Add a snprinf wrapper which checks that the buffer was big enough

If we scale our buffer to be wide enough for the format string, we
should expect that the calculation was correct.

char_array_0() invocations are removed, since snprintf nul-terminates
the output in any case.

A similar wrapper is used for strftime calls, but only in timedatectl.c.

1 files changed, 9 insertions, 17 deletions

diff --git a/src/shared/log.c b/src/shared/log.c
index a870415a0..9c0156026 100644
--- a/src/shared/log.c
+++ b/src/shared/log.c
@@ -331,7 +331,6 @@ static int write_to_console(
 
         if (show_location) {
                 snprintf(location, sizeof(location), "(%s:%i) ", file, line);
-                char_array_0(location);
                 IOVEC_SET_STRING(iovec[n++], location);
         }
 
@@ -375,7 +374,9 @@ static int write_to_syslog(
                 const char *object,
                 const char *buffer) {
 
-        char header_priority[1 + DECIMAL_STR_MAX(int) + 2], header_time[64], header_pid[1 + DECIMAL_STR_MAX(pid_t) + 4];
+        char header_priority[2 + DECIMAL_STR_MAX(int) + 1],
+             header_time[64],
+             header_pid[4 + DECIMAL_STR_MAX(pid_t) + 1];
         struct iovec iovec[5] = {};
         struct msghdr msghdr = {
                 .msg_iov = iovec,
@@ -387,8 +388,7 @@ static int write_to_syslog(
         if (syslog_fd < 0)
                 return 0;
 
-        snprintf(header_priority, sizeof(header_priority), "<%i>", level);
-        char_array_0(header_priority);
+        xsprintf(header_priority, "<%i>", level);
 
         t = (time_t) (now(CLOCK_REALTIME) / USEC_PER_SEC);
         tm = localtime(&t);
@@ -398,8 +398,7 @@ static int write_to_syslog(
         if (strftime(header_time, sizeof(header_time), "%h %e %T ", tm) <= 0)
                 return -EINVAL;
 
-        snprintf(header_pid, sizeof(header_pid), "["PID_FMT"]: ", getpid());
-        char_array_0(header_pid);
+        xsprintf(header_pid, "["PID_FMT"]: ", getpid());
 
         IOVEC_SET_STRING(iovec[0], header_priority);
         IOVEC_SET_STRING(iovec[1], header_time);
@@ -438,17 +437,15 @@ static int write_to_kmsg(
                 const char *object,
                 const char *buffer) {
 
-        char header_priority[1 + DECIMAL_STR_MAX(int) + 2], header_pid[1 + DECIMAL_STR_MAX(pid_t) + 4];
+        char header_priority[2 + DECIMAL_STR_MAX(int) + 1],
+             header_pid[4 + DECIMAL_STR_MAX(pid_t) + 1];
         struct iovec iovec[5] = {};
 
         if (kmsg_fd < 0)
                 return 0;
 
-        snprintf(header_priority, sizeof(header_priority), "<%i>", level);
-        char_array_0(header_priority);
-
-        snprintf(header_pid, sizeof(header_pid), "["PID_FMT"]: ", getpid());
-        char_array_0(header_pid);
+        xsprintf(header_priority, "<%i>", level);
+        xsprintf(header_pid, "["PID_FMT"]: ", getpid());
 
         IOVEC_SET_STRING(iovec[0], header_priority);
         IOVEC_SET_STRING(iovec[1], program_invocation_short_name);
@@ -497,7 +494,6 @@ static int log_do_header(
                  isempty(object) ? "" : object,
                  isempty(object) ? "" : "\n",
                  program_invocation_short_name);
-        header[size - 1] = '\0';
 
         return 0;
 }
@@ -659,7 +655,6 @@ int log_internalv(
                 errno = error;
 
         vsnprintf(buffer, sizeof(buffer), format, ap);
-        char_array_0(buffer);
 
         return log_dispatch(level, error, file, line, func, NULL, NULL, buffer);
 }
@@ -707,7 +702,6 @@ int log_object_internalv(
                 errno = error;
 
         vsnprintf(buffer, sizeof(buffer), format, ap);
-        char_array_0(buffer);
 
         return log_dispatch(level, error, file, line, func, object_field, object, buffer);
 }
@@ -749,7 +743,6 @@ static void log_assert(
         snprintf(buffer, sizeof(buffer), format, text, file, line, func);
         REENABLE_WARNING;
 
-        char_array_0(buffer);
         log_abort_msg = buffer;
 
         log_dispatch(level, 0, file, line, func, NULL, NULL, buffer);
@@ -875,7 +868,6 @@ int log_struct_internal(
                 va_copy(aq, ap);
                 vsnprintf(buf, sizeof(buf), format, aq);
                 va_end(aq);
-                char_array_0(buf);
 
                 if (startswith(buf, "MESSAGE=")) {
                         found = true;