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authorMichal Sekletar <msekleta@redhat.com>2013-03-14 18:12:27 +0100
committerZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>2013-03-15 22:56:40 -0400
commitc17ec25e4d9bd6c8e8617416f813e25b2ebbafc5 (patch)
tree6a414a30460e6a362180a059bc93e88cea946916 /src/core/namespace.c
parent3b953d68c628c6ae70adba871719ac0f16083b51 (diff)
core: reuse the same /tmp, /var/tmp and inaccessible dir
All Execs within the service, will get mounted the same /tmp and /var/tmp directories, if service is configured with PrivateTmp=yes. Temporary directories are cleaned up by service itself in addition to systemd-tmpfiles. Directory which is mounted as inaccessible is created at runtime in /run/systemd.
Diffstat (limited to 'src/core/namespace.c')
-rw-r--r--src/core/namespace.c226
1 files changed, 90 insertions, 136 deletions
diff --git a/src/core/namespace.c b/src/core/namespace.c
index ba18ddc5b0..ceeed2e1ae 100644
--- a/src/core/namespace.c
+++ b/src/core/namespace.c
@@ -36,23 +36,24 @@
#include "path-util.h"
#include "namespace.h"
#include "missing.h"
+#include "execute.h"
-typedef enum PathMode {
+typedef enum MountMode {
/* This is ordered by priority! */
INACCESSIBLE,
READONLY,
PRIVATE_TMP,
PRIVATE_VAR_TMP,
READWRITE
-} PathMode;
+} MountMode;
-typedef struct Path {
+typedef struct BindMount {
const char *path;
- PathMode mode;
+ MountMode mode;
bool done;
-} Path;
+} BindMount;
-static int append_paths(Path **p, char **strv, PathMode mode) {
+static int append_mounts(BindMount **p, char **strv, MountMode mode) {
char **i;
STRV_FOREACH(i, strv) {
@@ -68,8 +69,8 @@ static int append_paths(Path **p, char **strv, PathMode mode) {
return 0;
}
-static int path_compare(const void *a, const void *b) {
- const Path *p = a, *q = b;
+static int mount_path_compare(const void *a, const void *b) {
+ const BindMount *p = a, *q = b;
if (path_equal(p->path, q->path)) {
@@ -93,14 +94,13 @@ static int path_compare(const void *a, const void *b) {
return 0;
}
-static void drop_duplicates(Path *p, unsigned *n, bool *need_inaccessible) {
- Path *f, *t, *previous;
+static void drop_duplicates(BindMount *m, unsigned *n) {
+ BindMount *f, *t, *previous;
- assert(p);
+ assert(m);
assert(n);
- assert(need_inaccessible);
- for (f = p, t = p, previous = NULL; f < p+*n; f++) {
+ for (f = m, t = m, previous = NULL; f < m+*n; f++) {
/* The first one wins */
if (previous && path_equal(f->path, previous->path))
@@ -109,37 +109,33 @@ static void drop_duplicates(Path *p, unsigned *n, bool *need_inaccessible) {
t->path = f->path;
t->mode = f->mode;
- if (t->mode == INACCESSIBLE)
- *need_inaccessible = true;
-
previous = t;
t++;
}
- *n = t - p;
+ *n = t - m;
}
static int apply_mount(
- Path *p,
+ BindMount *m,
const char *tmp_dir,
- const char *var_tmp_dir,
- const char *inaccessible_dir) {
+ const char *var_tmp_dir) {
const char *what;
int r;
- assert(p);
+ assert(m);
- switch (p->mode) {
+ switch (m->mode) {
case INACCESSIBLE:
- what = inaccessible_dir;
+ what = "/run/systemd/inaccessible";
break;
case READONLY:
case READWRITE:
- what = p->path;
+ what = m->path;
break;
case PRIVATE_TMP:
@@ -156,133 +152,99 @@ static int apply_mount(
assert(what);
- r = mount(what, p->path, NULL, MS_BIND|MS_REC, NULL);
+ r = mount(what, m->path, NULL, MS_BIND|MS_REC, NULL);
if (r >= 0)
- log_debug("Successfully mounted %s to %s", what, p->path);
+ log_debug("Successfully mounted %s to %s", what, m->path);
return r;
}
-static int make_read_only(Path *p) {
+static int make_read_only(BindMount *m) {
int r;
- assert(p);
+ assert(m);
- if (p->mode != INACCESSIBLE && p->mode != READONLY)
+ if (m->mode != INACCESSIBLE && m->mode != READONLY)
return 0;
- r = mount(NULL, p->path, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_REC, NULL);
+ r = mount(NULL, m->path, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY|MS_REC, NULL);
if (r < 0)
return -errno;
return 0;
}
-int setup_namespace(
- char **writable,
- char **readable,
- char **inaccessible,
- bool private_tmp,
- unsigned long flags) {
-
- char
- tmp_dir[] = "/tmp/systemd-private-XXXXXX",
- var_tmp_dir[] = "/var/tmp/systemd-private-XXXXXX",
