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nspawn: introduce new --link-journal= switch to link container journals into host

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This commit is contained in:
Lennart Poettering
2012-07-19 02:02:39 +02:00
parent 4a299a7ad5
commit 57fb9fb56d
3 changed files with 246 additions and 12 deletions
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src/nspawn/nspawn.c
+196 -11
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@@ -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;