From 3ea24eb8e68ba18e215aec0f10d96f75b23c340b Mon Sep 17 00:00:00 2001 From: Christian Seiler Date: Thu, 23 Feb 2012 09:57:13 +0100 Subject: [PATCH] Enable get_cgroup_mount to search for mount points satisfying multiple subsystems at once lxc-attach functionality reads /proc/init_pid/cgroup to determine the cgroup of the container for a given subsystem. However, since subsystems may be mounted together, we want to be on the safe side and be sure that we really find the correct mount point, so we allow get_cgroup_mount to check for *all* the subsystems; the subsystem parameter may now be a comma-separated list. Signed-off-by: Daniel Lezcano --- src/lxc/cgroup.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c index 6ae67bd0d..2e04c7910 100644 --- a/src/lxc/cgroup.c +++ b/src/lxc/cgroup.c @@ -52,6 +52,35 @@ enum { CGROUP_CLONE_CHILDREN, }; +static char *hasmntopt_multiple(struct mntent *mntent, const char *options) +{ + const char *ptr = options; + const char *ptr2 = strchr(options, ','); + char *result; + + while (ptr2 != NULL) { + char *option = strndup(ptr, ptr2 - ptr); + if (!option) { + SYSERROR("Temporary memory allocation error"); + return NULL; + } + + result = hasmntopt(mntent, option); + free(option); + + if (!result) { + return NULL; + } + + ptr = ptr2 + 1; + ptr2 = strchr(ptr, ','); + } + + /* for multiple mount options, the return value is basically NULL + * or non-NULL, so this should suffice for our purposes */ + return hasmntopt(mntent, ptr); +} + static int get_cgroup_mount(const char *subsystem, char *mnt) { struct mntent *mntent; @@ -67,7 +96,7 @@ static int get_cgroup_mount(const char *subsystem, char *mnt) if (strcmp(mntent->mnt_type, "cgroup")) continue; - if (!subsystem || hasmntopt(mntent, subsystem)) { + if (!subsystem || hasmntopt_multiple(mntent, subsystem)) { strcpy(mnt, mntent->mnt_dir); fclose(file); DEBUG("using cgroup mounted at '%s'", mnt);