我很困惑，我尝试了很多方法，但还是没有找到任何方法来解决错误。我发布了同样的帖子。我希望有人能帮助我。
我的问题是，
当我运行时ulimit -n 它显示12000。
当我跑步时rsh localhost ulimit -n，它显示12000。
到目前为止，一切都进展顺利。但实际问题出现了，我对 rsh 做了一些更改，通过添加一个功能和其他一些功能，它构建了一个名为 的新 rsh modified-rsh。请不要索要代码，因为那不是公开的，也不要说转移到 ssh ，因为 rsh 不安全。
这些我都知道。
当我运行命令时，modified-rsh localhost ulimit -n它显示 1024。为什么 ？？
你能告诉我这些事情发生的背后是什么原因吗？
我感到很无助。请帮我解决这种情况。提前谢谢。期待您的回复。
编辑 3
我认为这个编辑会有所帮助。这个编辑显示了在 modified-rsh 跟踪期间访问 ulimit 的位置和时间
命令 ：- strace -o log.txt modified-rsh localhost ulimit -n
writev(3, [{"service\0", 8}, {"service\0", 8}, {"ulimit -n\0", 10}], 3) = 26
read(3, "\0", 1) = 1
rt_sigprocmask(SIG_SETMASK, [], [URG], 8) = 0
setuid(500) = 0
rt_sigprocmask(SIG_BLOCK, [INT QUIT TERM], [], 8) = 0
rt_sigaction(SIGINT, {0x1, [INT], SA_RESTORER|SA_RESTART, 0x3454030330}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, {0x401650, [INT], SA_RESTORER|SA_RESTART, 0x3454030330}, {0x1, [INT], SA_RESTORER|SA_RESTART, 0x3454030330}, 8) = 0
rt_sigaction(SIGQUIT, {0x1, [QUIT], SA_RESTORER|SA_RESTART, 0x3454030330}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, {0x401650, [QUIT], SA_RESTORER|SA_RESTART, 0x3454030330}, {0x1, [QUIT], SA_RESTORER|SA_RESTART, 0x3454030330}, 8) = 0
rt_sigaction(SIGTERM, {0x1, [TERM], SA_RESTORER|SA_RESTART, 0x3454030330}, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTERM, {0x401650, [TERM], SA_RESTORER|SA_RESTART, 0x3454030330}, {0x1, [TERM], SA_RESTORER|SA_RESTART, 0x3454030330}, 8) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x2b749c27cd80) = 4583
ioctl(5, FIONBIO, [1]) = 0
ioctl(3, FIONBIO, [1]) = 0
rt_sigprocmask(SIG_SETMASK, [], [INT QUIT TERM], 8) = 0
select(6, [3 5], NULL, NULL, NULL) = 1 (in [3])
read(3, "1024\n", 8192) = 5
write(1, "1024\n", 5) = 5
select(6, [3 5], NULL, NULL, NULL) = 1 (in [3])
read(3, "", 8192) = 0
select(6, [5], NULL, NULL, NULL) = 1 (in [5])
read(5, "", 8192) = 0
kill(4583, SIGKILL) = 0
exit_group(0) = ?
看到read system call读取的是 1024。但应该读取的是 12000，问题出在哪里，你现在能识别出来吗？
编辑4
strace -e 打开修改后的 rsh 本地主机 ulimit -n
open("/etc/ld.so.cache", O_RDONLY) = 3
open("/lib64/libcrypt.so.1", O_RDONLY) = 3
open("/lib64/libutil.so.1", O_RDONLY) = 3
open("/lib64/libc.so.6", O_RDONLY) = 3
open("/etc/nsswitch.conf", O_RDONLY) = 3
open("/etc/ld.so.cache", O_RDONLY) = 3
open("/lib64/libnss_files.so.2", O_RDONLY) = 3
open("/etc/passwd", O_RDONLY) = 3
open("/etc/services", O_RDONLY) = 3
open("/etc/resolv.conf", O_RDONLY) = 3
open("/etc/host.conf", O_RDONLY) = 3
open("/etc/hosts", O_RDONLY) = 3
open("/etc/hosts", O_RDONLY) = 3
这些打开的系统调用是按顺序调用的，其中有 3 个是命令。其中只有四个是可读的，即 /etc/nsswitch.conf、/etc/passwd、/etc/services、/etc/resolv.conf
strace -e 打开 rsh 本地主机 ulimit -n
1 open("/etc/ld.so.cache", O_RDONLY) = 3
2 open("/lib64/libcrypt.so.1", O_RDONLY) = 3
3 open("/lib64/libutil.so.1", O_RDONLY) = 3
4 open("/lib64/libc.so.6", O_RDONLY) = 3
5 open("/etc/nsswitch.conf", O_RDONLY) = 3
6 open("/etc/ld.so.cache", O_RDONLY) = 3
7 open("/lib64/libnss_files.so.2", O_RDONLY) = 3
8 open("/etc/passwd", O_RDONLY) = 3
9 open("/etc/services", O_RDONLY) = 3
10 open("/etc/host.conf", O_RDONLY) = 3
11 open("/etc/resolv.conf", O_RDONLY) = 3
12 open("/etc/hosts", O_RDONLY) = 3
13 open("/etc/hosts", O_RDONLY) = 3
14 open("/etc/hosts", O_RDONLY) = 3
cat /etc/services | grep rsh
kshell 544/tcp krcmd # Kerberized `rsh' (v5)
rsh-spx 222/tcp # Berkeley rshd with SPX auth
rsh-spx 222/udp # Berkeley rshd with SPX auth
carrius-rshell 1197/tcp # Carrius Remote Access
carrius-rshell 1197/udp # Carrius Remote Access
airshot 3975/tcp # Air Shot
airshot 3975/udp # Air Shot
watershed-lm 6143/tcp # Watershed License Manager
watershed-lm 6143/udp # Watershed License Manager
modified-rsh 2529/tcp
我使用的以下命令是该论坛上的一个问题所使用的，其链接在这里
[root@jhamb ~]# sudo grep limits /etc/pam.d/*
/etc/pam.d/atd:# To enable PAM user limits for atd, please uncomment the
/etc/pam.d/atd:# following line and configure /etc/security/limits.conf:
/etc/pam.d/atd:# session required pam_limits.so
/etc/pam.d/runuser:session required pam_limits.so
/etc/pam.d/sudo:session required pam_limits.so
/etc/pam.d/sudo-i:session required pam_limits.so
/etc/pam.d/system-auth:session required pam_limits.so
/etc/pam.d/system-auth-ac:session required pam_limits.so
答案1
您应该使用 strace 连接到 rsh 守护进程并查找 setrlimit 调用：
strace -p $PID -f -e trace=setrlimit
这两个版本应该有所不同。这应该能帮你找到问题所在。