#define FUSE_USE_VERSION 26
+#define __STDC_FORMAT_MACROS
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <fuse.h>
+#include <inttypes.h>
#include <libgen.h>
#include <pthread.h>
#include <sched.h>
#include <stdbool.h>
+#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <wait.h>
+#include <linux/magic.h>
#include <linux/sched.h>
#include <sys/epoll.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/syscall.h>
+#include <sys/sysinfo.h>
+#include <sys/vfs.h>
#include "bindings.h"
#include "config.h" // for VERSION
+/* Maximum number for 64 bit integer is a string with 21 digits: 2^64 - 1 = 21 */
+#define LXCFS_NUMSTRLEN64 21
+
/* Define pivot_root() if missing from the C library */
#ifndef HAVE_PIVOT_ROOT
static int pivot_root(const char * new_root, const char * put_old)
int cached;
};
-/* reserve buffer size, for cpuall in /proc/stat */
-#define BUF_RESERVE_SIZE 256
+/* Reserve buffer size to account for file size changes. */
+#define BUF_RESERVE_SIZE 512
/*
* A table caching which pid is init for a pid namespace.
* another namespace using the *at() family of functions
* {openat(), fchownat(), ...}. */
static int *fd_hierarchies;
+static int cgroup_mount_ns_fd = -1;
static void unlock_mutex(pthread_mutex_t *l)
{
{
int i;
+ fprintf(stderr, "mount namespace: %d\n", cgroup_mount_ns_fd);
fprintf(stderr, "hierarchies:\n");
for (i = 0; i < num_hierarchies; i++) {
if (hierarchies[i])
fnam = alloca(len);
ret = snprintf(fnam, len, "%s%s/%s", *cgroup == '/' ? "." : "", cgroup, file);
if (ret < 0 || (size_t)ret >= len)
- return NULL;
+ return false;
fd = openat(cfd, fnam, O_RDONLY);
if (fd < 0)
- return NULL;
+ return false;
*value = slurp_file(fnam, fd);
return *value != NULL;
ret = -ENOENT;
goto out;
}
- if (!fc_may_access(fc, controller, path1, path2, O_RDONLY)) {
- ret = -EACCES;
- goto out;
- }
-
ret = 0;
}
if (initpid <= 0)
initpid = fc->pid;
if (!caller_is_in_ancestor(initpid, controller, cgroup, &next)) {
- if (!last || strcmp(next, last) == 0)
+ if (!last || (next && (strcmp(next, last) == 0)))
ret = -EBUSY;
else
ret = -ENOENT;
char *eol;
while (*memstat) {
- if (startswith(memstat, "cache")) {
+ if (startswith(memstat, "total_cache")) {
sscanf(memstat + 11, "%lu", cached);
*cached /= 1024;
- } else if (startswith(memstat, "active_anon")) {
- sscanf(memstat + 11, "%lu", active_anon);
+ } else if (startswith(memstat, "total_active_anon")) {
+ sscanf(memstat + 17, "%lu", active_anon);
*active_anon /= 1024;
- } else if (startswith(memstat, "inactive_anon")) {
- sscanf(memstat + 11, "%lu", inactive_anon);
+ } else if (startswith(memstat, "total_inactive_anon")) {
+ sscanf(memstat + 19, "%lu", inactive_anon);
*inactive_anon /= 1024;
- } else if (startswith(memstat, "active_file")) {
- sscanf(memstat + 11, "%lu", active_file);
+ } else if (startswith(memstat, "total_active_file")) {
+ sscanf(memstat + 17, "%lu", active_file);
*active_file /= 1024;
- } else if (startswith(memstat, "inactive_file")) {
