libbb: optionally honour libc provided SIGRTMIN/SIGRTMAX in get_signum()

When an application documents that it responds such and such to SIGRTMIN+n, that almost always means with respect to the libc-provided SIGRTMIN. Hence I disagree with the "more correct" in commit 7b276fc17594. In any case, this is rather unfortunate: 36 34 (the first shell is bash). We probably can't change default behaviour after 7 years, but at least we can provide a config option. We avoid a little code generation (repeated calls to __libc_current_sigrtmin) by stashing SIGRTMIN/SIGRTMAX in local variables, but it does cost ~50 bytes. The next patch serves as penance for that. Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
author: Rasmus Villemoes <rasmus.villemoes@prevas.dk> 2018-09-12 16:06:36 +0200
committer: Denys Vlasenko <vda.linux@googlemail.com> 2018-10-31 11:13:55 +0100
commit: 571e525a141a2de87b9c2ced485745e96418d921 (patch)
tree: 0841c003d074777df7cb3a0fd7ece733b7bf9988 /libbb/u_signal_names.c
parent: 93ef5dd640ef41edc72c80fa59c7cc9427b5945b (diff)
download: busybox-w32-571e525a141a2de87b9c2ced485745e96418d921.tar.gz
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busybox-w32-571e525a141a2de87b9c2ced485745e96418d921.zip
1 files changed, 53 insertions, 23 deletions
diff --git a/libbb/u_signal_names.c b/libbb/u_signal_names.c
index b3038e32d..866ca85fd 100644
--- a/libbb/u_signal_names.c
+++ b/libbb/u_signal_names.c
@@ -12,6 +12,18 @@
 //config:       help
 //config:       Support RTMIN[+n] and RTMAX[-n] signal names
 //config:       in kill, killall etc. This costs ~250 bytes.
+//config:
+//config:config FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
+//config:       bool "Use the definitions of SIGRTMIN/SIGRTMAX provided by libc"
+//config:       default y
+//config:       depends on FEATURE_RTMINMAX
+//config:       help
+//config:       Some C libraries reserve a few real-time signals for internal
+//config:       use, and adjust the values of SIGRTMIN/SIGRTMAX seen by
+//config:       applications accordingly. Saying yes here means that a signal
+//config:       name RTMIN+n will be interpreted according to the libc definition
+//config:       of SIGRTMIN, and not the raw definition provided by the kernel.
+//config:       This behavior matches "kill -l RTMIN+n" from bash.
 #include "libbb.h"
@@ -123,7 +135,7 @@ static const char signals[][7] ALIGN1 = {
 #ifdef SIGSYS
        [SIGSYS   ] = "SYS",
 #endif
-#if ENABLE_FEATURE_RTMINMAX
+#if ENABLE_FEATURE_RTMINMAX && !ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
 # ifdef __SIGRTMIN
        [__SIGRTMIN] = "RTMIN",
 # endif
@@ -168,36 +180,46 @@ int FAST_FUNC get_signum(const char *name)
 # endif
 #endif
-#if ENABLE_FEATURE_RTMINMAX
+#if ENABLE_FEATURE_RTMINMAX && defined(SIGRTMIN) && defined(SIGRTMAX)
-# if defined(SIGRTMIN) && defined(SIGRTMAX)
+        {
-/* libc may use some rt sigs for pthreads and therefore "remap" SIGRTMIN/MAX,
+# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
- * but we want to use "raw" SIGRTMIN/MAX. Underscored names, if exist, provide
+                /* Use the libc provided values. */
- * them. If they don't exist, fall back to non-underscored ones: */
+                unsigned sigrtmin = SIGRTMIN;
+                unsigned sigrtmax = SIGRTMAX;
+# else
+        /* Use the "raw" SIGRTMIN/MAX. Underscored names, if exist, provide
+         * them. If they don't exist, fall back to non-underscored ones: */
 #  if !defined(__SIGRTMIN)
 #   define __SIGRTMIN SIGRTMIN
 #  endif
 #  if !defined(__SIGRTMAX)
 #   define __SIGRTMAX SIGRTMAX
 #  endif
-        if (strncasecmp(name, "RTMIN", 5) == 0) {
-                if (!name[5])
+#  define sigrtmin __SIGRTMIN
-                        return __SIGRTMIN;
+#  define sigrtmax __SIGRTMAX
-                if (name[5] == '+') {
+# endif
-                        i = bb_strtou(name + 6, NULL, 10);
+                if (strncasecmp(name, "RTMIN", 5) == 0) {
-                        if (!errno && i <= __SIGRTMAX - __SIGRTMIN)
+                        if (!name[5])
