 0) { | |
138 | int status; | |
139 | ||
140 | /* | |
141 | * Parent: wait for child to return, in which case the | |
142 | * shared memory map will have been created. | |
143 | */ | |
144 | pid = wait(&status); | |
145 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { | |
146 | ret = -1; | |
147 | goto end; | |
148 | } | |
149 | goto end; | |
150 | } else if (pid == 0) { | |
151 | /* Child */ | |
152 | setegid(gid); | |
153 | if (ret < 0) { | |
154 | perror("setegid"); | |
155 | exit(EXIT_FAILURE); | |
156 | } | |
157 | ret = seteuid(uid); | |
158 | if (ret < 0) { | |
159 | perror("seteuid"); | |
160 | exit(EXIT_FAILURE); | |
161 | } | |
162 | umask(0); | |
163 | ret = (*cmd)(data); | |
164 | if (!ret) | |
165 | exit(EXIT_SUCCESS); | |
166 | else | |
167 | exit(EXIT_FAILURE); | |
168 | } else { | |
169 | return -1; | |
170 | } | |
171 | end: | |
172 | return ret; | |
173 | } | |
174 | ||
175 | int mkdir_recursive_run_as(const char *path, mode_t mode, uid_t uid, gid_t gid) | |
176 | { | |
177 | struct mkdir_data data; | |
178 | ||
179 | DBG3("mkdir() recursive %s with mode %d for uid %d and gid %d", | |
180 | path, mode, uid, gid); | |
181 | data.path = path; | |
182 | data.mode = mode; | |
183 | return run_as(_mkdir_recursive, &data, uid, gid); | |
184 | } | |
185 | ||
186 | int mkdir_run_as(const char *path, mode_t mode, uid_t uid, gid_t gid) | |
187 | { | |
188 | struct mkdir_data data; | |
189 | ||
190 | DBG3("mkdir() %s with mode %d for uid %d and gid %d", | |
191 | path, mode, uid, gid); | |
192 | data.path = path; | |
193 | data.mode = mode; | |
194 | return run_as(_mkdir, &data, uid, gid); | |
195 | } | |
196 | ||
197 | /* | |
198 | * Note: open_run_as is currently not working. We'd need to pass the fd | |
199 | * opened in the child to the parent. | |
200 | */ | |
201 | int open_run_as(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid) | |
202 | { | |
203 | //struct open_data data; | |
204 | int fd, ret; | |
205 | ||
206 | DBG3("open() %s with flags %d mode %d for uid %d and gid %d", | |
207 | path, flags, mode, uid, gid); | |
208 | fd = open(path, flags, mode); | |
209 | if (fd < 0) { | |
210 | perror("open"); | |
211 | return fd; | |
212 | } | |
213 | ret = fchown(fd, uid, gid); | |
214 | if (ret < 0) { | |
215 | perror("fchown"); | |
216 | close(fd); | |
217 | return ret; | |
218 | } | |
219 | return fd; | |
220 | #if 0 | |
221 | data.path = path; | |
222 | data.flags = flags; | |
223 | data.mode = mode; | |
224 | return run_as(_open, &data, uid, gid); | |
225 | #endif | |
226 | } |