[libvirt] [PATCH] util: allow creation of file with virFileWriteStr
Eric Blake
eblake at redhat.com
Fri Dec 3 00:12:17 UTC 2010
Making this change will allow the future patches to use
virFileWriteStr to create a file, rather than its current limitation
of only working on pre-existing files.
* src/util/util.h (virFileWriteStr): Alter signature.
* src/util/util.c (virFileWriteStr): Allow file creation.
* src/network/bridge_driver.c (networkEnableIpForwarding)
(networkDisableIPV6): Adjust clients.
* src/node_device/node_device_driver.c
(nodeDeviceVportCreateDelete): Likewise.
* src/util/cgroup.c (virCgroupSetValueStr): Likewise.
* src/util/pci.c (pciBindDeviceToStub, pciUnBindDeviceFromStub):
Likewise.
Based on a report from Jean-Baptiste Rouault.
---
> Alternatively, I only counted 16 existing users of virFileWriteStr; and
> this is an internal API. We could easily rewrite all clients to always
> pass a third parameter, and change the signature of virFileWriteStr to
> require a mode_t argument. Hmm; some of those clients are writing to
> kernel files that should always exist (/proc/sys/net/ipv4/ip_forward,
> for example), where it's tough to justify what we would pass as a mode_t
> argument. So maybe pass mode==0 as a sentinel to require a pre-existing
> file
How does this look? Admittedly, all existing uses were okay with a
mode parameter of 0; and I haven't yet seen your patch that would
use a non-zero mode, but this still makes more sense to me.
Oh, and VIR_FORCE_CLOSE preserves errno, so I was able to simplify
virFileWriteStr in the process.
src/network/bridge_driver.c | 8 ++++----
src/node_device/node_device_driver.c | 2 +-
src/util/cgroup.c | 2 +-
src/util/pci.c | 16 ++++++++--------
src/util/util.c | 13 ++++++++-----
src/util/util.h | 3 ++-
6 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
index 54890f9..62639e4 100644
--- a/src/network/bridge_driver.c
+++ b/src/network/bridge_driver.c
@@ -1024,7 +1024,7 @@ networkReloadIptablesRules(struct network_driver *driver)
static int
networkEnableIpForwarding(void)
{
- return virFileWriteStr("/proc/sys/net/ipv4/ip_forward", "1\n");
+ return virFileWriteStr("/proc/sys/net/ipv4/ip_forward", "1\n", 0);
}
#define SYSCTL_PATH "/proc/sys"
@@ -1045,7 +1045,7 @@ static int networkDisableIPV6(virNetworkObjPtr network)
goto cleanup;
}
- if (virFileWriteStr(field, "1") < 0) {
+ if (virFileWriteStr(field, "1", 0) < 0) {
virReportSystemError(errno,
_("cannot enable %s"), field);
goto cleanup;
@@ -1057,7 +1057,7 @@ static int networkDisableIPV6(virNetworkObjPtr network)
goto cleanup;
}
- if (virFileWriteStr(field, "0") < 0) {
+ if (virFileWriteStr(field, "0", 0) < 0) {
virReportSystemError(errno,
_("cannot disable %s"), field);
goto cleanup;
@@ -1069,7 +1069,7 @@ static int networkDisableIPV6(virNetworkObjPtr network)
goto cleanup;
}
- if (virFileWriteStr(field, "1") < 0) {
+ if (virFileWriteStr(field, "1", 0) < 0) {
virReportSystemError(errno,
_("cannot enable %s"), field);
goto cleanup;
diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c
index 448cfd3..a6c6042 100644
--- a/src/node_device/node_device_driver.c
+++ b/src/node_device/node_device_driver.c
@@ -454,7 +454,7 @@ nodeDeviceVportCreateDelete(const int parent_host,
goto cleanup;
}
- if (virFileWriteStr(operation_path, vport_name) == -1) {
+ if (virFileWriteStr(operation_path, vport_name, 0) == -1) {
virReportSystemError(errno,
_("Write of '%s' to '%s' during "
"vport create/delete failed"),
diff --git a/src/util/cgroup.c b/src/util/cgroup.c
index 2758a8f..3ba6325 100644
--- a/src/util/cgroup.c
+++ b/src/util/cgroup.c
@@ -288,7 +288,7 @@ static int virCgroupSetValueStr(virCgroupPtr group,
return rc;
VIR_DEBUG("Set value '%s' to '%s'", keypath, value);
- rc = virFileWriteStr(keypath, value);
+ rc = virFileWriteStr(keypath, value, 0);
if (rc < 0) {
DEBUG("Failed to write value '%s': %m", value);
rc = -errno;
diff --git a/src/util/pci.c b/src/util/pci.c
index d38cefa..095ad3f 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -849,7 +849,7 @@ pciBindDeviceToStub(pciDevice *dev, const char *driver)
* bound by the stub.
*/
pciDriverFile(path, sizeof(path), driver, "new_id");
- if (virFileWriteStr(path, dev->id) < 0) {
+ if (virFileWriteStr(path, dev->id, 0) < 0) {
virReportSystemError(errno,
_("Failed to add PCI device ID '%s' to %s"),
dev->id, driver);
@@ -862,7 +862,7 @@ pciBindDeviceToStub(pciDevice *dev, const char *driver)
* your root filesystem.
