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"
26 #include <sys/types.h>
27 #include <pwd.h>
28 #include <signal.h>
30 #include <pthread.h>
32 /*
33 * Private data types
34 */
35 struct program_list_s;
36 typedef struct program_list_s program_list_t;
37 struct program_list_s
38 {
39 char *user;
40 char *exec;
41 int pid;
42 program_list_t *next;
43 };
45 /*
46 * Private variables
47 */
48 static const char *config_keys[] =
49 {
50 "Exec"
51 };
52 static int config_keys_num = STATIC_ARRAY_SIZE (config_keys);
54 static program_list_t *pl_head = NULL;
56 /*
57 * Functions
58 */
59 static int exec_config (const char *key, const char *value)
60 {
61 if (strcasecmp ("Exec", key) == 0)
62 {
63 program_list_t *pl;
64 pl = (program_list_t *) malloc (sizeof (program_list_t));
65 if (pl == NULL)
66 return (1);
67 memset (pl, '\0', sizeof (program_list_t));
69 pl->user = strdup (value);
70 if (pl->user == NULL)
71 {
72 sfree (pl);
73 return (1);
74 }
76 pl->exec = strchr (pl->user, ' ');
77 if (pl->exec == NULL)
78 {
79 sfree (pl->user);
80 sfree (pl);
81 return (1);
82 }
83 while (*pl->exec == ' ')
84 {
85 *pl->exec = '\0';
86 pl->exec++;
87 }
89 if (*pl->exec == '\0')
90 {
91 sfree (pl->user);
92 sfree (pl);
93 return (1);
94 }
96 pl->next = pl_head;
97 pl_head = pl;
98 }
99 else
100 {
101 return (-1);
102 }
104 return (0);
105 } /* int exec_config */
107 static void exec_child (program_list_t *pl)
108 {
109 int status;
110 int uid;
111 char *arg0;
113 struct passwd *sp_ptr;
114 struct passwd sp;
115 char pwnambuf[2048];
116 char errbuf[1024];
118 sp_ptr = NULL;
119 status = getpwnam_r (pl->user, &sp, pwnambuf, sizeof (pwnambuf), &sp_ptr);
120 if (status != 0)
121 {
122 ERROR ("exec plugin: getpwnam_r failed: %s",
123 sstrerror (errno, errbuf, sizeof (errbuf)));
124 exit (-1);
125 }
126 if (sp_ptr == NULL)
127 {
128 ERROR ("exec plugin: No such user: `%s'", pl->user);
129 exit (-1);
130 }
132 uid = sp.pw_uid;
133 if (uid == 0)
134 {
135 ERROR ("exec plugin: Cowardly refusing to exec program as root.");
136 exit (-1);
137 }
139 status = setuid (uid);
140 if (status != 0)
141 {
142 ERROR ("exec plugin: setuid failed: %s",
143 sstrerror (errno, errbuf, sizeof (errbuf)));
144 exit (-1);
145 }
147 arg0 = strrchr (pl->exec, '/');
148 if (arg0 != NULL)
149 arg0++;
150 if ((arg0 == NULL) || (*arg0 == '\0'))
151 arg0 = pl->exec;
153 status = execlp (pl->exec, arg0, (char *) 0);
155 ERROR ("exec plugin: exec failed: %s",
156 sstrerror (errno, errbuf, sizeof (errbuf)));
157 exit (-1);
158 } /* void exec_child */
160 static int fork_child (program_list_t *pl)
161 {
162 int fd_pipe[2];
163 int status;
165 if (pl->pid != 0)
166 return (-1);
168 status = pipe (fd_pipe);
169 if (status != 0)
170 {
171 char errbuf[1024];
172 ERROR ("exec plugin: pipe failed: %s",
173 sstrerror (errno, errbuf, sizeof (errbuf)));
174 return (-1);
175 }
177 pl->pid = fork ();
178 if (pl->pid < 0)
179 {
180 char errbuf[1024];
181 ERROR ("exec plugin: fork failed: %s",
182 sstrerror (errno, errbuf, sizeof (errbuf)));
183 return (-1);
184 }
185 else if (pl->pid == 0)
186 {
187 close (fd_pipe[0]);
189 /* Connect the pipe to STDOUT and STDERR */
190 if (fd_pipe[1] != STDOUT_FILENO)
191 dup2 (fd_pipe[1], STDOUT_FILENO);
192 if (fd_pipe[1] != STDERR_FILENO)
193 dup2 (fd_pipe[1], STDERR_FILENO);
194 if ((fd_pipe[1] != STDOUT_FILENO) && (fd_pipe[1] != STDERR_FILENO))
195 close (fd_pipe[1]);
197 exec_child (pl);
198 /* does not return */
199 }
201 close (fd_pipe[1]);
202 return (fd_pipe[0]);
203 } /* int fork_child */
205 static int parse_line (char *buffer)
206 {
207 char *fields[4];
208 int fields_num;
210 char *hostname;
211 char *plugin;
212 char *plugin_instance;
213 char *type;
214 char *type_instance;
216 const data_set_t *ds;
