Use initalization instead of explicit zeroing

Before, we would initialize many fields twice: first
by filling the structure with zeros, and then a second
time with the real values. We can let the compiler do
the job for us, avoiding one copy.

A downside of this patch is that text gets slightly
bigger. This is because all zero() calls are effectively
inlined:

$ size build/.libs/systemd
         text    data     bss     dec     hex filename
before 897737  107300    2560 1007597   f5fed build/.libs/systemd
after  897873  107300    2560 1007733   f6075 build/.libs/systemd

… actually less than 1‰.

A few asserts that the parameter is not null had to be removed. I
don't think this changes much, because first, it is quite unlikely
for the assert to fail, and second, an immediate SEGV is almost as
good as an assert.

7 files changed, 92 insertions, 132 deletions

diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
index 277efd302e..4557155d45 100644
--- a/src/shared/ask-password-api.c
+++ b/src/shared/ask-password-api.c
@@ -109,7 +109,6 @@ int ask_password_tty(
         }
 
         zero(pollfd);
-
         pollfd[POLL_TTY].fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO;
         pollfd[POLL_TTY].events = POLLIN;
         pollfd[POLL_INOTIFY].fd = notify;
@@ -248,7 +247,9 @@ static int create_socket(char **name) {
         union {
                 struct sockaddr sa;
                 struct sockaddr_un un;
-        } sa;
+        } sa = {
+                .un.sun_family = AF_UNIX,
+        };
         int one = 1, r;
         char *c;
 
@@ -260,8 +261,6 @@ static int create_socket(char **name) {
                 return -errno;
         }
 
-        zero(sa);
-        sa.un.sun_family = AF_UNIX;
         snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%llu", random_ull());
 
         RUN_WITH_UMASK(0177) {
diff --git a/src/shared/dbus-loop.c b/src/shared/dbus-loop.c
index fec8998bc1..b42ae14511 100644
--- a/src/shared/dbus-loop.c
+++ b/src/shared/dbus-loop.c
@@ -45,7 +45,7 @@ typedef struct EpollData {
 
 static dbus_bool_t add_watch(DBusWatch *watch, void *data) {
         EpollData _cleanup_free_ *e = NULL;
-        struct epoll_event ev;
+        struct epoll_event ev = { .data.ptr = e };
 
         assert(watch);
 
@@ -57,9 +57,7 @@ static dbus_bool_t add_watch(DBusWatch *watch, void *data) {
         e->object = watch;
         e->is_timeout = false;
 
-        zero(ev);
         ev.events = bus_flags_to_events(watch);
-        ev.data.ptr = e;
 
         if (epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_ADD, e->fd, &ev) < 0) {
 
@@ -106,7 +104,7 @@ static void remove_watch(DBusWatch *watch, void *data) {
 
 static void toggle_watch(DBusWatch *watch, void *data) {
         EpollData *e;
-        struct epoll_event ev;
+        struct epoll_event ev = {};
 
         assert(watch);
 
@@ -114,21 +112,18 @@ static void toggle_watch(DBusWatch *watch, void *data) {
         if (!e)
                 return;
 
-        zero(ev);
-        ev.events = bus_flags_to_events(watch);
         ev.data.ptr = e;
+        ev.events = bus_flags_to_events(watch);
 
         assert_se(epoll_ctl(PTR_TO_INT(data), EPOLL_CTL_MOD, e->fd, &ev) == 0);
 }
 
 static int timeout_arm(EpollData *e) {
-        struct itimerspec its;
+        struct itimerspec its = {};
 
         assert(e);
         assert(e->is_timeout);
 
-        zero(its);
-
         if (dbus_timeout_get_enabled(e->object)) {
                 timespec_store(&its.it_value, dbus_timeout_get_interval(e->object) * USEC_PER_MSEC);
                 its.it_interval = its.it_value;
@@ -142,7 +137,7 @@ static int timeout_arm(EpollData *e) {
 
 static dbus_bool_t add_timeout(DBusTimeout *timeout, void *data) {
         EpollData *e;
-        struct epoll_event ev;
+        struct epoll_event ev = {};
 
         assert(timeout);
 
