1.头文件
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <string.h>
#include <linux/rtc.h>
#include <termios.h>
#include <sys/shm.h>
#include <semaphore.h>
#include <pthread.h>
#include <linux/serial.h>
2. 获取内存信息
int GetSystemMemory(int *piTotalMem, int *piFreeMem)
{
char* file = "/proc/meminfo";
FILE *fd;
char name[32];
char line_buff[256] = {0};
fd = fopen (file, "r");
if (fd < 0)
return -1;
//总内存
memset(name, 0, sizeof(name));
memset(line_buff, 0, sizeof(line_buff));
fgets (line_buff, sizeof(line_buff), fd);
sscanf(line_buff, "%s %d", name, piTotalMem);
//剩余内存
memset(name, 0, sizeof(name));
memset(line_buff, 0, sizeof(line_buff));
fgets (line_buff, sizeof(line_buff), fd);
sscanf (line_buff, "%s %d", name, piFreeMem);
fclose(fd);
return 1;
}
3. 获取CPU信息
int GetSystemCpuInfo(char *pszCpuCoreName, char *pszCpuFactoryName)
{
char *pszCmpInfo[2] = {"model name", "Hardware"};
char* file = "/proc/cpuinfo";
FILE *fd;
char name[32];
char line_buff[1024] = {0};
int i;
char *p;
fd = fopen(file, "r");
if (fd < 0)
return -1;
while (fgets (line_buff, sizeof(line_buff), fd) != NULL)
{
for (i=0; i<sizeof(pszCmpInfo)/sizeof(pszCmpInfo[0]); i++)
{
if (memcmp(line_buff, pszCmpInfo[i], strlen(pszCmpInfo[i])) == 0)
{
p = strchr(line_buff, ':')+2;
printf("%s\n", p);
if (i==0)
strcpy(pszCpuCoreName, p);
else
strcpy(pszCpuFactoryName, p);
//printf("i=%d, p=%s, pszCpuCoreName=%s, pszCpuFactoryName=%s.\n", i, p, pszCpuCoreName, pszCpuFactoryName);
}
}
}
fclose(fd);
}
4. 内存信息举例
void main(void)
{
int iTotalMem, iFreeMem;
char szCpuCoreName[128], szCpuFactoryName[128];
GetSystemMemory(&iTotalMem, &iFreeMem);
printf("iTotalMem=%.02fM, iFreeMem=%.02fM, Use percent=%%%.02f.\n", \
(float)iTotalMem/1024, (float)iFreeMem/1024, (float)(iTotalMem-iFreeMem)/iTotalMem*100);
memset(szCpuCoreName, 0, sizeof(szCpuCoreName));
memset(szCpuFactoryName, 0, sizeof(szCpuFactoryName));
GetSystemCpuInfo(szCpuCoreName, szCpuFactoryName);
printf("szCpuCoreName=%s, szCpuFactoryName=%s.\n", szCpuCoreName, szCpuFactoryName);
}
5.系统内存、CPU信息
iTotalMem=59.04M, iFreeMem=42.37M, Use percent=28.24%.
szCpuCoreName=ARM926EJ-S rev 5 (v5l), szCpuFactoryName=NUC970.
