1 /**
2 * collectd - src/exec.c
3 * Copyright (C) 2007 Florian octo Forster
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
7 * Free Software Foundation; only version 2 of the License is applicable.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 *
18 * Authors:
19 * Florian octo Forster <octo at verplant.org>
20 **/
22 #include "collectd.h"
23 #include "common.h"
24 #include "plugin.h"
25 #include "utils_cmd_putval.h"
27 #include <sys/types.h>
28 #include <pwd.h>
29 #include <signal.h>
31 #include <pthread.h>
33 /*
34 * Private data types
35 */
36 struct program_list_s;
37 typedef struct program_list_s program_list_t;
38 struct program_list_s
39 {
40 char *user;
41 char *exec;
42 int pid;
43 program_list_t *next;
44 };
46 /*
47 * Private variables
48 */
49 static const char *config_keys[] =
50 {
51 "Exec"
52 };
53 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
55 static program_list_t *pl_head = NULL;
57 /*
58 * Functions
59 */
60 static int exec_config (const char *key, const char *value)
61 {
62 if (strcasecmp ("Exec", key) == 0)
63 {
64 program_list_t *pl;
65 pl = (program_list_t *) malloc (sizeof (program_list_t));
66 if (pl == NULL)
67 return (1);
68 memset (pl, '\0', sizeof (program_list_t));
70 pl->user = strdup (value);
71 if (pl->user == NULL)
72 {
73 sfree (pl);
74 return (1);
75 }
77 pl->exec = strchr (pl->user, ' ');
78 if (pl->exec == NULL)
79 {
80 sfree (pl->user);
81 sfree (pl);
82 return (1);
83 }
84 while (*pl->exec == ' ')
85 {
86 *pl->exec = '\0';
87 pl->exec++;
88 }
90 if (*pl->exec == '\0')
91 {
92 sfree (pl->user);
93 sfree (pl);
94 return (1);
95 }
97 pl->next = pl_head;
98 pl_head = pl;
99 }
100 else
101 {
102 return (-1);
103 }
105 return (0);
106 } /* int exec_config */
108 static void exec_child (program_list_t *pl)
109 {
110 int status;
111 int uid;
112 char *arg0;
114 struct passwd *sp_ptr;
115 struct passwd sp;
116 char pwnambuf[2048];
117 char errbuf[1024];
119 sp_ptr = NULL;
120 status = getpwnam_r (pl->user, &sp, pwnambuf, sizeof (pwnambuf), &sp_ptr);
121 if (status != 0)
122 {
123 ERROR ("exec plugin: getpwnam_r failed: %s",
124 sstrerror (errno, errbuf, sizeof (errbuf)));
125 exit (-1);
126 }
127 if (sp_ptr == NULL)
128 {
129 ERROR ("exec plugin: No such user: `%s'", pl->user);
130 exit (-1);
131 }
133 uid = sp.pw_uid;
134 if (uid == 0)
135 {
136 ERROR ("exec plugin: Cowardly refusing to exec program as root.");
137 exit (-1);
138 }
140 status = setuid (uid);
141 if (status != 0)
142 {
143 ERROR ("exec plugin: setuid failed: %s",
144 sstrerror (errno, errbuf, sizeof (errbuf)));
145 exit (-1);
146 }
148 arg0 = strrchr (pl->exec, '/');
149 if (arg0 != NULL)
150 arg0++;
151 if ((arg0 == NULL) || (*arg0 == '\0'))
152 arg0 = pl->exec;
154 status = execlp (pl->exec, arg0, (char *) 0);
156 ERROR ("exec plugin: exec failed: %s",
157 sstrerror (errno, errbuf, sizeof (errbuf)));
158 exit (-1);
159 } /* void exec_child */
161 static int fork_child (program_list_t *pl)
162 {
163 int fd_pipe[2];
164 int status;
166 if (pl->pid != 0)
167 return (-1);
169 status = pipe (fd_pipe);
170 if (status != 0)
171 {
172 char errbuf[1024];
173 ERROR ("exec plugin: pipe failed: %s",