@@ -160,7 +155,6 @@ static dbus_bool_t add_timeout(DBusTimeout *timeout, void *data) {
         if (timeout_arm(e) < 0)
                 goto fail;
 
-        zero(ev);
         ev.events = EPOLLIN;
         ev.data.ptr = e;
 
@@ -227,13 +221,11 @@ int bus_loop_open(DBusConnection *c) {
 
 int bus_loop_dispatch(int fd) {
         int n;
-        struct epoll_event event;
+        struct epoll_event event = {};
         EpollData *d;
 
         assert(fd >= 0);
 
-        zero(event);
-
         n = epoll_wait(fd, &event, 1, 0);
         if (n < 0)
                 return errno == EAGAIN || errno == EINTR ? 0 : -errno;
diff --git a/src/shared/install.c b/src/shared/install.c
index 2555a36c0a..9e870392f2 100644
--- a/src/shared/install.c
+++ b/src/shared/install.c
@@ -700,7 +700,7 @@ int unit_file_link(
                 UnitFileChange **changes,
                 unsigned *n_changes) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
         char **i;
         char _cleanup_free_ *config_path = NULL;
         int r, q;
@@ -1116,7 +1116,7 @@ static int unit_file_can_install(
                 const char *name,
                 bool allow_symlink) {
 
-        InstallContext _cleanup_install_context_done_ c = {NULL};
+        InstallContext _cleanup_install_context_done_ c = {};
         InstallInfo *i;
         int r;
 
@@ -1452,8 +1452,8 @@ int unit_file_enable(
                 UnitFileChange **changes,
                 unsigned *n_changes) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
-        InstallContext _cleanup_install_context_done_ c = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
+        InstallContext _cleanup_install_context_done_ c = {};
         char **i;
         char _cleanup_free_ *config_path = NULL;
         int r;
@@ -1491,8 +1491,8 @@ int unit_file_disable(
                 UnitFileChange **changes,
                 unsigned *n_changes) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
-        InstallContext _cleanup_install_context_done_ c = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
+        InstallContext _cleanup_install_context_done_ c = {};
         char **i;
         char _cleanup_free_ *config_path = NULL;
         Set _cleanup_set_free_free_ *remove_symlinks_to = NULL;
@@ -1533,8 +1533,8 @@ int unit_file_reenable(
                 UnitFileChange **changes,
                 unsigned *n_changes) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
-        InstallContext _cleanup_install_context_done_ c = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
+        InstallContext _cleanup_install_context_done_ c = {};
         char **i;
         char _cleanup_free_ *config_path = NULL;
         Set _cleanup_set_free_free_ *remove_symlinks_to = NULL;
@@ -1576,7 +1576,7 @@ UnitFileState unit_file_get_state(
                 const char *root_dir,
                 const char *name) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
         UnitFileState state = _UNIT_FILE_STATE_INVALID;
         char **i;
         char _cleanup_free_ *path = NULL;
@@ -1734,8 +1734,8 @@ int unit_file_preset(
                 UnitFileChange **changes,
                 unsigned *n_changes) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
-        InstallContext _cleanup_install_context_done_ plus = {NULL}, minus = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
+        InstallContext _cleanup_install_context_done_ plus = {}, minus = {NULL};
         char **i;
         char _cleanup_free_ *config_path = NULL;
         Set _cleanup_set_free_free_ *remove_symlinks_to = NULL;
@@ -1800,7 +1800,7 @@ int unit_file_get_list(
                 const char *root_dir,
                 Hashmap *h) {
 
