11:20 p.m.
Rather than making the iohelper subject to a race in reopening
the file, it is nicer to pass an already-open fd by inheritance.
The old synopsis form must continue to work - if someone updates
their libvirt package and installs a new libvirt_iohelper but
without restarting the old libvirtd daemon, then the daemon can
still make calls using the old syntax but the new iohelper.
* src/util/iohelper.c (runIO): Split code for open...
(prepare): ...to new function.
(usage): Update synopsis.
(main): Allow alternate calling form.
* src/fdstream.c (virFDStreamOpenFileInternal): Use alternate form.
---
v2: unchanged from patch 5 of v1
src/fdstream.c | 34 ++++--------
src/util/iohelper.c | 142 +++++++++++++++++++++++++++++++++++---------------
2 files changed, 111 insertions(+), 65 deletions(-)
diff --git a/src/fdstream.c b/src/fdstream.c
index d25b3f0..2b7812f 100644
--- a/src/fdstream.c
+++ b/src/fdstream.c
@@ -535,9 +535,17 @@ virFDStreamOpenFileInternal(virStreamPtr st,
goto error;
}
+ if (offset &&
+ lseek(fd, offset, SEEK_SET) != offset) {
+ virReportSystemError(errno,
+ _("Unable to seek %s to %llu"),
+ path, offset);
+ goto error;
+ }
+
/* Thanks to the POSIX i/o model, we can't reliably get
* non-blocking I/O on block devs/regular files. To
- * support those we need to fork a helper process todo
+ * support those we need to fork a helper process to do
* the I/O so we just have a fifo. Or use AIO :-(
*/
if ((st->flags & VIR_STREAM_NONBLOCK) &&
@@ -545,14 +553,13 @@ virFDStreamOpenFileInternal(virStreamPtr st,
!S_ISFIFO(sb.st_mode))) {
int childfd;
- if ((oflags & O_RDWR) == O_RDWR) {
+ if ((oflags & O_ACCMODE) == O_RDWR) {
streamsReportError(VIR_ERR_INTERNAL_ERROR,
_("%s: Cannot request read and write flags
together"),
path);
goto error;
}
- VIR_FORCE_CLOSE(fd);
if (pipe(fds) < 0) {
virReportSystemError(errno, "%s",
_("Unable to create pipe"));
@@ -562,18 +569,9 @@ virFDStreamOpenFileInternal(virStreamPtr st,
cmd = virCommandNewArgList(LIBEXECDIR "/libvirt_iohelper",
path,
NULL);
- virCommandAddArgFormat(cmd, "%d", oflags);
- virCommandAddArgFormat(cmd, "%d", mode);
- virCommandAddArgFormat(cmd, "%llu", offset);
virCommandAddArgFormat(cmd, "%llu", length);
- virCommandAddArgFormat(cmd, "%u", delete);
-
- /* when running iohelper we don't want to delete file now,
- * because a race condition may occur in which we delete it
- * before iohelper even opens it. We want iohelper to remove
- * the file instead.
- */
- delete = false;
+ virCommandTransferFD(cmd, fd);
+ virCommandAddArgFormat(cmd, "%d", fd);
if (oflags == O_RDONLY) {
childfd = fds[1];
@@ -590,14 +588,6 @@ virFDStreamOpenFileInternal(virStreamPtr st,
goto error;
VIR_FORCE_CLOSE(childfd);
- } else {
- if (offset &&
- lseek(fd, offset, SEEK_SET) != offset) {
- virReportSystemError(errno,
- _("Unable to seek %s to %llu"),
- path, offset);
- goto error;
- }
}
if (virFDStreamOpenInternal(st, fd, cmd, errfd, length) < 0)
diff --git a/src/util/iohelper.c b/src/util/iohelper.c
index 6a9f355..502bce5 100644
--- a/src/util/iohelper.c
+++ b/src/util/iohelper.c
@@ -42,19 +42,11 @@
#define VIR_FROM_THIS VIR_FROM_STORAGE
-static int runIO(const char *path,
- int oflags,
- int mode,
- unsigned long long offset,
- unsigned long long length)
+static int
+prepare(const char *path, int oflags, int mode,
+ unsigned long long offset)
{
- char *buf = NULL;
- size_t buflen = 1024*1024;
- int fd;
- int ret = -1;
- int fdin, fdout;
- const char *fdinname, *fdoutname;
- unsigned long long total = 0;
+ int fd = -1;
if (oflags & O_CREAT) {
fd = open(path, oflags, mode);
@@ -70,10 +62,25 @@ static int runIO(const char *path,
if (lseek(fd, offset, SEEK_SET) < 0) {
virReportSystemError(errno, _("Unable to seek %s to %llu"),
path, offset);
+ VIR_FORCE_CLOSE(fd);
goto cleanup;
}
}
+cleanup:
+ return fd;
+}
+
+static int
+runIO(const char *path, int fd, int oflags, unsigned long long length)
+{
+ char *buf = NULL;
+ size_t buflen = 1024*1024;
+ int ret = -1;
+ int fdin, fdout;
+ const char *fdinname, *fdoutname;
+ unsigned long long total = 0;
+
if (VIR_ALLOC_N(buf, buflen) < 0) {
virReportOOMError();
goto cleanup;
@@ -138,61 +145,109 @@ cleanup:
return ret;
}
-int main(int argc, char **argv)
