ref: c77a1e252be396d8f47d80608dc0123cb370ed9e
parent: 24a662087135196fe58ac85265c5d1b9840c5a3b
author: Natanael Copa <ncopa@alpinelinux.org>
date: Wed Sep 23 06:29:22 CDT 2015
add new tool nlplug-findfs nlplug-findfs is a tool that will help us to find a given filesystem using coldplug. The only reason that initramfs exist in first place is to set up a rootfs and switch to it. The nlplug-findfs will handle coldplug events til a given filesystem/device is found and then mount it.
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@
datarootdir ?= /usr/share
datadir ?= $(datarootdir)/mkinitfs
-SBIN_FILES := mkinitfs bootchartd
+SBIN_FILES := mkinitfs bootchartd nlplug-findfs
SHARE_FILES := initramfs-init fstab passwd group
CONF_FILES := mkinitfs.conf \
features.d/ata.modules \
@@ -42,7 +42,7 @@
features.d/virtio.modules \
features.d/xfs.modules
-SCRIPTS := $(SBIN_FILES) initramfs-init
+SCRIPTS := mkinitfs bootchartd initramfs-init
IN_FILES := $(addsuffix .in,$(SCRIPTS))
GIT_REV := $(shell test -d .git && git describe || echo exported)
@@ -63,8 +63,9 @@
-e 's:@datadir@:$(datadir):g'
-all: $(SCRIPTS)
+all: $(SBIN_FILES) $(SCRIPTS)
+
clean:
rm -f $(SCRIPTS)
@@ -71,6 +72,24 @@
help:
@echo mkinitfs $(VERSION)
@echo "usage: make install [DESTDIR=]"
+
+CFLAGS ?= -Wall -Werror -g
+CFLAGS += -D_GNU_SOURCE -DDEBUG
+
+PKGCONF ?= pkg-config
+BLKID_CFLAGS := $(shell $(PKGCONF) --cflags blkid)
+BLKID_LIBS := $(shell $(PKGCONF) --libs blkid)
+LIBKMOD_CFLAGS := $(shell $(PKGCONF) --cflags libkmod)
+LIBKMOD_LIBS := $(shell $(PKGCONF) --libs libkmod)
+
+CFLAGS += $(BLKID_CFLAGS) $(LIBKMOD_CFLAGS)
+LIBS = $(BLKID_LIBS) $(LIBKMOD_LIBS)
+
+%.o: %.c
+ $(CC) $(CFLAGS) -o $@ -c $<
+
+nlplug-findfs: nlplug-findfs.o
+ $(CC) $(LDFLAGS) -o $@ $^ $(LIBS)
.SUFFIXES: .in
.in:
--- /dev/null
+++ b/arg.h
@@ -1,0 +1,39 @@
+/*
+ * Copy me if you can.
+ * by 20h
+ */
+
+#ifndef __ARG_H__
+#define __ARG_H__
+
+#define USED(x) ((void)(x))
+
+#define ARGBEGIN for (argv++, argc--;\
+ argv[0] && argv[0][1]\
+ && argv[0][0] == '-';\
+ argc--, argv++) {\+ char _argc;\
+ char **_argv;\
+ if (argv[0][1] == '-' && argv[0][2] == '\0') {\+ argv++;\
+ argc--;\
+ break;\
+ }\
+ for (argv[0]++, _argv = argv; argv[0][0];\
+ argv[0]++) {\+ if (_argv != argv)\
+ break;\
+ _argc = argv[0][0];\
+ switch (_argc)
+
+#define ARGEND }\
+ USED(_argc);\
+ }\
+ USED(argv);\
+ USED(argc);
+
+#define EARGF(x) ((argv[1] == NULL)? ((x), abort(), (char *)0) :\
+ (argc--, argv++, argv[0]))
+
+#endif
+
--- /dev/null
+++ b/nlplug-findfs.c
@@ -1,0 +1,511 @@
+
+/*
+ * Copy me if you can.
+ * by 20h
+ *
+ * Copyright (c) 2015 Natanael Copa <ncopa@alpinelinux.org>
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/mount.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
+
+#include <linux/netlink.h>
+
+#include <libkmod.h>
+#include <blkid.h>
+
+#include "arg.h"
+
+#define EVENT_TIMEOUT 2000
+
+static int dodebug;
+char *argv0;
+
+#if defined(DEBUG)
+#include <stdarg.h>
+static void dbg(const char *fmt, ...)
