This commit improves the error messages from the tar-in, tgz-in (etc)
commands by capturing the stderr from the tar command in a file and
sending that back in the error message.
The method used for the error file is primitive, and there is a case
for a more generic error file mechanism, but this will do for now.
Sample error messages after this change:
$ virt-tar -u /tmp/test1.img /tmp/not.tar /
tar_in: tar subcommand failed on directory: /: tar: This does not look like a tar archive
tar: Skipping to next header
tar: Exiting with failure status due to previous errors at /home/rjones/d/libguestfs/tools/virt-tar line 247.
$ virt-tar -u /tmp/test1.img /tmp/test.tar /
tar_in: tar subcommand failed on directory: /: tar: access.log: Cannot open: Read-only file system
tar: Exiting with failure status due to previous errors at /home/rjones/d/libguestfs/tools/virt-tar line 247.
m4/priv-set.m4
m4/rawmemchr.m4
m4/readlink.m4
m4/priv-set.m4
m4/rawmemchr.m4
m4/readlink.m4
m4/realloc.m4
m4/rmdir.m4
m4/safe-read.m4
m4/realloc.m4
m4/rmdir.m4
m4/safe-read.m4
# Specification in the form of a command-line invocation:
# Specification in the form of a command-line invocation:
-# gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --with-tests --no-libtool --macro-prefix=gl byteswap c-ctype connect fsusage futimens getaddrinfo getline glob hash ignore-value manywarnings mkdtemp netdb openat perror pread readlink select sleep socket strchrnul strndup symlinkat sys_select sys_wait vasprintf warnings
+# gnulib-tool --import --dir=. --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --with-tests --no-libtool --macro-prefix=gl byteswap c-ctype connect error fsusage futimens getaddrinfo getline glob hash ignore-value manywarnings mkdtemp netdb openat perror pread read-file readlink select sleep socket strchrnul strndup symlinkat sys_select sys_wait vasprintf warnings
# Specification in the form of a few gnulib-tool.m4 macro invocations:
gl_LOCAL_DIR([])
# Specification in the form of a few gnulib-tool.m4 macro invocations:
gl_LOCAL_DIR([])
#include <string.h>
#include <fcntl.h>
#include <string.h>
#include <fcntl.h>
+#include "read-file.h"
+
#include "../src/guestfs_protocol.h"
#include "daemon.h"
#include "actions.h"
#include "../src/guestfs_protocol.h"
#include "daemon.h"
#include "actions.h"
+/* Redirect errors from the tar command to the error file, then
+ * provide functions for reading it in. We overwrite the file each
+ * time, and since it's small and stored on the appliance we don't
+ * bother to delete it.
+ */
+static const char *error_file = "/tmp/error";
+
+static char *
+read_error_file (void)
+{
+ size_t len;
+ char *str = read_file (error_file, &len);
+ if (str == NULL) {
+ str = strdup ("(no error)");
+ if (str == NULL) {
+ perror ("strdup");
+ exit (EXIT_FAILURE);
+ }
+ len = strlen (str);
+ }
+
+ /* Remove trailing \n character if any. */
+ if (len > 0 && str[len-1] == '\n')
+ str[--len] = '\0';
+
+ return str; /* caller frees */
+}
+
static int
write_cb (void *fd_ptr, const void *buf, size_t len)
{
static int
write_cb (void *fd_ptr, const void *buf, size_t len)
{
char *cmd;
/* "tar -C /sysroot%s -xf -" but we have to quote the dir. */
char *cmd;
/* "tar -C /sysroot%s -xf -" but we have to quote the dir. */
- if (asprintf_nowarn (&cmd, "tar -C %R -%sxf -",
- dir, filter) == -1) {
+ if (asprintf_nowarn (&cmd, "tar -C %R -%sxf - 2> %s",
+ dir, filter, error_file) == -1) {
err = errno;
r = cancel_receive ();
errno = err;
err = errno;
r = cancel_receive ();
errno = err;
r = receive_file (write_cb, &fd);
if (r == -1) { /* write error */
r = receive_file (write_cb, &fd);
if (r == -1) { /* write error */
- if (cancel_receive () != -2)
- reply_with_error ("write error on directory: %s", dir);
+ if (cancel_receive () != -2) {
+ char *errstr = read_error_file ();
+ reply_with_error ("write error on directory: %s: %s", dir, errstr);
+ free (errstr);
+ }
pclose (fp);
return -1;
}
pclose (fp);
return -1;
}
if (pclose (fp) != 0) {
if (r == -1) /* if r == 0, file transfer ended already */
r = cancel_receive ();
if (pclose (fp) != 0) {
if (r == -1) /* if r == 0, file transfer ended already */
r = cancel_receive ();
- if (r != -2)
- reply_with_error ("tar subcommand failed on directory: %s", dir);
+ if (r != -2) {
+ char *errstr = read_error_file ();
+ reply_with_error ("tar subcommand failed on directory: %s: %s",
+ dir, errstr);
+ free (errstr);
+ }