- inaccessible_dir[] = "/tmp/systemd-inaccessible-XXXXXX";
-
- Path *paths, *p;
- unsigned n;
- bool need_inaccessible = false;
- bool remove_tmp = false, remove_var_tmp = false, remove_inaccessible = false;
- int r;
-
- if (!flags)
- flags = MS_SHARED;
+int setup_tmpdirs(char **tmp_dir,
+ char **var_tmp_dir) {
+ int r = 0;
+ char tmp_dir_template[] = "/tmp/systemd-private-XXXXXX",
+ var_tmp_dir_template[] = "/var/tmp/systemd-private-XXXXXX";
- n =
- strv_length(writable) +
- strv_length(readable) +
- strv_length(inaccessible) +
- (private_tmp ? 2 : 0);
+ assert(tmp_dir);
+ assert(var_tmp_dir);
- p = paths = alloca(sizeof(Path) * n);
- if ((r = append_paths(&p, writable, READWRITE)) < 0 ||
- (r = append_paths(&p, readable, READONLY)) < 0 ||
- (r = append_paths(&p, inaccessible, INACCESSIBLE)) < 0)
- goto fail;
+ r = create_tmp_dir(tmp_dir_template, 0000, true, tmp_dir);
+ if (r < 0)
+ goto fail2;
- if (private_tmp) {
- p->path = "/tmp";
- p->mode = PRIVATE_TMP;
- p++;
+ r = create_tmp_dir(var_tmp_dir_template, 0000, true, var_tmp_dir);
+ if (r < 0)
+ goto fail1;
- p->path = "/var/tmp";
- p->mode = PRIVATE_VAR_TMP;
- p++;
- }
+ return 0;
- assert(paths + n == p);
+fail1:
+ rmdir(*tmp_dir);
+ free(*tmp_dir);
+ *tmp_dir = NULL;
- qsort(paths, n, sizeof(Path), path_compare);
- drop_duplicates(paths, &n, &need_inaccessible);
+fail2:
+ return r;
+}
- if (need_inaccessible) {
- mode_t u;
- char *d;
+int setup_namespace(char** read_write_dirs,
+ char** read_only_dirs,
+ char** inaccessible_dirs,
+ char* tmp_dir,
+ char* var_tmp_dir,
+ bool private_tmp,
+ unsigned mount_flags) {
- u = umask(0777);
- d = mkdtemp(inaccessible_dir);
- umask(u);
+ unsigned n = strv_length(read_write_dirs) +
+ strv_length(read_only_dirs) +
+ strv_length(inaccessible_dirs) +
+ (private_tmp ? 2 : 0);
+ BindMount *m, *mounts;
+ int r = 0;
- if (!d) {
- r = -errno;
- goto fail;
- }
+ if (!mount_flags)
+ mount_flags = MS_SHARED;
- remove_inaccessible = true;
+ if (unshare(CLONE_NEWNS) < 0) {
+ r = -errno;
+ goto fail;
}
- if (private_tmp) {
- mode_t u;
- char *d;
-
- u = umask(0000);
- d = mkdtemp(tmp_dir);
- umask(u);
-
- if (!d) {
- r = -errno;
- goto fail;
- }
-
- remove_tmp = true;
-
- u = umask(0000);
- d = mkdtemp(var_tmp_dir);
- umask(u);
-
- if (!d) {
- r = -errno;
- goto fail;
- }
-
- remove_var_tmp = true;
+ m = mounts = (BindMount *) alloca(n * sizeof(BindMount));
+ if ((r = append_mounts(&m, read_write_dirs, READWRITE)) < 0 ||
+ (r = append_mounts(&m, read_only_dirs, READONLY)) < 0 ||
+ (r = append_mounts(&m, inaccessible_dirs, INACCESSIBLE)) < 0)
+ goto fail;
- if (chmod(tmp_dir, 0777 + S_ISVTX) < 0) {
- r = -errno;
- goto fail;
- }
+ if (private_tmp) {
+ m->path = "/tmp";
+ m->mode = PRIVATE_TMP;
+ m++;
- if (chmod(var_tmp_dir, 0777 + S_ISVTX) < 0) {
- r = -errno;
- goto fail;
- }
+ m->path = "/var/tmp";
+ m->mode = PRIVATE_VAR_TMP;
+ m++;
}
- if (unshare(CLONE_NEWNS) < 0) {
- r = -errno;
- goto fail;
- }
+ assert(mounts + n == m);
+
+ qsort(mounts, n, sizeof(BindMount), mount_path_compare);
+ drop_duplicates(mounts, &n);
/* Remount / as SLAVE so that nothing now mounted in the namespace
shows up in the parent */
@@ -291,20 +253,20 @@ int setup_namespace(
goto fail;
}
- for (p = paths; p < paths + n; p++) {
- r = apply_mount(p, tmp_dir, var_tmp_dir, inaccessible_dir);
+ for (m = mounts; m < mounts + n; ++m) {
+ r = apply_mount(m, tmp_dir, var_tmp_dir);
if (r < 0)
goto undo_mounts;
}
- for (p = paths; p < paths + n; p++) {
- r = make_read_only(p);
+ for (m = mounts; m < mounts + n; ++m) {
+ r = make_read_only(m);
if (r < 0)
goto undo_mounts;
}
/* Remount / as the desired mode */
- if (mount(NULL, "/", NULL, flags|MS_REC, NULL) < 0) {
+ if (mount(NULL, "/", NULL, mount_flags | MS_REC, NULL) < 0) {
r = -errno;
goto undo_mounts;
}
@@ -312,19 +274,11 @@ int setup_namespace(
return 0;
undo_mounts:
- for (p = paths; p < paths + n; p++)
- if (p->done)
- umount2(p->path, MNT_DETACH);
+ for (m = mounts; m < mounts + n; ++m) {
+ if (m->done)
+ umount2(m->path, MNT_DETACH);
+ }
fail:
- if (remove_inaccessible)
- rmdir(inaccessible_dir);
-
- if (remove_tmp)
- rmdir(tmp_dir);
-
- if (remove_var_tmp)
- rmdir(var_tmp_dir);
-
return r;
}