-        LookupPaths _cleanup_lookup_paths_free_ paths = {NULL};
+        LookupPaths _cleanup_lookup_paths_free_ paths = {};
         char **i;
         char _cleanup_free_ *buf = NULL;
         DIR _cleanup_closedir_ *d = NULL;
diff --git a/src/shared/log.c b/src/shared/log.c
index 0dd04bc51e..876f22dfc5 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -129,16 +129,15 @@ static int create_log_socket(int type) {
 }
 
 static int log_open_syslog(void) {
-        union sockaddr_union sa;
         int r;
+        union sockaddr_union sa = {
+                .un.sun_family = AF_UNIX,
+                .un.sun_path = "/dev/log",
+        };
 
         if (syslog_fd >= 0)
                 return 0;
 
-        zero(sa);
-        sa.un.sun_family = AF_UNIX;
-        strncpy(sa.un.sun_path, "/dev/log", sizeof(sa.un.sun_path));
-
         syslog_fd = create_log_socket(SOCK_DGRAM);
         if (syslog_fd < 0) {
                 r = syslog_fd;
@@ -183,7 +182,10 @@ void log_close_journal(void) {
 }
 
 static int log_open_journal(void) {
-        union sockaddr_union sa;
+        union sockaddr_union sa = {
+                .un.sun_family = AF_UNIX,
+                .un.sun_path = "/run/systemd/journal/socket",
+        };
         int r;
 
         if (journal_fd >= 0)
@@ -195,10 +197,6 @@ static int log_open_journal(void) {
                 goto fail;
         }
 
-        zero(sa);
-        sa.un.sun_family = AF_UNIX;
-        strncpy(sa.un.sun_path, "/run/systemd/journal/socket", sizeof(sa.un.sun_path));
-
         if (connect(journal_fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) {
                 r = -errno;
                 goto fail;
@@ -313,7 +311,7 @@ static int write_to_console(
                 const char *buffer) {
 
         char location[64];
-        struct iovec iovec[5];
+        struct iovec iovec[5] = {};
         unsigned n = 0;
         bool highlight;
 
@@ -322,8 +320,6 @@ static int write_to_console(
 
         highlight = LOG_PRI(level) <= LOG_ERR && show_color;
 
-        zero(iovec);
-
         if (show_location) {
                 snprintf(location, sizeof(location), "(%s:%u) ", file, line);
                 char_array_0(location);
@@ -353,8 +349,11 @@ static int write_to_syslog(
         const char *buffer) {
 
         char header_priority[16], header_time[64], header_pid[16];
-        struct iovec iovec[5];
-        struct msghdr msghdr;
+        struct iovec iovec[5] = {};
+        struct msghdr msghdr = {
+                .msg_iov = iovec,
+                .msg_iovlen = ELEMENTSOF(iovec),
+        };
         time_t t;
         struct tm *tm;
 
@@ -375,7 +374,6 @@ static int write_to_syslog(
         snprintf(header_pid, sizeof(header_pid), "[%lu]: ", (unsigned long) getpid());
         char_array_0(header_pid);
 
-        zero(iovec);
         IOVEC_SET_STRING(iovec[0], header_priority);
         IOVEC_SET_STRING(iovec[1], header_time);
         IOVEC_SET_STRING(iovec[2], program_invocation_short_name);
@@ -386,10 +384,6 @@ static int write_to_syslog(
         if (syslog_is_stream)
                 iovec[4].iov_len++;
 
-        zero(msghdr);
-        msghdr.msg_iov = iovec;
-        msghdr.msg_iovlen = ELEMENTSOF(iovec);
-
         for (;;) {
                 ssize_t n;
 
@@ -417,7 +411,7 @@ static int write_to_kmsg(
         const char *buffer) {
 
         char header_priority[16], header_pid[16];
-        struct iovec iovec[5];
+        struct iovec iovec[5] = {};
 
         if (kmsg_fd < 0)
                 return 0;
@@ -428,7 +422,6 @@ static int write_to_kmsg(
         snprintf(header_pid, sizeof(header_pid), "[%lu]: ", (unsigned long) getpid());
         char_array_0(header_pid);
 
