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631923e7f2
libvirt/src/internal.h
Eric Blake 631923e7f2 virFork: give specific status on failure prior to exec 
When a child fails without exec'ing, we want a well-known status;
best is to match what env(1), nice(1), su(1), and other wrapper
programs do.  This patch adds enum values that later patches will
use, and sets up virFork as the first client of EXIT_CANCELED
for errors detected prior to even attempting exec, as well as
virExec to distinguish between a missing executable vs. a binary
that cannot be executed.

This is a slight semantic change in the unlikely case of a child
process failing to restore its signal mask - we now kill the
child with a known status instead of relying on the caller to
notice and do an appropriate _exit().  A subsequent patch will
make further cleanups based on an audit of all callers.

* src/internal.h (EXIT_CANCELED, EXIT_CANNOT_INVOKE)
(EXIT_ENOENT): New enum.
* src/util/vircommand.c (virFork): Document specific exit value if
child aborts early.
(virExec): Distinguish between various exec failures.
* tests/commandtest.c (test1): Enhance test.
(test22): New test.

Signed-off-by: Eric Blake <eblake@redhat.com>
2014-03-03 12:40:31 -07:00

450 lines
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/*
* internal.h: internal definitions just used by code from the library
*
* Copyright (C) 2006-2014 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#ifndef __VIR_INTERNAL_H__
# define __VIR_INTERNAL_H__
# include <errno.h>
# include <limits.h>
# include <verify.h>
# include <stdbool.h>
# include <stdint.h>
# if STATIC_ANALYSIS
# undef NDEBUG /* Don't let a prior NDEBUG definition cause trouble. */
# include <assert.h>
# define sa_assert(expr) assert (expr)
# else
# define sa_assert(expr) /* empty */
# endif
/* The library itself is allowed to use deprecated functions /
* variables, so effectively undefine the deprecated attribute
* which would otherwise be defined in libvirt.h.
*/
# undef VIR_DEPRECATED
# define VIR_DEPRECATED /*empty*/
/* The library itself needs to know enum sizes. */
# define VIR_ENUM_SENTINELS
/* All uses of _() within the library should pick up translations from
* libvirt's message files, rather than from the package that is
* linking in the library. Setting this macro before including
* "gettext.h" means that gettext() (and _()) will properly expand to
* dgettext. */
# define DEFAULT_TEXT_DOMAIN PACKAGE
# include "gettext.h"
# define _(str) gettext(str)
# define N_(str) str
# include "libvirt/libvirt.h"
# include "libvirt/libvirt-lxc.h"
# include "libvirt/libvirt-qemu.h"
# include "libvirt/virterror.h"
# include "c-strcase.h"
# include "ignore-value.h"
/* On architectures which lack these limits, define them (ie. Cygwin).
* Note that the libvirt code should be robust enough to handle the
* case where actual value is longer than these limits (eg. by setting
* length correctly in second argument to gethostname and by always
* using strncpy instead of strcpy).
*/
# ifndef HOST_NAME_MAX
# define HOST_NAME_MAX 256
# endif
# ifndef INET_ADDRSTRLEN
# define INET_ADDRSTRLEN 16
# endif
/* String equality tests, suggested by Jim Meyering. */