+{+ va_list fmtargs;
+ if (!dodebug)
+ return;
+
+ fprintf(stderr, "%s: ", argv0);
+ va_start(fmtargs, fmt);
+ vfprintf(stderr, fmt, fmtargs);
+ va_end(fmtargs);
+ fprintf(stderr, "\n");
+}
+#else
+#define dbg(...)
+#endif
+
+struct uevent {+ char *buf;
+ size_t bufsize;
+ char *message;
+ char *subsystem;
+ char *action;
+ char *modalias;
+ char *devname;
+ char *major;
+ char *minor;
+ char devnode[256];
+};
+
+struct ueventconf {+ char **program_argv;
+ char *search_device;
+ char *crypt_device;
+ char *crypt_name;
+ char *mountpoint;
+ char *subsystem_filter;
+ int modalias_count;
+ int fork_count;
+};
+
+
+static void sighandler(int sig)
+{+ switch(sig) {+ case SIGHUP:
+ case SIGINT:
+ case SIGQUIT:
+ case SIGABRT:
+ case SIGTERM:
+ exit(0);
+ break;
+ default:
+ break;
+ }
+}
+
+static void initsignals(void)
+{+ signal(SIGHUP, sighandler);
+ signal(SIGINT, sighandler);
+ signal(SIGQUIT, sighandler);
+ signal(SIGABRT, sighandler);
+ signal(SIGTERM, sighandler);
+ signal(SIGPIPE, SIG_IGN);
+}
+
+static int init_netlink_socket(void)
+{+ struct sockaddr_nl nls;
+ int fd, slen;
+
+ memset(&nls, 0, sizeof(nls));
+ nls.nl_family = AF_NETLINK;
+ nls.nl_pid = getpid();
+ nls.nl_groups = -1;
+
+ fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_KOBJECT_UEVENT);
+ if (fd < 0)
+ err(1, "socket");
+
+ /* kernel will not create events bigger than 16kb, but we need
+ buffer up all events during coldplug */
+ slen = 1024*1024;
+ if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &slen,
+ sizeof(slen)) < 0) {+ err(1, "setsockopt");
+ }
+ slen = 1;
+ if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &slen,
+ sizeof(slen)) < 0) {+ err(1, "setsockopt");
+ }
+
+ if (bind(fd, (void *)&nls, sizeof(nls)))
+ err(1, "bind");
+
+ fcntl(fd, F_SETFD, FD_CLOEXEC);
+ return fd;
+}
+
+void run_child(char **argv)
+{+ pid_t pid;
+
+ if (!(pid = fork())) {+ dbg("running %s", argv[0]);+ if (execv(argv[0], argv) < 0)
+ err(1, argv[0]);
+ exit(0);
+ }
+ if (pid < 0)
+ err(1,"fork");
+
+ waitpid(pid, NULL, 0);
+}
+
+
+int load_kmod(const char *modalias)
+{+ static struct kmod_ctx *ctx = NULL;
+ struct kmod_list *list = NULL;
+ struct kmod_list *node;
+ int r, count=0;
+
+ if (ctx == NULL) {+ dbg("initializing kmod");+ ctx = kmod_new(NULL, NULL);
+ if (ctx == NULL)
+ return -1;
+ kmod_set_log_fn(ctx, NULL, NULL);
+ r = kmod_load_resources(ctx);
+ }
+
+ r = kmod_module_new_from_lookup(ctx, modalias, &list);
+ if (r < 0) {+ dbg("alias '%s' lookup failure", modalias);+ return r;
+ }
+
+ kmod_list_foreach(node, list) {+ struct kmod_module *mod = kmod_module_get_module(node);
+ const char *fmt;
+ r = kmod_module_probe_insert_module(mod,
+ KMOD_PROBE_APPLY_BLACKLIST,
+ NULL, NULL, NULL, NULL);
+ if (r == 0) {+ fmt = "module '%s' inserted";
+ count++;
+ } else if (r == KMOD_PROBE_APPLY_BLACKLIST) {+ fmt = "module '%s' is blacklisted";
+ } else {+ fmt = "module '%s' failed";
+ }
+ dbg(fmt, kmod_module_get_name(mod));
+ kmod_module_unref(mod);
+ }
+ kmod_module_unref_list(list);
+ return count;
+}
+
+void start_mdadm(char *devnode)
+{+ char *mdadm_argv[] = {+ "/sbin/mdadm",
+ "--incremental",
+ "--quiet",
+ devnode,
+ NULL
+ };
+ run_child(mdadm_argv);
+}
+