-        zero(iovec);
         IOVEC_SET_STRING(iovec[0], header_priority);
         IOVEC_SET_STRING(iovec[1], program_invocation_short_name);
         IOVEC_SET_STRING(iovec[2], header_pid);
@@ -482,8 +475,8 @@ static int write_to_journal(
         const char *buffer) {
 
         char header[LINE_MAX];
-        struct iovec iovec[4] = {{0}};
-        struct msghdr mh = {0};
+        struct iovec iovec[4] = {};
+        struct msghdr mh = {};
 
         if (journal_fd < 0)
                 return 0;
@@ -742,7 +735,7 @@ int log_struct_internal(
             journal_fd >= 0) {
 
                 char header[LINE_MAX];
-                struct iovec iovec[17] = {{0}};
+                struct iovec iovec[17] = {};
                 unsigned n = 0, i;
                 struct msghdr mh;
                 static const char nl = '\n';
diff --git a/src/shared/util.c b/src/shared/util.c
index 1bffd84d1f..2f66597de3 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -889,15 +889,14 @@ int reset_all_signal_handlers(void) {
         int sig;
 
         for (sig = 1; sig < _NSIG; sig++) {
-                struct sigaction sa;
+                struct sigaction sa = {
+                        .sa_handler = SIG_DFL,
+                        .sa_flags = SA_RESTART,
+                };
 
                 if (sig == SIGKILL || sig == SIGSTOP)
                         continue;
 
-                zero(sa);
-                sa.sa_handler = SIG_DFL;
-                sa.sa_flags = SA_RESTART;
-
                 /* On Linux the first two RT signals are reserved by
                  * glibc, and sigaction() will return EINVAL for them. */
                 if ((sigaction(sig, &sa, NULL) < 0))
@@ -1858,11 +1857,10 @@ int open_terminal(const char *name, int mode) {
 }
 
 int flush_fd(int fd) {
-        struct pollfd pollfd;
-
-        zero(pollfd);
-        pollfd.fd = fd;
-        pollfd.events = POLLIN;
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = POLLIN,
+        };
 
         for (;;) {
                 char buf[LINE_MAX];
@@ -1903,7 +1901,6 @@ int acquire_terminal(
 
         int fd = -1, notify = -1, r = 0, wd = -1;
         usec_t ts = 0;
-        struct sigaction sa_old, sa_new;
 
         assert(name);
 
@@ -1938,6 +1935,11 @@ int acquire_terminal(
         }
 
         for (;;) {
+                struct sigaction sa_old, sa_new = {
+                        .sa_handler = SIG_IGN,
+                        .sa_flags = SA_RESTART,
+                };
+
                 if (notify >= 0) {
                         r = flush_fd(notify);
                         if (r < 0)
@@ -1953,9 +1955,6 @@ int acquire_terminal(
 
                 /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
                  * if we already own the tty. */
-                zero(sa_new);
-                sa_new.sa_handler = SIG_IGN;
-                sa_new.sa_flags = SA_RESTART;
                 assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 
                 /* First, try to get the tty */
@@ -2063,7 +2062,10 @@ fail:
 
 int release_terminal(void) {
         int r = 0;
-        struct sigaction sa_old, sa_new;
+        struct sigaction sa_old, sa_new = {
+                .sa_handler = SIG_IGN,
+                .sa_flags = SA_RESTART,
+        };
         int _cleanup_close_ fd;
 
         fd = open("/dev/tty", O_RDWR|O_NOCTTY|O_NDELAY|O_CLOEXEC);
@@ -2072,10 +2074,6 @@ int release_terminal(void) {
 
         /* Temporarily ignore SIGHUP, so that we don't get SIGHUP'ed
          * by our own TIOCNOTTY */
-
-        zero(sa_new);
-        sa_new.sa_handler = SIG_IGN;
-        sa_new.sa_flags = SA_RESTART;
         assert_se(sigaction(SIGHUP, &sa_new, &sa_old) == 0);
 
         if (ioctl(fd, TIOCNOTTY) < 0)
@@ -2100,13 +2098,13 @@ int sigaction_many(const struct sigaction *sa, ...) {
 }
 
 int ignore_signals(int sig, ...) {
-        struct sigaction sa;
+        struct sigaction sa = {
+                .sa_handler = SIG_IGN,
+                .sa_flags = SA_RESTART,
+        };
         va_list ap;
         int r = 0;
 
