Is there any way to know how many sockets have been created by a C program?
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I have been running a C program which connects to a Redis database every once in a while. After running the program for a few hours it was displaying "Cannot create socket: too many files open". I'm pretty sure that I'm closing the connection every time after I'm done with the logic part at the database. So I wanted to know if there is any way to know how many sockets have been created by a C program, while it is running?
I'm using Ubuntu 16.04.
shell networking c socket
asked Mar 14 at 7:03
yashyash
256
add a comment |
I have been running a C program which connects to a Redis database every once in a while. After running the program for a few hours it was displaying "Cannot create socket: too many files open". I'm pretty sure that I'm closing the connection every time after I'm done with the logic part at the database. So I wanted to know if there is any way to know how many sockets have been created by a C program, while it is running?
I'm using Ubuntu 16.04.
shell networking c socket
asked Mar 14 at 7:03
yashyash
256
1
On linux:find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.
– mosvy
Mar 14 at 8:04
add a comment |
I have been running a C program which connects to a Redis database every once in a while. After running the program for a few hours it was displaying "Cannot create socket: too many files open". I'm pretty sure that I'm closing the connection every time after I'm done with the logic part at the database. So I wanted to know if there is any way to know how many sockets have been created by a C program, while it is running?
I'm using Ubuntu 16.04.
shell networking c socket
asked Mar 14 at 7:03
yashyash
256
I have been running a C program which connects to a Redis database every once in a while. After running the program for a few hours it was displaying "Cannot create socket: too many files open". I'm pretty sure that I'm closing the connection every time after I'm done with the logic part at the database. So I wanted to know if there is any way to know how many sockets have been created by a C program, while it is running?
I'm using Ubuntu 16.04.
shell networking c socket
shell networking c socket
asked Mar 14 at 7:03
yashyash
256
asked Mar 14 at 7:03
yashyash
256
edited Mar 14 at 10:01
yash
asked Mar 14 at 7:03
yashyash
256
asked Mar 14 at 7:03
yashyash
256
asked Mar 14 at 7:03
yashyash
256
256
1
On linux:find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.
– mosvy
Mar 14 at 8:04
add a comment |
1
On linux:find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.
– mosvy
Mar 14 at 8:04
1
1
On linux:
find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.– mosvy
Mar 14 at 8:04
On linux:
find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.– mosvy
Mar 14 at 8:04
add a comment |
2 Answers
2
active
oldest
votes
You did not specify an operating system, and /proc/*/fd/ does not exist on all operating systems.
You actually need to list all of the currently open file descriptors for the process, from which you can determine what is actually being leaked. It is not necessarily a socket file descriptor that is being leaked.
On FreeBSD, NetBSD, OpenBSD …
… and their various derivatives (e.g. TrueOS, DragonFly BSD).
Use the fstat command with the -p option and the relevant process ID:
fstat -p 718
fstat. NetBSD General Commands Manual. 2013-12-15.
On AIX
Use the procfiles command similarly, with the -n option to print names:
procfiles -n 6679
procfiles. AIX 7.2. IBM Knowledge Centre.
On OpenSolaris …
… and thus on Illumos, Schillix, et al.
Use the pfiles command:
pfiles 13253
pfiles. User Commands. SunOS 10.5 Manual. 2008-12-10.
On Linux
Use the lsof command similarly:
lsof -p 41467
Furthermore
In my C++ programs, a simple class that owns a file descriptor and closes it in its destructor works wonders. Unfortunately, you'll have to resort to GNU-specific language extensions (i.e. __attribute__(__cleanup__)) to get that in C programs.
You can of course go further with other tools. With DTrace and a suitable script, you can monitor the process as it opens and closes file descriptors. (You can do this with truss, or ktrace or strace, too; although the their mechanisms for selecting subsets of the system calls made are either fairly basic or nonexistent. You can also do this with a debugger and some suitable breakpoints.)
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
add a comment |
At a system level at does not better what language the program is written in.
Looking in /proc/«pid»/fd will tell you total number of file descriptors, that the process has open (not just sockets), but will be a close approximation. Maybe some one else can tell you for sockets.
There is also strace you can use this to trace system calls that your process makes. strace «my-program» «program args…»
in the program
Add some logging: printf when you open and close a socket, to a logfile.