+static const char *program_name;
+
+ATTRIBUTE_NORETURN static void
+usage(int status)
+{
+ if (status) {
+ fprintf(stderr, _("%s: try --help for more details"), program_name);
+ } else {
+ printf(_("Usage: %s FILENAME OFLAGS MODE OFFSET LENGTH DELETE\n"
+ " or: %s FILENAME LENGTH FD\n"),
+ program_name, program_name);
+ }
+ exit(status);
+}
+
+int
+main(int argc, char **argv)
{
const char *path;
virErrorPtr err;
unsigned long long offset;
unsigned long long length;
- int oflags;
+ int oflags = -1;
int mode;
- unsigned int delete;
+ unsigned int delete = 0;
+ int fd = -1;
+ int lengthIndex = 0;
+
+ program_name = argv[0];
if (setlocale(LC_ALL, "") == NULL ||
bindtextdomain(PACKAGE, LOCALEDIR) == NULL ||
textdomain(PACKAGE) == NULL) {
- fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
+ fprintf(stderr, _("%s: initialization failed\n"), program_name);
exit(EXIT_FAILURE);
}
if (virThreadInitialize() < 0 ||
virErrorInitialize() < 0 ||
virRandomInitialize(time(NULL) ^ getpid())) {
- fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
- exit(EXIT_FAILURE);
- }
-
- if (argc != 7) {
- fprintf(stderr, _("%s: syntax FILENAME FLAGS MODE OFFSET LENGTH
DELETE\n"), argv[0]);
+ fprintf(stderr, _("%s: initialization failed\n"), program_name);
exit(EXIT_FAILURE);
}
path = argv[1];
- if (virStrToLong_i(argv[2], NULL, 10, &oflags) < 0) {
- fprintf(stderr, _("%s: malformed file flags %s"), argv[0], argv[2]);
- exit(EXIT_FAILURE);
- }
-
- if (virStrToLong_i(argv[3], NULL, 10, &mode) < 0) {
- fprintf(stderr, _("%s: malformed file mode %s"), argv[0], argv[3]);
- exit(EXIT_FAILURE);
+ if (argc > 1 && STREQ(argv[1], "--help"))
+ usage(EXIT_SUCCESS);
+ if (argc == 7) { /* FILENAME OFLAGS MODE OFFSET LENGTH DELETE */
+ lengthIndex = 5;
+ if (virStrToLong_i(argv[2], NULL, 10, &oflags) < 0) {
+ fprintf(stderr, _("%s: malformed file flags %s"),
+ program_name, argv[2]);
+ exit(EXIT_FAILURE);
+ }
+ if (virStrToLong_i(argv[3], NULL, 10, &mode) < 0) {
+ fprintf(stderr, _("%s: malformed file mode %s"),
+ program_name, argv[3]);
+ exit(EXIT_FAILURE);
+ }
+ if (virStrToLong_ull(argv[4], NULL, 10, &offset) < 0) {
+ fprintf(stderr, _("%s: malformed file offset %s"),
+ program_name, argv[4]);
+ exit(EXIT_FAILURE);
+ }
+ if (argc == 7 && virStrToLong_ui(argv[6], NULL, 10, &delete) < 0)
{
+ fprintf(stderr, _("%s: malformed delete flag %s"),
+ program_name, argv[6]);
+ exit(EXIT_FAILURE);
+ }
+ fd = prepare(path, oflags, mode, offset);
+ } else if (argc == 4) { /* FILENAME LENGTH FD */
+ lengthIndex = 2;
+ if (virStrToLong_i(argv[3], NULL, 10, &fd) < 0) {
+ fprintf(stderr, _("%s: malformed fd %s"),
+ program_name, argv[3]);
+ exit(EXIT_FAILURE);
+ }
+#ifdef F_GETFL
+ oflags = fcntl(fd, F_GETFL);
+#else
+ /* Stupid mingw. */
+ if (fd == STDIN_FILENO)
+ oflags = O_RDONLY;
+ else if (fd == STDOUT_FILENO)
+ oflags = O_WRONLY;
+#endif
+ if (oflags < 0) {
+ fprintf(stderr, _("%s: unable to determine access mode of fd %d"),
+ program_name, fd);
+ exit(EXIT_FAILURE);
+ }
+ } else { /* unknown argc pattern */
+ usage(EXIT_FAILURE);
}
- if (virStrToLong_ull(argv[4], NULL, 10, &offset) < 0) {
- fprintf(stderr, _("%s: malformed file offset %s"), argv[0], argv[4]);
- exit(EXIT_FAILURE);
- }
- if (virStrToLong_ull(argv[5], NULL, 10, &length) < 0) {
- fprintf(stderr, _("%s: malformed file length %s"), argv[0], argv[5]);
- exit(EXIT_FAILURE);
- }
- if (virStrToLong_ui(argv[6], NULL, 10, &delete) < 0) {
- fprintf(stderr, _("%s: malformed delete flag %s"), argv[0],argv[6]);
+ if (virStrToLong_ull(argv[lengthIndex], NULL, 10, &length) < 0) {
+ fprintf(stderr, _("%s: malformed file length %s"),
+ program_name, argv[lengthIndex]);
exit(EXIT_FAILURE);
}
- if (runIO(path, oflags, mode, offset, length) < 0)
+ if (fd < 0 || runIO(path, fd, oflags, length) < 0)
goto error;
if (delete)
@@ -203,9 +258,10 @@ int main(int argc, char **argv)
error:
err = virGetLastError();
if (err) {
- fprintf(stderr, "%s: %s\n", argv[0], err->message);
+ fprintf(stderr, "%s: %s\n", program_name, err->message);
} else {
- fprintf(stderr, _("%s: unknown failure with %s\n"), argv[0], path);
+ fprintf(stderr, _("%s: unknown failure with %s\n"),
+ program_name, path);
}
exit(EXIT_FAILURE);
}
--
1.7.4.4