From 2bd7a0b4f54e74ac976c14d631643676bea70819 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Tue, 28 May 2019 15:42:37 -0400

Subject: [PATCH 16/86] Always log to a memfd regardless of loglevel.

This writes all debug logs to a memfd, so that they'll always show up in

strace.

Signed-off-by: Peter Jones <pjones@redhat.com>

---

 src/error.c                 | 88 ++++++++++++++++++++++++++++++++++---

 src/include/efivar/efivar.h |  7 +++

 src/libefivar.map.in        |  1 +

 src/util.h                  | 26 +++++------

 4 files changed, 102 insertions(+), 20 deletions(-)

diff --git a/src/error.c b/src/error.c

index df03d7f45e0..5dc43197c50 100644

--- a/src/error.c

+++ b/src/error.c

@@ -26,6 +26,7 @@

 #include <stdlib.h>

 #include <stdio.h>

 #include <string.h>

+#include <sys/mman.h>

 #include <unistd.h>

 #include "efiboot.h"

@@ -162,7 +163,58 @@ efi_error_pop(void)

 	clear_error_entry(&error_table[current]);

 }

-void PUBLIC DESTRUCTOR

+static int efi_verbose;

+static FILE *efi_errlog, *efi_dbglog;

+static int efi_dbglog_fd = -1;

+static int stashed_log_level;

+static char efi_dbglog_buf[4096];

+

+void PUBLIC

+efi_stash_loglevel_(int level)

+{

+	stashed_log_level = level;

+}

+

+static ssize_t

+dbglog_write(void *cookie UNUSED, const char *buf, size_t size)

+{

+	FILE *log = efi_errlog ? efi_errlog : stderr;

+	ssize_t ret = size;

+

+	if (efi_get_verbose() >= stashed_log_level) {

+		ret = fwrite(buf, 1, size, log);

+	} else if (efi_dbglog_fd >= 0) {

+		lseek(efi_dbglog_fd, 0, SEEK_SET);

+		write(efi_dbglog_fd, buf, size);

+	}

+	return ret;

+}

+

+static int

+dbglog_seek(void *cookie UNUSED, off64_t *offset, int whence)

+{

+	FILE *log = efi_errlog ? efi_errlog : stderr;

+	return fseek(log, *offset, whence);

+}

+

+static int

+dbglog_close(void *cookie UNUSED)

+{

+	if (efi_dbglog_fd >= 0) {

+		close(efi_dbglog_fd);

+		efi_dbglog_fd = -1;

+	}

+	if (efi_errlog) {

+		int ret = fclose(efi_errlog);

+		efi_errlog = NULL;

+		return ret;

+	}

+

+	errno = EBADF;

+	return -1;

+}

+

+void PUBLIC

 efi_error_clear(void)

 {

 	if (error_table) {

@@ -177,15 +229,39 @@ efi_error_clear(void)

 	current = 0;

 }

-static int efi_verbose;

-static FILE *efi_errlog;

+void DESTRUCTOR

+efi_error_fini(void)

+{

+	efi_error_clear();

+	if (efi_dbglog) {

+		fclose(efi_dbglog);

+		efi_dbglog = NULL;

+	}

+}

+

+static void CONSTRUCTOR

+efi_error_init(void)

+{

+	cookie_io_functions_t io_funcs = {

+		.write = dbglog_write,

+		.seek = dbglog_seek,

+		.close = dbglog_close,

+	};

+

+	efi_dbglog_fd = memfd_create("efivar-debug.log", MFD_CLOEXEC);

+	if (efi_dbglog_fd == -1)

+		return;

+

+	efi_dbglog = fopencookie(NULL, "a", io_funcs);

+	if (efi_dbglog)

+		setvbuf(efi_dbglog, efi_dbglog_buf, _IOLBF,

+			sizeof(efi_dbglog_buf));

+}

 FILE PUBLIC *

 efi_get_logfile(void)

 {

-	if (efi_errlog)

-		return efi_errlog;

-	return stderr;

+	return efi_dbglog;

 }

 void PUBLIC

diff --git a/src/include/efivar/efivar.h b/src/include/efivar/efivar.h

index dabf41789e5..343d1c557da 100644

--- a/src/include/efivar/efivar.h

+++ b/src/include/efivar/efivar.h

@@ -188,6 +188,7 @@ extern int efi_error_set(const char *filename,

 			__attribute__((__format__ (printf, 5, 6)));

 extern void efi_error_clear(void);

 extern void efi_error_pop(void);

+extern void efi_stash_loglevel_(int level);

 #else

 static inline int

 __attribute__((__nonnull__ (2, 3, 4, 5, 6)))

@@ -225,6 +226,12 @@ efi_error_pop(void)

 {

 	return;

 }

+

+static inline void

+efi_stash_loglevel_(int level __attribute__((__unused__)))

+{

+	return;

+}

 #endif

 #define efi_error_real__(errval, file, function, line, fmt, args...) \

diff --git a/src/libefivar.map.in b/src/libefivar.map.in

index 8e50d574f10..8965b729917 100644

--- a/src/libefivar.map.in

+++ b/src/libefivar.map.in

@@ -133,4 +133,5 @@ LIBEFIVAR_1.37 {

 LIBEFIVAR_1.38 {

 	global: efi_error_pop;

+		efi_stash_loglevel_;

 } LIBEFIVAR_1.37;

diff --git a/src/util.h b/src/util.h

index a6a80e754ec..337762c9902 100644

--- a/src/util.h

+++ b/src/util.h

@@ -382,15 +382,14 @@ swizzle_guid_to_uuid(efi_guid_t *guid)

 #define log_(file, line, func, level, fmt, args...)                     \

         ({                                                              \

-                if (efi_get_verbose() >= level) {                       \

-                        FILE *logfile_ = efi_get_logfile();             \

-                        int len_ = strlen(fmt);                         \

-                        fprintf(logfile_, "%s:%d %s(): ",               \

-                                file, line, func);                      \

-                        fprintf(logfile_, fmt, ## args);                \

-                        if (!len_ || fmt[len_ - 1] != '\n')             \

-                                fprintf(logfile_, "\n");                \

-                }                                                       \

+                efi_stash_loglevel_(level);                             \

+                FILE *logfile_ = efi_get_logfile();                     \

+                int len_ = strlen(fmt);                                 \

+                fprintf(logfile_, "%s:%d %s(): ",                       \

+                        file, line, func);                              \

+                fprintf(logfile_, fmt, ## args);                        \

+                if (!len_ || fmt[len_ - 1] != '\n')                     \

+                        fprintf(logfile_, "\n");                        \

         })

 #define LOG_VERBOSE 0

@@ -402,11 +401,10 @@ swizzle_guid_to_uuid(efi_guid_t *guid)

 #define debug(fmt, args...) log(LOG_DEBUG, fmt, ## args)

 #define log_hex_(file, line, func, level, buf, size)                    \

         ({                                                              \

-                if (efi_get_verbose() >= level) {                       \

-                        fhexdumpf(efi_get_logfile(), "%s:%d %s(): ",    \

-                                  (uint8_t *)buf, size,                 \

-                                  file, line, func);                    \

-                }                                                       \

+                efi_stash_loglevel_(level);                             \

+                fhexdumpf(efi_get_logfile(), "%s:%d %s(): ",            \

+                          (uint8_t *)buf, size,                         \

+                          file, line, func);                            \

         })

 #define log_hex(level, buf, size) log_hex_(__FILE__, __LINE__, __func__, level, buf, size)

 #define debug_hex(buf, size) log_hex(LOG_DEBUG, buf, size)

-- 

2.24.1