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https://gitlab.com/libvirt/libvirt.git
synced 2024-12-24 14:45:24 +00:00
save: let iohelper handle inherited fd
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.
This commit is contained in:
Eric Blake
parent
38149ec145
commit
1eb6647979
@ -535,9 +535,17 @@ virFDStreamOpenFileInternal(virStreamPtr st,
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goto error;
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}
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if (offset &&
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lseek(fd, offset, SEEK_SET) != offset) {
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virReportSystemError(errno,
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_("Unable to seek %s to %llu"),
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path, offset);
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goto error;
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}
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/* Thanks to the POSIX i/o model, we can't reliably get
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* non-blocking I/O on block devs/regular files. To
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* support those we need to fork a helper process todo
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* support those we need to fork a helper process to do
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* the I/O so we just have a fifo. Or use AIO :-(
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*/
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if ((st->flags & VIR_STREAM_NONBLOCK) &&
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@ -545,14 +553,13 @@ virFDStreamOpenFileInternal(virStreamPtr st,
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!S_ISFIFO(sb.st_mode))) {
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int childfd;
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if ((oflags & O_RDWR) == O_RDWR) {
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if ((oflags & O_ACCMODE) == O_RDWR) {
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streamsReportError(VIR_ERR_INTERNAL_ERROR,
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_("%s: Cannot request read and write flags together"),
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path);
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goto error;
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}
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VIR_FORCE_CLOSE(fd);
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if (pipe(fds) < 0) {
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virReportSystemError(errno, "%s",
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_("Unable to create pipe"));
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@ -562,18 +569,9 @@ virFDStreamOpenFileInternal(virStreamPtr st,
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cmd = virCommandNewArgList(LIBEXECDIR "/libvirt_iohelper",
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path,
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NULL);
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virCommandAddArgFormat(cmd, "%d", oflags);
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virCommandAddArgFormat(cmd, "%d", mode);
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virCommandAddArgFormat(cmd, "%llu", offset);
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virCommandAddArgFormat(cmd, "%llu", length);
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virCommandAddArgFormat(cmd, "%u", delete);
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/* when running iohelper we don't want to delete file now,
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* because a race condition may occur in which we delete it
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* before iohelper even opens it. We want iohelper to remove
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* the file instead.
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*/
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delete = false;
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virCommandTransferFD(cmd, fd);
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virCommandAddArgFormat(cmd, "%d", fd);
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if (oflags == O_RDONLY) {
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childfd = fds[1];
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@ -590,14 +588,6 @@ virFDStreamOpenFileInternal(virStreamPtr st,
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goto error;
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VIR_FORCE_CLOSE(childfd);
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} else {
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if (offset &&
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lseek(fd, offset, SEEK_SET) != offset) {
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virReportSystemError(errno,
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_("Unable to seek %s to %llu"),
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path, offset);
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goto error;
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}
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}
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if (virFDStreamOpenInternal(st, fd, cmd, errfd, length) < 0)
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@ -42,19 +42,11 @@
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#define VIR_FROM_THIS VIR_FROM_STORAGE
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static int runIO(const char *path,
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int oflags,
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int mode,
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unsigned long long offset,
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unsigned long long length)
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static int
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prepare(const char *path, int oflags, int mode,
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unsigned long long offset)
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{
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char *buf = NULL;
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size_t buflen = 1024*1024;
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int fd;
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int ret = -1;
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int fdin, fdout;
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const char *fdinname, *fdoutname;
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unsigned long long total = 0;
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int fd = -1;
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if (oflags & O_CREAT) {
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fd = open(path, oflags, mode);
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@ -70,10 +62,25 @@ static int runIO(const char *path,
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if (lseek(fd, offset, SEEK_SET) < 0) {
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virReportSystemError(errno, _("Unable to seek %s to %llu"),
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path, offset);
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VIR_FORCE_CLOSE(fd);
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goto cleanup;
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}
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}
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cleanup:
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return fd;
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}
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static int
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runIO(const char *path, int fd, int oflags, unsigned long long length)
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{
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char *buf = NULL;
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size_t buflen = 1024*1024;
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int ret = -1;
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int fdin, fdout;
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const char *fdinname, *fdoutname;
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unsigned long long total = 0;
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if (VIR_ALLOC_N(buf, buflen) < 0) {
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virReportOOMError();
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goto cleanup;
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@ -138,61 +145,109 @@ cleanup:
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return ret;
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}
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int main(int argc, char **argv)
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static const char *program_name;
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ATTRIBUTE_NORETURN static void
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usage(int status)
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{
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if (status) {
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fprintf(stderr, _("%s: try --help for more details"), program_name);
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} else {
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printf(_("Usage: %s FILENAME OFLAGS MODE OFFSET LENGTH DELETE\n"
