From 57fb9fb56db0584581ce33ee842dcbf5f1136856 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 19 Jul 2012 02:02:39 +0200 Subject: [PATCH 1/1] nspawn: introduce new --link-journal= switch to link container journals into host --- Makefile.am | 3 +- man/systemd-nspawn.xml | 48 ++++++++++ src/nspawn/nspawn.c | 207 ++++++++++++++++++++++++++++++++++++++--- 3 files changed, 246 insertions(+), 12 deletions(-) diff --git a/Makefile.am b/Makefile.am index 95758429e..985e8eff4 100644 --- a/Makefile.am +++ b/Makefile.am @@ -1468,7 +1468,8 @@ systemd_nspawn_LDADD = \ libsystemd-label.la \ libsystemd-capability.la \ libsystemd-shared.la \ - libsystemd-daemon.la + libsystemd-daemon.la \ + libsystemd-id128-internal.la # ------------------------------------------------------------------------------ systemd_stdio_bridge_SOURCES = \ diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml index b6f2c278d..9f8b8e2ae 100644 --- a/man/systemd-nspawn.xml +++ b/man/systemd-nspawn.xml @@ -235,6 +235,54 @@ CAP_SYS_RESOURCE. + + + + Control whether the + container's journal shall be made + visible to the host system. If enabled + allows viewing the container's journal + files from the host (but not vice + versa). Takes one of + no, + host, + guest, + auto. If + no the journal is + not linked. If host + the journal files are stored on the + host file system (beneath the host's + /var/log/journal) + and a per-machine subdirectory of this + directory is created and bind mounted + into the container at the same + location. If guest + the journal files are stored on the + guest file system (beneath the guest's + /var/log/journal) + and a per-machine subdirectory of this + directory is symlinked into the host + at the same location. If + auto (the default) + and the subdirectory of + /var/log/journal + exists as directory it is bind mounted + into the container, but nothing is + done otherwise. Effectively, booting a + container once with + guest or + host will link the + journal persistantly if further one + the default of auto + is used. + + + + + + Equivalent to + . + diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c index 2879db11e..14de7f8b4 100644 --- a/src/nspawn/nspawn.c +++ b/src/nspawn/nspawn.c @@ -52,6 +52,14 @@ #include "strv.h" #include "path-util.h" #include "loopback-setup.h" +#include "sd-id128.h" + +typedef enum LinkJournal { + LINK_NO, + LINK_AUTO, + LINK_HOST, + LINK_GUEST +} LinkJournal; static char *arg_directory = NULL; static char *arg_user = NULL; @@ -60,6 +68,7 @@ static char *arg_uuid = NULL; static bool arg_private_network = false; static bool arg_read_only = false; static bool arg_boot = false; +static LinkJournal arg_link_journal = LINK_AUTO; static uint64_t arg_retain = (1ULL << CAP_CHOWN) | (1ULL << CAP_DAC_OVERRIDE) | @@ -88,15 +97,17 @@ static int help(void) { printf("%s [OPTIONS...] [PATH] [ARGUMENTS...]\n\n" "Spawn a minimal namespace container for debugging, testing and building.\n\n" - " -h --help Show this help\n" - " -D --directory=NAME Root directory for the container\n" - " -b --boot Boot up full system (i.e. invoke init)\n" - " -u --user=USER Run the command under specified user or uid\n" - " -C --controllers=LIST Put the container in specified comma-separated cgroup hierarchies\n" - " --uuid=UUID Set a specific machine UUID for the container\n" - " --private-network Disable network in container\n" - " --read-only Mount the root directory read-only\n" - " --capability=CAP In addition to the default, retain specified capability\n", + " -h --help Show this help\n" + " -D --directory=NAME Root directory for the container\n" + " -b --boot Boot up full system (i.e. invoke init)\n" + " -u --user=USER Run the command under specified user or uid\n" + " -C --controllers=LIST Put the container in specified comma-separated cgroup hierarchies\n" + " --uuid=UUID Set a specific machine UUID for the container\n" + " --private-network Disable network in container\n" + " --read-only Mount the root directory read-only\n" + " --capability=CAP In addition to the default, retain specified capability\n" + " --link-journal=MODE Link up guest journal, one of no, auto, guest, host\n" + " -j Equivalent to --link-journal=host\n", program_invocation_short_name); return 0; @@ -108,7 +119,8 @@ static int parse_argv(int argc, char *argv[]) { ARG_PRIVATE_NETWORK = 0x100, ARG_UUID, ARG_READ_ONLY, - ARG_CAPABILITY + ARG_CAPABILITY, + ARG_LINK_JOURNAL }; static const struct option options[] = { @@ -121,6 +133,7 @@ static int parse_argv(int argc, char *argv[]) { { "uuid", required_argument, NULL, ARG_UUID }, { "read-only", no_argument, NULL, ARG_READ_ONLY }, { "capability", required_argument, NULL, ARG_CAPABILITY }, + { "link-journal", required_argument, NULL, ARG_LINK_JOURNAL }, { NULL, 0, NULL, 0 } }; @@ -129,7 +142,7 @@ static int parse_argv(int argc, char *argv[]) { assert(argc >= 0); assert(argv); - while ((c = getopt_long(argc, argv, "+hD:u:C:b", options, NULL)) >= 0) { + while ((c = getopt_long(argc, argv, "+hD:u:C:bj", options, NULL)) >= 0) { switch (c) { @@ -210,6 +223,26 @@ static int parse_argv(int argc, char *argv[]) { break; } + case 'j': + arg_link_journal = LINK_GUEST; + break; + + case ARG_LINK_JOURNAL: + if (streq(optarg, "auto")) + arg_link_journal = LINK_AUTO; + else if (streq(optarg, "no")) + arg_link_journal = LINK_NO; + else if (streq(optarg, "guest")) + arg_link_journal = LINK_GUEST; + else if (streq(optarg, "host")) + arg_link_journal = LINK_HOST; + else { + log_error("Failed to parse link journal mode %s", optarg); + return -EINVAL; + } + + break; + case '?': return -EINVAL; @@ -596,6 +629,155 @@ static int setup_hostname(void) { return r; } +static int setup_journal(const char *directory) { + sd_id128_t machine_id; + char *p = NULL, *b = NULL, *l, *q = NULL, *d = NULL; + int r; + + if (arg_link_journal == LINK_NO) + return 0; + + p = strappend(directory, "/etc/machine-id"); + if (!p) { + log_error("Out of memory"); + r = -ENOMEM; + goto finish; + } + + r = read_one_line_file(p, &b); + if (r == -ENOENT && arg_link_journal == LINK_AUTO) { + r = 0; + goto finish; + } else if (r < 0) { + log_error("Failed to read machine ID: %s", strerror(-r)); + return r; + } + + l = strstrip(b); + if (isempty(l) && arg_link_journal == LINK_AUTO) { + r = 0; + goto finish; + } + + /* Verify validaty */ + r = sd_id128_from_string(l, &machine_id); + if (r < 0) { + log_error("Failed to parse machine ID: %s", strerror(-r)); + goto finish; + } + + free(p); + p = strappend("/var/log/journal/", l); + q = strjoin(directory, "/var/log/journal/", l, NULL); + if (!p || !q) { + log_error("Out of memory"); + r = -ENOMEM; + goto finish; + } + + if (path_is_mount_point(p, false) > 0 || + path_is_mount_point(q, false) > 0) { + if (arg_link_journal != LINK_AUTO) { + log_error("Journal already a mount point, refusing."); + r = -EEXIST; + goto finish; + } + + r = 0; + goto finish; + } + + r = readlink_and_make_absolute(p, &d); + if (r >= 0) { + if ((arg_link_journal == LINK_GUEST || + arg_link_journal == LINK_AUTO) && + path_equal(d, q)) { + + mkdir_p(q, 0755); + + r = 0; + goto finish; + } + + if (unlink(p) < 0) { + log_error("Failed to remove symlink %s: %m", p); + r = -errno; + goto finish; + } + } else if (r == -EINVAL) { + + if (arg_link_journal == LINK_GUEST && + rmdir(p) < 0) { + + if (errno == ENOTDIR) + log_error("%s already exists and is neither symlink nor directory.", p); + else { + log_error("Failed to remove %s: %m", p); + r = -errno; + } + + goto finish; + } + } else if (r != -ENOENT) { + log_error("readlink(%s) failed: %m", p); + goto finish; + } + + if (arg_link_journal == LINK_GUEST) { + + if (symlink(q, p) < 0) { + log_error("Failed to symlink %s to %s: %m", q, p); + r = -errno; + goto finish; + } + + mkdir_p(q, 0755); + + r = 0; + goto finish; + } + + if (arg_link_journal == LINK_HOST) { + r = mkdir_p(p, 0755); + if (r < 0) { + log_error("Failed to create %s: %m", p); + goto finish; + } + + } else if (access(p, F_OK) < 0) { + r = 0; + goto finish; + } + + if (dir_is_empty(q) == 0) { + log_error("%s not empty.", q); + r = -ENOTEMPTY; + goto finish; + } + + r = mkdir_p(q, 0755); + if (r < 0) { + log_error("Failed to create %s: %m", q); + goto finish; + } + + if (mount(p, q, "bind", MS_BIND, NULL) < 0) { + log_error("Failed to bind mount journal from host into guest: %m"); + r = -errno; + goto finish; + } + + r = 0; + +finish: + free(p); + free(q); + free(d); + free(b); + return r; + +} + static int drop_capabilities(void) { return capability_bounding_set_drop(~arg_retain, false); } @@ -1023,6 +1205,9 @@ int main(int argc, char *argv[]) { if (setup_resolv_conf(arg_directory) < 0) goto child_fail; + if (setup_journal(arg_directory) < 0) + goto child_fail; + if (chdir(arg_directory) < 0) { log_error("chdir(%s) failed: %m", arg_directory); goto child_fail; -- 2.30.2