*/
pciDeviceFile(path, sizeof(path), dev->name, "driver/unbind");
- if (virFileExists(path) && virFileWriteStr(path, dev->name) < 0) {
+ if (virFileExists(path) && virFileWriteStr(path, dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to unbind PCI device '%s'"), dev->name);
return -1;
@@ -875,7 +875,7 @@ pciBindDeviceToStub(pciDevice *dev, const char *driver)
if (!virFileLinkPointsTo(path, drvdir)) {
/* Xen's pciback.ko wants you to use new_slot first */
pciDriverFile(path, sizeof(path), driver, "new_slot");
- if (virFileExists(path) && virFileWriteStr(path, dev->name) < 0) {
+ if (virFileExists(path) && virFileWriteStr(path, dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to add slot for PCI device '%s' to %s"),
dev->name, driver);
@@ -883,7 +883,7 @@ pciBindDeviceToStub(pciDevice *dev, const char *driver)
}
pciDriverFile(path, sizeof(path), driver, "bind");
- if (virFileWriteStr(path, dev->name) < 0) {
+ if (virFileWriteStr(path, dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to bind PCI device '%s' to %s"),
dev->name, driver);
@@ -895,7 +895,7 @@ pciBindDeviceToStub(pciDevice *dev, const char *driver)
* ID table so that 'drivers_probe' works below.
*/
pciDriverFile(path, sizeof(path), driver, "remove_id");
- if (virFileExists(path) && virFileWriteStr(path, dev->id) < 0) {
+ if (virFileExists(path) && virFileWriteStr(path, dev->id, 0) < 0) {
virReportSystemError(errno,
_("Failed to remove PCI ID '%s' from %s"),
dev->id, driver);
@@ -936,7 +936,7 @@ pciUnBindDeviceFromStub(pciDevice *dev, const char *driver)
pciDeviceFile(path, sizeof(path), dev->name, "driver");
if (virFileExists(drvdir) && virFileLinkPointsTo(path, drvdir)) {
pciDriverFile(path, sizeof(path), driver, "unbind");
- if (virFileWriteStr(path, dev->name) < 0) {
+ if (virFileWriteStr(path, dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to bind PCI device '%s' to %s"),
dev->name, driver);
@@ -946,7 +946,7 @@ pciUnBindDeviceFromStub(pciDevice *dev, const char *driver)
/* Xen's pciback.ko wants you to use remove_slot on the specific device */
pciDriverFile(path, sizeof(path), driver, "remove_slot");
- if (virFileExists(path) && virFileWriteStr(path, dev->name) < 0) {
+ if (virFileExists(path) && virFileWriteStr(path, dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to remove slot for PCI device '%s' to %s"),
dev->name, driver);
@@ -961,7 +961,7 @@ pciUnBindDeviceFromStub(pciDevice *dev, const char *driver)
*/
pciDriverFile(path, sizeof(path), driver, "remove_id");
if (!virFileExists(drvdir) || virFileExists(path)) {
- if (virFileWriteStr(PCI_SYSFS "drivers_probe", dev->name) < 0) {
+ if (virFileWriteStr(PCI_SYSFS "drivers_probe", dev->name, 0) < 0) {
virReportSystemError(errno,
_("Failed to trigger a re-probe for PCI device '%s'"),
dev->name);
diff --git a/src/util/util.c b/src/util/util.c
index f6050de..79ca5d3 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -1125,20 +1125,23 @@ int virFileReadAll(const char *path, int maxlen, char **buf)
return len;
}
-/* Truncate @path and write @str to it.
+/* Truncate @path and write @str to it. If @mode is 0, ensure that
+ @path exists; otherwise, use @mode if @path must be created.
Return 0 for success, nonzero for failure.
Be careful to preserve any errno value upon failure. */
-int virFileWriteStr(const char *path, const char *str)
+int virFileWriteStr(const char *path, const char *str, mode_t mode)
{
int fd;
- if ((fd = open(path, O_WRONLY|O_TRUNC)) == -1)
+ if (mode)
+ fd = open(path, O_WRONLY|O_TRUNC|O_CREAT, mode);
+ else
+ fd = open(path, O_WRONLY|O_TRUNC);
+ if (fd == -1)
return -1;
if (safewrite(fd, str, strlen(str)) < 0) {
- int saved_errno = errno;
VIR_FORCE_CLOSE(fd);
- errno = saved_errno;
return -1;
}
diff --git a/src/util/util.h b/src/util/util.h
index deaf8bb..ef4fc13 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -97,7 +97,8 @@ int virFileReadLimFD(int fd, int maxlen, char **buf) ATTRIBUTE_RETURN_CHECK;
int virFileReadAll(const char *path, int maxlen, char **buf) ATTRIBUTE_RETURN_CHECK;
-int virFileWriteStr(const char *path, const char *str) ATTRIBUTE_RETURN_CHECK;
+int virFileWriteStr(const char *path, const char *str, mode_t mode)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
int virFileMatchesNameSuffix(const char *file,
const char *name,
--
1.7.3.2
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