174 sstrerror (errno, errbuf, sizeof (errbuf)));
175 return (-1);
176 }
178 pl->pid = fork ();
179 if (pl->pid < 0)
180 {
181 char errbuf[1024];
182 ERROR ("exec plugin: fork failed: %s",
183 sstrerror (errno, errbuf, sizeof (errbuf)));
184 return (-1);
185 }
186 else if (pl->pid == 0)
187 {
188 close (fd_pipe[0]);
190 /* Connect the pipe to STDOUT and STDERR */
191 if (fd_pipe[1] != STDOUT_FILENO)
192 dup2 (fd_pipe[1], STDOUT_FILENO);
193 if (fd_pipe[1] != STDERR_FILENO)
194 dup2 (fd_pipe[1], STDERR_FILENO);
195 if ((fd_pipe[1] != STDOUT_FILENO) && (fd_pipe[1] != STDERR_FILENO))
196 close (fd_pipe[1]);
198 exec_child (pl);
199 /* does not return */
200 }
202 close (fd_pipe[1]);
203 return (fd_pipe[0]);
204 } /* int fork_child */
206 static int parse_line (char *buffer)
207 {
208 char *fields[256];
209 int fields_num;
211 fields[0] = "PUTVAL";
212 fields_num = strsplit (buffer, &fields[1], STATIC_ARRAY_SIZE(fields) - 1);
214 handle_putval (stdout, fields, fields_num + 1);
215 } /* int parse_line */
217 static void *exec_read_one (void *arg)
218 {
219 program_list_t *pl = (program_list_t *) arg;
220 int fd;
221 FILE *fh;
222 char buffer[1024];
224 fd = fork_child (pl);
225 if (fd < 0)
226 pthread_exit ((void *) 1);
228 assert (pl->pid != 0);
230 fh = fdopen (fd, "r");
231 if (fh == NULL)
232 {
233 char errbuf[1024];
234 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
235 sstrerror (errno, errbuf, sizeof (errbuf)));
236 kill (pl->pid, SIGTERM);
237 close (fd);
238 pthread_exit ((void *) 1);
239 }
241 while (fgets (buffer, sizeof (buffer), fh) != NULL)
242 {
243 int len;
245 len = strlen (buffer);
247 /* Remove newline from end. */
248 while ((len > 0) && ((buffer[len - 1] == '\n')
249 || (buffer[len - 1] == '\r')))
250 buffer[--len] = '\0';
252 DEBUG ("exec plugin: exec_read_one: buffer = %s", buffer);
254 parse_line (buffer);
255 } /* while (fgets) */
257 fclose (fh);
258 pl->pid = 0;
260 pthread_exit ((void *) 0);
261 return (NULL);
262 } /* void *exec_read_one */
264 static int exec_read (void)
265 {
266 program_list_t *pl;
268 for (pl = pl_head; pl != NULL; pl = pl->next)
269 {
270 pthread_t t;
271 pthread_attr_t attr;
273 if (pl->pid != 0)
274 continue;
276 pthread_attr_init (&attr);
277 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
278 pthread_create (&t, &attr, exec_read_one, (void *) pl);
279 } /* for (pl) */
281 return (0);
282 } /* int exec_read */
284 static int exec_shutdown (void)
285 {
286 program_list_t *pl;
287 program_list_t *next;
289 pl = pl_head;
290 while (pl != NULL)
291 {
292 next = pl->next;
294 if (pl->pid > 0)
295 {
296 kill (pl->pid, SIGTERM);
297 INFO ("exec plugin: Sent SIGTERM to %hu", (unsigned short int) pl->pid);
298 }
300 sfree (pl->user);
301 sfree (pl);
303 pl = next;
304 } /* while (pl) */
305 pl_head = NULL;
307 return (0);
308 } /* int exec_shutdown */
310 void module_register (void)
311 {
312 plugin_register_config ("exec", exec_config, config_keys, config_keys_num);
313 plugin_register_read ("exec", exec_read);
314 plugin_register_shutdown ("exec", exec_shutdown);
315 } /* void module_register */
317 /*
318 * vim:shiftwidth=2:softtabstop=2:tabstop=8
319 */