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Re: [Qemu-devel] [PATCH] tpm: Simplify creation of cancel path
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH] tpm: Simplify creation of cancel path |
Date: |
Tue, 16 Apr 2013 13:16:57 -0500 |
User-agent: |
Notmuch/0.15.2+77~g661dcf8 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Stefan Berger <address@hidden> writes:
> 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 <address@hidden>
No longer applies. Had you sent with git-send-patch, git am --3way
would have figured it out. Please use git-send-patch in the future.
Regards,
Anthony Liguori
>
> ---
> tpm/tpm_passthrough.c | 74
> +++++++++++---------------------------------------
> 1 file changed, 17 insertions(+), 57 deletions(-)
>
> Index: qemu-git.pt/tpm/tpm_passthrough.c
> ===================================================================
> --- qemu-git.pt.orig/tpm/tpm_passthrough.c
> +++ qemu-git.pt/tpm/tpm_passthrough.c
> @@ -336,45 +336,17 @@ static int tpm_passthrough_test_tpmdev(i
> }
>
> /*
> - * 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);
> @@ -385,34 +357,22 @@ static int tpm_passthrough_open_sysfs_ca
> 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;