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 = '';

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

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

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

二、测试

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

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

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

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

3.查看进程运行环境
sfl@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
sfl@ubuntu:/proc/4626$ ls fd -l 查看所有打开的文件的路径
total 0
lrwx------ 1 sfl sfl 64 Sep 27 08:36 0 -> /dev/pts/0 std_in
lrwx------ 1 sfl sfl 64 Sep 27 08:36 1 -> /dev/pts/0 std_out
lrwx------ 1 sfl sfl 64 Sep 27 08:34 2 -> /dev/pts/0 std_error
lrwx------ 1 sfl sfl 64 Sep 27 08:36 3 -> /home/sfl/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/# 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                          unlimited            bytes
Max core file size                            unlimited            bytes
Max resident set          unlimited            unlimited            bytes
Max processes                                             processes
Max open files                                              files
Max locked memory                                         bytes
Max address space         unlimited            unlimited            bytes
Max file locks            unlimited            unlimited            locks
Max pending signals                                       signals
Max msgqueue size                                       bytes
Max nice priority
Max realtime priority
Max realtime timeout      unlimited            unlimited            us  

11.查看文件系统的挂载信息 per-thread的!!

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

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

root@ubuntu:/proc/# 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//gvfs with fstype fuse.gvfsd-fuse

12.查看进程状态信息

root@ubuntu:/proc/# cat status
Name:    pp
State:    S (sleeping)
Tgid:
Ngid:
Pid:
PPid:
TracerPid:
Uid:
Gid:
FDSize:
Groups:
NStgid:
NSpid:
NSpgid:
NSsid:
VmPeak:         kB 最大虚拟内存峰值
VmSize:         kB 虚拟内存
VmLck:            kB
VmPin:            kB
VmHWM:          kB
VmRSS:          kB
VmData:           kB
VmStk:          kB
VmExe:            kB
VmLib:         kB
VmPTE:           kB
VmPMD:           kB
VmSwap:            kB
HugetlbPages:            kB
Threads:
SigQ:    /
SigPnd:
ShdPnd:
SigBlk:
SigIgn:
SigCgt:
CapInh:
CapPrm:
CapEff:
CapBnd:    0000003fffffffff
CapAmb:
Seccomp:
Cpus_allowed:    ff        允许运行的CPU掩码
Cpus_allowed_list:    -
Mems_allowed:
Mems_allowed_list:
voluntary_ctxt_switches:
nonvoluntary_ctxt_switches:    

13.查看可执行文件的内存映射

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

14.task/4626/目录下面又有一层一样的东西

root@ubuntu:/proc/# ls task//
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/# 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