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authorLennart Weller <lhw@ring0.de>2017-09-17 22:17:33 +0000
committerLennart Weller <lhw@ring0.de>2017-09-17 22:17:33 +0000
commit6aaf5ba7ed0980c14bdc554fc8839a2126455ed5 (patch)
tree6161925716661486e7f47c479668a9487b039d83 /src/cgroup-network.c
parentNew upstream version 1.7.0+dfsg (diff)
downloadnetdata-6aaf5ba7ed0980c14bdc554fc8839a2126455ed5.tar.xz
netdata-6aaf5ba7ed0980c14bdc554fc8839a2126455ed5.zip
New upstream version 1.8.0+dfsgupstream/1.8.0+dfsg
Diffstat (limited to 'src/cgroup-network.c')
-rw-r--r--src/cgroup-network.c340
1 files changed, 340 insertions, 0 deletions
diff --git a/src/cgroup-network.c b/src/cgroup-network.c
new file mode 100644
index 000000000..8894d60ee
--- /dev/null
+++ b/src/cgroup-network.c
@@ -0,0 +1,340 @@
+#include "common.h"
+
+#ifdef HAVE_SETNS
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE /* See feature_test_macros(7) */
+#endif
+#include <sched.h>
+#endif
+
+// ----------------------------------------------------------------------------
+// callback required by fatal()
+
+void netdata_cleanup_and_exit(int ret) {
+ exit(ret);
+}
+
+struct iface {
+ const char *device;
+ uint32_t hash;
+
+ unsigned int ifindex;
+ unsigned int iflink;
+
+ struct iface *next;
+};
+
+unsigned int read_iface_iflink(const char *prefix, const char *iface) {
+ char filename[FILENAME_MAX + 1];
+ snprintfz(filename, FILENAME_MAX, "%s/sys/class/net/%s/iflink", prefix?prefix:"", iface);
+
+ unsigned long long iflink = 0;
+ int ret = read_single_number_file(filename, &iflink);
+ if(ret) error("Cannot read '%s'.", filename);
+
+ return (unsigned int)iflink;
+}
+
+unsigned int read_iface_ifindex(const char *prefix, const char *iface) {
+ char filename[FILENAME_MAX + 1];
+ snprintfz(filename, FILENAME_MAX, "%s/sys/class/net/%s/ifindex", prefix?prefix:"", iface);
+
+ unsigned long long ifindex = 0;
+ int ret = read_single_number_file(filename, &ifindex);
+ if(ret) error("Cannot read '%s'.", filename);
+
+ return (unsigned int)ifindex;
+}
+
+struct iface *read_proc_net_dev(const char *prefix) {
+ procfile *ff = NULL;
+ char filename[FILENAME_MAX + 1];
+
+ snprintfz(filename, FILENAME_MAX, "%s%s", prefix?prefix:"", "/proc/net/dev");
+ ff = procfile_open(filename, " \t,:|", PROCFILE_FLAG_DEFAULT);
+ if(unlikely(!ff)) {
+ error("Cannot open file '%s'", filename);
+ return NULL;
+ }
+
+ ff = procfile_readall(ff);
+ if(unlikely(!ff)) {
+ error("Cannot read file '%s'", filename);
+ return NULL;
+ }
+
+ size_t lines = procfile_lines(ff), l;
+ struct iface *root = NULL;
+ for(l = 2; l < lines ;l++) {
+ if (unlikely(procfile_linewords(ff, l) < 1)) continue;
+
+ struct iface *t = callocz(1, sizeof(struct iface));
+ t->device = strdupz(procfile_lineword(ff, l, 0));
+ t->hash = simple_hash(t->device);
