chg: close file descriptors when starting the daemon
It's good practice to close file descriptors when forking to start a daemon.
This did not appear to happen yet, which results in flock hanging
in one location in our system (because the chg daemon keeps
the locked file open).
Differential Revision: https://phab.mercurial-scm.org/D9268
--- a/contrib/chg/chg.c Sat Oct 31 17:42:31 2020 -0400
+++ b/contrib/chg/chg.c Mon Nov 02 11:58:34 2020 +0100
@@ -8,6 +8,7 @@
*/
#include <assert.h>
+#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
@@ -269,6 +270,31 @@
}
}
+ /* close any open files to avoid hanging locks */
+ DIR *dp = opendir("/proc/self/fd");
+ if (dp != NULL) {
+ debugmsg("closing files based on /proc contents");
+ struct dirent *de;
+ while ((de = readdir(dp))) {
+ char *end;
+ long fd_value = strtol(de->d_name, &end, 10);
+ if (end == de->d_name) {
+ /* unable to convert to int (. or ..) */
+ continue;
+ }
+ if (errno == ERANGE) {
+ debugmsg("tried to parse %s, but range error occurred", de->d_name);
+ continue;
+ }
+ if (fd_value > STDERR_FILENO) {
+ int res = close(fd_value);
+ if (res) {
+ debugmsg("tried to close fd %ld: %d (errno: %d)", fd_value, res, errno);
+ }
+ }
+ }
+ }
+
if (putenv("CHGINTERNALMARK=") != 0)
abortmsgerrno("failed to putenv");
if (execvp(hgcmd, (char **)argv) < 0)