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author | Stefan Berger <stefanb@linux.vnet.ibm.com> | 2013-04-16 17:08:36 -0400 |
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committer | Anthony Liguori <aliguori@us.ibm.com> | 2013-04-22 09:30:13 -0500 |
commit | 8e36d6ca34243fdc9f48f4bdbe5fca2b19162bfa (patch) | |
tree | 2b555b5ae5429110bfe3ae3da1ba453ad06aa483 | |
parent | 56863d4f19c854acc5ebf5f5c1b590eb8164851a (diff) | |
download | hqemu-8e36d6ca34243fdc9f48f4bdbe5fca2b19162bfa.zip hqemu-8e36d6ca34243fdc9f48f4bdbe5fca2b19162bfa.tar.gz |
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 <stefanb@linux.vnet.ibm.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1366146516-23814-1-git-send-email-stefanb@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
-rw-r--r-- | hw/tpm/tpm_passthrough.c | 74 |
1 files changed, 17 insertions, 57 deletions
diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c index 416b9b6..ce74e97 100644 --- a/hw/tpm/tpm_passthrough.c +++ b/hw/tpm/tpm_passthrough.c @@ -352,45 +352,17 @@ static int tpm_passthrough_test_tpmdev(int fd) } /* - * 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; |