+ t->ifindex = read_iface_ifindex(prefix, t->device);
+ t->iflink = read_iface_iflink(prefix, t->device);
+ t->next = root;
+ root = t;
+ }
+
+ procfile_close(ff);
+
+ return root;
+}
+
+int iface_is_eligible(struct iface *iface) {
+ if(iface->iflink != iface->ifindex)
+ return 1;
+
+ return 0;
+}
+
+int eligible_ifaces(struct iface *root) {
+ int eligible = 0;
+
+ struct iface *t;
+ for(t = root; t ; t = t->next)
+ if(iface_is_eligible(t))
+ eligible++;
+
+ return eligible;
+}
+
+static void continue_as_child(void) {
+ pid_t child = fork();
+ int status;
+ pid_t ret;
+
+ if (child < 0)
+ error("fork() failed");
+
+ /* Only the child returns */
+ if (child == 0)
+ return;
+
+ for (;;) {
+ ret = waitpid(child, &status, WUNTRACED);
+ if ((ret == child) && (WIFSTOPPED(status))) {
+ /* The child suspended so suspend us as well */
+ kill(getpid(), SIGSTOP);
+ kill(child, SIGCONT);
+ } else {
+ break;
+ }
+ }
+
+ /* Return the child's exit code if possible */
+ if (WIFEXITED(status)) {
+ exit(WEXITSTATUS(status));
+ } else if (WIFSIGNALED(status)) {
+ kill(getpid(), WTERMSIG(status));
+ }
+
+ exit(EXIT_FAILURE);
+}
+
+int proc_pid_fd(const char *prefix, const char *ns, pid_t pid) {
+ char filename[FILENAME_MAX + 1];
+ snprintfz(filename, FILENAME_MAX, "%s/proc/%d/%s", prefix?prefix:"", (int)pid, ns);
+ int fd = open(filename, O_RDONLY);
+
+ if(fd == -1)
+ error("Cannot open file '%s'", filename);
+
+ return fd;
+}
+
+static struct ns {
+ int nstype;
+ int fd;
+ int status;
+ const char *name;
+ const char *path;
+} all_ns[] = {
+ // { .nstype = CLONE_NEWUSER, .fd = -1, .status = -1, .name = "user", .path = "ns/user" },
+ // { .nstype = CLONE_NEWCGROUP, .fd = -1, .status = -1, .name = "cgroup", .path = "ns/cgroup" },
+ // { .nstype = CLONE_NEWIPC, .fd = -1, .status = -1, .name = "ipc", .path = "ns/ipc" },
+ // { .nstype = CLONE_NEWUTS, .fd = -1, .status = -1, .name = "uts", .path = "ns/uts" },
+ { .nstype = CLONE_NEWNET, .fd = -1, .status = -1, .name = "network", .path = "ns/net" },
+ { .nstype = CLONE_NEWPID, .fd = -1, .status = -1, .name = "pid", .path = "ns/pid" },
+ { .nstype = CLONE_NEWNS, .fd = -1, .status = -1, .name = "mount", .path = "ns/mnt" },
+
+ // terminator
+ { .nstype = 0, .fd = -1, .status = -1, .name = NULL, .path = NULL }
+};
+
+int switch_namespace(const char *prefix, pid_t pid) {
+#ifdef HAVE_SETNS
+
+ int i;
+ for(i = 0; all_ns[i].name ; i++)
+ all_ns[i].fd = proc_pid_fd(prefix, all_ns[i].path, pid);
+
+ int root_fd = proc_pid_fd(prefix, "root", pid);
+ int cwd_fd = proc_pid_fd(prefix, "cwd", pid);
+
+ setgroups(0, NULL);
+
+ // 2 passes - found it at nsenter source code
+ // this is related CLONE_NEWUSER functionality
+
+ // FIXME: this code cannot switch user namespace
+ // Fortunately, we don't need it.