# define STREQ(a,b) (strcmp(a,b) == 0)
# define STRCASEEQ(a,b) (c_strcasecmp(a,b) == 0)
# define STRNEQ(a,b) (strcmp(a,b) != 0)
# define STRCASENEQ(a,b) (c_strcasecmp(a,b) != 0)
# define STREQLEN(a,b,n) (strncmp(a,b,n) == 0)
# define STRCASEEQLEN(a,b,n) (c_strncasecmp(a,b,n) == 0)
# define STRNEQLEN(a,b,n) (strncmp(a,b,n) != 0)
# define STRCASENEQLEN(a,b,n) (c_strncasecmp(a,b,n) != 0)
# define STRPREFIX(a,b) (strncmp(a,b,strlen(b)) == 0)
# define STRSKIP(a,b) (STRPREFIX(a,b) ? (a) + strlen(b) : NULL)
# define STREQ_NULLABLE(a, b) \
((a) ? (b) && STREQ((a) ? (a) : "", (b) ? (b) : "") : !(b))
# define STRNEQ_NULLABLE(a, b) \
((a) ? !(b) || STRNEQ((a) ? (a) : "", (b) ? (b) : "") : !!(b))
# define NUL_TERMINATE(buf) do { (buf)[sizeof(buf)-1] = '\0'; } while (0)
# define ARRAY_CARDINALITY(Array) (sizeof(Array) / sizeof(*(Array)))
/* C99 uses __func__. __FUNCTION__ is legacy. */
# ifndef __GNUC__
# define __FUNCTION__ __func__
# endif
# ifdef __GNUC__
# ifndef __GNUC_PREREQ
# if defined __GNUC__ && defined __GNUC_MINOR__
# define __GNUC_PREREQ(maj, min) \
((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
# else
# define __GNUC_PREREQ(maj,min) 0
# endif
/* Work around broken limits.h on debian etch */
# if defined _GCC_LIMITS_H_ && ! defined ULLONG_MAX
# define ULLONG_MAX ULONG_LONG_MAX
# endif
# endif /* __GNUC__ */
/**
* ATTRIBUTE_UNUSED:
*
* Macro to flag consciously unused parameters to functions
*/
# ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED __attribute__((__unused__))
# endif
/**
* ATTRIBUTE_NORETURN:
*
* Macro to indicate that a function won't return to the caller
*/
# ifndef ATTRIBUTE_NORETURN
# define ATTRIBUTE_NORETURN __attribute__((__noreturn__))
# endif
/**
* ATTRIBUTE_SENTINEL:
*
* Macro to check for NULL-terminated varargs lists
*/
# ifndef ATTRIBUTE_SENTINEL
# if __GNUC_PREREQ (4, 0)
# define ATTRIBUTE_SENTINEL __attribute__((__sentinel__))
# else
# define ATTRIBUTE_SENTINEL
# endif
# endif
/**
* ATTRIBUTE_FMT_PRINTF
*
* Macro used to check printf like functions, if compiling
* with gcc.
*
* We use gnulib which guarantees we always have GNU style
* printf format specifiers even on broken Win32 platforms
* hence we have to force 'gnu_printf' for new GCC
*/
# ifndef ATTRIBUTE_FMT_PRINTF
# if __GNUC_PREREQ (4, 4)
# define ATTRIBUTE_FMT_PRINTF(fmtpos,argpos) \
__attribute__((__format__ (__gnu_printf__, fmtpos, argpos)))
# else
# define ATTRIBUTE_FMT_PRINTF(fmtpos,argpos) \
__attribute__((__format__ (__printf__, fmtpos, argpos)))
# endif
# endif
# ifndef ATTRIBUTE_RETURN_CHECK
# if __GNUC_PREREQ (3, 4)
# define ATTRIBUTE_RETURN_CHECK __attribute__((__warn_unused_result__))
# else
# define ATTRIBUTE_RETURN_CHECK
# endif
# endif
/**
* ATTRIBUTE_PACKED
*
* force a structure to be packed, i.e. not following architecture and
* compiler best alignments for its sub components. It's needed for example
* for the network filetering code when defining the content of raw
* ethernet packets.
* Others compiler than gcc may use something different e.g. #pragma pack(1)
