From cccfffbe04c01be12fb42cb12f3f7aa5e2a22dd4 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Wed, 7 Apr 2010 09:24:25 +0200 Subject: [PATCH] cdrom_id: retry to open the device, if EBUSY We might fight about the device with polling processes, or other users who probe the device. Retry a few times if the other one goes away in the meantime. Based on a patch from Harald Hoyer. --- extras/cdrom_id/cdrom_id.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/extras/cdrom_id/cdrom_id.c b/extras/cdrom_id/cdrom_id.c index 036ef284b..7c9f8cc73 100644 --- a/extras/cdrom_id/cdrom_id.c +++ b/extras/cdrom_id/cdrom_id.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -591,7 +592,22 @@ int main(int argc, char *argv[]) goto exit; } - fd = open(node, O_RDONLY|O_NONBLOCK|(is_mounted(node) ? 0 : O_EXCL)); + if (is_mounted(node)) { + fd = open(node, O_RDONLY|O_NONBLOCK); + } else { + int cnt; + struct timespec duration; + + srand((unsigned int)getpid()); + for (cnt = 40; cnt > 0; cnt--) { + fd = open(node, O_RDONLY|O_NONBLOCK|O_EXCL); + if (fd >= 0 || errno != EBUSY) + break; + duration.tv_sec = 0; + duration.tv_nsec = (100 * 1000 * 1000) + (rand() % 100 * 1000 * 1000); + nanosleep(&duration, NULL); + } + } if (fd < 0) { info(udev, "unable to open '%s'\n", node); fprintf(stderr, "unable to open '%s'\n", node); -- 2.30.2