+
+ int pass, errors = 0;
+ for(pass = 0; pass < 2 ;pass++) {
+ for(i = 0; all_ns[i].name ; i++) {
+ if (all_ns[i].fd != -1 && all_ns[i].status == -1) {
+ if(setns(all_ns[i].fd, all_ns[i].nstype) == -1) {
+ if(pass == 1) {
+ all_ns[i].status = 0;
+ error("Cannot switch to %s namespace of pid %d", all_ns[i].name, (int) pid);
+ errors++;
+ }
+ }
+ else
+ all_ns[i].status = 1;
+ }
+ }
+ }
+
+ setgroups(0, NULL);
+
+ if(root_fd != -1) {
+ if(fchdir(root_fd) < 0)
+ error("Cannot fchdir() to pid %d root directory", (int)pid);
+
+ if(chroot(".") < 0)
+ error("Cannot chroot() to pid %d root directory", (int)pid);
+
+ close(root_fd);
+ }
+
+ if(cwd_fd != -1) {
+ if(fchdir(cwd_fd) < 0)
+ error("Cannot fchdir() to pid %d current working directory", (int)pid);
+
+ close(cwd_fd);
+ }
+
+ int do_fork = 0;
+ for(i = 0; all_ns[i].name ; i++)
+ if(all_ns[i].fd != -1) {
+
+ // CLONE_NEWPID requires a fork() to become effective
+ if(all_ns[i].nstype == CLONE_NEWPID && all_ns[i].status)
+ do_fork = 1;
+
+ close(all_ns[i].fd);
+ }
+
+ if(do_fork)
+ continue_as_child();
+
+ return 0;
+
+#else
+
+ errno = ENOSYS;
+ error("setns() is missing on this system.");
+ return 1;
+
+#endif
+}
+
+pid_t read_pid_from_cgroup(const char *path) {
+ char buffer[FILENAME_MAX + 1];
+
+ snprintfz(buffer, FILENAME_MAX, "%s/cgroup.procs", path);
+ FILE *fp = fopen(buffer, "r");
+ if(!fp) {
+ error("Cannot read file '%s'.", buffer);
+ snprintfz(buffer, FILENAME_MAX, "%s/tasks", path);
+ fp = fopen(buffer, "r");
+ }
+
+ if(!fp) {
+ error("Cannot read file '%s'.", buffer);
+ return 0;
+ }
+
+ pid_t pid = 0;
+ char *s;
+ while((s = fgets(buffer, FILENAME_MAX, fp))) {
+ pid = atoi(s);
+ if(pid > 0) break;
+ }
+
+ fclose(fp);
+ return pid;
+}
+
+void usage(void) {
+ fprintf(stderr, "%s [ -p PID | --pid PID | --cgroup /path/to/cgroup ]\n", program_name);
+ exit(1);
+}
+
+int main(int argc, char **argv) {
+ pid_t pid = 0;
+
+ program_name = argv[0];
+ program_version = VERSION;
+ error_log_syslog = 0;
+
+ if(argc == 2 && (!strcmp(argv[1], "version") || !strcmp(argv[1], "-version") || !strcmp(argv[1], "--version") || !strcmp(argv[1], "-v") || !strcmp(argv[1], "-V"))) {
+ fprintf(stderr, "cgroup-network %s\n", VERSION);
+ exit(0);
+ }
+
+ if(argc != 3)
+ usage();
+
+ if(!strcmp(argv[1], "-p") || !strcmp(argv[1], "--pid")) {
+ pid = atoi(argv[2]);
+ }
+ else if(!strcmp(argv[1], "--cgroup")) {
+ pid = read_pid_from_cgroup(argv[2]);
+ }
+ else
+ usage();
+
+ if(pid <= 0)
+ fatal("Invalid pid %d", (int)pid);
+
+ struct iface *host, *cgroup, *h, *c;
+ const char *prefix = getenv("NETDATA_HOST_PREFIX");
+
+ host = read_proc_net_dev(prefix);
+ if(!host)
+ fatal("cannot read host interface list.");
+
+ if(!eligible_ifaces(host))
+ fatal("there are no double-linked host interfaces available.");
+
+ if(switch_namespace(prefix, pid))
+ fatal("cannot switch to the namespace of pid %u", (unsigned int)pid);
+
+ cgroup = read_proc_net_dev(NULL);
+ if(!cgroup)
+ fatal("cannot read cgroup interface list.");
+
+ if(!eligible_ifaces(cgroup))
+ fatal("there are not double-linked cgroup interfaces available.");
+
+ int found = 0;
+ for(h = host; h ; h = h->next) {
+ if(iface_is_eligible(h)) {
+ for (c = cgroup; c; c = c->next) {
+ if(iface_is_eligible(c) && h->ifindex == c->iflink && h->iflink == c->ifindex) {
+ printf("%s %s\n", h->device, c->device);
+ found++;
+ }
+ }
+ }
+ }
+
+ if(!found)
+ return 1;
+
+ return 0;
+}