From 8e36d6ca34243fdc9f48f4bdbe5fca2b19162bfa Mon Sep 17 00:00:00 2001 From: Stefan Berger Date: Tue, 16 Apr 2013 17:08:36 -0400 Subject: tpm: Simplify creation of cancel path Simplify the creation of the cancel path given the TPM's device path. Given the path /dev/tpm0 build the path /sys/class/misc/tpm0/device/cancel. Signed-off-by: Stefan Berger Reviewed-by: Eric Blake Message-id: 1366146516-23814-1-git-send-email-stefanb@linux.vnet.ibm.com Signed-off-by: Anthony Liguori --- hw/tpm/tpm_passthrough.c | 74 +++++++++++------------------------------------- 1 file changed, 17 insertions(+), 57 deletions(-) (limited to 'hw/tpm') diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c index 416b9b65c7..ce74e97043 100644 --- a/hw/tpm/tpm_passthrough.c +++ b/hw/tpm/tpm_passthrough.c @@ -351,46 +351,18 @@ static int tpm_passthrough_test_tpmdev(int fd) return 0; } -/* - * Check whether the given base path, e.g., /sys/class/misc/tpm0/device, - * is the sysfs directory of a TPM. A TPM sysfs directory should be uniquely - * recognizable by the file entries 'pcrs' and 'cancel'. - * Upon success 'true' is returned and the basebath buffer has '/cancel' - * appended. - */ -static bool tpm_passthrough_check_sysfs_cancel(char *basepath, size_t bufsz) -{ - char path[PATH_MAX]; - struct stat statbuf; - - snprintf(path, sizeof(path), "%s/pcrs", basepath); - if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) { - return false; - } - - snprintf(path, sizeof(path), "%s/cancel", basepath); - if (stat(path, &statbuf) == -1 || !S_ISREG(statbuf.st_mode)) { - return false; - } - - strncpy(basepath, path, bufsz); - - return true; -} - /* * Unless path or file descriptor set has been provided by user, * determine the sysfs cancel file following kernel documentation * in Documentation/ABI/stable/sysfs-class-tpm. + * From /dev/tpm0 create /sys/class/misc/tpm0/device/cancel */ static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb) { + TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb); int fd = -1; - unsigned int idx; - DIR *pnp_dir; + char *dev; char path[PATH_MAX]; - struct dirent entry, *result; - int len; if (tb->cancel_path) { fd = qemu_open(tb->cancel_path, O_WRONLY); @@ -401,34 +373,22 @@ static int tpm_passthrough_open_sysfs_cancel(TPMBackend *tb) return fd; } - snprintf(path, sizeof(path), "/sys/class/misc"); - pnp_dir = opendir(path); - if (pnp_dir != NULL) { - while (readdir_r(pnp_dir, &entry, &result) == 0 && - result != NULL) { - /* - * only allow /sys/class/misc/tpm%u type of paths - */ - if (sscanf(entry.d_name, "tpm%u%n", &idx, &len) < 1 || - len <= strlen("tpm") || - len != strlen(entry.d_name)) { - continue; - } - - snprintf(path, sizeof(path), "/sys/class/misc/%s/device", - entry.d_name); - if (!tpm_passthrough_check_sysfs_cancel(path, sizeof(path))) { - continue; - } - + dev = strrchr(tpm_pt->tpm_dev, '/'); + if (dev) { + dev++; + if (snprintf(path, sizeof(path), "/sys/class/misc/%s/device/cancel", + dev) < sizeof(path)) { fd = qemu_open(path, O_WRONLY); - break; + if (fd >= 0) { + tb->cancel_path = g_strdup(path); + } else { + error_report("tpm_passthrough: Could not open TPM cancel " + "path %s : %s", path, strerror(errno)); + } } - closedir(pnp_dir); - } - - if (fd >= 0) { - tb->cancel_path = g_strdup(path); + } else { + error_report("tpm_passthrough: Bad TPM device path %s", + tpm_pt->tpm_dev); } return fd; -- cgit v1.2.1