6. struct sysinfo结构体
该结构体是另外一种获取系统资源的结构体，比上面的功能简单！
struct sysinfo {
__kernel_long_t uptime; /* Seconds since boot */
__kernel_ulong_t loads[3]; /* 1, 5, and 15 minute load averages */
__kernel_ulong_t totalram; /* Total usable main memory size */
__kernel_ulong_t freeram; /* Available memory size */
__kernel_ulong_t sharedram; /* Amount of shared memory */
__kernel_ulong_t bufferram; /* Memory used by buffers */
__kernel_ulong_t totalswap; /* Total swap space size */
__kernel_ulong_t freeswap; /* swap space still available */
__u16 procs; /* Number of current processes */
__u16 pad; /* Explicit padding for m68k */
__kernel_ulong_t totalhigh; /* Total high memory size */
__kernel_ulong_t freehigh; /* Available high memory size */
__u32 mem_unit; /* Memory unit size in bytes */
char _f[20-2*sizeof(__kernel_ulong_t)-sizeof(__u32)]; /* Padding: libc5 uses this.. */
};
7. 获取系统中打开的文件句柄个数
[root@szclou /proc/sys/fs]#ls
aio-max-nr file-nr nr_open protected_symlinks
aio-nr inode-nr overflowgid suid_dumpable
dentry-state inode-state overflowuid
epoll lease-break-time pipe-max-size
file-max leases-enable protected_hardlinks
其中file-nr的内容如下
[root@szclou /proc/sys/fs]#cat file-nr
85 0 8192
参数分解:
85--表示当前系统打开的文件描述符fd
0--？？？
8192--表示当前支持最大的文件描述符fd
8. 文件系统查看应用程序打开的设备
列举进程
[root@szclou /proc]#ps
PID USER COMMAND
1 root init
2 root [kthreadd]
3 root [ksoftirqd/0]
4 root [kworker/0:0]
5 root [kworker/0:0H]
6 root [kworker/u2:0]
7 root [rcu_preempt]
8 root [rcu_bh]
9 root [rcu_sched]
10 root [khelper]
11 root [kdevtmpfs]
12 root [netns]
147 root [writeback]
150 root [bioset]
151 root [crypto]
153 root [kblockd]
165 root [khubd]
265 root [kswapd0]
408 root [nuc970-spi0]
412 root [nuc970-spi1]
470 root [deferwq]
471 root [kworker/0:1H]
486 root [yaffs-bg-1]
488 root [yaffs-bg-1]
493 root /sbin/syslogd -n
496 root /sbin/klogd -n
519 root /usr/sbin/telnetd -F
520 root -/bin/sh
529 root tcpsvd 0 21 ftpd -w /mnt
536 root {.config} /bin/sh /mnt/app/.config
546 root [yaffs-bg-1]
584 root [kworker/u2:2]
640 root /clou/clmain
903 root [kworker/0:2]
1132 root -sh
1564 root [kworker/u2:1]
2005 root [kworker/u2:3]
2072 root ps
可以看到640进程，进入该目录，在该目录下有个task，进入到里面，看到很多目录，这些目录分别代表不同的进程号，继续进入640
[root@szclou /proc/640/task]#ls
640 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 676 678 679
[root@szclou /proc/640/task/640]#ls
auxv cpuset fdinfo mounts pagemap stat
cgroup cwd limits ns personality statm
clear_refs environ maps oom_adj root status
cmdline exe mem oom_score sched syscall
comm fd mountinfo oom_score_adj smaps wchan
在该目录下有个fd目录，进入到里面，列举如下信息
[root@szclou /proc/640/task/640/fd]#ls
0 1 10 11 12 13 14 15 16 17 19 2 3 4 5 6 7 8 9
[root@szclou /proc/640/task/640/fd]#ls -la
total 0
dr-x------ 2 root root 0 Jun 10 10:44 .
dr-xr-xr-x 5 root root 0 Jun 10 10:44 ..
lrwx------ 1 root root 64 Jun 10 10:44 0 -> /dev/console
lrwx------ 1 root root 64 Jun 10 10:44 1 -> /dev/console
lrwx------ 1 root root 64 Jun 10 10:44 10 -> /dev/nuc972_timer
lr-x------ 1 root root 64 Jun 10 10:44 11 -> /dev/nuc972_key
lrwx------ 1 root root 64 Jun 10 10:44 12 -> /dev/nuc972_adc
lrwx------ 1 root root 64 Jun 10 10:44 13 -> /dev/nuc972_timer
lrwx------ 1 root root 64 Jun 10 10:44 14 -> /dev/nuc972_adc
lrwx------ 1 root root 64 Jun 10 10:44 15 -> /dev/esam
lrwx------ 1 root root 64 Jun 10 10:44 16 -> /dev/nuc972_timer
lrwx------ 1 root root 64 Jun 10 10:44 17 -> /dev/ttyS6
lrwx------ 1 root root 64 Jun 10 10:44 19 -> socket:[2128]
lrwx------ 1 root root 64 Jun 10 10:44 2 -> /dev/console
lrwx------ 1 root root 64 Jun 10 10:44 3 -> socket:[1987]
lrwx------ 1 root root 64 Jun 10 10:44 4 -> /sys/devices/platform/nuc970-i2c0/i2c-0/0-0050/fram
lrwx------ 1 root root 64 Jun 10 10:44 5 -> /dev/ttyS5
lrwx------ 1 root root 64 Jun 10 10:44 6 -> /dev/ttyS10
lrwx------ 1 root root 64 Jun 10 10:44 7 -> /dev/ttyS2
lrwx------ 1 root root 64 Jun 10 10:44 8 -> /dev/nuc972_lcd
lrwx------ 1 root root 64 Jun 10 10:44 9 -> /dev/att7022
可以看到当前应用程序打开的设备。