- sscanf(memstat + 11, "%lu", inactive_file);
+ } else if (startswith(memstat, "total_inactive_file")) {
+ sscanf(memstat + 19, "%lu", inactive_file);
*inactive_file /= 1024;
- } else if (startswith(memstat, "unevictable")) {
- sscanf(memstat + 11, "%lu", unevictable);
+ } else if (startswith(memstat, "total_unevictable")) {
+ sscanf(memstat + 17, "%lu", unevictable);
*unevictable /= 1024;
}
eol = strchr(memstat, '\n');
* FUSE ops for /proc
*/
-static unsigned long get_memlimit(const char *cgroup)
+static unsigned long get_memlimit(const char *cgroup, const char *file)
{
char *memlimit_str = NULL;
unsigned long memlimit = -1;
- if (cgfs_get_value("memory", cgroup, "memory.limit_in_bytes", &memlimit_str))
+ if (cgfs_get_value("memory", cgroup, file, &memlimit_str))
memlimit = strtoul(memlimit_str, NULL, 10);
free(memlimit_str);
return memlimit;
}
-static unsigned long get_min_memlimit(const char *cgroup)
+static unsigned long get_min_memlimit(const char *cgroup, const char *file)
{
char *copy = strdupa(cgroup);
unsigned long memlimit = 0, retlimit;
- retlimit = get_memlimit(copy);
+ retlimit = get_memlimit(copy, file);
while (strcmp(copy, "/") != 0) {
copy = dirname(copy);
- memlimit = get_memlimit(copy);
+ memlimit = get_memlimit(copy, file);
if (memlimit != -1 && memlimit < retlimit)
retlimit = memlimit;
};
struct file_info *d = (struct file_info *)fi->fh;
char *cg;
char *memusage_str = NULL, *memstat_str = NULL,
- *memswlimit_str = NULL, *memswusage_str = NULL,
- *memswlimit_default_str = NULL, *memswusage_default_str = NULL;
+ *memswlimit_str = NULL, *memswusage_str = NULL;
unsigned long memlimit = 0, memusage = 0, memswlimit = 0, memswusage = 0,
cached = 0, hosttotal = 0, active_anon = 0, inactive_anon = 0,
- active_file = 0, inactive_file = 0, unevictable = 0;
+ active_file = 0, inactive_file = 0, unevictable = 0,
+ hostswtotal = 0;
char *line = NULL;
size_t linelen = 0, total_len = 0, rv = 0;
char *cache = d->buf;
return read_file("/proc/meminfo", buf, size, d);
prune_init_slice(cg);
- memlimit = get_min_memlimit(cg);
+ memlimit = get_min_memlimit(cg, "memory.limit_in_bytes");
if (!cgfs_get_value("memory", cg, "memory.usage_in_bytes", &memusage_str))
goto err;
if (!cgfs_get_value("memory", cg, "memory.stat", &memstat_str))
if(cgfs_get_value("memory", cg, "memory.memsw.limit_in_bytes", &memswlimit_str) &&
cgfs_get_value("memory", cg, "memory.memsw.usage_in_bytes", &memswusage_str))
{
- /* If swapaccounting is turned on, then default value is assumed to be that of cgroup / */
- if (!cgfs_get_value("memory", "/", "memory.memsw.limit_in_bytes", &memswlimit_default_str))
- goto err;
- if (!cgfs_get_value("memory", "/", "memory.memsw.usage_in_bytes", &memswusage_default_str))
- goto err;
-
- memswlimit = strtoul(memswlimit_str, NULL, 10);
+ memswlimit = get_min_memlimit(cg, "memory.memsw.limit_in_bytes");
memswusage = strtoul(memswusage_str, NULL, 10);
- if (!strcmp(memswlimit_str, memswlimit_default_str))
- memswlimit = 0;
