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lib: Implement vfuncs for logging to default location and common fail…
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…ure logging handling
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@Sergey-Kitov @villesavolainen
Sergey-Kitov authored and villesavolainen committed Sep 7, 2018
1 parent 2362760 commit 7867f9f
Showing 1 changed file with 121 additions and 62 deletions.
183 changes: 121 additions & 62 deletions src/lib/failures.c
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Expand Up @@ -32,6 +32,11 @@ const char *failure_log_type_names[LOG_TYPE_COUNT] = {
"debug", "info", "warning", "error", "fatal", "panic"
};

static int log_fd_write(int fd, const unsigned char *data, size_t len);

static void error_handler_real(const struct failure_context *ctx,
const char *format, va_list args);

/* Initialize working defaults */
static failure_callback_t *fatal_handler ATTR_NORETURN =
default_fatal_handler;
Expand All @@ -51,6 +56,7 @@ static char *log_prefix = NULL;
static char *log_stamp_format = NULL, *log_stamp_format_suffix = NULL;
static bool failure_ignore_errors = FALSE, log_prefix_sent = FALSE;
static bool coredump_on_error = FALSE;
static void log_prefix_add(const struct failure_context *ctx, string_t *str);

typedef int (*failure_write_to_file_t)(enum log_type type, string_t *data, size_t prefix_len);
typedef string_t *(*failure_format_str_t)(const struct failure_context *ctx,
Expand All @@ -59,6 +65,64 @@ typedef string_t *(*failure_format_str_t)(const struct failure_context *ctx,
typedef void (*failure_on_handler_failure_t)(const struct failure_context *ctx);
typedef void (*failure_post_handler_t)(const struct failure_context *ctx);

static string_t * ATTR_FORMAT(3, 0) default_format(const struct failure_context *ctx,
size_t *prefix_len_r ATTR_UNUSED,
const char *format,
va_list args)
{
string_t *str = t_str_new(256);
log_prefix_add(ctx, str);
str_append(str, failure_log_type_prefixes[ctx->type]);

/* make sure there's no %n in there and fix %m */
str_vprintfa(str, printf_format_fix(format), args);
str_append_c(str, '\n');
return str;
}

static int default_write(enum log_type type, string_t *data, size_t prefix_len ATTR_UNUSED)
{
int fd;

switch (type) {
case LOG_TYPE_DEBUG:
fd = log_debug_fd;
break;
case LOG_TYPE_INFO:
fd = log_info_fd;
break;
default:
fd = log_fd;
break;
}
return log_fd_write(fd, str_data(data), str_len(data));
}

static void default_on_handler_failure(const struct failure_context *ctx)
{
const char *log_type = "info";
switch (ctx->type) {
case LOG_TYPE_DEBUG:
log_type = "debug";
/* fall through */
case LOG_TYPE_INFO:
/* we failed to log to info/debug log, try to log the
write error to error log - maybe that'll work. */
i_fatal_status(FATAL_LOGWRITE, "write() failed to %s log: %m",
log_type);
break;
default:
failure_exit(FATAL_LOGWRITE);
break;
}
}

static void default_post_handler(const struct failure_context *ctx)
{
if (ctx->type == LOG_TYPE_ERROR && coredump_on_error)
abort();
}


struct failure_handler_vfuncs {
failure_write_to_file_t write;
Expand All @@ -72,6 +136,48 @@ struct failure_handler_config {
struct failure_handler_vfuncs *v;
};

struct failure_handler_vfuncs default_handler_vfuncs = { .write = &default_write,
.format = &default_format,
.on_handler_failure = &default_on_handler_failure,
.post_handler = &default_post_handler };

struct failure_handler_config handler_config = { .fatal_err_reset = FATAL_LOGWRITE,
.v = &default_handler_vfuncs };

static int common_handler(const struct failure_context *ctx,
const char *format, va_list args)
{
static int recursed = 0;
int ret;
size_t prefix_len = 0;

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 = handler_config.v->format(ctx, &prefix_len, format, args);
ret = handler_config.v->write(ctx->type, str, prefix_len);
} T_END;

if (ret < 0 && failure_ignore_errors)
ret = 0;

recursed--;
return ret;
}

static void error_handler_real(const struct failure_context *ctx,
const char *format, va_list args)
{
if (common_handler(ctx, format, args) < 0)
handler_config.v->on_handler_failure(ctx);
handler_config.v->post_handler(ctx);
}

static void ATTR_FORMAT(2, 0)
i_internal_error_handler(const struct failure_context *ctx,
const char *format, va_list args);
Expand Down Expand Up @@ -215,39 +321,6 @@ static int log_fd_write(int fd, const unsigned char *data, size_t len)
return failed ? -1 : 0;
}

static int ATTR_FORMAT(3, 0)
default_handler(const struct failure_context *ctx, int fd,
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 = t_str_new(256);
log_prefix_add(ctx, str);
str_append(str, failure_log_type_prefixes[ctx->type]);

/* make sure there's no %n in there and fix %m */
str_vprintfa(str, printf_format_fix(format), args);
str_append_c(str, '\n');

ret = log_fd_write(fd, str_data(str), str_len(str));
} T_END;

if (ret < 0 && failure_ignore_errors)
ret = 0;

recursed--;
return ret;
}

static void ATTR_NORETURN
default_fatal_finish(enum log_type type, int status)
{
Expand All @@ -269,44 +342,30 @@ default_fatal_finish(enum log_type type, int status)
failure_exit(status);
}

void default_fatal_handler(const struct failure_context *ctx,
const char *format, va_list args)
static void ATTR_NORETURN fatal_handler_real(const struct failure_context *ctx,
const char *format, va_list args)
{
int status = ctx->exit_status;

if (default_handler(ctx, log_fd, format, args) < 0 &&
if (common_handler(ctx, format, args) < 0 &&
status == FATAL_DEFAULT)
status = FATAL_LOGWRITE;

status = handler_config.fatal_err_reset;
default_fatal_finish(ctx->type, status);
}

void default_error_handler(const struct failure_context *ctx,
void default_fatal_handler(const struct failure_context *ctx,
const char *format, va_list args)
{
int fd;

switch (ctx->type) {
case LOG_TYPE_DEBUG:
fd = log_debug_fd;
break;
case LOG_TYPE_INFO:
fd = log_info_fd;
break;
default:
fd = log_fd;
}
handler_config.v = &default_handler_vfuncs;
handler_config.fatal_err_reset = FATAL_LOGWRITE;
fatal_handler_real(ctx, format, args);
}

if (default_handler(ctx, fd, format, args) < 0) {
if (fd == log_fd)
failure_exit(FATAL_LOGWRITE);
/* we failed to log to info/debug log, try to log the
write error to error log - maybe that'll work. */
i_fatal_status(FATAL_LOGWRITE, "write() failed to %s log: %m",
fd == log_info_fd ? "info" : "debug");
}
if (ctx->type == LOG_TYPE_ERROR && coredump_on_error)
abort();
void default_error_handler(const struct failure_context *ctx,
const char *format, va_list args)
{
handler_config.v = &default_handler_vfuncs;
handler_config.fatal_err_reset = FATAL_LOGWRITE;
error_handler_real(ctx, format, args);
}

void i_log_type(const struct failure_context *ctx, const char *format, ...)
Expand Down

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