finally decided to upgrade my host os to F15_XFCE.
fetch livecd and install as hardware img, all goes wel.
it’s very nice to see that firefox already upto 4.0.1 and kernel 2.6.38-27.
will upgrade kernel if necessary.
Category: Linux Development
rpm –target: Unkown option
today when Im tring to refresh kernel 2.6.39 on my Fedora11 node, some small issue hit during make rpm progress.
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[root@suse-pc linux-2.6.39]# make rpm make clean ... ... rpm --target i386 -ta ../kernel-2.6.39.ZIP.tar.gz --target: Unkown option |
double check and file the problem,
in the file linux-2.6.39/scripts/package/Makefile, this scriptwill detect the current installation of rpmbuild. If failed it will choose rpm instead. That’s why I hit the problem.
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23 24 # Do we have rpmbuild, otherwise fall back to the older rpm 25 RPM := $(shell if [ -x "/usr/bin/rpmbuild" ]; then echo rpmbuild; 26 else echo rpm; fi) 27 |
fix:
just refresh the rpm-build package and continue,.
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yum install rpm-build -y |
setjmp and longjmp
I’m reading <Expert C Programming>
this topic 6.8 is on setjmp/longjmp mechanism,
compared with throw/catch this setting obviously has an re-enter callback.
notes,
-zip
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#include <setjmp.h> jmp_buf buf; banana(){ printf("In banana()n"); longjmp(buf,1); printf("You'll never see this line.n"); } main(){ if (setjmp(buf)) printf("back into mainn"); else{ printf("first time running n"); banana(); } } |
SIGLOST not support on Linux
这两天正好在看TLPI，有一处问题，正好给Mark写了一封信，人家回答也比较nice，不过更多么。。还是靠google了
SIGLOST This signal name exists on Linux, but is unused.
基本上我这边的Linux相关代码，都没有使用这个值，甚至一些架构(如MIPS)连comments这样的待遇都么有。
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72 #define SIGIO 29 73 #define SIGPOLL SIGIO 74 /* 75 #define SIGLOST 29 76 */ 77 #define SIGPWR 30 |
只有在Linux.SPARC上才找到这个信号的定义
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76 #define SIGWINCH 28 77 #define SIGLOST 29 78 #define SIGPWR SIGLOST 79 #define SIGUSR1 30 |
当然，Solaris 10也有找到
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#define SIGLOST 37 /* resource lost (eg, record-lock lost) */</em></em> |
觉得比较有趣，记一下，顺便记一下Linux下 man signal(7)的描述
BUGS
SIGIO and SIGLOST have the same value. The latter is commented out in the kernel source, but the build process of some software still thinks that signal 29 is SIGLOST.
SSHd Debugging mode
今天同事有一个cluster出了点小问题，nodes之间passwdless SSH配不成功。我上去试了一下也不行。 重新generate key也没用。
后来才试着debug，google了一下发现ssh和sshd的debug mode,(或者可以通过man ssh/sshd来得到)
SERVER> /usr/sbin/sshd -d -e
CLIENT > ssh -v hostname
关于几个参数的意思，
man sshd>
-d Debug mode. The server sends verbose debug output to the system log, and does not put itself in the background. The server
also will not fork and will only process one connection. This option is only intended for debugging for the server. Multiple
-d options increase the debugging level. Maximum is 3.
-e When this option is specified, sshd will send the output to the standard error instead of the system log.
man ssh>
-v Verbose mode. Causes ssh to print debugging messages about its progress. This is helpful in debugging connection, authentica-
tion, and configuration problems. Multiple -v options increase the verbosity. The maximum is 3.
这边可以尝试ssh -vvv ， sshd -dd来处理，
然后发现在client端发出请求后被拒绝，在log里看到server端打出的信息，原来是人家$HOME目录权限问题，居然为了方便把$HOME权限设成了777…..实在太无语了….改成700后一切正常。
debug2: monitor_read: 3 used once, disabling now
debug2: monitor_read: 4 used once, disabling now
debug1: temporarily_use_uid: 94068/55536 (e=0/0)
debug1: trying public key file /scratch/crsusr/.ssh/authorized_keys
Authentication refused: bad ownership or modes for directory /scratch/crsusr
debug1: restore_uid: 0/0
debug1: temporarily_use_uid: 94068/55536 (e=0/0)
debug1: trying public key file /scratch/crsusr/.ssh/authorized_keys2
debug1: restore_uid: 0/0