- if (!strcmp(memswusage_str, memswusage_default_str))
- memswusage = 0;
-
memswlimit = memswlimit / 1024;
memswusage = memswusage / 1024;
}
memset(lbuf, 0, 100);
if (startswith(line, "MemTotal:")) {
- sscanf(line+14, "%lu", &hosttotal);
+ sscanf(line+sizeof("MemTotal:")-1, "%lu", &hosttotal);
if (hosttotal < memlimit)
memlimit = hosttotal;
snprintf(lbuf, 100, "MemTotal: %8lu kB\n", memlimit);
snprintf(lbuf, 100, "MemFree: %8lu kB\n", memlimit - memusage);
printme = lbuf;
} else if (startswith(line, "MemAvailable:")) {
- snprintf(lbuf, 100, "MemAvailable: %8lu kB\n", memlimit - memusage);
+ snprintf(lbuf, 100, "MemAvailable: %8lu kB\n", memlimit - memusage + cached);
printme = lbuf;
} else if (startswith(line, "SwapTotal:") && memswlimit > 0) {
- snprintf(lbuf, 100, "SwapTotal: %8lu kB\n", memswlimit - memlimit);
+ sscanf(line+sizeof("SwapTotal:")-1, "%lu", &hostswtotal);
+ if (hostswtotal < memswlimit)
+ memswlimit = hostswtotal;
+ snprintf(lbuf, 100, "SwapTotal: %8lu kB\n", memswlimit);
printme = lbuf;
} else if (startswith(line, "SwapFree:") && memswlimit > 0 && memswusage > 0) {
- unsigned long swaptotal = memswlimit - memlimit,
+ unsigned long swaptotal = memswlimit,
swapusage = memswusage - memusage,
swapfree = swapusage < swaptotal ? swaptotal - swapusage : 0;
snprintf(lbuf, 100, "SwapFree: %8lu kB\n", swapfree);
} else if (startswith(line, "SwapCached:")) {
snprintf(lbuf, 100, "SwapCached: %8lu kB\n", 0UL);
printme = lbuf;
- } else if (startswith(line, "Active")) {
+ } else if (startswith(line, "Active:")) {
snprintf(lbuf, 100, "Active: %8lu kB\n",
active_anon + active_file);
printme = lbuf;
- } else if (startswith(line, "Inactive")) {
+ } else if (startswith(line, "Inactive:")) {
snprintf(lbuf, 100, "Inactive: %8lu kB\n",
inactive_anon + inactive_file);
printme = lbuf;
free(memswlimit_str);
free(memswusage_str);
free(memstat_str);
- free(memswlimit_default_str);
- free(memswusage_default_str);
return rv;
}
return rv;
}
+static uint64_t get_reaper_start_time(pid_t pid)
+{
+ int ret;
+ FILE *f;
+ uint64_t starttime;
+ /* strlen("/proc/") = 6
+ * +
+ * LXCFS_NUMSTRLEN64
+ * +
+ * strlen("/stat") = 5
+ * +
+ * \0 = 1
+ * */
+#define __PROC_PID_STAT_LEN (6 + LXCFS_NUMSTRLEN64 + 5 + 1)
+ char path[__PROC_PID_STAT_LEN];
+ pid_t qpid;
+
+ qpid = lookup_initpid_in_store(pid);
+ if (qpid <= 0) {
+ /* Caller can check for EINVAL on 0. */
+ errno = EINVAL;
+ return 0;
+ }
+
+ ret = snprintf(path, __PROC_PID_STAT_LEN, "/proc/%d/stat", qpid);
+ if (ret < 0 || ret >= __PROC_PID_STAT_LEN) {
+ /* Caller can check for EINVAL on 0. */
+ errno = EINVAL;
+ return 0;
+ }
+
+ f = fopen(path, "r");
+ if (!f) {
+ /* Caller can check for EINVAL on 0. */
+ errno = EINVAL;
+ return 0;
+ }
+
+ /* Note that the *scanf() argument supression requires that length
+ * modifiers such as "l" are omitted. Otherwise some compilers will yell
+ * at us. It's like telling someone you're not married and then asking
+ * if you can bring your wife to the party.
