[libvirt] [PATCH 09/10] qemuDomainAttachDeviceMknod: Deal with symlinks
Michal Privoznik
mprivozn at redhat.com
Fri Jan 20 09:42:49 UTC 2017
Similarly to one of the previous commits, we need to deal
properly with symlinks in hotplug case too.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
src/qemu/qemu_domain.c | 120 ++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 94 insertions(+), 26 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 448583313..bcfb2446f 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -7590,6 +7590,7 @@ struct qemuDomainAttachDeviceMknodData {
virDomainObjPtr vm;
virDomainDeviceDefPtr devDef;
const char *file;
+ const char *target;
struct stat sb;
void *acl;
#ifdef WITH_SELINUX
@@ -7605,6 +7606,7 @@ qemuDomainAttachDeviceMknodHelper(pid_t pid ATTRIBUTE_UNUSED,
struct qemuDomainAttachDeviceMknodData *data = opaque;
int ret = -1;
bool delDevice = false;
+ bool isLink = S_ISLNK(data->sb.st_mode);
virSecurityManagerPostFork(data->driver->securityManager);
@@ -7614,24 +7616,47 @@ qemuDomainAttachDeviceMknodHelper(pid_t pid ATTRIBUTE_UNUSED,
goto cleanup;
}
- VIR_DEBUG("Creating dev %s (%d,%d)",
- data->file, major(data->sb.st_rdev), minor(data->sb.st_rdev));
- if (mknod(data->file, data->sb.st_mode, data->sb.st_rdev) < 0) {
- /* Because we are not removing devices on hotunplug, or
- * we might be creating part of backing chain that
- * already exist due to a different disk plugged to
- * domain, accept EEXIST. */
- if (errno != EEXIST) {
- virReportSystemError(errno,
- _("Unable to create device %s"),
- data->file);
- goto cleanup;
+ if (isLink) {
+ VIR_DEBUG("Creating symlink %s -> %s", data->file, data->target);
+ if (symlink(data->target, data->file) < 0) {
+ if (errno != EEXIST) {
+ virReportSystemError(errno,
+ _("Unable to create symlink %s"),
+ data->target);
+ goto cleanup;
+ }
+ } else {
+ delDevice = true;
}
} else {
- delDevice = true;
+ VIR_DEBUG("Creating dev %s (%d,%d)",
+ data->file, major(data->sb.st_rdev), minor(data->sb.st_rdev));
+ if (mknod(data->file, data->sb.st_mode, data->sb.st_rdev) < 0) {
+ /* Because we are not removing devices on hotunplug, or
+ * we might be creating part of backing chain that
+ * already exist due to a different disk plugged to
+ * domain, accept EEXIST. */
+ if (errno != EEXIST) {
+ virReportSystemError(errno,
+ _("Unable to create device %s"),
+ data->file);
+ goto cleanup;
+ }
+ } else {
+ delDevice = true;
+ }
}
- if (virFileSetACLs(data->file, data->acl) < 0 &&
+ if (lchown(data->file, data->sb.st_uid, data->sb.st_gid) < 0) {
+ virReportSystemError(errno,
+ _("Failed to chown device %s"),
+ data->file);
+ goto cleanup;
+ }
+
+ /* Symlinks don't have ACLs. */
+ if (!isLink &&
+ virFileSetACLs(data->file, data->acl) < 0 &&
errno != ENOTSUP) {
virReportSystemError(errno,
_("Unable to set ACLs on %s"), data->file);
@@ -7639,7 +7664,8 @@ qemuDomainAttachDeviceMknodHelper(pid_t pid ATTRIBUTE_UNUSED,