217 value_list_t vl = VALUE_LIST_INIT;
219 int status;
221 fields_num = strsplit (buffer, fields, 4);
222 if (fields_num != 2)
223 {
224 WARNING ("exec plugin: Number of fields is not 2.");
225 return (-1);
226 }
228 status = parse_identifier (fields[0], &hostname,
229 &plugin, &plugin_instance,
230 &type, &type_instance);
231 if (status != 0)
232 {
233 WARNING ("exec plugin: Cannot parse `%s'", fields[0]);
234 return (-1);
235 }
237 if ((strlen (hostname) >= sizeof (vl.host))
238 || (strlen (plugin) >= sizeof (vl.plugin))
239 || ((plugin_instance != NULL)
240 && (strlen (plugin_instance) >= sizeof (vl.plugin_instance)))
241 || ((type_instance != NULL)
242 && (strlen (type_instance) >= sizeof (vl.type_instance))))
243 {
244 WARNING ("exec plugin: An identifier is too long.");
245 return (-1);
246 }
248 strcpy (vl.host, hostname);
249 strcpy (vl.plugin, plugin);
250 if (plugin_instance != NULL)
251 strcpy (vl.plugin_instance, plugin_instance);
252 if (type_instance != NULL)
253 strcpy (vl.type_instance, type_instance);
255 ds = plugin_get_ds (type);
256 if (ds == NULL)
257 {
258 WARNING ("exec plugin: No such type: `%s'", type);
259 return (-1);
260 }
262 vl.values_len = ds->ds_num;
263 vl.values = (value_t *) malloc (sizeof (value_t) * vl.values_len);
264 if (vl.values == NULL)
265 return (-1);
267 /* Sets vl.values and vl.time */
268 status = parse_values (fields[1], &vl, ds);
269 if (status != 0)
270 {
271 WARNING ("exec plugin: Cannot parse `%s'", fields[1]);
272 sfree (vl.values);
273 return (-1);
274 }
276 plugin_dispatch_values (type, &vl);
278 sfree (vl.values);
280 return (0);
281 } /* int parse_line */
283 static void *exec_read_one (void *arg)
284 {
285 program_list_t *pl = (program_list_t *) arg;
286 int fd;
287 FILE *fh;
288 char buffer[1024];
290 fd = fork_child (pl);
291 if (fd < 0)
292 pthread_exit ((void *) 1);
294 assert (pl->pid != 0);
296 fh = fdopen (fd, "r");
297 if (fh == NULL)
298 {
299 char errbuf[1024];
300 ERROR ("exec plugin: fdopen (%i) failed: %s", fd,
301 sstrerror (errno, errbuf, sizeof (errbuf)));
302 kill (pl->pid, SIGTERM);
303 close (fd);
304 pthread_exit ((void *) 1);
305 }
307 while (fgets (buffer, sizeof (buffer), fh) != NULL)
308 {
309 int len;
311 len = strlen (buffer);
313 /* Remove newline from end. */
314 while ((len > 0) && ((buffer[len - 1] == '\n')
315 || (buffer[len - 1] == '\r')))
316 buffer[--len] = '\0';
318 DEBUG ("exec plugin: exec_read_one: buffer = %s", buffer);
320 parse_line (buffer);
321 } /* while (fgets) */
323 fclose (fh);
324 pl->pid = 0;
326 pthread_exit ((void *) 0);
327 return (NULL);
328 } /* void *exec_read_one */
330 static int exec_read (void)
331 {
332 program_list_t *pl;
334 for (pl = pl_head; pl != NULL; pl = pl->next)
335 {
336 pthread_t t;
337 pthread_attr_t attr;
339 if (pl->pid != 0)
340 continue;
342 pthread_attr_init (&attr);
343 pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
344 pthread_create (&t, &attr, exec_read_one, (void *) pl);
345 } /* for (pl) */
347 return (0);
348 } /* int exec_read */
350 static int exec_shutdown (void)
351 {
352 program_list_t *pl;
353 program_list_t *next;
355 pl = pl_head;
356 while (pl != NULL)
357 {
358 next = pl->next;
360 if (pl->pid > 0)
361 {
362 kill (pl->pid, SIGTERM);
363 INFO ("exec plugin: Sent SIGTERM to %hu", (unsigned short int) pl->pid);
364 }
366 sfree (pl->user);
367 sfree (pl);
369 pl = next;
370 } /* while (pl) */
371 pl_head = NULL;
373 return (0);
374 } /* int exec_shutdown */
376 void module_register (void)
377 {
378 plugin_register_config ("exec", exec_config, config_keys, config_keys_num);
379 plugin_register_read ("exec", exec_read);
380 plugin_register_shutdown ("exec", exec_shutdown);
381 } /* void module_register */
383 /*
384 * vim:shiftwidth=2:softtabstop=2:tabstop=8
385 */