libuuid: Close all file descriptors before running uuidd

This avoids problems when the calling program has open file
descriptors (especially sockets) open.

Also fix up some warn_unused_result warnings from gcc.

Addresses-Launchpad-bug: #305057

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

3 files changed, 40 insertions, 5 deletions

diff --git a/configure b/configure
index a6b787b4..cf1bc1b9 100755
--- a/configure
+++ b/configure
@@ -14712,7 +14712,9 @@ fi
 
 
 
-for ac_func in chflags getrusage llseek lseek64 open64 fstat64 ftruncate64 getmntinfo strtoull strcasecmp srandom jrand48 fchown mallinfo fdatasync strnlen strptime strdup sysconf pathconf posix_memalign memalign valloc __secure_getenv prctl mmap utime setresuid setresgid usleep nanosleep
+
+
+for ac_func in chflags getrusage llseek lseek64 open64 fstat64 ftruncate64 getmntinfo strtoull strcasecmp srandom jrand48 fchown mallinfo fdatasync strnlen strptime strdup sysconf pathconf posix_memalign memalign valloc __secure_getenv prctl mmap utime setresuid setresgid usleep nanosleep getdtablesize getrlimit
 do
 as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
 { echo "$as_me:$LINENO: checking for $ac_func" >&5
diff --git a/configure.in b/configure.in
index 2534df4c..caf2cb45 100644
--- a/configure.in
+++ b/configure.in
@@ -701,7 +701,7 @@ AC_CHECK_MEMBER(struct sockaddr.sa_len,
 	[#include <sys/types.h>
 	 #include <sys/socket.h>])
 dnl
-AC_CHECK_FUNCS(chflags getrusage llseek lseek64 open64 fstat64 ftruncate64 getmntinfo strtoull strcasecmp srandom jrand48 fchown mallinfo fdatasync strnlen strptime strdup sysconf pathconf posix_memalign memalign valloc __secure_getenv prctl mmap utime setresuid setresgid usleep nanosleep)
+AC_CHECK_FUNCS(chflags getrusage llseek lseek64 open64 fstat64 ftruncate64 getmntinfo strtoull strcasecmp srandom jrand48 fchown mallinfo fdatasync strnlen strptime strdup sysconf pathconf posix_memalign memalign valloc __secure_getenv prctl mmap utime setresuid setresgid usleep nanosleep getdtablesize getrlimit)
 dnl
 dnl Check to see if -lsocket is required (solaris) to make something
 dnl that uses socket() to compile; this is needed for the UUID library
diff --git a/lib/uuid/gen_uuid.c b/lib/uuid/gen_uuid.c
index a3052d4b..b7a12eed 100644
--- a/lib/uuid/gen_uuid.c
+++ b/lib/uuid/gen_uuid.c
@@ -86,6 +86,9 @@
 #if defined(__linux__) && defined(HAVE_SYS_SYSCALL_H)
 #include <sys/syscall.h>
 #endif
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
 
 #include "uuidP.h"
 #include "uuidd.h"
@@ -311,6 +314,7 @@ static int get_clock(uint32_t *clock_high, uint32_t *clock_low,
 	struct flock			fl;
 	uint64_t			clock_reg;
 	mode_t				save_umask;
+	int				len;
 
 	if (state_fd == -2) {
 		save_umask = umask(0);
@@ -392,10 +396,14 @@ try_again:
 
 	if (state_fd > 0) {
 		rewind(state_f);
-		ftruncate(state_fd, 0);
-		fprintf(state_f, "clock: %04x tv: %lu %lu adj: %d\n",
-			clock_seq, last.tv_sec, last.tv_usec, adjustment);
+		len = fprintf(state_f, 
+			      "clock: %04x tv: %016lu %08lu adj: %08d\n",
+			      clock_seq, last.tv_sec, last.tv_usec, adjustment);
 		fflush(state_f);
+		if (ftruncate(state_fd, len) < 0) {
+			fprintf(state_f, "                   \n");
+			fflush(state_f);
+		}
 		rewind(state_f);
 		fl.l_type = F_UNLCK;
 		fcntl(state_fd, F_SETLK, &fl);
@@ -427,6 +435,30 @@ static ssize_t read_all(int fd, char *buf, size_t count)
 	return c;
 }
 
+/*
+ * Close all file descriptors
+ */
+static void close_all_fds(void)
+{
+	int i, max;
+
+#if defined(HAVE_SYSCONF) && defined(_SC_OPEN_MAX)
+	max = sysconf(_SC_OPEN_MAX);
+#elif defined(HAVE_GETDTABLESIZE)
+	max = getdtablesize();
+#elif defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
+	struct rlimit rl;
+
+	getrlimit(RLIMIT_NOFILE, &rl);
+	max = rl.rlim_cur;
+#else
+	max = OPEN_MAX;
+#endif
+
+	for (i=0; i < max; i++)
+		close(i);
+}
+
 
 /*
  * Try using the uuidd daemon to generate the UUID
@@ -459,6 +491,7 @@ static int get_uuid_via_daemon(int op, uuid_t out, int *num)
 			access_ret = access(uuidd_path, X_OK);
 		if (access_ret == 0 && start_attempts++ < 5) {
 			if ((pid = fork()) == 0) {
+				close_all_fds();
 				execl(uuidd_path, "uuidd", "-qT", "300",
 				      (char *) NULL);
 				exit(1);