我写了一个小守护进程。
这是守护进程的流程，通常是：
获取变量
从数据库中获取满足查询参数的所有行（可能是MySQL或Oracle）（在这种情况下获取具有此当前时间的所有行）。
如果找到任何行，则为每行运行一个Perl脚本（使用execv）。
这个守护进程运行良好，但问题是当我从查询中返回两行或更多行时，它们会启动，但Perl脚本输出是混合的。它们应该独立运行而不会相互干扰。
我做错了吗？
这是内存泄漏吗？
这是我的代码：
/*
============================================================================
Name : main.c
Description : Daemon for scheduler
============================================================================
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <syslog.h>
#include <string.h>
#include <strings.h>
#include <regex.h>
#include <time.h>
#ifdef MYSQL_CODE
#include <mysql.h>
#endif
#ifdef ORACLE_CODE
#include <ocilib.h>
#endif
#define DAEMON_NAME "schedulerd"
void start_job(char *automation_user,char *automation_path,char *automation_log_path, char *id, char *site, char *db_type,char *db_host,char *db_user,char *db_password,char *db_schemata){
pid_t pid;
pid = fork();
if (pid < 0) { exit(EXIT_FAILURE); }
//We got a good pid, Continue to the next result
if (pid > 0) {
return;
}
char *file_format = "scheduler";
char *seperator = "_";
char *postfix = "_XXXXXX";
char *extension = ".log";
//get Time
time_t now;
struct tm *now_tm;
char hour[2],min[2],sec[2];
now = time(NULL);
now_tm = localtime(&now);
sprintf(hour, "%d", now_tm->tm_hour);
sprintf(min, "%d", now_tm->tm_min);
sprintf(sec, "%d", now_tm->tm_sec);
char *str = (char *)automation_log_path;
strcat(str,(char *)file_format);
strcat(str,seperator);
strcat(str,hour);
strcat(str,seperator);
strcat(str,min);
strcat(str,seperator);
strcat(str,sec);
strcat(str,postfix);
// buffer to hold the temporary file name
char nameBuff[128];
int filedes = -1;
// memset the buffers to 0
memset(nameBuff,0,sizeof(nameBuff));
// Copy the relevant information in the buffers
strncpy(nameBuff,str,128);
// Create the temporary file, this function will replace the 'X's
filedes = mkstemp(nameBuff);
if(filedes<1)
{
syslog (LOG_NOTICE, "Creation of temp file [%s] failed with error [%s]\n",nameBuff,strerror(errno));
}else{
mode_t perm = 0644;
fchmod(filedes, perm); //Change permission to the file so everyone can read
close(filedes); // Close created file
//Rename file
int ret;
char newname[128];
sprintf(newname, "%s%s", nameBuff,extension);
ret = rename(nameBuff, newname);
if(ret != 0) {
syslog (LOG_NOTICE, "Renaming of temp file %s to %s failed \n",nameBuff,newname);
exit(EXIT_FAILURE);
}
char statement[256];
sprintf(statement, "UPDATE scheduler_list SET log_file='%s' WHERE id='%s'", newname,id);
syslog (LOG_NOTICE,"Adding to DB : %s\n", statement);
char command[2048];
sprintf(command, "cd %s ; ./runner.pl -site %s -log %s -scheduler_id %s -command \\\"./run_me.pl\\\"", automation_path,site,newname,id);
//sprintf(command, "cd /net/10.7.5.50/opt/trunk/ ; ./runner.pl -site %s -log %s -scheduler_id %s -command \\\"./run_me.pl\\\"",site,newname,id);
if (strcasestr(db_type,"mysql")){/* mysql */
#ifdef MYSQL_CODE
MYSQL *conn;
//mysql_free_result(res); // Free mysql
conn = mysql_init(NULL);
/* Connect to database */
if (!mysql_real_connect(conn, db_host,db_user, db_password, db_schemata, 0, NULL, 0)) {
syslog (LOG_NOTICE,"%s\n", mysql_error(conn));
exit(EXIT_FAILURE);
}
if (mysql_query(conn,statement)) {
syslog (LOG_NOTICE,"%s\n", mysql_error(conn));
exit(EXIT_FAILURE);
}
#endif
}else{
#ifdef ORACLE_CODE
OCI_Connection* cn;
OCI_Statement* st;
OCI_Initialize(NULL, NULL, OCI_ENV_DEFAULT);
char query_command[128];
