进程的proc文件系统信息

一、实验代码

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

void main()
{
    int fd;
    char buf = '1';

    char *pname = "/home/hello/mytest/proc_test/abc/aaa.txt";

    fd = open(pname, O_RDWR);
    if (fd < 0) {
        printf("Open failed: %m");
        return;
    }

    while(1) {
        write(fd, &buf, 1); usleep(1000);
    }
}

 

二、测试

hello@ubuntu:~/mytest/proc_test$ tree
.
├── abc
│ └── aaa.txt
├── pp
└── test.c

# gcc test.c -o pp
# ./pp
# ps -aux | grep pp
hello 4626 93.0 0.0 2036 512 pts/0 R 08:34 0:07 ./pp

 

1.查看进程的路径：
hello@ubuntu:/proc/4626$ ls cwd -l
lrwxrwxrwx 1 hello hello 0 Sep 27 08:34 cwd -> /home/hello/mytest/proc_test

2.查看可执行程序路径名
hello@ubuntu:/proc/4626$ ls exe -l
lrwxrwxrwx 1 hello hello 0 Sep 27 08:34 exe -> /home/hello/mytest/proc_test/pp

3.查看进程运行环境
hello@ubuntu:/proc/4626$ strings environ 可查看进程运行的环境，包括pwd和cmdline等信息

4.查看进程打开的文件描述符
hello@ubuntu:/proc/4626$ ls fd -l 查看所有打开的文件的路径
total 0
lrwx------ 1 hello hello 64 Sep 27 08:36 0 -> /dev/pts/0 std_in
lrwx------ 1 hello hello 64 Sep 27 08:36 1 -> /dev/pts/0 std_out
lrwx------ 1 hello hello 64 Sep 27 08:34 2 -> /dev/pts/0 std_error
lrwx------ 1 hello hello 64 Sep 27 08:36 3 -> /home/hello/mytest/proc_test/abc/aaa.txt

5.获取执行时的cmdline
root@ubuntu:/proc/4626# strings cmdline
./pp

6.查看io操作已经读写的字节数
root@ubuntu:/proc/4626# cat io
rchar: 1223
wchar: 57672
syscr: 7
syscw: 57672
read_bytes: 0
write_bytes: 73728

7.查看进程nice值
root@ubuntu:/proc/4626# cat autogroup
/autogroup-311 nice 0

8.comm应该是可执行文件名
root@ubuntu:/proc/4626# cat comm
pp

9.查看系统调用
root@ubuntu:/proc/4626# cat syscall
running
root@ubuntu:/proc/4626# cat syscall
162 0xbf9d71b8 0x0 0xb7762000 0x0 0x0 0xbf9d71f8 0xbf9d718c 0xb777ecf9

10.查看系统对此可执行程序的限制

root@ubuntu:/proc/4626# cat limits 
Limit                     Soft Limit           Hard Limit           Units     
Max cpu time              unlimited            unlimited            seconds   
Max file size             unlimited            unlimited            bytes     
Max data size             unlimited            unlimited            bytes     
Max stack size            8388608              unlimited            bytes     
Max core file size        0                    unlimited            bytes     
Max resident set          unlimited            unlimited            bytes     
Max processes             48392                48392                processes 
Max open files            1024                 4096                 files     
Max locked memory         65536                65536                bytes     
Max address space         unlimited            unlimited            bytes     
Max file locks            unlimited            unlimited            locks     
Max pending signals       48392                48392                signals   
Max msgqueue size         819200               819200               bytes     
Max nice priority         0                    0                    
Max realtime priority     0                    0                    
Max realtime timeout      unlimited            unlimited            us  

11.查看文件系统的挂载信息 per-thread的!!

