[libvirt] [PATCH] command: allow merging stdout and stderr in string capture
Eric Blake
eblake at redhat.com
Fri Feb 3 00:17:37 UTC 2012
Sometimes, its easier to run children with 2>&1 in shell notation,
and just deal with stdout and stderr interleaved. This was already
possible for fd handling; extend it to also work when doing string
capture of a child process.
* docs/internals/command.html.in: Document this.
* src/util/command.c (virCommandSetErrorBuffer): Likewise.
(virCommandRun, virExecWithHook): Implement it.
* tests/commandtest.c (test14): Test it.
* daemon/remote.c (remoteDispatchAuthPolkit): Use new command
feature.
---
In response to:
https://www.redhat.com/archives/libvir-list/2012-January/msg01262.html
Hmm, I thought I sent this earlier, but can't find it on the archives.
daemon/remote.c | 11 +++--------
docs/internals/command.html.in | 5 ++++-
src/util/command.c | 16 ++++++++++++++--
tests/commandtest.c | 26 +++++++++++++++++++++++++-
4 files changed, 46 insertions(+), 12 deletions(-)
diff --git a/daemon/remote.c b/daemon/remote.c
index 26ac4a6..1cea942 100644
--- a/daemon/remote.c
+++ b/daemon/remote.c
@@ -2477,7 +2477,7 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED,
int status = -1;
char *ident = NULL;
bool authdismissed = 0;
- char *pkout = NULL, *pkerr = NULL;
+ char *pkout = NULL;
struct daemonClientPrivate *priv =
virNetServerClientGetPrivateData(client);
virCommandPtr cmd = NULL;
@@ -2489,7 +2489,7 @@ remoteDispatchAuthPolkit(virNetServerPtr server ATTRIBUTE_UNUSED,
cmd = virCommandNewArgList(PKCHECK_PATH, "--action-id", action, NULL);
virCommandSetOutputBuffer(cmd, &pkout);
- virCommandSetErrorBuffer(cmd, &pkerr);
+ virCommandSetErrorBuffer(cmd, &pkout);
VIR_DEBUG("Start PolicyKit auth %d", virNetServerClientGetFD(client));
if (virNetServerClientGetAuth(client) != VIR_NET_SERVER_SERVICE_AUTH_POLKIT) {
@@ -2548,17 +2548,12 @@ error:
if (authdismissed) {
virNetError(VIR_ERR_AUTH_CANCELLED, "%s",
_("authentication cancelled by user"));
- } else if (pkout || pkerr) {
- virNetError(VIR_ERR_AUTH_FAILED, "%s %s",
- pkerr ? pkerr : "",
- pkout ? pkout : "");
} else {
virNetError(VIR_ERR_AUTH_FAILED, "%s",
- _("authentication failed"));
+ pkout && *pkout ? pkout : _("authentication failed"));
}
VIR_FREE(pkout);
- VIR_FREE(pkerr);
virNetMessageSaveError(rerr);
virMutexUnlock(&priv->lock);
return -1;
diff --git a/docs/internals/command.html.in b/docs/internals/command.html.in
index 7dcf462..7bb9aa3 100644
--- a/docs/internals/command.html.in
+++ b/docs/internals/command.html.in
@@ -373,7 +373,10 @@
allocation of collected information (however, on an
out-of-memory condition, the buffer may still be NULL). The
caller is responsible for freeing registered buffers, since the
- buffers are designed to persist beyond virCommandFree.
+ buffers are designed to persist beyond virCommandFree. It
+ is possible to pass the same pointer to both
+ virCommandSetOutputBuffer and virCommandSetErrorBuffer, in which
+ case the child process interleaves output into a single string.
</p>
<h3><a name="directory">Setting working directory</a></h3>
diff --git a/src/util/command.c b/src/util/command.c
index 6f51fbb..a2d5f84 100644
--- a/src/util/command.c
+++ b/src/util/command.c
@@ -464,7 +464,9 @@ virExecWithHook(const char *const*argv,
}
if (errfd != NULL) {
- if (*errfd == -1) {
+ if (errfd == outfd) {
+ childerr = childout;
+ } else if (*errfd == -1) {
if (pipe2(pipeerr, O_CLOEXEC) < 0) {
virReportSystemError(errno,
"%s", _("Failed to create pipe"));
@@ -1428,7 +1430,10 @@ virCommandSetOutputBuffer(virCommandPtr cmd, char **outbuf)
* guaranteed to be allocated after successful virCommandRun or
* virCommandWait, and is best-effort allocated after failed
* virCommandRun; caller is responsible for freeing *errbuf.
- * This requires the use of virCommandRun.
+ * This requires the use of virCommandRun. It is possible to
+ * pass the same pointer as for virCommandSetOutputBuffer(), in
+ * which case the child process will interleave all output into
+ * a single string.
*/
void
virCommandSetErrorBuffer(virCommandPtr cmd, char **errbuf)
@@ -1940,6 +1945,13 @@ virCommandRun(virCommandPtr cmd, int *exitstatus)
cmd->inpipe = infd[1];
}
+ /* If caller requested the same string for stdout and stderr, then
+ * merge those into one string. */
+ if (cmd->outbuf && cmd->outbuf == cmd->errbuf) {
+ cmd->errfdptr = &cmd->outfd;
+ cmd->errbuf = NULL;
+ }
+
/* If caller hasn't requested capture of stdout/err, then capture
* it ourselves so we can log it. But the intermediate child for
* a daemon has no expected output, and we don't want our
diff --git a/tests/commandtest.c b/tests/commandtest.c
index 9b9130c..3997d2c 100644
--- a/tests/commandtest.c
+++ b/tests/commandtest.c
@@ -508,6 +508,14 @@ static int test14(const void *unused ATTRIBUTE_UNUSED)
const char *errexpect = "BEGIN STDERR\n"
"Hello World\n"
"END STDERR\n";
+
+ char *jointactual = NULL;
+ const char *jointexpect = "BEGIN STDOUT\n"
+ "BEGIN STDERR\n"
+ "Hello World\n"
+ "Hello World\n"
+ "END STDOUT\n"
+ "END STDERR\n";
int ret = -1;
virCommandSetInputBuffer(cmd, "Hello World\n");
@@ -523,7 +531,18 @@ static int test14(const void *unused ATTRIBUTE_UNUSED)
goto cleanup;
virCommandFree(cmd);
- cmd = NULL;
+
+ cmd = virCommandNew(abs_builddir "/commandhelper");
+ virCommandSetInputBuffer(cmd, "Hello World\n");
+ virCommandSetOutputBuffer(cmd, &jointactual);
+ virCommandSetErrorBuffer(cmd, &jointactual);
+ if (virCommandRun(cmd, NULL) < 0) {
+ virErrorPtr err = virGetLastError();
+ printf("Cannot run child %s\n", err->message);
+ goto cleanup;
+ }
+ if (!jointactual)
+ goto cleanup;
if (!STREQ(outactual, outexpect)) {
virtTestDifference(stderr, outexpect, outactual);
@@ -533,6 +552,10 @@ static int test14(const void *unused ATTRIBUTE_UNUSED)
virtTestDifference(stderr, errexpect, erractual);
goto cleanup;
}
+ if (!STREQ(jointactual, jointexpect)) {
+ virtTestDifference(stderr, jointexpect, jointactual);
+ goto cleanup;
+ }
ret = checkoutput("test14");
@@ -540,6 +563,7 @@ cleanup:
virCommandFree(cmd);
VIR_FREE(outactual);
VIR_FREE(erractual);
+ VIR_FREE(jointactual);
return ret;
}
--
1.7.7.6
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