1 /* Copyright (C) 2009 Intel Corporation
2 Author: Andi Kleen
3 Manage trigger commands running as separate processes.
4
5 mcelog is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public
7 License as published by the Free Software Foundation; version
8 2.
9
10 mcelog is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
14
15 You should find a copy of v2 of the GNU General Public License somewhere
16 on your Linux system; if not, write to the Free Software Foundation,
17 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
18 #define _GNU_SOURCE 1
19 #include <stdio.h>
20 #include <unistd.h>
21 #include <stdlib.h>
22 #include <signal.h>
23 #include <stdbool.h>
24 #include <string.h>
25 #include <sys/wait.h>
26 #include "trigger.h"
27 #include "eventloop.h"
28 #include "list.h"
29 #include "mcelog.h"
30 #include "memutil.h"
31 #include "config.h"
32
33 struct child {
34 struct list_head nd;
35 pid_t child;
36 const char *name;
37 };
38
39 static LIST_HEAD(childlist);
40 static int num_children;
41 static int children_max = 4;
42 static char *trigger_dir;
43
44 static void finish_child(pid_t child, int status);
45
mcelog_fork(const char * name)46 pid_t mcelog_fork(const char *name)
47 {
48 pid_t child;
49 struct child *c;
50
51 child = fork();
52 if (child <= 0)
53 return child;
54
55 num_children++;
56 c = xalloc(sizeof(struct child));
57 c->name = name;
58 c->child = child;
59 list_add_tail(&c->nd, &childlist);
60 return child;
61 }
62
63 // note: trigger must be allocated, e.g. from config
run_trigger(char * trigger,char * argv[],char ** env,bool sync,const char * reporter)64 void run_trigger(char *trigger, char *argv[], char **env, bool sync, const char* reporter)
65 {
66 pid_t child;
67
68 char *fallback_argv[] = {
69 trigger,
70 NULL,
71 };
72
73 if (!argv)
74 argv = fallback_argv;
75
76 Lprintf("Running trigger `%s' (reporter: %s)\n", trigger, reporter);
77 if (children_max > 0 && num_children >= children_max) {
78 Eprintf("Too many trigger children running already\n");
79 return;
80 }
81
82 child = mcelog_fork(trigger);
83 if (child < 0) {
84 SYSERRprintf("Cannot create process for trigger");
85 return;
86 }
87 if (child == 0) {
88 if (trigger_dir && chdir(trigger_dir) == -1)
89 SYSERRprintf("Cannot chdir(%s) for trigger", trigger_dir);
90 else
91 execve(trigger, argv, env);
92 _exit(127);
93 }
94 }
95
96 /* Clean up child on SIGCHLD */
finish_child(pid_t child,int status)97 static void finish_child(pid_t child, int status)
98 {
99 struct child *c, *tmpc;
100
101 list_for_each_entry_safe (c, tmpc, &childlist, nd) {
102 if (c->child == child) {
103 if (WIFEXITED(status) && WEXITSTATUS(status)) {
104 Eprintf("Trigger `%s' exited with status %d\n",
105 c->name, WEXITSTATUS(status));
106 } else if (WIFSIGNALED(status)) {
107 Eprintf("Trigger `%s' died with signal %s\n",
108 c->name, strsignal(WTERMSIG(status)));
109 }
110 list_del(&c->nd);
111 free(c);
112 num_children--;
113 return;
114 }
115 }
116 abort();
117 }
118
119 /* Runs only directly after ppoll */
child_handler(int sig,siginfo_t * si,void * ctx)120 static void child_handler(int sig, siginfo_t *si, void *ctx)
121 {
122 int status;
123 pid_t pid;
124
125 if (waitpid(si->si_pid, &status, WNOHANG) < 0) {
126 SYSERRprintf("Cannot collect child %d", si->si_pid);
127 return;
128 }
129 finish_child(si->si_pid, status);
130
131 /* Check other child(ren)'s status to avoid zombie process */
132 while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
133 finish_child(pid, status);
134 }
135 }
136
trigger_setup(void)137 void trigger_setup(void)
138 {
139 char *s;
140 struct sigaction sa = {
141 .sa_sigaction = child_handler,
142 .sa_flags = SA_SIGINFO|SA_NOCLDSTOP|SA_RESTART,
143 };
144 sigaction(SIGCHLD, &sa, NULL);
145 event_signal(SIGCHLD);
146
147 config_number("trigger", "children-max", "%d", &children_max);
148
149 s = config_string("trigger", "directory");
150 if (s) {
151 if (access(s, R_OK|X_OK) < 0)
152 SYSERRprintf("Cannot access trigger directory `%s'", s);
153 trigger_dir = s;
154 }
155 }
156
trigger_wait(void)157 void trigger_wait(void)
158 {
159 int status;
160 int pid;
161
162 while ((pid = waitpid((pid_t)-1, &status, 0)) > 0)
163 finish_child(pid, status);
164 }
165
trigger_check(char * s)166 int trigger_check(char *s)
167 {
168 char *name;
169 int rc;
170
171 if (trigger_dir)
172 xasprintf(&name, "%s/%s", trigger_dir, s);
173 else
174 name = s;
175
176 rc = access(name, R_OK|X_OK);
177
178 if (trigger_dir)
179 free(name);
180
181 return rc;
182 }
183