-        zero(sa);
-        sa.sa_handler = SIG_IGN;
-        sa.sa_flags = SA_RESTART;
 
         if (sigaction(sig, &sa, NULL) < 0)
                 r = -errno;
@@ -2121,14 +2119,13 @@ int ignore_signals(int sig, ...) {
 }
 
 int default_signals(int sig, ...) {
-        struct sigaction sa;
+        struct sigaction sa = {
+                .sa_handler = SIG_DFL,
+                .sa_flags = SA_RESTART,
+        };
         va_list ap;
         int r = 0;
 
-        zero(sa);
-        sa.sa_handler = SIG_DFL;
-        sa.sa_flags = SA_RESTART;
-
         if (sigaction(sig, &sa, NULL) < 0)
                 r = -errno;
 
@@ -2177,11 +2174,10 @@ ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
                                 continue;
 
                         if (k < 0 && errno == EAGAIN && do_poll) {
-                                struct pollfd pollfd;
-
-                                zero(pollfd);
-                                pollfd.fd = fd;
-                                pollfd.events = POLLIN;
+                                struct pollfd pollfd = {
+                                        .fd = fd,
+                                        .events = POLLIN,
+                                };
 
                                 if (poll(&pollfd, 1, -1) < 0) {
                                         if (errno == EINTR)
@@ -2226,11 +2222,10 @@ ssize_t loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
                                 continue;
 
                         if (k < 0 && errno == EAGAIN && do_poll) {
-                                struct pollfd pollfd;
-
-                                zero(pollfd);
-                                pollfd.fd = fd;
-                                pollfd.events = POLLOUT;
+                                struct pollfd pollfd = {
+                                        .fd = fd,
+                                        .events = POLLOUT,
+                                };
 
                                 if (poll(&pollfd, 1, -1) < 0) {
                                         if (errno == EINTR)
@@ -2933,7 +2928,7 @@ int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char
         static const char status_indent[] = "         "; /* "[" STATUS "] " */
         _cleanup_free_ char *s = NULL;
         _cleanup_close_ int fd = -1;
-        struct iovec iovec[6];
+        struct iovec iovec[6] = {};
         int n = 0;
         static bool prev_ephemeral;
 
@@ -2971,8 +2966,6 @@ int status_vprintf(const char *status, bool ellipse, bool ephemeral, const char
                 }
         }
 
-        zero(iovec);
-
         if (prev_ephemeral)
                 IOVEC_SET_STRING(iovec[n++], "\r" ANSI_ERASE_TO_END_OF_LINE);
         prev_ephemeral = ephemeral;
@@ -3162,8 +3155,7 @@ char **replace_env_argv(char **argv, char **env) {
 }
 
 int fd_columns(int fd) {
-        struct winsize ws;
-        zero(ws);
+        struct winsize ws = {};
 
         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
                 return -errno;
@@ -3197,8 +3189,7 @@ unsigned columns(void) {
 }
 
 int fd_lines(int fd) {
-        struct winsize ws;
-        zero(ws);
+        struct winsize ws = {};
 
         if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
                 return -errno;
@@ -3247,13 +3238,9 @@ bool on_tty(void) {
 }
 
 int running_in_chroot(void) {
-        struct stat a, b;
-
-        zero(a);
-        zero(b);
+        struct stat a = {}, b = {};
 
         /* Only works as root */
-
         if (stat("/proc/1/root", &a) < 0)
                 return -errno;
 
@@ -3731,10 +3718,9 @@ void execute_directory(const char *directory, DIR *d, char *argv[]) {
 
         while (!hashmap_isempty(pids)) {
                 pid_t pid = PTR_TO_UINT(hashmap_first_key(pids));
-                siginfo_t si;
+                siginfo_t si = {};
                 char *path;
 