}
#ifdef WITH_SELINUX
- if (setfilecon_raw(data->file, (VIR_SELINUX_CTX_CONST char *) data->tcon) < 0) {
+ if (data->tcon &&
+ lsetfilecon_raw(data->file, (VIR_SELINUX_CTX_CONST char *) data->tcon) < 0) {
VIR_WARNINGS_NO_WLOGICALOP_EQUAL_EXPR
if (errno != EOPNOTSUPP && errno != ENOTSUP) {
VIR_WARNINGS_RESET
@@ -7671,6 +7697,8 @@ qemuDomainAttachDeviceMknod(virQEMUDriverPtr driver,
{
struct qemuDomainAttachDeviceMknodData data;
int ret = -1;
+ char *target = NULL;
+ bool isLink;
memset(&data, 0, sizeof(data));
@@ -7679,21 +7707,55 @@ qemuDomainAttachDeviceMknod(virQEMUDriverPtr driver,
data.devDef = devDef;
data.file = file;
- if (stat(file, &data.sb) < 0) {
+ if (lstat(file, &data.sb) < 0) {
virReportSystemError(errno,
_("Unable to access %s"), file);
return ret;
}
- if (virFileGetACLs(file, &data.acl) < 0 &&
+ isLink = S_ISLNK(data.sb.st_mode);
+
+ if (isLink) {
+ if (virFileReadLink(file, &target) < 0) {
+ virReportSystemError(errno,
+ _("unable to resolve symlink %s"),
+ file);
+ return ret;
+ }
+
+ if (IS_RELATIVE_FILE_NAME(target)) {
+ char *c = NULL, *tmp = NULL, *fileTmp = NULL;
+
+ if (VIR_STRDUP(fileTmp, file) < 0)
+ goto cleanup;
+
+ if ((c = strrchr(fileTmp, '/')))
+ *(c + 1) = '\0';
+
+ if (virAsprintf(&tmp, "%s%s", fileTmp, target) < 0) {
+ VIR_FREE(fileTmp);
+ goto cleanup;
+ }
+ VIR_FREE(fileTmp);
+ VIR_FREE(target);
+ target = tmp;
+ tmp = NULL;
+ }
+
+ data.target = target;
+ }
+
+ /* Symlinks don't have ACLs. */
+ if (!isLink &&
+ virFileGetACLs(file, &data.acl) < 0 &&
errno != ENOTSUP) {
virReportSystemError(errno,
_("Unable to get ACLs on %s"), file);
- return ret;
+ goto cleanup;
}
#ifdef WITH_SELINUX
- if (getfilecon_raw(file, &data.tcon) < 0 &&
+ if (lgetfilecon_raw(file, &data.tcon) < 0 &&
(errno != ENOTSUP && errno != ENODATA)) {
virReportSystemError(errno,
_("Unable to get SELinux label from %s"), file);
@@ -7701,17 +7763,22 @@ qemuDomainAttachDeviceMknod(virQEMUDriverPtr driver,
}
#endif
- if (virSecurityManagerPreFork(driver->securityManager) < 0)
- goto cleanup;
+ if (STRPREFIX(file, DEVPREFIX)) {
+ if (virSecurityManagerPreFork(driver->securityManager) < 0)
+ goto cleanup;
- if (virProcessRunInMountNamespace(vm->pid,
- qemuDomainAttachDeviceMknodHelper,
- &data) < 0) {
+ if (virProcessRunInMountNamespace(vm->pid,
+ qemuDomainAttachDeviceMknodHelper,
+ &data) < 0) {
+ virSecurityManagerPostFork(driver->securityManager);
+ goto cleanup;
+ }
virSecurityManagerPostFork(driver->securityManager);
- goto cleanup;
}
- virSecurityManagerPostFork(driver->securityManager);
+ if (isLink &&
+ qemuDomainAttachDeviceMknod(driver, vm, devDef, target) < 0)
+ goto cleanup;
ret = 0;
cleanup:
@@ -7719,6 +7786,7 @@ qemuDomainAttachDeviceMknod(virQEMUDriverPtr driver,
freecon(data.tcon);
#endif
virFileFreeACLs(&data.acl);
+ VIR_FREE(target);
return ret;
}
--
2.11.0
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