Logging: Make sure we don't recurse infinitely when running out of memory.

Also cleaned up the logging handlers' code a bit.

--HG--
branch : HEAD

diff --git a/src/lib/failures.c b/src/lib/failures.c
index d7ed550894c4b6fa34e5d5f4d408a26a9b22390a..17e0f42a80ff4d306ebccf162f015b13d9585a86 100644 (file)
--- a/src/lib/failures.c
+++ b/src/lib/failures.c
@@ -110,16 +110,15 @@ static int ATTR_FORMAT(3, 0)
 default_handler(const char *prefix, int fd, const char *format, va_list args)
 {
        static int recursed = 0;
-       int ret, old_errno = errno;
+       int ret;
 
        if (recursed >= 2) {
                /* we're being called from some signal handler or we ran
                   out of memory */
-               return 0;
+               return -1;
        }
 
        recursed++;
-
        T_BEGIN {
                string_t *str = t_str_new(256);
                log_prefix_add(str);
@@ -132,9 +131,7 @@ default_handler(const char *prefix, int fd, const char *format, va_list args)
                ret = log_fd_write(fd, str_data(str), str_len(str));
        } T_END;
 
-       errno = old_errno;
        recursed--;
-
        return ret;
 }
 
@@ -274,9 +271,8 @@ syslog_handler(int level, enum log_type type, const char *format, va_list args)
 {
        static int recursed = 0;
 
-       if (recursed != 0)
+       if (recursed >= 2)
                return -1;
-
        recursed++;
 
        /* syslogs don't generatelly bother to log the level in any way,
@@ -391,8 +387,16 @@ void i_set_failure_prefix(const char *prefix)
 static int ATTR_FORMAT(2, 0)
 internal_handler(char log_type, const char *format, va_list args)
 {
+       static int recursed = 0;
        int ret;
 
+       if (recursed >= 2) {
+               /* we're being called from some signal handler or we ran
+                  out of memory */
+               return -1;
+       }
+
+       recursed++;
        T_BEGIN {
                string_t *str;
 
@@ -404,6 +408,7 @@ internal_handler(char log_type, const char *format, va_list args)
                ret = write_full(2, str_data(str), str_len(str));
        } T_END;
 
+       recursed--;
        return ret;
 }