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" or: %s FILENAME LENGTH FD\n"),
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program_name, program_name);
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}
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exit(status);
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}
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int
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main(int argc, char **argv)
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{
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const char *path;
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virErrorPtr err;
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unsigned long long offset;
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unsigned long long length;
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int oflags;
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int oflags = -1;
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int mode;
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unsigned int delete;
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unsigned int delete = 0;
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int fd = -1;
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int lengthIndex = 0;
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program_name = argv[0];
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if (setlocale(LC_ALL, "") == NULL ||
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bindtextdomain(PACKAGE, LOCALEDIR) == NULL ||
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textdomain(PACKAGE) == NULL) {
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fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
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fprintf(stderr, _("%s: initialization failed\n"), program_name);
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exit(EXIT_FAILURE);
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}
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if (virThreadInitialize() < 0 ||
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virErrorInitialize() < 0 ||
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virRandomInitialize(time(NULL) ^ getpid())) {
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fprintf(stderr, _("%s: initialization failed\n"), argv[0]);
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exit(EXIT_FAILURE);
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}
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if (argc != 7) {
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fprintf(stderr, _("%s: syntax FILENAME FLAGS MODE OFFSET LENGTH DELETE\n"), argv[0]);
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fprintf(stderr, _("%s: initialization failed\n"), program_name);
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exit(EXIT_FAILURE);
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}
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path = argv[1];
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if (virStrToLong_i(argv[2], NULL, 10, &oflags) < 0) {
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fprintf(stderr, _("%s: malformed file flags %s"), argv[0], argv[2]);
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if (argc > 1 && STREQ(argv[1], "--help"))
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usage(EXIT_SUCCESS);
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if (argc == 7) { /* FILENAME OFLAGS MODE OFFSET LENGTH DELETE */
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lengthIndex = 5;
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if (virStrToLong_i(argv[2], NULL, 10, &oflags) < 0) {
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fprintf(stderr, _("%s: malformed file flags %s"),
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program_name, argv[2]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_i(argv[3], NULL, 10, &mode) < 0) {
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fprintf(stderr, _("%s: malformed file mode %s"),
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program_name, argv[3]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_ull(argv[4], NULL, 10, &offset) < 0) {
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fprintf(stderr, _("%s: malformed file offset %s"),
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program_name, argv[4]);
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exit(EXIT_FAILURE);
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}
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if (argc == 7 && virStrToLong_ui(argv[6], NULL, 10, &delete) < 0) {
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fprintf(stderr, _("%s: malformed delete flag %s"),
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program_name, argv[6]);
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exit(EXIT_FAILURE);
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}
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fd = prepare(path, oflags, mode, offset);
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} else if (argc == 4) { /* FILENAME LENGTH FD */
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lengthIndex = 2;
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if (virStrToLong_i(argv[3], NULL, 10, &fd) < 0) {
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fprintf(stderr, _("%s: malformed fd %s"),
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program_name, argv[3]);
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exit(EXIT_FAILURE);
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}
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#ifdef F_GETFL
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oflags = fcntl(fd, F_GETFL);
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#else
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/* Stupid mingw. */
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if (fd == STDIN_FILENO)
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oflags = O_RDONLY;
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else if (fd == STDOUT_FILENO)
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oflags = O_WRONLY;
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#endif
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if (oflags < 0) {
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fprintf(stderr, _("%s: unable to determine access mode of fd %d"),
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program_name, fd);
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exit(EXIT_FAILURE);
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}
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} else { /* unknown argc pattern */
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usage(EXIT_FAILURE);
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}
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if (virStrToLong_ull(argv[lengthIndex], NULL, 10, &length) < 0) {
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fprintf(stderr, _("%s: malformed file length %s"),
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program_name, argv[lengthIndex]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_i(argv[3], NULL, 10, &mode) < 0) {
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fprintf(stderr, _("%s: malformed file mode %s"), argv[0], argv[3]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_ull(argv[4], NULL, 10, &offset) < 0) {
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fprintf(stderr, _("%s: malformed file offset %s"), argv[0], argv[4]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_ull(argv[5], NULL, 10, &length) < 0) {
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fprintf(stderr, _("%s: malformed file length %s"), argv[0], argv[5]);
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exit(EXIT_FAILURE);
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}
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if (virStrToLong_ui(argv[6], NULL, 10, &delete) < 0) {
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fprintf(stderr, _("%s: malformed delete flag %s"), argv[0],argv[6]);
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exit(EXIT_FAILURE);
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}
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if (runIO(path, oflags, mode, offset, length) < 0)
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if (fd < 0 || runIO(path, fd, oflags, length) < 0)
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goto error;
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if (delete)
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@ -203,9 +258,10 @@ int main(int argc, char **argv)
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error:
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err = virGetLastError();
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if (err) {
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fprintf(stderr, "%s: %s\n", argv[0], err->message);
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fprintf(stderr, "%s: %s\n", program_name, err->message);
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} else {
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fprintf(stderr, _("%s: unknown failure with %s\n"), argv[0], path);
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fprintf(stderr, _("%s: unknown failure with %s\n"),
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program_name, path);
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}
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exit(EXIT_FAILURE);
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}
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