[core] log_error, log_perror using printf-like fmt

src/buffer.h

@@ -178,6 +178,8 @@ void buffer_append_path_len(buffer *b, const char *a, size_t alen); /* join stri
 #define BUFFER_COPY_STRING_CONST(x, y) \
 	buffer_copy_string_len(x, y, sizeof(y) - 1)
 
+#define BUFFER_INTLEN_PTR(x) (x)->used ? (int)((x)->used - 1) : 0, (x)->ptr
+
 #define CONST_STR_LEN(x) x, (x) ? sizeof(x) - 1 : 0
 #define CONST_BUF_LEN(x) ((x) ? (x)->ptr : NULL), buffer_string_length(x)
 

src/log.c

@@ -1,3 +1,8 @@
+/* _XOPEN_SOURCE >= 500 for vsnprintf() */
+#ifndef _XOPEN_SOURCE
+#define _XOPEN_SOURCE 700
+#endif
+
 #include "first.h"
 
 #include "base.h"
@@ -8,6 +13,7 @@
 #include <time.h>
 #include <string.h>
 #include <stdarg.h>
+#include <stdio.h>      /* vsnprintf() */
 #include <stdlib.h>     /* malloc() free() */
 #include <unistd.h>
 
@@ -218,6 +224,88 @@ int log_error_write_multiline_buffer(server *srv, const char *filename, unsigned
 }
 
 
+static void
+log_buffer_vprintf (buffer * const b,
+                    const char * const fmt, va_list ap)
+{
+    /* NOTE: log_buffer_prepare() ensures 0 != b->used */
+    /*assert(0 != b->used);*//*(only because code calcs below assume this)*/
+    /*assert(0 != b->size);*//*(errh->b should not have 0 size here)*/
+    size_t blen = buffer_string_length(b);
+    size_t bsp  = buffer_string_space(b)+1;
+    char *s = b->ptr + blen;
+    size_t n;
+
+    va_list aptry;
+    va_copy(aptry, ap);
+    n = (size_t)vsnprintf(s, bsp, fmt, aptry);
+    va_end(aptry);
+
+    if (n >= bsp) {
+        buffer_string_prepare_append(b, n); /*(must re-read s after realloc)*/
+        vsnprintf((s = b->ptr + blen), buffer_string_space(b)+1, fmt, ap);
+    }
+
+    size_t i;
+    for (i = 0; i < n && ' ' <= s[i] && s[i] <= '~'; ++i) ;/*(ASCII isprint())*/
+    if (i == n) {
+        buffer_string_set_length(b, blen + n);
+        return; /* common case; nothing to encode */
+    }
+
+    /* need to encode log line
+     * copy original line fragment, append encoded line to buffer, free copy */
+    char * const src = (char *)malloc(n);
+    memcpy(src, s, n); /*(note: not '\0'-terminated)*/
+    buffer_append_string_c_escaped(b, src, n);
+    free(src);
+}
+
+
+static void
+log_error_va_list_impl (const log_error_st * const errh,
+                        const char * const filename,
+                        const unsigned int line,
+                        const char * const fmt, va_list ap,
+                        const int perr)
+{
+    const int errnum = errno;
+    buffer * const b = errh->b;
+    if (-1 == log_buffer_prepare(errh, filename, line, b)) return;
+    log_buffer_vprintf(b, fmt, ap);
+    if (perr) {
+        buffer_append_string_len(b, CONST_STR_LEN(": "));
+        buffer_append_string(b, strerror(errnum));
+    }
+    log_write(errh, b);
+    errno = errnum;
+}
+
+
+void
+log_error(const log_error_st * const errh,
+          const char * const filename, const unsigned int line,
+          const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    log_error_va_list_impl(errh, filename, line, fmt, ap, 0);
+    va_end(ap);
+}
+
+
+void
+log_perror (const log_error_st * const errh,
+            const char * const filename, const unsigned int line,
+            const char * const fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    log_error_va_list_impl(errh, filename, line, fmt, ap, 1);
+    va_end(ap);
+}
+
+
 log_error_st *
 log_error_st_init (time_t *cur_ts_ptr, time_t *last_ts_ptr)
 {

src/log.h

@@ -31,4 +31,12 @@ log_error_st * log_error_st_init (time_t *cur_ts_ptr, time_t *last_ts_ptr);
 __attribute_cold__
 void log_error_st_free (log_error_st *errh);
 
+__attribute_cold__
+__attribute_format__((__printf__, 4, 5))
+void log_error(const log_error_st *errh, const char *filename, unsigned int line, const char *fmt, ...);
+
+__attribute_cold__
+__attribute_format__((__printf__, 4, 5))
+void log_perror(const log_error_st *errh, const char *filename, unsigned int line, const char *fmt, ...);
+
 #endif