sprintf(query_command, "%s:1521/%s", db_host,db_schemata);
cn = OCI_ConnectionCreate(query_command, db_user, db_password, OCI_SESSION_DEFAULT);
st = OCI_StatementCreate(cn);
OCI_Prepare(st, statement);
OCI_Execute(st);
OCI_Commit(cn);
OCI_Cleanup();
#endif
}
char *args[] = {"sudo", "-u", automation_user, "bash","-c",command,NULL};
FILE *log_file_h = fopen(newname, "w");
if (log_file_h == NULL)
{
syslog (LOG_NOTICE,"Error opening file %s !\n",newname);
exit(EXIT_FAILURE);
}
syslog (LOG_NOTICE,"Starting scheduler job %s , command : %s",id, command);
fclose(log_file_h);
execv("/usr/bin/sudo",args);
syslog (LOG_NOTICE,"Failed to start job %s ",id);
perror("error");
}
exit(EXIT_FAILURE);
}
void process(char *automation_user,char *automation_path, char *automation_log_path ,char *db_type,char *db_host,char *db_user,char *db_password,char *db_schemata){
if (strcasestr(db_type,"mysql")){/* mysql */
#ifdef MYSQL_CODE
MYSQL *conn;
MYSQL_RES *res;
MYSQL_ROW row;
conn = mysql_init(NULL);
/* Connect to database */
if (!mysql_real_connect(conn, db_host,db_user, db_password, db_schemata, 0, NULL, 0)) {
syslog (LOG_NOTICE,"%s\n", mysql_error(conn));
return;
}
/* send SQL query */
if (mysql_query(conn, "SELECT id,site from scheduler_list where start_date = DATE_FORMAT(now(),'%Y-%m-%d %k:%i:00') AND id != father_id AND run='yes'")) {
syslog (LOG_NOTICE,"%s\n", mysql_error(conn));
return;
}
res = mysql_use_result(conn);
/* output table name */
while ((row = mysql_fetch_row(res)) != NULL){
char *id = malloc(strlen(row[0]) +1);
strcpy(id,row[0]);
char *site = malloc(strlen(row[1]) +1);
strcpy(site,row[1]);
start_job(automation_user,automation_path,automation_log_path,id,site,db_type, db_host,db_user,db_password,db_schemata);
}
/* close connection */
mysql_free_result(res);
mysql_close(conn);
#endif
}else{/* oracle */
#ifdef ORACLE_CODE
OCI_Connection* cn;
OCI_Statement* st;
OCI_Resultset* rs;
OCI_Initialize(NULL, NULL, OCI_ENV_DEFAULT);
char query_command[128];
sprintf(query_command, "%s:1521/%s", db_host,db_schemata);
cn = OCI_ConnectionCreate(query_command, db_user, db_password, OCI_SESSION_DEFAULT);
st = OCI_StatementCreate(cn);
OCI_ExecuteStmt(st, "SELECT id,site from scheduler_list where to_char(start_date, 'yyyy-mm-dd hh24:mi') = to_char(SYSDATE, 'yyyy-mm-dd hh24:mi') AND id != father_id AND run='yes'");
rs = OCI_GetResultset(st);
while (OCI_FetchNext(rs)){
char *id = malloc(strlen(OCI_GetString(rs, 1)) +1);
strcpy(id,OCI_GetString(rs,1));
char *site = malloc(strlen(OCI_GetString(rs,2)) +1);
strcpy(site,OCI_GetString(rs,2));
start_job(automation_user,automation_path,automation_log_path,id,site,db_type, db_host,db_user,db_password,db_schemata);
}
OCI_Cleanup();
#endif
}
}
char * set_conf_param (char *line, int addSlash){
char *param = malloc(strlen(line) + 2 + addSlash);
strcpy(param,line);
param = strchr(line,'=');
param = param+1; //Remove '='
strtok(param, "\n"); //remove /n
if (addSlash == 1){
int len = strlen(param);
param[len] = '/';
param[len+1] = '\0';
}
return strdup(param);
}
int main(int argc, char *argv[]) {
FILE * fp;
char * line = NULL;
size_t len = 0;
int found_db = 0;
ssize_t read;
pid_t pid, sid;
char *automation_user=NULL,*automation_log_path=NULL ,*db_type=NULL, *db_host=NULL , *db_user=NULL, *db_password=NULL, *db_schemata=NULL;
char *automation_path = getenv("AUTOMATION_PATH");
//char *automation_path = "/net/10.7.5.50/opt/trunk/";