+ */
+ ret = fscanf(f, "%*d " /* (1) pid %d */
+ "%*s " /* (2) comm %s */
+ "%*c " /* (3) state %c */
+ "%*d " /* (4) ppid %d */
+ "%*d " /* (5) pgrp %d */
+ "%*d " /* (6) session %d */
+ "%*d " /* (7) tty_nr %d */
+ "%*d " /* (8) tpgid %d */
+ "%*u " /* (9) flags %u */
+ "%*u " /* (10) minflt %lu */
+ "%*u " /* (11) cminflt %lu */
+ "%*u " /* (12) majflt %lu */
+ "%*u " /* (13) cmajflt %lu */
+ "%*u " /* (14) utime %lu */
+ "%*u " /* (15) stime %lu */
+ "%*d " /* (16) cutime %ld */
+ "%*d " /* (17) cstime %ld */
+ "%*d " /* (18) priority %ld */
+ "%*d " /* (19) nice %ld */
+ "%*d " /* (20) num_threads %ld */
+ "%*d " /* (21) itrealvalue %ld */
+ "%" PRIu64, /* (22) starttime %llu */
+ &starttime);
+ if (ret != 1) {
+ fclose(f);
+ /* Caller can check for EINVAL on 0. */
+ errno = EINVAL;
+ return 0;
+ }
+
+ fclose(f);
+
+ errno = 0;
+ return starttime;
+}
+
+static uint64_t get_reaper_start_time_in_sec(pid_t pid)
+{
+ uint64_t clockticks;
+ int64_t ticks_per_sec;
+
+ clockticks = get_reaper_start_time(pid);
+ if (clockticks == 0 && errno == EINVAL) {
+ lxcfs_debug("failed to retrieve start time of pid %d\n", pid);
+ return 0;
+ }
+
+ ticks_per_sec = sysconf(_SC_CLK_TCK);
+ if (ticks_per_sec < 0 && errno == EINVAL) {
+ lxcfs_debug(
+ "%s\n",
+ "failed to determine number of clock ticks in a second");
+ return 0;
+ }
+
+ return (clockticks /= ticks_per_sec);
+}
+
+static uint64_t get_reaper_age(pid_t pid)
+{
+ uint64_t procstart, uptime, procage;
+
+ /* We need to substract the time the process has started since system
+ * boot minus the time when the system has started to get the actual
+ * reaper age.
+ */
+ procstart = get_reaper_start_time_in_sec(pid);
+ procage = procstart;
+ if (procstart > 0) {
+ int ret;
+ struct timespec spec;
+
+ ret = clock_gettime(CLOCK_BOOTTIME, &spec);
+ if (ret < 0)
+ return 0;
+ /* We could make this more precise here by using the tv_nsec
+ * field in the timespec struct and convert it to milliseconds
+ * and then create a double for the seconds and milliseconds but
+ * that seems more work than it is worth.
+ */
+ uptime = spec.tv_sec;
+ procage = uptime - procstart;
+ }
+
+ return procage;
+}
+
+#define CPUALL_MAX_SIZE (BUF_RESERVE_SIZE / 2)
static int proc_stat_read(char *buf, size_t size, off_t offset,
struct fuse_file_info *fi)
{
char *line = NULL;
size_t linelen = 0, total_len = 0, rv = 0;
int curcpu = -1; /* cpu numbering starts at 0 */
- unsigned long user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0;
+ unsigned long user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0, guest_nice = 0;
unsigned long user_sum = 0, nice_sum = 0, system_sum = 0, idle_sum = 0, iowait_sum = 0,
- irq_sum = 0, softirq_sum = 0, steal_sum = 0, guest_sum = 0;
-#define CPUALL_MAX_SIZE BUF_RESERVE_SIZE
+ irq_sum = 0, softirq_sum = 0, steal_sum = 0, guest_sum = 0, guest_nice_sum = 0;
char cpuall[CPUALL_MAX_SIZE];
/* reserve for cpu all */
char *cache = d->buf + CPUALL_MAX_SIZE;
cache_size -= l;
total_len += l;
- if (sscanf(line, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu", &user, &nice, &system, &idle, &iowait, &irq,
