Skip to content

ci: Improve daemonisation by closing only open FDs #309

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
aarontomlin wants to merge 1 commit into
base: master
Choose a base branch
from
+40 −4
Open

ci: Improve daemonisation by closing only open FDs #309

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
44 changes: 40 additions & 4 deletions src/lib/citools/onload_server.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,10 +6,13 @@
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <dirent.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/types.h>

#include <ci/tools/log.h>
#include <ci/tools/debug.h>
Expand Down Expand Up @@ -37,6 +40,42 @@ void ci_server_set_log_prefix(char** log_prefix, const char* srv_bin)
ci_set_log_prefix(*log_prefix);
}

/*
* close_extra_fds - Close all open file descriptors excluding 0, 1 and 2
*/
static void close_extra_fds(void)
{
int i, dfd;
long long fd;
char *endp = NULL;
DIR *dir;
struct dirent *de;
struct rlimit rlim;

dir = opendir("/proc/self/fd");
if (dir) {
dfd = dirfd(dir);

while ( (de = readdir(dir)) != NULL ) {
/* Entries are numeric fd names; skip . and .. */
endp = NULL;
fd = strtoll(de->d_name, &endp, 10);
if ( endp == de->d_name || *endp != '\0' )
/* Not a number */
continue;

if ( fd <= STDERR_FILENO || fd == dfd )
continue;

(void)close((int)fd);
}
closedir(dir);
return;
}
if( getrlimit(RLIMIT_NOFILE, &rlim) == 0 )
for( i = STDERR_FILENO + 1; i < rlim.rlim_max; ++i )
close(i);
}

/* Fork off a daemon process according to the recipe in "man 7 daemon". This
* function returns only in the context of the daemon, and only on success;
Expand All @@ -49,15 +88,12 @@ void ci_server_daemonise(bool log_to_kern, char** log_prefix,
int devnull;
int i;
sigset_t sigset;
struct rlimit rlim;

/* Start with some tidy-up. We don't check errors here as failure is non-
* fatal. */

/* Close all files above stderr. */
if( getrlimit(RLIMIT_NOFILE, &rlim) == 0 )
for( i = STDERR_FILENO + 1; i < rlim.rlim_max; ++i )
close(i);
close_extra_fds();

/* Reset all signal handlers. */
for( i = 0; i < _NSIG; ++i )
Expand Down