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
add a comment |
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2 Answers
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You did not specify an operating system, and /proc/*/fd/ does not exist on all operating systems.
You actually need to list all of the currently open file descriptors for the process, from which you can determine what is actually being leaked. It is not necessarily a socket file descriptor that is being leaked.
On FreeBSD, NetBSD, OpenBSD …
… and their various derivatives (e.g. TrueOS, DragonFly BSD).
Use the fstat command with the -p option and the relevant process ID:
fstat -p 718
fstat. NetBSD General Commands Manual. 2013-12-15.
On AIX
Use the procfiles command similarly, with the -n option to print names:
procfiles -n 6679
procfiles. AIX 7.2. IBM Knowledge Centre.
On OpenSolaris …
… and thus on Illumos, Schillix, et al.
Use the pfiles command:
pfiles 13253
pfiles. User Commands. SunOS 10.5 Manual. 2008-12-10.
On Linux
Use the lsof command similarly:
lsof -p 41467
Furthermore
In my C++ programs, a simple class that owns a file descriptor and closes it in its destructor works wonders. Unfortunately, you'll have to resort to GNU-specific language extensions (i.e. __attribute__(__cleanup__)) to get that in C programs.
You can of course go further with other tools. With DTrace and a suitable script, you can monitor the process as it opens and closes file descriptors. (You can do this with truss, or ktrace or strace, too; although the their mechanisms for selecting subsets of the system calls made are either fairly basic or nonexistent. You can also do this with a debugger and some suitable breakpoints.)
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
add a comment |
You did not specify an operating system, and /proc/*/fd/ does not exist on all operating systems.
You actually need to list all of the currently open file descriptors for the process, from which you can determine what is actually being leaked. It is not necessarily a socket file descriptor that is being leaked.
On FreeBSD, NetBSD, OpenBSD …
… and their various derivatives (e.g. TrueOS, DragonFly BSD).
Use the fstat command with the -p option and the relevant process ID:
fstat -p 718
fstat. NetBSD General Commands Manual. 2013-12-15.
On AIX
Use the procfiles command similarly, with the -n option to print names:
procfiles -n 6679
procfiles. AIX 7.2. IBM Knowledge Centre.
On OpenSolaris …
… and thus on Illumos, Schillix, et al.
Use the pfiles command:
pfiles 13253
pfiles. User Commands. SunOS 10.5 Manual. 2008-12-10.
On Linux
Use the lsof command similarly:
lsof -p 41467
Furthermore
In my C++ programs, a simple class that owns a file descriptor and closes it in its destructor works wonders. Unfortunately, you'll have to resort to GNU-specific language extensions (i.e. __attribute__(__cleanup__)) to get that in C programs.
You can of course go further with other tools. With DTrace and a suitable script, you can monitor the process as it opens and closes file descriptors. (You can do this with truss, or ktrace or strace, too; although the their mechanisms for selecting subsets of the system calls made are either fairly basic or nonexistent. You can also do this with a debugger and some suitable breakpoints.)
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
add a comment |
You did not specify an operating system, and /proc/*/fd/ does not exist on all operating systems.
You actually need to list all of the currently open file descriptors for the process, from which you can determine what is actually being leaked. It is not necessarily a socket file descriptor that is being leaked.
On FreeBSD, NetBSD, OpenBSD …
… and their various derivatives (e.g. TrueOS, DragonFly BSD).
Use the fstat command with the -p option and the relevant process ID:
fstat -p 718
fstat. NetBSD General Commands Manual. 2013-12-15.
On AIX
Use the procfiles command similarly, with the -n option to print names:
procfiles -n 6679
procfiles. AIX 7.2. IBM Knowledge Centre.
On OpenSolaris …
… and thus on Illumos, Schillix, et al.
Use the pfiles command:
pfiles 13253
pfiles. User Commands. SunOS 10.5 Manual. 2008-12-10.
On Linux
Use the lsof command similarly:
lsof -p 41467
Furthermore
In my C++ programs, a simple class that owns a file descriptor and closes it in its destructor works wonders. Unfortunately, you'll have to resort to GNU-specific language extensions (i.e. __attribute__(__cleanup__)) to get that in C programs.
You can of course go further with other tools. With DTrace and a suitable script, you can monitor the process as it opens and closes file descriptors. (You can do this with truss, or ktrace or strace, too; although the their mechanisms for selecting subsets of the system calls made are either fairly basic or nonexistent. You can also do this with a debugger and some suitable breakpoints.)