root@ubuntu:/proc/4626# cat mountinfo 
18 23 0:17 / /sys rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw
19 23 0:4 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw
20 23 0:6 / /dev rw,relatime - devtmpfs udev rw,size=3097160k,nr_inodes=204098,mode=755
21 20 0:14 / /dev/pts rw,nosuid,noexec,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000
22 23 0:18 / /run rw,nosuid,noexec,relatime - tmpfs tmpfs rw,size=621552k,mode=755
23 0 8:1 / / rw,relatime - ext4 /dev/sda1 rw,errors=remount-ro,data=ordered
24 18 0:19 / /sys/fs/cgroup rw,relatime - tmpfs none rw,size=4k,mode=755
25 18 0:20 / /sys/fs/fuse/connections rw,relatime - fusectl none rw
26 18 0:7 / /sys/kernel/debug rw,relatime - debugfs none rw
27 18 0:12 / /sys/kernel/security rw,relatime - securityfs none rw
28 22 0:21 / /run/lock rw,nosuid,nodev,noexec,relatime - tmpfs none rw,size=5120k
29 22 0:22 / /run/shm rw,nosuid,nodev,relatime - tmpfs none rw
30 22 0:23 / /run/user rw,nosuid,nodev,noexec,relatime - tmpfs none rw,size=102400k,mode=755
31 18 0:24 / /sys/fs/pstore rw,relatime - pstore none rw
33 24 0:26 / /sys/fs/cgroup/systemd rw,nosuid,nodev,noexec,relatime - cgroup systemd rw,name=systemd
34 30 0:27 / /run/user/1000/gvfs rw,nosuid,nodev,relatime - fuse.gvfsd-fuse gvfsd-fuse rw,user_id=1000,group_id=1000

root@ubuntu:/proc/4626# cat mounts
sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
udev /dev devtmpfs rw,relatime,size=3097160k,nr_inodes=204098,mode=755 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,nosuid,noexec,relatime,size=621552k,mode=755 0 0
/dev/sda1 / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0
none /sys/fs/cgroup tmpfs rw,relatime,size=4k,mode=755 0 0
none /sys/fs/fuse/connections fusectl rw,relatime 0 0
none /sys/kernel/debug debugfs rw,relatime 0 0
none /sys/kernel/security securityfs rw,relatime 0 0
none /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0
none /run/shm tmpfs rw,nosuid,nodev,relatime 0 0
none /run/user tmpfs rw,nosuid,nodev,noexec,relatime,size=102400k,mode=755 0 0
none /sys/fs/pstore pstore rw,relatime 0 0
systemd /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,name=systemd 0 0
gvfsd-fuse /run/user/1000/gvfs fuse.gvfsd-fuse rw,nosuid,nodev,relatime,user_id=1000,group_id=1000 0 0

root@ubuntu:/proc/4626# cat mountstats 
device sysfs mounted on /sys with fstype sysfs
device proc mounted on /proc with fstype proc
device udev mounted on /dev with fstype devtmpfs
device devpts mounted on /dev/pts with fstype devpts
device tmpfs mounted on /run with fstype tmpfs
device /dev/sda1 mounted on / with fstype ext4
device none mounted on /sys/fs/cgroup with fstype tmpfs
device none mounted on /sys/fs/fuse/connections with fstype fusectl
device none mounted on /sys/kernel/debug with fstype debugfs
device none mounted on /sys/kernel/security with fstype securityfs
device none mounted on /run/lock with fstype tmpfs
device none mounted on /run/shm with fstype tmpfs
device none mounted on /run/user with fstype tmpfs
device none mounted on /sys/fs/pstore with fstype pstore
device systemd mounted on /sys/fs/cgroup/systemd with fstype cgroup
device gvfsd-fuse mounted on /run/user/1000/gvfs with fstype fuse.gvfsd-fuse