+void start_lvm2(char *devnode)
+{+ char *lvm2_argv[] = {+ "/sbin/lvm", "vgchange",
+ "--activate" , "ay", "--noudevsync", "--sysinit",
+ NULL
+ };
+ run_child(lvm2_argv);
+}
+
+void start_cryptsetup(char *devnode, char *cryptdm)
+{+ char *cryptsetup_argv[] = {+ "/sbin/cryptsetup", "luksOpen",
+ devnode, cryptdm ? cryptdm : "crypdm", NULL
+ };
+ load_kmod("dm-crypt");+ run_child(cryptsetup_argv);
+}
+
+int is_searchdev(char *devname, const char *searchdev, const char *mountpoint)
+{+ static blkid_cache cache = NULL;
+ char *type = NULL, *label = NULL, *uuid = NULL;
+ char devnode[256];
+ int rc = 0;
+
+ if (searchdev == NULL)
+ return 0;
+
+ if (strcmp(devname, searchdev) == 0) {+ return 1;
+ }
+
+ if (cache == NULL)
+ blkid_get_cache(&cache, NULL);
+
+ snprintf(devnode, sizeof(devnode), "/dev/%s", devname);
+ type = blkid_get_tag_value(cache, "TYPE", devnode);
+
+ if (strncmp("LABEL=", searchdev, 6) == 0) {+ label = blkid_get_tag_value(cache, "LABEL", devnode);
+ rc = label && strcmp(label, searchdev+6) == 0;
+ } else if (strncmp("UUID=", searchdev, 5) == 0) {+ uuid = blkid_get_tag_value(cache, "UUID", devnode);
+ rc = (uuid && strcmp(uuid, searchdev+5) == 0);
+ }
+
+ if (type || label || uuid) {+ dbg("%s:\n"+ "\ttype='%s'\n"
+ "\tlabel='%s'\n"
+ "\tuuid='%s'\n", devnode,
+ type ? type : NULL,
+ label ? label : NULL,
+ uuid ? uuid : NULL);
+ }
+
+ if (!rc && type) {+ if (strcmp("linux_raid_member", type) == 0) {+ start_mdadm(devnode);
+ } else if (strcmp("LVM2_member", type) == 0) {+ start_lvm2(devnode);
+ }
+ }
+
+ if (rc && type && mountpoint)
+ if(mount(devnode, mountpoint, type, MS_RDONLY, NULL))
+ err(1, "mount %s on %s", devnode, mountpoint);
+
+ if (type)
+ free(type);
+ if (label)
+ free(label);
+ if (uuid)
+ free(uuid);
+
+ return rc;
+}
+
+int dispatch_uevent(struct uevent *ev, struct ueventconf *conf)
+{+ if (conf->subsystem_filter && ev->subsystem
+ && strcmp(ev->subsystem, conf->subsystem_filter) != 0) {+ dbg("subsystem '%s' filtered out (by '%s').",+ ev->subsystem, conf->subsystem_filter);
+ return 0;
+ }
+
+ if (ev->action == NULL)
+ return 0;
+
+ if (ev->modalias != NULL && strcmp(ev->action, "add") == 0) {+ load_kmod(ev->modalias);
+ conf->modalias_count++;
+
+ } else if (ev->devname != NULL) {+ if (conf->program_argv[0] != NULL) {+ run_child(conf->program_argv);
+ conf->fork_count++;
+ }
+
+ if (ev->subsystem && strcmp(ev->subsystem, "block") == 0
+ && strcmp(ev->action, "add") == 0) {+ snprintf(ev->devnode, sizeof(ev->devnode), "/dev/%s",
+ ev->devname);
+ if (is_searchdev(ev->devname, conf->search_device,
+ conf->mountpoint))
+ return 1;
+
+ if (is_searchdev(ev->devname, conf->crypt_device, NULL))
+ start_cryptsetup(ev->devnode, conf->crypt_name);
+ }
+ }
+ return 0;
+}
+
+int process_uevent(char *buf, const size_t len, struct ueventconf *conf)
+{+ struct uevent ev;
+
+ int i, slen = 0;
+ char *key, *value;
+
+ memset(&ev, 0, sizeof(ev));
+ ev.buf = buf;
+ ev.bufsize = len;
+ clearenv();
+ setenv("PATH", "/sbin:/bin", 1);+
+ for (i = 0; i < len; i += slen + 1) {+
+ key = buf + i;
+ value = strchr(key, '=');
+ slen = strlen(buf+i);
+
+ if (i == 0 && slen != 0) {+ /* first line, the message */
+ ev.message = key;