- &softirq, &steal, &guest) != 9)
+ if (sscanf(line, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+ &user,
+ &nice,
+ &system,
+ &idle,
+ &iowait,
+ &irq,
+ &softirq,
+ &steal,
+ &guest,
+ &guest_nice) != 10)
continue;
user_sum += user;
nice_sum += nice;
softirq_sum += softirq;
steal_sum += steal;
guest_sum += guest;
+ guest_nice_sum += guest_nice;
}
cache = d->buf;
- int cpuall_len = snprintf(cpuall, CPUALL_MAX_SIZE, "%s %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
- "cpu ", user_sum, nice_sum, system_sum, idle_sum, iowait_sum, irq_sum, softirq_sum, steal_sum, guest_sum);
- if (cpuall_len > 0 && cpuall_len < CPUALL_MAX_SIZE){
+ int cpuall_len = snprintf(cpuall, CPUALL_MAX_SIZE, "cpu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
+ user_sum,
+ nice_sum,
+ system_sum,
+ idle_sum,
+ iowait_sum,
+ irq_sum,
+ softirq_sum,
+ steal_sum,
+ guest_sum,
+ guest_nice_sum);
+ if (cpuall_len > 0 && cpuall_len < CPUALL_MAX_SIZE) {
memcpy(cache, cpuall, cpuall_len);
cache += cpuall_len;
- } else{
+ } else {
/* shouldn't happen */
lxcfs_error("proc_stat_read copy cpuall failed, cpuall_len=%d.", cpuall_len);
cpuall_len = 0;
total_len += cpuall_len;
d->cached = 1;
d->size = total_len;
- if (total_len > size ) total_len = size;
+ if (total_len > size)
+ total_len = size;
memcpy(buf, d->buf, total_len);
rv = total_len;
return rv;
}
-static long int getreaperage(pid_t pid)
-{
- char fnam[100];
- struct stat sb;
- int ret;
- pid_t qpid;
-
- qpid = lookup_initpid_in_store(pid);
- if (qpid <= 0)
- return 0;
-
- ret = snprintf(fnam, 100, "/proc/%d", qpid);
- if (ret < 0 || ret >= 100)
- return 0;
-
- if (lstat(fnam, &sb) < 0)
- return 0;
-
- return time(NULL) - sb.st_ctime;
-}
-
+/* This function retrieves the busy time of a group of tasks by looking at
+ * cpuacct.usage. Unfortunately, this only makes sense when the container has
+ * been given it's own cpuacct cgroup. If not, this function will take the busy
+ * time of all other taks that do not actually belong to the container into
+ * account as well. If someone has a clever solution for this please send a
+ * patch!
+ */
static unsigned long get_reaper_busy(pid_t task)
{
pid_t initpid = lookup_initpid_in_store(task);
{
struct fuse_context *fc = fuse_get_context();
struct file_info *d = (struct file_info *)fi->fh;
- long int reaperage = getreaperage(fc->pid);
- unsigned long int busytime = get_reaper_busy(fc->pid), idletime;
+ unsigned long int busytime = get_reaper_busy(fc->pid);
char *cache = d->buf;
ssize_t total_len = 0;
+ uint64_t idletime, reaperage;
#if RELOADTEST
iwashere();
#endif
if (offset){
- if (offset > d->size)
- return -EINVAL;
if (!d->cached)
return 0;
+ if (offset > d->size)
+ return -EINVAL;
int left = d->size - offset;
total_len = left > size ? size: left;
memcpy(buf, cache + offset, total_len);
return total_len;
}
- idletime = reaperage - busytime;
- if (idletime > reaperage)
- idletime = reaperage;
+ reaperage = get_reaper_age(fc->pid);
+ /* To understand why this is done, please read the comment to the
+ * get_reaper_busy() function.
