swtpm: Also remove pidfile at end if fd was passed

Address the issue that the pidfile needs to be removed at the end if
a file descriptor was passed in. So we have to look up the file
given the file descriptor and by using /proc/self/fd/.
We also want to make sure that the given file descriptor describes
a regular file.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

src/swtpm/common.c

@@ -432,6 +432,7 @@ parse_pid_options(char *options, char **pidfile, int *pidfilefd)
     OptionValues *ovs = NULL;
     char *error = NULL;
     const char *filename = NULL;
+    struct stat stat;
 
     ovs = options_parse(options, pid_opt_desc, &error);
     if (!ovs) {
@@ -454,6 +455,12 @@ parse_pid_options(char *options, char **pidfile, int *pidfilefd)
             logprintf(STDERR_FILENO, "Out of memory.");
             goto error;
         }
+    } else {
+        if (fstat(*pidfilefd, &stat) < 0 || !S_ISREG(stat.st_mode)) {
+            logprintf(STDERR_FILENO,
+                      "Bad filedescriptor %d for pid file\n", *pidfilefd);
+            goto error;
+        }
     }
 
     option_values_free(ovs);
@@ -462,6 +469,7 @@ parse_pid_options(char *options, char **pidfile, int *pidfilefd)
 
 error:
     option_values_free(ovs);
+    close(*pidfilefd);
 
     return -1;
 }

src/swtpm/pidfile.c

@@ -45,6 +45,7 @@
 
 #include "pidfile.h"
 #include "logging.h"
+#include "utils.h"
 
 static char *g_pidfile;
 static int pidfilefd = -1;
@@ -82,6 +83,11 @@ int pidfile_write(pid_t pid)
         f = fopen(g_pidfile, "w+");
     } else if (pidfilefd >= 0) {
         f = fdopen(pidfilefd, "w");
+        if (f) {
+            g_pidfile = fd_to_filename(pidfilefd);
+            if (!g_pidfile)
+                goto error;
+        }
     } else {
         return 0;
     }
@@ -95,7 +101,6 @@ int pidfile_write(pid_t pid)
     if (fprintf(f, "%d", pid) < 0) {
         logprintf(STDERR_FILENO, "Could not write to pidfile : %s\n",
                   strerror(errno));
-        fclose(f);
         goto error;
     }
 
@@ -104,6 +109,8 @@ int pidfile_write(pid_t pid)
     return 0;
 
 error:
+    if (f)
+        fclose(f);
     return -1;
 }
 

src/swtpm/utils.c

@@ -41,6 +41,10 @@
 #include <pwd.h>
 #include <fcntl.h>
 #include <unistd.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
 
 #include "utils.h"
 #include "logging.h"
@@ -135,3 +139,20 @@ void tpmlib_debug_libtpms_parameters(void)
         tpmlib_get_tpm_property(TPMPROP_TPM_MAX_NV_DEFINED_SIZE));
 #endif
 }
+
+char *fd_to_filename(int fd)
+{
+    char buffer[64];
+    char *path;
+
+    snprintf(buffer, sizeof(buffer), "/proc/self/fd/%d", fd);
+
+    path = realpath(buffer, NULL);
+    if (!path) {
+        logprintf(STDERR_FILENO, "Could not read %s: %s\n",
+                  buffer, strerror(errno));
+        return NULL;
+    }
+
+    return path;
+}

src/swtpm/utils.h

@@ -51,4 +51,6 @@ int change_process_owner(const char *owner);
 
 void tpmlib_debug_libtpms_parameters(void);
 
+char *fd_to_filename(int fd);
+
 #endif /* _SWTPM_UTILS_H_ */