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util-linux/include/debug.h

181 lines
4.5 KiB

/*
* Copyright (C) 2014 Ondrej Oprala <ooprala@redhat.com>
* Copyright (C) 2014 Karel Zak <kzak@redhat.com>
*
* This file may be distributed under the terms of the
* GNU Lesser General Public License.
*/
#ifndef UTIL_LINUX_DEBUG_H
#define UTIL_LINUX_DEBUG_H
/*
* util-linux debug macros
*
* The debug stuff is based on <name>_debug_mask that controls what outputs is
* expected. The mask is usually initialized by <NAME>_DEBUG= env.variable
*
* After successful initialization the flag <PREFIX>_DEBUG_INIT is always set
* to the mask (this flag is required). The <PREFIX> is usually library API
* prefix (e.g. MNT_) or program name (e.g. CFDISK_)
*
* In the code is possible to use
*
* DBG(FOO, ul_debug("this is output for foo"));
*
* where for the FOO has to be defined <PREFIX>_DEBUG_FOO.
*
* It's possible to initialize the mask by comma delimited strings with
* subsystem names (e.g. "LIBMOUNT_DEBUG=options,tab"). In this case is
* necessary to define mask names array. This functionality is optional.
*
* It's strongly recommended to use UL_* macros to define/declare/use
* the debug stuff.
*
* See disk-utils/cfdisk.c: cfdisk_init_debug() for programs debug
* or libmount/src/init.c: mnt_init_debug() for library debug
*
*/
#include <stdarg.h>
#include <string.h>
struct ul_debug_maskname {
const char *name;
int mask;
const char *help;
};
#define UL_DEBUG_EMPTY_MASKNAMES {{ NULL, 0, NULL }}
#define UL_DEBUG_DEFINE_MASKNAMES(m) static const struct ul_debug_maskname m ## _masknames[]
#define UL_DEBUG_MASKNAMES(m) m ## _masknames
#define UL_DEBUG_MASK(m) m ## _debug_mask
#define UL_DEBUG_DEFINE_MASK(m) int UL_DEBUG_MASK(m)
#define UL_DEBUG_DECLARE_MASK(m) extern UL_DEBUG_DEFINE_MASK(m)
/*
* Internal mask flags (above 0xffffff)
*/
#define __UL_DEBUG_FL_NOADDR (1 << 24) /* Don't print object address */
/* l - library name, p - flag prefix, m - flag postfix, x - function */
#define __UL_DBG(l, p, m, x) \
do { \
if ((p ## m) & l ## _debug_mask) { \
fprintf(stderr, "%d: %s: %8s: ", getpid(), # l, # m); \
x; \
} \
} while (0)
#define __UL_DBG_CALL(l, p, m, x) \
do { \
if ((p ## m) & l ## _debug_mask) { \
x; \
} \
} while (0)
#define __UL_DBG_FLUSH(l, p) \
do { \
if (l ## _debug_mask && \
l ## _debug_mask != p ## INIT) { \
fflush(stderr); \
} \
} while (0)
#define __UL_INIT_DEBUG_FROM_STRING(lib, pref, mask, str) \
do { \
if (lib ## _debug_mask & pref ## INIT) \
; \
else if (!mask && str) { \
lib ## _debug_mask = ul_debug_parse_mask(lib ## _masknames, str); \
} else \
lib ## _debug_mask = mask; \
if (lib ## _debug_mask) { \
if (getuid() != geteuid() || getgid() != getegid()) { \
lib ## _debug_mask |= __UL_DEBUG_FL_NOADDR; \
fprintf(stderr, "%d: %s: don't print memory addresses (SUID executable).\n", getpid(), # lib); \
} \
} \
lib ## _debug_mask |= pref ## INIT; \
} while (0)
#define __UL_INIT_DEBUG_FROM_ENV(lib, pref, mask, env) \
do { \
const char *envstr = mask ? NULL : getenv(# env); \
__UL_INIT_DEBUG_FROM_STRING(lib, pref, mask, envstr); \
} while (0)
static inline void __attribute__ ((__format__ (__printf__, 1, 2)))
ul_debug(const char *mesg, ...)
{
va_list ap;
va_start(ap, mesg);
vfprintf(stderr, mesg, ap);
va_end(ap);
fputc('\n', stderr);
}
static inline int ul_debug_parse_mask(
const struct ul_debug_maskname flagnames[],
const char *mask)
{
int res;
char *ptr;
/* let's check for a numeric mask first */
res = strtoul(mask, &ptr, 0);
/* perhaps it's a comma-separated string? */
if (ptr && *ptr && flagnames && flagnames[0].name) {
char *msbuf, *ms, *name;
res = 0;
ms = msbuf = strdup(mask);
if (!ms)
return res;
while ((name = strtok_r(ms, ",", &ptr))) {
const struct ul_debug_maskname *d;
ms = ptr;
for (d = flagnames; d && d->name; d++) {
if (strcmp(name, d->name) == 0) {
res |= d->mask;
break;
}
}
/* nothing else we can do by OR-ing the mask */
if (res == 0xffff)
break;
}
free(msbuf);
} else if (ptr && strcmp(ptr, "all") == 0)
res = 0xffff;
return res;
}
static inline void ul_debug_print_masks(
const char *env,
const struct ul_debug_maskname flagnames[])
{
const struct ul_debug_maskname *d;
if (!flagnames)
return;
fprintf(stderr, "Available \"%s=<name>[,...]|<mask>\" debug masks:\n",
env);
for (d = flagnames; d && d->name; d++) {
if (!d->help)
continue;
fprintf(stderr, " %-8s [0x%04x] : %s\n",
d->name, d->mask, d->help);
}
}
#endif /* UTIL_LINUX_DEBUG_H */