From: Chen Hanxiao <chenhanxiao@gmail.com> We may overwrite existed save image by 'virsh save' command. This patch will check qemu save headers before trying to rewrite it. Signed-off-by: Chen Hanxiao <chenhanxiao@gmail.com> --- src/qemu/qemu_driver.c | 141 +++++++++++++++++++++++++++++++------------------ 1 file changed, 89 insertions(+), 52 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index a0ac2ef..56aa079 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -2806,6 +2806,73 @@ bswap_header(virQEMUSaveHeaderPtr hdr) } +static int +qemuSaveHeaderCheck(int fd, + virQEMUSaveHeaderPtr header, + const char *path, + bool unlink_corrupt) +{ + int ret = -1; + + if (saferead(fd, header, sizeof(*header)) != sizeof(*header)) { + if (unlink_corrupt) { + if (VIR_CLOSE(fd) < 0 || unlink(path) < 0) { + virReportSystemError(errno, + _("cannot remove corrupt file: %s"), + path); + goto error; + } + return -3; + } + virReportError(VIR_ERR_OPERATION_FAILED, + "%s", _("failed to read qemu header")); + goto error; + } + + if (memcmp((*header).magic, QEMU_SAVE_MAGIC, sizeof((*header).magic)) != 0) { + const char *msg = _("image magic is incorrect"); + + if (memcmp((*header).magic, QEMU_SAVE_PARTIAL, + sizeof((*header).magic)) == 0) { + msg = _("save image is incomplete"); + if (unlink_corrupt) { + if (VIR_CLOSE(fd) < 0 || unlink(path) < 0) { + virReportSystemError(errno, + _("cannot remove corrupt file: %s"), + path); + goto error; + } + return -3; + } + } + virReportError(VIR_ERR_OPERATION_FAILED, "%s", msg); + goto error; + } + + if ((*header).version > QEMU_SAVE_VERSION) { + /* convert endianess and try again */ + bswap_header(header); + } + + if ((*header).version > QEMU_SAVE_VERSION) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("image version is not supported (%d > %d)"), + (*header).version, QEMU_SAVE_VERSION); + goto error; + } + + if ((*header).xml_len <= 0) { + virReportError(VIR_ERR_OPERATION_FAILED, + _("invalid XML length: %d"), (*header).xml_len); + goto error; + } + + ret = 0; + + error: + return ret; +} + /* return -errno on failure, or 0 on success */ static int qemuDomainSaveHeader(int fd, const char *path, const char *xml, @@ -2827,6 +2894,7 @@ qemuDomainSaveHeader(int fd, const char *path, const char *xml, _("failed to write xml to '%s'"), path); goto endjob; } + endjob: return ret; } @@ -3067,6 +3135,24 @@ qemuDomainSaveMemory(virQEMUDriverPtr driver, goto cleanup; } } + + /* don't overwrite exsited save files */ + if (virFileExists(path)) { + virQEMUSaveHeader header_tmp; + fd = qemuOpenFile(driver, NULL, path, O_RDONLY, NULL, NULL); + if (fd < 0) + goto cleanup; + + if (qemuSaveHeaderCheck(fd, &header_tmp, path, false) >= 0) { + ret = -EEXIST; + virReportError(VIR_ERR_OPERATION_FAILED, + _("failed to write existed image file '%s'"), + path); + goto cleanup; + } + VIR_FORCE_CLOSE(fd); + } + fd = qemuOpenFile(driver, vm, path, O_WRONLY | O_TRUNC | O_CREAT | directFlag, &needUnlink, &bypassSecurityDriver); @@ -6327,6 +6413,7 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver, bool unlink_corrupt) { int fd = -1; + int ret = -1; virQEMUSaveHeader header; char *xml = NULL; virDomainDefPtr def = NULL; @@ -6353,58 +6440,8 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver, VIR_FILE_WRAPPER_BYPASS_CACHE))) goto error; - if (saferead(fd, &header, sizeof(header)) != sizeof(header)) { - if (unlink_corrupt) { - if (VIR_CLOSE(fd) < 0 || unlink(path) < 0) { - virReportSystemError(errno, - _("cannot remove corrupt file: %s"), - path); - goto error; - } - return -3; - } - virReportError(VIR_ERR_OPERATION_FAILED, - "%s", _("failed to read qemu header")); + if ((ret = qemuSaveHeaderCheck(fd, &header, path, unlink_corrupt)) < 0) goto error; - } - - if (memcmp(header.magic, QEMU_SAVE_MAGIC, sizeof(header.magic)) != 0) { - const char *msg = _("image magic is incorrect"); - - if (memcmp(header.magic, QEMU_SAVE_PARTIAL, - sizeof(header.magic)) == 0) { - msg = _("save image is incomplete"); - if (unlink_corrupt) { - if (VIR_CLOSE(fd) < 0 || unlink(path) < 0) { - virReportSystemError(errno, - _("cannot remove corrupt file: %s"), - path); - goto error; - } - return -3; - } - } - virReportError(VIR_ERR_OPERATION_FAILED, "%s", msg); - goto error; - } - - if (header.version > QEMU_SAVE_VERSION) { - /* convert endianess and try again */ - bswap_header(&header); - } - - if (header.version > QEMU_SAVE_VERSION) { - virReportError(VIR_ERR_OPERATION_FAILED, - _("image version is not supported (%d > %d)"), - header.version, QEMU_SAVE_VERSION); - goto error; - } - - if (header.xml_len <= 0) { - virReportError(VIR_ERR_OPERATION_FAILED, - _("invalid XML length: %d"), header.xml_len); - goto error; - } if (VIR_ALLOC_N(xml, header.xml_len) < 0) goto error; @@ -6439,7 +6476,7 @@ qemuDomainSaveImageOpen(virQEMUDriverPtr driver, VIR_FORCE_CLOSE(fd); virObjectUnref(caps); - return -1; + return ret; } static int ATTRIBUTE_NONNULL(4) ATTRIBUTE_NONNULL(5) ATTRIBUTE_NONNULL(6) -- 1.8.3.1