tree-wide: use xsprintf() where applicable

Also add a coccinelle receipt to help with such transitions.

src/basic/cgroup-util.c

@@ -53,6 +53,7 @@
 #include "set.h"
 #include "special.h"
 #include "stat-util.h"
+#include "stdio-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "unit-name.h"
@@ -716,7 +717,7 @@ int cg_attach(const char *controller, const char *path, pid_t pid) {
         if (pid == 0)
                 pid = getpid();
 
-        snprintf(c, sizeof(c), PID_FMT"\n", pid);
+        xsprintf(c, PID_FMT "\n", pid);
 
         return write_string_file(fs, c, 0);
 }

src/basic/log.c

@@ -352,7 +352,7 @@ static int write_to_console(
         highlight = LOG_PRI(level) <= LOG_ERR && show_color;
 
         if (show_location) {
-                snprintf(location, sizeof(location), "(%s:%i) ", file, line);
+                xsprintf(location, "(%s:%i) ", file, line);
                 IOVEC_SET_STRING(iovec[n++], location);
         }
 
@@ -777,7 +777,7 @@ static void log_assert(
                 return;
 
         DISABLE_WARNING_FORMAT_NONLITERAL;
-        snprintf(buffer, sizeof(buffer), format, text, file, line, func);
+        xsprintf(buffer, format, text, file, line, func);
         REENABLE_WARNING;
 
         log_abort_msg = buffer;

src/basic/signal-util.c

@@ -26,6 +26,7 @@
 #include "macro.h"
 #include "parse-util.h"
 #include "signal-util.h"
+#include "stdio-util.h"
 #include "string-table.h"
 #include "string-util.h"
 
@@ -234,9 +235,9 @@ const char *signal_to_string(int signo) {
                 return name;
 
         if (signo >= SIGRTMIN && signo <= SIGRTMAX)
-                snprintf(buf, sizeof(buf), "RTMIN+%d", signo - SIGRTMIN);
+                xsprintf(buf, "RTMIN+%d", signo - SIGRTMIN);
         else
-                snprintf(buf, sizeof(buf), "%d", signo);
+                xsprintf(buf, "%d", signo);
 
         return buf;
 }