autodev: don't always create /dev/console

In particular, only create /dev/console when it is set to "none".
Otherwise, we will bind mount a pts device later, so let's just leave it.

Also, when bind mounting the pts device, let's create /dev/console if it
doesn't exist, since it may not already exist due to the above :)

v2: s/ot/to
v3: add O_EXCL so we actually get EEXIST, use the right condition for
    mount_console (we want to compare against console.path, not
    console.name, and console.path can be null)

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 56dd467b77ee0381b5c6f5a37b5e18cf97fdfbe4..2f8338dad02f3c126d00c76e76be0da467f892bb 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1130,7 +1130,7 @@ static const struct lxc_devs lxc_devs[] = {
        { "console",    S_IFCHR | S_IRUSR | S_IWUSR,           5, 1     },
 };
 
-static int fill_autodev(const struct lxc_rootfs *rootfs)
+static int fill_autodev(const struct lxc_rootfs *rootfs, bool mount_console)
 {
        int ret;
        char path[MAXPATHLEN];
@@ -1152,6 +1152,10 @@ static int fill_autodev(const struct lxc_rootfs *rootfs)
        cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
        for (i = 0; i < sizeof(lxc_devs) / sizeof(lxc_devs[0]); i++) {
                const struct lxc_devs *d = &lxc_devs[i];
+
+               if (!strcmp(d->name, "console") && !mount_console)
+                       continue;
+
                ret = snprintf(path, MAXPATHLEN, "%s/dev/%s", rootfs->path ? rootfs->mount : "", d->name);
                if (ret < 0 || ret >= MAXPATHLEN)
                        return -1;
@@ -1395,8 +1399,7 @@ static int setup_dev_console(const struct lxc_rootfs *rootfs,
                         const struct lxc_console *console)
 {
        char path[MAXPATHLEN];
-       struct stat s;
-       int ret;
+       int ret, fd;
 
        ret = snprintf(path, sizeof(path), "%s/dev/console", rootfs->mount);
        if (ret >= sizeof(path)) {
@@ -1404,9 +1407,14 @@ static int setup_dev_console(const struct lxc_rootfs *rootfs,
                return -1;
        }
 
-       if (access(path, F_OK)) {
-               WARN("rootfs specified but no console found at '%s'", path);
-               return 0;
+       fd = open(path, O_CREAT | O_EXCL, S_IXUSR | S_IXGRP | S_IXOTH);
+       if (fd < 0) {
+               if (errno != EEXIST) {
+                       SYSERROR("failed to create console");
+                       return -1;
+               }
+       } else {
+               close(fd);
        }
 
        if (console->master < 0) {
@@ -1414,14 +1422,9 @@ static int setup_dev_console(const struct lxc_rootfs *rootfs,
                return 0;
        }
 
-       if (stat(path, &s)) {
-               SYSERROR("failed to stat '%s'", path);
-               return -1;
-       }
-
-       if (chmod(console->name, s.st_mode)) {
+       if (chmod(console->name, S_IXUSR | S_IXGRP | S_IXOTH)) {
                SYSERROR("failed to set mode '0%o' to '%s'",
-                        s.st_mode, console->name);
+                        S_IXUSR | S_IXGRP | S_IXOTH, console->name);
                return -1;
        }
 
@@ -3749,11 +3752,13 @@ int lxc_setup(struct lxc_handler *handler)
        }
 
        if (lxc_conf->autodev > 0) {
+               bool mount_console = lxc_conf->console.path && !strcmp(lxc_conf->console.path, "none");
+
                if (run_lxc_hooks(name, "autodev", lxc_conf, lxcpath, NULL)) {
                        ERROR("failed to run autodev hooks for container '%s'.", name);
                        return -1;
                }
-               if (fill_autodev(&lxc_conf->rootfs)) {
+               if (fill_autodev(&lxc_conf->rootfs, mount_console)) {
                        ERROR("failed to populate /dev in the container");
                        return -1;
                }