*/
# ifndef ATTRIBUTE_PACKED
# if __GNUC_PREREQ (3, 3)
# define ATTRIBUTE_PACKED __attribute__((packed))
# else
# error "Need an __attribute__((packed)) equivalent"
# endif
# endif
/* gcc's handling of attribute nonnull is less than stellar - it does
* NOT improve diagnostics, and merely allows gcc to optimize away
* null code checks even when the caller manages to pass null in spite
* of the attribute, leading to weird crashes. Coverity, on the other
* hand, knows how to do better static analysis based on knowing
* whether a parameter is nonnull. Make this attribute conditional
* based on whether we are compiling for real or for analysis, while
* still requiring correct gcc syntax when it is turned off. See also
* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17308 */
# ifndef ATTRIBUTE_NONNULL
# if __GNUC_PREREQ (3, 3)
# if STATIC_ANALYSIS
# define ATTRIBUTE_NONNULL(m) __attribute__((__nonnull__(m)))
# else
# define ATTRIBUTE_NONNULL(m) __attribute__(())
# endif
# else
# define ATTRIBUTE_NONNULL(m)
# endif
# endif
# else
# ifndef ATTRIBUTE_UNUSED
# define ATTRIBUTE_UNUSED
# endif
# ifndef ATTRIBUTE_FMT_PRINTF
# define ATTRIBUTE_FMT_PRINTF(...)
# endif
# ifndef ATTRIBUTE_RETURN_CHECK
# define ATTRIBUTE_RETURN_CHECK
# endif
# endif /* __GNUC__ */
# if WORKING_PRAGMA_PUSH
# define VIR_WARNINGS_NO_CAST_ALIGN \
_Pragma ("GCC diagnostic push") \
_Pragma ("GCC diagnostic ignored \"-Wcast-align\"")
# define VIR_WARNINGS_RESET \
_Pragma ("GCC diagnostic pop")
# else
# define VIR_WARNINGS_NO_CAST_ALIGN
# define VIR_WARNINGS_RESET
# endif
/*
* Use this when passing possibly-NULL strings to printf-a-likes.
*/
# define NULLSTR(s) ((s) ? (s) : "<null>")
/**
* TODO:
*
* macro to flag unimplemented blocks
*/
# define TODO \
fprintf(stderr, "Unimplemented block at %s:%d\n", \
__FILE__, __LINE__);
/**
* virCheckFlags:
* @supported: an OR'ed set of supported flags
* @retval: return value in case unsupported flags were passed
*
* To avoid memory leaks this macro has to be used before any non-trivial
* code which could possibly allocate some memory.
*
* Returns nothing. Exits the caller function if unsupported flags were
* passed to it.
*/
# define virCheckFlags(supported, retval) \
do { \
unsigned long __unsuppflags = flags & ~(supported); \
if (__unsuppflags) { \
virReportInvalidArg(flags, \
_("unsupported flags (0x%lx) in function %s"), \
__unsuppflags, __FUNCTION__); \
return retval; \
} \
} while (0)
/**
* virCheckFlagsGoto:
* @supported: an OR'ed set of supported flags
* @label: label to jump to on error
*
* To avoid memory leaks this macro has to be used before any non-trivial
* code which could possibly allocate some memory.
*
* Returns nothing. Jumps to a label if unsupported flags were
* passed to it.
*/
# define virCheckFlagsGoto(supported, label) \
do { \
unsigned long __unsuppflags = flags & ~(supported); \
if (__unsuppflags) { \
virReportInvalidArg(flags, \
_("unsupported flags (0x%lx) in function %s"), \
__unsuppflags, __FUNCTION__); \
goto label; \
} \
} while (0)
# define virCheckNonNullArgReturn(argname, retval) \
do { \
if (argname == NULL) { \
virReportInvalidNonNullArg(argname); \
return retval; \
} \
} while (0)
# define virCheckNullArgGoto(argname, label) \
do { \
if (argname != NULL) { \
virReportInvalidNullArg(argname); \
goto label; \
} \
} while (0)
# define virCheckNonNullArgGoto(argname, label) \
do { \
if (argname == NULL) { \
virReportInvalidNonNullArg(argname); \
goto label; \
} \
} while (0)
# define virCheckPositiveArgGoto(argname, label) \
do { \
if (argname <= 0) { \
virReportInvalidPositiveArg(argname); \
goto label; \
} \
} while (0)
# define virCheckNonZeroArgGoto(argname, label) \
do { \
if (argname == 0) { \
virReportInvalidNonZeroArg(argname); \
goto label; \
} \
} while (0)
# define virCheckZeroArgGoto(argname, label) \
do { \
if (argname != 0) { \
virReportInvalidNonZeroArg(argname); \
goto label; \
} \
} while (0)
# define virCheckNonNegativeArgGoto(argname, label) \
do { \
if (argname < 0) { \
virReportInvalidNonNegativeArg(argname); \
goto label; \
} \
} while (0)
# define virCheckReadOnlyGoto(flags, label) \
do { \
if ((flags) & VIR_CONNECT_RO) { \
virReportRestrictedError(_("read only access prevents %s"), \
__FUNCTION__); \
goto label; \
} \
} while (0)
/* divide value by size, rounding up */
# define VIR_DIV_UP(value, size) (((value) + (size) - 1) / (size))
/* round up value to the closest multiple of size */
# define VIR_ROUND_UP(value, size) (VIR_DIV_UP(value, size) * (size))
# if WITH_DTRACE_PROBES
# ifndef LIBVIRT_PROBES_H
# define LIBVIRT_PROBES_H
# include "libvirt_probes.h"
# endif /* LIBVIRT_PROBES_H */
/* Systemtap 1.2 headers have a bug where they cannot handle a
* variable declared with array type. Work around this by casting all
* arguments. This is some gross use of the preprocessor because
* PROBE is a var-arg macro, but it is better than the alternative of
* making all callers to PROBE have to be aware of the issues. And
* hopefully, if we ever add a call to PROBE with other than 9
* end arguments, you can figure out the pattern to extend this hack.
