Daniel P. Berrange wrote:
> On Thu, Oct 30, 2008 at 02:06:35PM -0400, Cole Robinson wrote:
>
>> The attached patch is my second cut at reading
>> stdout and stderr of the command virRun kicks
>> off. There is no hard limit to the amount of
>> data we read now, and we use a poll loop to
>> avoid any possible full buffer issues.
>>
>> If stdout or stderr had any content, we DEBUG
>> it, and if the command appears to fail we
>> return stderr in the error message. So now,
>> trying to stop a logical pool with active
>> volumes will return:
>>
>> $ sudo virsh pool-destroy vgdata
>> libvir: error : internal error '/sbin/vgchange -an vgdata' exited with
>> non-zero status 5 and signal 0: Can't deactivate volume group "vgdata"
>> with 2 open logical volume(s)
>> error: Failed to destroy pool vgdata
>>
<snip>
> I think it'd be nice to move the I/O processing loop out of the
> virRun() function and into a separate helper functiion along the
> lines of
>
> virPipeReadUntilEOF(int outfd, int errfd, char **outbuf, char **errbuf)
>
> Daniel
>
Okay, updated patch attached. Also addresses the point Jim
raised about poll.h
Thanks,
Cole
diff --git a/src/util.c b/src/util.c
index 691c85f..c66ee70 100644
--- a/src/util.c
+++ b/src/util.c
@@ -31,6 +31,7 @@
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
+#include <poll.h>
#include <sys/types.h>
#include <sys/stat.h>
#if HAVE_SYS_WAIT_H
@@ -414,6 +415,86 @@ virExec(virConnectPtr conn,
flags);
}
+static int
+virPipeReadUntilEOF(virConnectPtr conn, int outfd, int errfd,
+ char **outbuf, char **errbuf) {
+
+ struct pollfd fds[2];
+ int i;
+ int finished[2];
+
+ fds[0].fd = outfd;
+ fds[0].events = POLLIN;
+ finished[0] = 0;
+ fds[1].fd = errfd;
+ fds[1].events = POLLIN;
+ finished[1] = 0;
+
+ while(!(finished[0] && finished[1])) {
+
+ if (poll(fds, ARRAY_CARDINALITY(fds), -1) < 0) {
+ if (errno == EAGAIN)
+ continue;
+ goto pollerr;
+ }
+
+ for (i = 0; i < ARRAY_CARDINALITY(fds); ++i) {
+ char data[1024], **buf;
+ int got, size;
+
+ if (!(fds[i].revents))
+ continue;
+ else if (fds[i].revents & POLLHUP)
+ finished[i] = 1;
+
+ if (!(fds[i].revents & POLLIN)) {
+ if (fds[i].revents & POLLHUP)
+ continue;
+
+ ReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ "%s", _("Unknown poll response."));
+ goto error;
+ }
+
+ got = read(fds[i].fd, data, sizeof(data));
+
+ if (got == 0) {
+ finished[i] = 1;
+ continue;
+ }
+ if (got < 0) {
+ if (errno == EINTR)
+ continue;
+ if (errno == EAGAIN)
+ break;
+ goto pollerr;
+ }
+
+ buf = ((fds[i].fd == outfd) ? outbuf : errbuf);
+ size = (*buf ? strlen(*buf) : 0);
+ if (VIR_REALLOC_N(*buf, size+got+1) < 0) {
+ ReportError(conn, VIR_ERR_NO_MEMORY, NULL);
+ goto error;
+ }
+ memmove(*buf+size, data, got);
+ (*buf)[size+got] = '\0';
+ }
+ continue;
+
+ pollerr:
+ ReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ _("poll error: %s"), strerror(errno));
+ goto error;
+ }
+
+ return 0;
+
+error:
+ VIR_FREE(*outbuf);
+ VIR_FREE(*errbuf);
+ return -1;
+}
+
/**
* @conn connection to report errors against
* @argv NULL terminated argv to run
@@ -433,43 +514,66 @@ int
virRun(virConnectPtr conn,
const char *const*argv,
int *status) {
- int childpid, exitstatus, ret;
- char *argv_str;
+ int childpid, exitstatus, execret, waitret;
+ int ret = -1;
+ int errfd = -1, outfd = -1;
+ char *outbuf = NULL;
+ char *errbuf = NULL;
+ char *argv_str = NULL;
if ((argv_str = virArgvToString(argv)) == NULL) {
ReportError(conn, VIR_ERR_NO_MEMORY, _("command debug string"));
- return -1;
+ goto error;
}
DEBUG0(argv_str);
- VIR_FREE(argv_str);
- if ((ret = __virExec(conn, argv, NULL, NULL,
- &childpid, -1, NULL, NULL, VIR_EXEC_NONE)) < 0)
- return ret;
+ if ((execret = __virExec(conn, argv, NULL, NULL,
+ &childpid, -1, &outfd, &errfd,
+ VIR_EXEC_NONE)) < 0) {
+ ret = execret;
+ goto error;
+ }
+
+ if (virPipeReadUntilEOF(conn, outfd, errfd, &outbuf, &errbuf) < 0)
+ goto error;
+
+ if (outbuf)
+ DEBUG("Command stdout: %s", outbuf);
+ if (errbuf)
+ DEBUG("Command stderr: %s", errbuf);
- while ((ret = waitpid(childpid, &exitstatus, 0) == -1) && errno == EINTR);
- if (ret == -1) {
+ while ((waitret = waitpid(childpid, &exitstatus, 0) == -1) &&
+ errno == EINTR);
+ if (waitret == -1) {
ReportError(conn, VIR_ERR_INTERNAL_ERROR,
_("cannot wait for '%s': %s"),
argv[0], strerror(errno));
- return -1;
+ goto error;
}
if (status == NULL) {
errno = EINVAL;
- if (WIFEXITED(exitstatus) && WEXITSTATUS(exitstatus) == 0)
- return 0;
+ if (WIFEXITED(exitstatus) && WEXITSTATUS(exitstatus) != 0) {
- ReportError(conn, VIR_ERR_INTERNAL_ERROR,
- _("%s exited with non-zero status %d and signal %d"),
- argv[0],
- WIFEXITED(exitstatus) ? WEXITSTATUS(exitstatus) : 0,
- WIFSIGNALED(exitstatus) ? WTERMSIG(exitstatus) : 0);
- return -1;
+ ReportError(conn, VIR_ERR_INTERNAL_ERROR,
+ _("'%s' exited with non-zero status %d and "
+ "signal %d: %s"), argv_str,
+ WIFEXITED(exitstatus) ? WEXITSTATUS(exitstatus) : 0,
+ WIFSIGNALED(exitstatus) ? WTERMSIG(exitstatus) : 0,
+ (errbuf ? errbuf : ""));
+ goto error;
+ }
} else {
*status = exitstatus;
- return 0;
}
+
+ ret = 0;
+
+ error:
+ VIR_FREE(outbuf);
+ VIR_FREE(errbuf);
+ VIR_FREE(argv_str);
+ return ret;
}
#else /* __MINGW32__ */
--
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