+ */
+ idletime = reaperage;
+ if (reaperage >= busytime)
+ idletime = reaperage - busytime;
- total_len = snprintf(d->buf, d->size, "%ld.0 %lu.0\n", reaperage, idletime);
- if (total_len < 0){
- perror("Error writing to cache");
+ total_len = snprintf(d->buf, d->buflen, "%"PRIu64".00 %"PRIu64".00\n", reaperage, idletime);
+ if (total_len < 0 || total_len >= d->buflen){
+ lxcfs_error("%s\n", "failed to write to cache");
return 0;
}
struct fuse_context *fc = fuse_get_context();
struct file_info *d = (struct file_info *)fi->fh;
char *cg = NULL;
- char *memswlimit_str = NULL, *memlimit_str = NULL, *memusage_str = NULL, *memswusage_str = NULL,
- *memswlimit_default_str = NULL, *memswusage_default_str = NULL;
+ char *memswlimit_str = NULL, *memlimit_str = NULL, *memusage_str = NULL, *memswusage_str = NULL;
unsigned long memswlimit = 0, memlimit = 0, memusage = 0, memswusage = 0, swap_total = 0, swap_free = 0;
ssize_t total_len = 0, rv = 0;
ssize_t l = 0;
return read_file("/proc/swaps", buf, size, d);
prune_init_slice(cg);
- if (!cgfs_get_value("memory", cg, "memory.limit_in_bytes", &memlimit_str))
- goto err;
+ memlimit = get_min_memlimit(cg, "memory.limit_in_bytes");
if (!cgfs_get_value("memory", cg, "memory.usage_in_bytes", &memusage_str))
goto err;
- memlimit = strtoul(memlimit_str, NULL, 10);
memusage = strtoul(memusage_str, NULL, 10);
if (cgfs_get_value("memory", cg, "memory.memsw.usage_in_bytes", &memswusage_str) &&
cgfs_get_value("memory", cg, "memory.memsw.limit_in_bytes", &memswlimit_str)) {
- /* If swap accounting is turned on, then default value is assumed to be that of cgroup / */
- if (!cgfs_get_value("memory", "/", "memory.memsw.limit_in_bytes", &memswlimit_default_str))
- goto err;
- if (!cgfs_get_value("memory", "/", "memory.memsw.usage_in_bytes", &memswusage_default_str))
- goto err;
-
- memswlimit = strtoul(memswlimit_str, NULL, 10);
+ memswlimit = get_min_memlimit(cg, "memory.memsw.limit_in_bytes");
memswusage = strtoul(memswusage_str, NULL, 10);
- if (!strcmp(memswlimit_str, memswlimit_default_str))
- memswlimit = 0;
- if (!strcmp(memswusage_str, memswusage_default_str))
- memswusage = 0;
-
swap_total = (memswlimit - memlimit) / 1024;
swap_free = (memswusage - memusage) / 1024;
}
free(memlimit_str);
free(memusage_str);
free(memswusage_str);
- free(memswusage_default_str);
- free(memswlimit_default_str);
return rv;
}
return true;
}
-static int pivot_enter(void)
+/* __typeof__ should be safe to use with all compilers. */
+typedef __typeof__(((struct statfs *)NULL)->f_type) fs_type_magic;
+static bool has_fs_type(const struct statfs *fs, fs_type_magic magic_val)
+{
+ return (fs->f_type == (fs_type_magic)magic_val);
+}
+
+/*
+ * looking at fs/proc_namespace.c, it appears we can
+ * actually expect the rootfs entry to very specifically contain
+ * " - rootfs rootfs "
+ * IIUC, so long as we've chrooted so that rootfs is not our root,
+ * the rootfs entry should always be skipped in mountinfo contents.