*/
# define VIR_COUNT_ARGS(...) VIR_ARG11(__VA_ARGS__, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1)
# define VIR_ARG11(_1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, ...) _11
# define VIR_ADD_CAST_EXPAND(a, b, ...) VIR_ADD_CAST_PASTE(a, b, __VA_ARGS__)
# define VIR_ADD_CAST_PASTE(a, b, ...) a##b(__VA_ARGS__)
/* The double cast is necessary to silence gcc warnings; any pointer
* can safely go to intptr_t and back to void *, which collapses
* arrays into pointers; while any integer can be widened to intptr_t
* then cast to void *. */
# define VIR_ADD_CAST(a) ((void *)(intptr_t)(a))
# define VIR_ADD_CAST1(a) \
VIR_ADD_CAST(a)
# define VIR_ADD_CAST2(a, b) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b)
# define VIR_ADD_CAST3(a, b, c) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c)
# define VIR_ADD_CAST4(a, b, c, d) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d)
# define VIR_ADD_CAST5(a, b, c, d, e) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d), VIR_ADD_CAST(e)
# define VIR_ADD_CAST6(a, b, c, d, e, f) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d), VIR_ADD_CAST(e), VIR_ADD_CAST(f)
# define VIR_ADD_CAST7(a, b, c, d, e, f, g) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d), VIR_ADD_CAST(e), VIR_ADD_CAST(f), \
VIR_ADD_CAST(g)
# define VIR_ADD_CAST8(a, b, c, d, e, f, g, h) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d), VIR_ADD_CAST(e), VIR_ADD_CAST(f), \
VIR_ADD_CAST(g), VIR_ADD_CAST(h)
# define VIR_ADD_CAST9(a, b, c, d, e, f, g, h, i) \
VIR_ADD_CAST(a), VIR_ADD_CAST(b), VIR_ADD_CAST(c), \
VIR_ADD_CAST(d), VIR_ADD_CAST(e), VIR_ADD_CAST(f), \
VIR_ADD_CAST(g), VIR_ADD_CAST(h), VIR_ADD_CAST(i)
# define VIR_ADD_CASTS(...) \
VIR_ADD_CAST_EXPAND(VIR_ADD_CAST, VIR_COUNT_ARGS(__VA_ARGS__), \
__VA_ARGS__)
# define PROBE_EXPAND(NAME, ARGS) NAME(ARGS)
# define PROBE(NAME, FMT, ...) \
VIR_DEBUG_INT(VIR_LOG_FROM_TRACE, \
__FILE__, __LINE__, __func__, \
#NAME ": " FMT, __VA_ARGS__); \
if (LIBVIRT_ ## NAME ## _ENABLED()) { \
PROBE_EXPAND(LIBVIRT_ ## NAME, \
VIR_ADD_CASTS(__VA_ARGS__)); \
}
# else
# define PROBE(NAME, FMT, ...) \
VIR_DEBUG_INT(VIR_LOG_FROM_TRACE, \
__FILE__, __LINE__, __func__, \
#NAME ": " FMT, __VA_ARGS__);
# endif
/* Specific error values for use in forwarding programs such as
* virt-login-shell; these values match what GNU env does. */
enum {
EXIT_CANCELED = 125, /* Failed before attempting exec */
EXIT_CANNOT_INVOKE = 126, /* Exists but couldn't exec */
EXIT_ENOENT = 127, /* Could not find program to exec */
};
#endif /* __VIR_INTERNAL_H__ */
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