12.查看进程状态信息

root@ubuntu:/proc/4626# cat status 
Name:    pp
State:    S (sleeping)
Tgid:    4626
Ngid:    0
Pid:    4626
PPid:    3978
TracerPid:    0
Uid:    1000    1000    1000    1000
Gid:    1000    1000    1000    1000
FDSize:    256
Groups:    4 24 27 30 46 108 124 1000 
NStgid:    4626
NSpid:    4626
NSpgid:    4626
NSsid:    3978
VmPeak:        2116 kB 最大虚拟内存峰值
VmSize:        2036 kB 虚拟内存
VmLck:           0 kB
VmPin:           0 kB
VmHWM:         544 kB
VmRSS:         544 kB
VmData:          40 kB
VmStk:         136 kB
VmExe:           4 kB
VmLib:        1824 kB
VmPTE:          16 kB
VmPMD:          12 kB
VmSwap:           0 kB
HugetlbPages:           0 kB
Threads:    1
SigQ:    0/48392
SigPnd:    0000000000000000
ShdPnd:    0000000000000000
SigBlk:    0000000000000000
SigIgn:    0000000000000000
SigCgt:    0000000000000000
CapInh:    0000000000000000
CapPrm:    0000000000000000
CapEff:    0000000000000000
CapBnd:    0000003fffffffff
CapAmb:    0000000000000000
Seccomp:    0
Cpus_allowed:    ff        允许运行的CPU掩码
Cpus_allowed_list:    0-7
Mems_allowed:    1
Mems_allowed_list:    0
voluntary_ctxt_switches:    296207
nonvoluntary_ctxt_switches:    26

13.查看可执行文件的内存映射

root@ubuntu:/proc/4626# cat maps 
08048000-08049000 r-xp 00000000 08:01 1310779    /home/hello/mytest/proc_test/pp    代码段
08049000-0804a000 r--p 00000000 08:01 1310779    /home/hello/mytest/proc_test/pp  只读存储区
0804a000-0804b000 rw-p 00001000 08:01 1310779    /home/hello/mytest/proc_test/pp  数据段
b75b6000-b75b7000 rw-p 00000000 00:00 0 
b75b7000-b775f000 r-xp 00000000 08:01 787745     /lib/i386-linux-gnu/libc-2.19.so
b775f000-b7760000 ---p 001a8000 08:01 787745     /lib/i386-linux-gnu/libc-2.19.so
b7760000-b7762000 r--p 001a8000 08:01 787745     /lib/i386-linux-gnu/libc-2.19.so
b7762000-b7763000 rw-p 001aa000 08:01 787745     /lib/i386-linux-gnu/libc-2.19.so
b7763000-b7766000 rw-p 00000000 00:00 0 
b777a000-b777c000 rw-p 00000000 00:00 0 
b777c000-b777e000 r--p 00000000 00:00 0          [vvar]
b777e000-b7780000 r-xp 00000000 00:00 0          [vdso]
b7780000-b77a0000 r-xp 00000000 08:01 787721     /lib/i386-linux-gnu/ld-2.19.so
b77a0000-b77a1000 r--p 0001f000 08:01 787721     /lib/i386-linux-gnu/ld-2.19.so
b77a1000-b77a2000 rw-p 00020000 08:01 787721     /lib/i386-linux-gnu/ld-2.19.so
bf9b8000-bf9d9000 rw-p 00000000 00:00 0          [stack]

14.task/4626/目录下面又有一层一样的东西

root@ubuntu:/proc/4626# ls task/4626/
attr      clear_refs  cwd      fdinfo   loginuid   mounts   oom_score      projid_map  sessionid  stat     uid_map
auxv      cmdline     environ  gid_map  maps       net      oom_score_adj  root        setgroups  statm    wchan
cgroup    comm        exe      io       mem        ns       pagemap        sched       smaps      status
children  cpuset      fd       limits   mountinfo  oom_adj  personality    schedstat   stack      syscall

15.net目录下又有这么多文件

root@ubuntu:/proc/4626# ls net/
anycast6   dev_mcast     icmp      ip6_flowlabel  ipv6_route  netlink    ptype   rt6_stats  snmp6         tcp      udplite6
arp        dev_snmp6     icmp6     ip6_mr_cache   l2cap       netstat    raw     rt_acct    sockstat      tcp6     unix
bnep       fib_trie      if_inet6  ip6_mr_vif     mcfilter    packet     raw6    rt_cache   sockstat6     udp      wireless
connector  fib_triestat  igmp      ip_mr_cache    mcfilter6   protocols  rfcomm  sco        softnet_stat  udp6     xfrm_stat
dev        hci           igmp6     ip_mr_vif      netfilter   psched     route   snmp       stat          udplite