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
You did not specify an operating system, and /proc/*/fd/ does not exist on all operating systems.
You actually need to list all of the currently open file descriptors for the process, from which you can determine what is actually being leaked. It is not necessarily a socket file descriptor that is being leaked.
On FreeBSD, NetBSD, OpenBSD …
… and their various derivatives (e.g. TrueOS, DragonFly BSD).
Use the fstat command with the -p option and the relevant process ID:
fstat -p 718
fstat. NetBSD General Commands Manual. 2013-12-15.
On AIX
Use the procfiles command similarly, with the -n option to print names:
procfiles -n 6679
procfiles. AIX 7.2. IBM Knowledge Centre.
On OpenSolaris …
… and thus on Illumos, Schillix, et al.
Use the pfiles command:
pfiles 13253
pfiles. User Commands. SunOS 10.5 Manual. 2008-12-10.
On Linux
Use the lsof command similarly:
lsof -p 41467
Furthermore
In my C++ programs, a simple class that owns a file descriptor and closes it in its destructor works wonders. Unfortunately, you'll have to resort to GNU-specific language extensions (i.e. __attribute__(__cleanup__)) to get that in C programs.
You can of course go further with other tools. With DTrace and a suitable script, you can monitor the process as it opens and closes file descriptors. (You can do this with truss, or ktrace or strace, too; although the their mechanisms for selecting subsets of the system calls made are either fairly basic or nonexistent. You can also do this with a debugger and some suitable breakpoints.)
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
answered Mar 14 at 9:40
JdeBPJdeBP
38.1k478185
38.1k478185
add a comment |
add a comment |
At a system level at does not better what language the program is written in.
Looking in /proc/«pid»/fd will tell you total number of file descriptors, that the process has open (not just sockets), but will be a close approximation. Maybe some one else can tell you for sockets.
There is also strace you can use this to trace system calls that your process makes. strace «my-program» «program args…»
in the program
Add some logging: printf when you open and close a socket, to a logfile.
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
add a comment |
At a system level at does not better what language the program is written in.
Looking in /proc/«pid»/fd will tell you total number of file descriptors, that the process has open (not just sockets), but will be a close approximation. Maybe some one else can tell you for sockets.
There is also strace you can use this to trace system calls that your process makes. strace «my-program» «program args…»
in the program
Add some logging: printf when you open and close a socket, to a logfile.
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
add a comment |
At a system level at does not better what language the program is written in.
Looking in /proc/«pid»/fd will tell you total number of file descriptors, that the process has open (not just sockets), but will be a close approximation. Maybe some one else can tell you for sockets.
There is also strace you can use this to trace system calls that your process makes. strace «my-program» «program args…»
in the program
Add some logging: printf when you open and close a socket, to a logfile.
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
At a system level at does not better what language the program is written in.
Looking in /proc/«pid»/fd will tell you total number of file descriptors, that the process has open (not just sockets), but will be a close approximation. Maybe some one else can tell you for sockets.
There is also strace you can use this to trace system calls that your process makes. strace «my-program» «program args…»
in the program
Add some logging: printf when you open and close a socket, to a logfile.
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
answered Mar 14 at 7:27
ctrl-alt-delorctrl-alt-delor
12.4k52662
12.4k52662
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
add a comment |
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
Does the count of files in /proc/«pid»/fd show the total number of sockets open at current time or does the count specify the total number of sockets created over time.
– yash
Mar 14 at 9:35
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
No. There is no count summary, there are just files. Each file represents an open file ( where file is a file, socket, pipe, … that is open at the time). Therefore there will be a few more than the number of open sockets. (3 plus one for every socket, file, pipe that the process opened).
– ctrl-alt-delor
Mar 14 at 16:45
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
@JdeBP`s answer is fuller, and shows how to get just the sockets.
– ctrl-alt-delor
Mar 14 at 16:47
add a comment |
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On linux:
find /proc/PID/fd -lname 'socket:*' | wc -l. But unless your C program is the next big thing, it has no business having open more than a couple sockets at the same time; go fix it so it stops leaking fds -- every open file or socket should be closed when no longer in use.– mosvy
Mar 14 at 8:04