I have been debugging a script that is called every thirty seconds. Basically it is doing a ps, well two actually, one to file (read by the getline below) and the other into a pipe. The one into the pipe is: -
V_SYSVPS=/usr/sysv/bin/ps
The problem is that the sysv ps intermittently takes longer than 30 seconds to come back, I have echoed the date to file either side of it and it is definitely blocking on the write to the pipe. I have also trussed the nawk and it hangs on the read from the pipe.
I spotted that the getline does not check for EOF or close the file but it still blocks on the write to the pipe after I fixed it.
Trussing the ps itself shows it goes to the /dev directory for some reason which contains 29000 files and does a statx on each. However most of the time it deals with that in under 2 seconds.
Can anyone tell me if there is anything about the sysv ps that can explain this 30 delay? (Sometimes it takes 20 or so seconds but this completes in time)
Apparently this is using both ps commands because they could not get all the info they wanted from just the one version.
I'm in highschool. They blocked my favorite site. How do I disable websense without getting caught on that particular webpage? Is it even possible? *twitch* I would also like to get as much UNIX for beginners information, so if someone might point me in the right direction so I don't have to read... (1 Reply)
I've got a legit DHCP server on my network. I've got a 3550 as my VTP server providing 4 vlans to 4 2950 switches. If somebody were to plug into one of those vlans with a DHCP server configured then it would throw off my whole network. How could i block the DHCP server that could plug into the... (2 Replies)
Hello,
My problem thus follows:
I am running a server which allows users to connect on UDP, not TCP.
There is a certain hacker, whom I have the IP of, who keeps crashing the server. I simply want to block him from accessing my box at all. I added him to the hosts.deny file, but am not sure if... (4 Replies)
Hello,
Would this be an acceptable way of creating a non-blocking pipe.
Basically I want to create kind of a server client arch.
This code would be in the server, and I don't want to have to wait for
clients to read before moving on to the next client. One problem I
can see is if... (4 Replies)
sed -n '/robots.txt/!{s/\(\{1,\}\.*\.*\.*\).*\/\(.*\.txt\).*/\1 \2/p;}' myaapache.log
Above command will search all txt except robots.txt from apache logs and show like
94.136.63.119 idsuper.txt
174.121.67.233 fx29id1.txt
I want to block that ip address automatically, i need script... (1 Reply)
OS : solaris 10 X86
I created stream socket, tries to connect to port 7 on the remote machine.
After doing the non blocking connect call I did select with time out value is 3 secs. I am always getting timed out though I am writing prior to select.
code:
x=fcntl(S,F_GETFL,0);... (1 Reply)
I know how to add signal to a set. But what if I want to add 2 or 3 signals to the set.
I know I can use sigaddset (&set,SIGBUS)....but what if I want to add SIGBUS and SIGALRM at once. Do i have to do it like this..
sigaddset (&set,SIGBUS);
sigaddset (&set,SIGALRM);
Is there another way to... (0 Replies)
Dear all,
I am new to this forum.I need some assistant from you people.
I have a server in which Linux 5 is installed and it is in the network. How i block any user to access my server.. Upto how many users i can block.. send me the procedure....
Thank you in advance...... (10 Replies)
Hi
I am starting to practice nmap for my own education.
Now I created two host in virtual box.
Bot are scientific linux, one in installed as web server and the other as developing station.
I tried to run nmap on so I did nmap on their IP address, I got an answer that ip is down or that... (8 Replies)
among the below socket programming api's, please let me know which are blocking and non-blocking.
socket
accept
bind
listen
write
read
close (2 Replies)
Discussion started by: VSSajjan
2 Replies
LEARN ABOUT NETBSD
getline
GETDELIM(3) BSD Library Functions Manual GETDELIM(3)NAME
getdelim, getline -- read a delimited record from a stream
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdio.h>
ssize_t
getdelim(char ** restrict lineptr, size_t * restrict n, int delimiter, FILE * restrict stream);
ssize_t
getline(char ** restrict lineptr, size_t * restrict n, FILE * restrict stream);
DESCRIPTION
The getdelim() function reads from the stream until it encounters a character matching delimiter, storing the input in *lineptr. The buffer
is NUL-terminated and includes the delimiter. The delimiter character must be representable as an unsigned char.
If *n is non-zero, then *lineptr must be pre-allocated to at least *n bytes. The buffer should be allocated dynamically; it must be possible
to free(3) *lineptr. getdelim() ensures that *lineptr is large enough to hold the input, updating *n to reflect the new size.
The getline() function is equivalent to getdelim() with delimiter set to the newline character.
RETURN VALUES
The getdelim() and getline() functions return the number of characters read, including the delimiter. If no characters were read and the
stream is at end-of-file, the functions return -1. If an error occurs, the functions return -1 and the global variable errno is set to indi-
cate the error.
The functions do not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.
EXAMPLES
The following code fragment reads lines from a file and writes them to standard output.
char *line = NULL;
size_t linesize = 0;
ssize_t linelen;
while ((linelen = getline(&line, &linesize, fp)) != -1)
fwrite(line, linelen, 1, stdout);
if (ferror(fp))
perror("getline");
ERRORS
[EINVAL] lineptr or n is a NULL pointer.
[EOVERFLOW] More than SSIZE_MAX characters were read without encountering the delimiter.
The getdelim() and getline() functions may also fail and set errno for any of the errors specified in the routines fflush(3), malloc(3),
read(2), stat(2), or realloc(3).
SEE ALSO ferror(3), fgets(3), fopen(3)STANDARDS
The getdelim() and getline() functions conform to IEEE Std 1003.1-2008 (``POSIX.1'').
BSD June 30, 2010 BSD