char *automation_user_search = "automation_user=";
char *automation_log_path_search = "automation_log=";
char *db_type_search = "type=";
char *db_host_search = "host=";
char *db_user_search = "user=";
char *db_password_search = "password=";
char *db_schemata_search = "schemata=";
const char comment = '#';
/* Change the working directory to the root directory */
/* or another appropriated directory */
chdir(automation_path);
//Set our Logging Mask and open the Log
setlogmask(LOG_UPTO(LOG_NOTICE));
openlog(DAEMON_NAME, LOG_CONS | LOG_NDELAY | LOG_PERROR | LOG_PID, LOG_USER);
syslog(LOG_NOTICE, "Entering Daemon");
//Read framework.conf
fp = fopen("framework.conf", "r");
if (fp == NULL){
syslog (LOG_NOTICE,"Failed to open framework.conf");
exit(1);
}
//Read framework.conf
fp = fopen("framework.conf", "r");
if (fp == NULL){
syslog (LOG_NOTICE,"Failed to open framework.conf");
exit(1);
}
while ((read = getline(&line, &len, fp)) != -1) {
//If line commented
if (strchr(line,comment) != NULL){
continue;
}
if (strstr(line,automation_user_search) != NULL){
automation_user = set_conf_param(line,0);
}
else if (strstr(line,automation_log_path_search) != NULL){
automation_log_path = set_conf_param(line,1);
}
else if (db_type!=NULL && strcasestr(line,db_type) != NULL){
found_db = 1;
}
else if (strstr(line,db_type_search) != NULL){
db_type = set_conf_param(line,0);
}
else if (found_db && db_host==NULL && strstr(line,db_host_search) != NULL){
db_host = set_conf_param(line,0);
}
else if (found_db && db_user==NULL && strstr(line,db_user_search) != NULL){
db_user = set_conf_param(line,0);
}
else if (found_db && db_password==NULL && strstr(line,db_password_search) != NULL){
db_password = set_conf_param(line,0);
}
else if (found_db && db_schemata==NULL && strstr(line,db_schemata_search) != NULL){
db_schemata = set_conf_param(line,0);
}
}
fclose(fp);
if (line)
free(line);
if (automation_user==NULL){
automation_user = "root";
}
//Fork the Parent Process
pid = fork();
if (pid < 0) { exit(EXIT_FAILURE); }
//We got a good pid, Close the Parent Process
if (pid > 0) { exit(EXIT_SUCCESS); }
//Change File Mask
umask(0);
//Create a new Signature Id for our child
sid = setsid();
if (sid < 0) { exit(EXIT_FAILURE); }
//Close Standard File Descriptors
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
//----------------
//Main Process
//----------------
while(1){
process(automation_user,automation_path,automation_log_path,db_type,db_host,db_user,db_password,db_schemata); //Run our Process
sleep(60); //Sleep for 60 seconds
}
//Close the log
closelog ();
exit(EXIT_FAILURE);
}
答案 0 :(得分：7)
您似乎没有任何努力撰写minimal, complete verifiable example。
这只是整个程序的转储，包括您未提供的配置文件的依赖关系，以及您未显示其架构的数据库。这些都与您的问题无关。
至少你编辑了公司名称，但作为参考，它仍然可以在编辑历史中看到。
C中的线程正在互相写stdout
我在你的程序中看不到任何线程，你也没有分叉线程 - 你有什么是子进程
......正在互相写stdout
好吧，stdout是从父级继承的，所以所有的孩子（以及他们的 sudo / bash / perl /无论孩子们）都写到同一个地方。写入本身被锁定，但可以交错。
如果您希望他们的输出不是交错的，请让他们写入不同的地方，并找出如何在以后显示/组合它们。
每个子进程临时文件是一种流行的选择，但请注意，父进程必须跟踪子进程完成情况，以便知道何时打印然后删除每个文件。此外，您可能应该从终端分离子进程，关闭stdin，并考虑如何处理stderr。
这是内存泄漏吗？
没有
答案 1 :(得分：0)
我想（在快速一瞥之后）问题出现在
中execv("/usr/bin/sudo",args);
您应该确保只有一个实例正在运行。 这可以通过相互排斥来完成。 一个很好的描述是： http://www.thegeekstuff.com/2012/05/c-mutex-examples/
简而言之：
// create a global mutex variable
pthread_mutex_t lock;
// initialise it in main
pthread_mutex_init(&lock, NULL);
// enclose your critical path
pthread_mutex_lock(&lock);
execv("/usr/bin/sudo",args);
pthread_mutex_unlock(&lock);
希望它有助于