+ continue;
+ }
+
+ if (!slen)
+ continue;
+
+ value[0] = '\0';
+ value++;
+
+ if (strcmp(key, "MODALIAS") == 0) {+ ev.modalias = value;
+ } else if (strcmp(key, "ACTION") == 0) {+ ev.action = value;
+ } else if (strcmp(key, "SUBSYSTEM") == 0) {+ ev.subsystem = value;
+ } else if (strcmp(key, "DEVNAME") == 0) {+ ev.devname = value;
+ } else if (strcmp(key, "MAJOR") == 0) {+ ev.major = value;
+ } else if (strcmp(key, "MINOR") == 0) {+ ev.minor = value;
+ }
+
+ if (strcmp(key, "PATH")) {+ setenv(key, value, 1);
+ // dbg("%s = \"%s\"", key, value);+ }
+ }
+ return dispatch_uevent(&ev, conf);
+}
+
+void usage(void)
+{+ errx(1, "usage: %s [-dku] [-f subsystem] [-s device] [-m dir] PATH\n", argv0);
+}
+
+int main(int argc, char *argv[])
+{+ struct pollfd fds;
+ int r;
+ struct ueventconf conf;
+ int event_count = 0;
+ size_t total_bytes;
+ int ret = 1;
+ char *trigger_argv[2] = {0,0};+ char *program_argv[2] = {0,0};+
+
+ memset(&conf, 0, sizeof(conf));
+ conf.program_argv = program_argv;
+ argv0 = argv[0];
+
+ ARGBEGIN {+ case 'c':
+ conf.crypt_device = EARGF(usage());
+ break;
+ case 'C':
+ conf.crypt_name = EARGF(usage());
+ break;
+ case 'd':
+ dodebug = 1;
+ break;
+ case 'm':
+ conf.mountpoint = EARGF(usage());
+ break;
+ case 'f':
+ conf.subsystem_filter = EARGF(usage());
+ break;
+ case 'p':
+ conf.program_argv[0] = EARGF(usage());
+ break;
+ case 's':
+ conf.search_device = EARGF(usage());
+ break;
+ case 't':
+ trigger_argv[0] = EARGF(usage());
+ break;
+ default:
+ usage();
+ } ARGEND;
+
+ if (argc > 0)
+ conf.search_device = argv[0];
+
+ if (argc > 1)
+ conf.mountpoint = argv[1];
+
+ initsignals();
+
+ fds.fd = init_netlink_socket();
+ fds.events = POLLIN;
+
+ /* trigger events here */
+ if (trigger_argv[0])
+ run_child(trigger_argv);
+
+ while ((r = poll(&fds, 1, EVENT_TIMEOUT)) > 0) {+ size_t len;
+ struct iovec iov;
+ char cbuf[CMSG_SPACE(sizeof(struct ucred))];
+ char buf[16384];
+ struct cmsghdr *chdr;
+ struct ucred *cred;
+ struct msghdr hdr;
+ struct sockaddr_nl cnls;
+
+ if (!(fds.revents & POLLIN))
+ continue;
+
+ iov.iov_base = &buf;
+ iov.iov_len = sizeof(buf);
+ memset(&hdr, 0, sizeof(hdr));
+ hdr.msg_iov = &iov;
+ hdr.msg_iovlen = 1;
+ hdr.msg_control = cbuf;
+ hdr.msg_controllen = sizeof(cbuf);
+ hdr.msg_name = &cnls;
+ hdr.msg_namelen = sizeof(cnls);
+
+ len = recvmsg(fds.fd, &hdr, 0);
+ if (len < 0) {+ if (errno == EINTR)
+ continue;
+ err(1, "recvmsg");
+ }
+ if (len < 32 || len >= sizeof(buf))
+ continue;
+
+ total_bytes += len;
+ chdr = CMSG_FIRSTHDR(&hdr);
+ if (chdr == NULL || chdr->cmsg_type != SCM_CREDENTIALS)
+ continue;
+
+ /* filter out messages that are not from root or kernel */
+ cred = (struct ucred *)CMSG_DATA(chdr);
+ if (cred->uid != 0 || cnls.nl_pid > 0)
+ continue;
+
+ event_count++;
+ if (process_uevent(buf, len, &conf)) {+ ret = 0;
+ dbg("FOUND %s", conf.search_device);+ break;
+ }
+
+ if (fds.revents & POLLHUP) {+ dbg("parent hung up\n");+ break;
+ }
+ }
+ if (r == -1)
+ err(1, "poll");
+
+ if (r == 0)
+ dbg("exit due to timeout");+ dbg("modaliases: %i, forks: %i, events: %i, total bufsize: %zu",+ conf.modalias_count,
+ conf.fork_count,
+ event_count, total_bytes);
+
+ return ret;
+}
+
+