+ */
+static bool is_on_ramfs(void)
+{
+ FILE *f;
+ char *p, *p2;
+ char *line = NULL;
+ size_t len = 0;
+ int i;
+
+ f = fopen("/proc/self/mountinfo", "r");
+ if (!f)
+ return false;
+
+ while (getline(&line, &len, f) != -1) {
+ for (p = line, i = 0; p && i < 4; i++)
+ p = strchr(p + 1, ' ');
+ if (!p)
+ continue;
+ p2 = strchr(p + 1, ' ');
+ if (!p2)
+ continue;
+ *p2 = '\0';
+ if (strcmp(p + 1, "/") == 0) {
+ // this is '/'. is it the ramfs?
+ p = strchr(p2 + 1, '-');
+ if (p && strncmp(p, "- rootfs rootfs ", 16) == 0) {
+ free(line);
+ fclose(f);
+ return true;
+ }
+ }
+ }
+ free(line);
+ fclose(f);
+ return false;
+}
+
+static int pivot_enter()
{
int ret = -1, oldroot = -1, newroot = -1;
lxcfs_error("%s\n", "Failed to enter old root.");
goto err;
}
+
if (umount2(".", MNT_DETACH) < 0) {
lxcfs_error("%s\n", "Failed to detach old root.");
goto err;
close(oldroot);
if (newroot > 0)
close(newroot);
+
return ret;
}
+static int chroot_enter()
+{
+ if (mount(ROOTDIR, "/", NULL, MS_REC | MS_BIND, NULL)) {
+ lxcfs_error("Failed to recursively bind-mount %s into /.", ROOTDIR);
+ return -1;
+ }
+
+ if (chroot(".") < 0) {
+ lxcfs_error("Call to chroot() failed: %s.\n", strerror(errno));
+ return -1;
+ }
+
+ if (chdir("/") < 0) {
+ lxcfs_error("Failed to change directory: %s.\n", strerror(errno));
+ return -1;
+ }
+
+ return 0;
+}
+
+static int permute_and_enter(void)
+{
+ struct statfs sb;
+
+ if (statfs("/", &sb) < 0) {
+ lxcfs_error("%s\n", "Could not stat / mountpoint.");
+ return -1;
+ }
+
+ /* has_fs_type() is not reliable. When the ramfs is a tmpfs it will
+ * likely report TMPFS_MAGIC. Hence, when it reports no we still check
+ * /proc/1/mountinfo. */
+ if (has_fs_type(&sb, RAMFS_MAGIC) || is_on_ramfs())
+ return chroot_enter();
+
+ if (pivot_enter() < 0) {
+ lxcfs_error("%s\n", "Could not perform pivot root.");
+ return -1;
+ }
+
+ return 0;
+}
+
/* Prepare our new clean root. */
-static int pivot_prepare(void)
+static int permute_prepare(void)
{
if (mkdir(ROOTDIR, 0700) < 0 && errno != EEXIST) {
lxcfs_error("%s\n", "Failed to create directory for new root.");
return 0;
}
-static bool pivot_new_root(void)
+/* Calls chroot() on ramfs, pivot_root() in all other cases. */
+static bool permute_root(void)
{
/* Prepare new root. */
- if (pivot_prepare() < 0)
+ if (permute_prepare() < 0)
return false;
/* Pivot into new root. */
- if (pivot_enter() < 0)
+ if (permute_and_enter() < 0)
return false;
return true;
}
-static bool setup_cgfs_dir(void)
+static int preserve_mnt_ns(int pid)
+{
+ int ret;
+ size_t len = sizeof("/proc/") + 21 + sizeof("/ns/mnt");
+ char path[len];
+
+ ret = snprintf(path, len, "/proc/%d/ns/mnt", pid);
+ if (ret < 0 || (size_t)ret >= len)
+ return -1;
+
+ return open(path, O_RDONLY | O_CLOEXEC);
+}
+
+static bool cgfs_prepare_mounts(void)
{
if (!mkdir_p(BASEDIR, 0700)) {
lxcfs_error("%s\n", "Failed to create lxcfs cgroup mountpoint.");
return false;
}
+ cgroup_mount_ns_fd = preserve_mnt_ns(getpid());
+ if (cgroup_mount_ns_fd < 0) {
