我们有一个如下的 C 代码。这就是我们编译它的方式 gcc -o get1Receive $(mysql_config --cflags) get1ReceiveSource.c $(mysql_config --libs) -lrt。当我们从终端运行时，我工作得很好。然后我们尝试使用 cron 作业运行它，当我们查看这两行时 printf("\nNumf of fields : %d",num_fields); 和 printf("\nNof of row : %lu",mysql_num_rows(localRes1));. 第一行显示 4 作为值，第二行从不给出任何值，始终为 0。我们采用了相同的选择查询并在 db 上运行并确认有值，但在通过 cron 作业运行时它没有提供。脚本也被赋予了可执行权限。
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <stdio.h>
#include <time.h>
#include <signal.h>
#include <mysql.h>
#include <string.h>
int flag = 0;
int main () {
MYSQL *localConn;
MYSQL_RES *localRes1;
MYSQL_ROW localRow1;
char *server = "localhost";
char *user = "user1";
char *password = "*****";
char *database = "test1";
localConn = mysql_init(NULL);
if (!mysql_real_connect(localConn, server,
user, password, database, 0, NULL, 0)) {
fprintf(stderr, "%s\n", mysql_error(localConn));
exit(1);
}
struct timeval tv;
char queryBuf1[500],queryBuf2[500];
char buff1[20] = {0};
char buff2[20] = {0};
gettimeofday (&tv, NULL);
//fprintf (stderr, "[%d.%06d] Flag set to 1 on ", tv.tv_sec, tv.tv_usec);
//tv.tv_sec -= 5;
strftime(buff1, 20, "%Y-%m-%d %H:%M:00", localtime(&tv.tv_sec));
strftime(buff2, 20, "%Y-%m-%d %H:%M:59", localtime(&tv.tv_sec));
printf("\nTime from %s", buff1);
printf("\nTime to %s", buff2);
sprintf(queryBuf1,"SELECT ipDest, macDest,portDest, sum(totalBits) FROM dataReceive WHERE timeStampID between '%s' And '%s' GROUP BY ipDest, macDest, portDest ",buff1,buff2);
printf("\nQuery receive %s",queryBuf1);
if(mysql_query(localConn, queryBuf1))
{
printf("Error in first query of select %s\n",mysql_error(localConn));
exit(1);
}
localRes1 = mysql_store_result(localConn);
int num_fields = mysql_num_fields(localRes1);
printf("\nNumf of fields : %d",num_fields);
printf("\nNof of row : %lu",mysql_num_rows(localRes1));
while((localRow1 = mysql_fetch_row(localRes1)) !=NULL)
{
int totalBits = atoi(localRow1[3]);
printf("totalBits %d\n", totalBits);
printf("RECEIVE %s,%s\n", localRow1[0], localRow1[1]);
if(totalBits>5000)
{
sprintf(queryBuf1,"INSERT INTO alertReceive1 (timeStampID,ipDest, macDest, portDest, totalBits)VALUES ('%s','%s','%s','%s',%s)",buff1, localRow1[0],localRow1[1],localRow1[2],localRow1[3]);
printf("Query 1 before executing %s\n",queryBuf1);
if (mysql_real_query(localConn,queryBuf1,strlen(queryBuf1))) {
printf("Error in first insert %s\n",mysql_error(localConn));
fprintf(stderr, "%s\n", mysql_error(localConn));
exit(1);
}
//printf("Query 1 after executing %s\n",queryBuf1);*/
}
}
mysql_free_result(localRes1);
mysql_close(localConn);
}
我们已经运行了这个命令文件 get1Receive 并导致
file get1Receive
get1Receive.c: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
我们还运行了这个命令 * * * * * set > /tmp/myvars，下面是结果。
GROUPS=()
HOME=/root
HOSTNAME=capture
HOSTTYPE=x86_64
IFS='
'
LOGNAME=root
MACHTYPE=x86_64-redhat-linux-gnu
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/bin:/bin
POSIXLY_CORRECT=y
PPID=11086
PS4='+ '
PWD=/root
SHELL=/bin/sh
SHELLOPTS=braceexpand:hashall:interactive-comments:posix
SHLVL=1
TERM=dumb
UID=0
USER=root
_=/bin/sh