-                zero(si);
                 if (waitid(P_PID, pid, &si, WEXITED) < 0) {
 
                         if (errno == EINTR)
@@ -3861,12 +3847,11 @@ char* hostname_cleanup(char *s) {
 }
 
 int pipe_eof(int fd) {
-        struct pollfd pollfd;
         int r;
-
-        zero(pollfd);
-        pollfd.fd = fd;
-        pollfd.events = POLLIN|POLLHUP;
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = POLLIN|POLLHUP,
+        };
 
         r = poll(&pollfd, 1, 0);
         if (r < 0)
@@ -3879,12 +3864,11 @@ int pipe_eof(int fd) {
 }
 
 int fd_wait_for_event(int fd, int event, usec_t t) {
-        struct pollfd pollfd;
         int r;
-
-        zero(pollfd);
-        pollfd.fd = fd;
-        pollfd.events = event;
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = event,
+        };
 
         r = poll(&pollfd, 1, t == (usec_t) -1 ? -1 : (int) (t / USEC_PER_MSEC));
         if (r < 0)
@@ -4343,7 +4327,6 @@ int glob_exists(const char *path) {
 
         assert(path);
 
-        zero(g);
         errno = 0;
         k = glob(path, GLOB_NOSORT|GLOB_BRACE, NULL, &g);
 
diff --git a/src/shared/utmp-wtmp.c b/src/shared/utmp-wtmp.c
index 3494b56908..5ee3d22e71 100644
--- a/src/shared/utmp-wtmp.c
+++ b/src/shared/utmp-wtmp.c
@@ -33,7 +33,7 @@
 #include "utmp-wtmp.h"
 
 int utmp_get_runlevel(int *runlevel, int *previous) {
-        struct utmpx lookup, *found;
+        struct utmpx *found, lookup = { .ut_type = RUN_LVL };
         int r;
         const char *e;
 
@@ -66,9 +66,6 @@ int utmp_get_runlevel(int *runlevel, int *previous) {
 
         setutxent();
 
-        zero(lookup);
-        lookup.ut_type = RUN_LVL;
-
         if (!(found = getutxid(&lookup)))
                 r = -errno;
         else {
@@ -102,14 +99,12 @@ static void init_timestamp(struct utmpx *store, usec_t t) {
 }
 
 static void init_entry(struct utmpx *store, usec_t t) {
-        struct utsname uts;
+        struct utsname uts = {};
 
         assert(store);
 
         init_timestamp(store, t);
 
-        zero(uts);
-
         if (uname(&uts) >= 0)
                 strncpy(store->ut_host, uts.release, sizeof(store->ut_host));
 
@@ -311,7 +306,10 @@ static int write_to_terminal(const char *tty, const char *message) {
 
         while (left > 0) {
                 ssize_t n;
-                struct pollfd pollfd;
+                struct pollfd pollfd = {
+                        .fd = fd,
+                        .events = POLLOUT,
+                };
                 usec_t t;
                 int k;
 
@@ -320,10 +318,6 @@ static int write_to_terminal(const char *tty, const char *message) {
                 if (t >= end)
                         return -ETIME;
 
-                zero(pollfd);
-                pollfd.fd = fd;
-                pollfd.events = POLLOUT;
-
                 k = poll(&pollfd, 1, (end - t) / USEC_PER_MSEC);
                 if (k < 0)
                         return -errno;
diff --git a/src/shared/virt.c b/src/shared/virt.c
index 78016eec89..fddb45d6e8 100644
--- a/src/shared/virt.c
+++ b/src/shared/virt.c
@@ -62,7 +62,7 @@ int detect_vm(const char **id) {
         union {
                 uint32_t sig32[3];
                 char text[13];
-        } sig;
+        } sig = {};
         unsigned i;
         const char *j, *k;
         bool hypervisor;
@@ -84,7 +84,6 @@ int detect_vm(const char **id) {
                 return r;
 
         /* http://lwn.net/Articles/301888/ */
-        zero(sig);
 
 #if defined (__i386__)
 #define REG_a "eax"