+ lxcfs_error("Failed to preserve mount namespace: %s.\n", strerror(errno));
+ return false;
+ }
+
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0) < 0) {
lxcfs_error("Failed to remount / private: %s.\n", strerror(errno));
return false;
return true;
}
-static bool do_mount_cgroups(void)
+static bool cgfs_mount_hierarchies(void)
{
char *target;
size_t clen, len;
for (i = 0; i < num_hierarchies; i++) {
char *controller = hierarchies[i];
+
clen = strlen(controller);
len = strlen(BASEDIR) + clen + 2;
target = malloc(len);
if (!target)
return false;
+
ret = snprintf(target, len, "%s/%s", BASEDIR, controller);
if (ret < 0 || ret >= len) {
free(target);
free(target);
return false;
}
- if (mount(controller, target, "cgroup", 0, controller) < 0) {
- lxcfs_error("Failed mounting cgroup %s\n", controller);
+ if (!strcmp(controller, "unified"))
+ ret = mount("none", target, "cgroup2", 0, NULL);
+ else
+ ret = mount(controller, target, "cgroup", 0, controller);
+ if (ret < 0) {
+ lxcfs_error("Failed mounting cgroup %s: %s\n", controller, strerror(errno));
free(target);
return false;
}
static bool cgfs_setup_controllers(void)
{
- if (!setup_cgfs_dir())
+ if (!cgfs_prepare_mounts())
return false;
- if (!do_mount_cgroups()) {
+ if (!cgfs_mount_hierarchies()) {
lxcfs_error("%s\n", "Failed to set up private lxcfs cgroup mounts.");
return false;
}
- if (!pivot_new_root())
+ if (!permute_root())
return false;
return true;
}
-static int preserve_ns(int pid)
-{
- int ret;
- size_t len = 5 /* /proc */ + 21 /* /int_as_str */ + 7 /* /ns/mnt */ + 1 /* \0 */;
- char path[len];
-
- ret = snprintf(path, len, "/proc/%d/ns/mnt", pid);
- if (ret < 0 || (size_t)ret >= len)
- return -1;
-
- return open(path, O_RDONLY | O_CLOEXEC);
-}
-
static void __attribute__((constructor)) collect_and_mount_subsystems(void)
{
FILE *f;
char cwd[MAXPATHLEN];
size_t len = 0;
int i, init_ns = -1;
+ bool found_unified = false;
if ((f = fopen("/proc/self/cgroup", "r")) == NULL) {
lxcfs_error("Error opening /proc/self/cgroup: %s\n", strerror(errno));
}
while (getline(&line, &len, f) != -1) {
- char *p, *p2;
+ char *idx, *p, *p2;
p = strchr(line, ':');
if (!p)
goto out;
+ idx = line;
*(p++) = '\0';
p2 = strrchr(p, ':');
* because it parses out the empty string "" and later on passes
* it to mount(). Let's skip such entries.
*/
- if (!strcmp(p, ""))
- continue;
+ if (!strcmp(p, "") && !strcmp(idx, "0") && !found_unified) {
+ found_unified = true;
+ p = "unified";
+ }
if (!store_hierarchy(line, p))
goto out;
}
/* Preserve initial namespace. */
- init_ns = preserve_ns(getpid());
+ init_ns = preserve_mnt_ns(getpid());
if (init_ns < 0) {
lxcfs_error("%s\n", "Failed to preserve initial mount namespace.");
goto out;
}
- fd_hierarchies = malloc(sizeof(int *) * num_hierarchies);
+ fd_hierarchies = malloc(sizeof(int) * num_hierarchies);
if (!fd_hierarchies) {
lxcfs_error("%s\n", strerror(errno));
goto out;
}
free(hierarchies);
free(fd_hierarchies);
+
+ if (cgroup_mount_ns_fd >= 0)
+ close(cgroup_mount_ns_fd);
}
projects / mirror_lxcfs.git / blobdiff