-                                return __SIGRTMIN + i;
+                                return sigrtmin;
+                        if (name[5] == '+') {
+                                i = bb_strtou(name + 6, NULL, 10);
+                                if (!errno && i <= sigrtmax - sigrtmin)
+                                        return sigrtmin + i;
+                        }
                }
-        }
+                else if (strncasecmp(name, "RTMAX", 5) == 0) {
-        else if (strncasecmp(name, "RTMAX", 5) == 0) {
+                        if (!name[5])
-                if (!name[5])
+                                return sigrtmax;
-                        return __SIGRTMAX;
+                        if (name[5] == '-') {
-                if (name[5] == '-') {
+                                i = bb_strtou(name + 6, NULL, 10);
-                        i = bb_strtou(name + 6, NULL, 10);
+                                if (!errno && i <= sigrtmax - sigrtmin)
-                        if (!errno && i <= __SIGRTMAX - __SIGRTMIN)
+                                        return sigrtmax - i;
-                                return __SIGRTMAX - i;
+                        }
                }
+# undef sigrtmin
+# undef sigrtmax
        }
-# endif
 #endif
        return -1;
@@ -228,8 +250,16 @@ void FAST_FUNC print_signames(void)
                        printf("%2u) %s\n", signo, name);
        }
 #if ENABLE_FEATURE_RTMINMAX
-# ifdef __SIGRTMAX
+# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
+#  if defined(SIGRTMIN) && defined(SIGRTMAX)
+        printf("%2u) %s\n", SIGRTMIN, "RTMIN");
+        printf("%2u) %s\n", SIGRTMAX, "RTMAX");
+#  endif
+# else
+// __SIGRTMIN is included in signals[] array.
+#  ifdef __SIGRTMAX
        printf("%2u) %s\n", __SIGRTMAX, "RTMAX");
+#  endif
 # endif
 #endif
 }
author	Rasmus Villemoes <rasmus.villemoes@prevas.dk>	2018-09-12 16:06:36 +0200
committer	Denys Vlasenko <vda.linux@googlemail.com>	2018-10-31 11:13:55 +0100
commit	571e525a141a2de87b9c2ced485745e96418d921 (patch)
tree	0841c003d074777df7cb3a0fd7ece733b7bf9988 /libbb/u_signal_names.c
parent	93ef5dd640ef41edc72c80fa59c7cc9427b5945b (diff)
download	busybox-w32-571e525a141a2de87b9c2ced485745e96418d921.tar.gz busybox-w32-571e525a141a2de87b9c2ced485745e96418d921.tar.bz2 busybox-w32-571e525a141a2de87b9c2ced485745e96418d921.zip

diff --git a/libbb/u_signal_names.c b/libbb/u_signal_names.c index b3038e32d..866ca85fd 100644 --- a/libbb/u_signal_names.c +++ b/libbb/u_signal_names.c
@@ -12,6 +12,18 @@
12	//config: help	12	//config: help
13	//config: Support RTMIN[+n] and RTMAX[-n] signal names	13	//config: Support RTMIN[+n] and RTMAX[-n] signal names
14	//config: in kill, killall etc. This costs ~250 bytes.	14	//config: in kill, killall etc. This costs ~250 bytes.
		15	//config:
		16	//config:config FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
		17	//config: bool "Use the definitions of SIGRTMIN/SIGRTMAX provided by libc"
		18	//config: default y
		19	//config: depends on FEATURE_RTMINMAX
		20	//config: help
		21	//config: Some C libraries reserve a few real-time signals for internal
		22	//config: use, and adjust the values of SIGRTMIN/SIGRTMAX seen by
		23	//config: applications accordingly. Saying yes here means that a signal
		24	//config: name RTMIN+n will be interpreted according to the libc definition
		25	//config: of SIGRTMIN, and not the raw definition provided by the kernel.
		26	//config: This behavior matches "kill -l RTMIN+n" from bash.
15		27
16	#include "libbb.h"	28	#include "libbb.h"
17		29
@@ -123,7 +135,7 @@ static const char signals[][7] ALIGN1 = {
123	#ifdef SIGSYS	135	#ifdef SIGSYS
124	[SIGSYS ] = "SYS",	136	[SIGSYS ] = "SYS",
125	#endif	137	#endif
126	#if ENABLE_FEATURE_RTMINMAX	138	#if ENABLE_FEATURE_RTMINMAX && !ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
127	# ifdef __SIGRTMIN	139	# ifdef __SIGRTMIN
128	[__SIGRTMIN] = "RTMIN",	140	[__SIGRTMIN] = "RTMIN",
129	# endif	141	# endif
@@ -168,36 +180,46 @@ int FAST_FUNC get_signum(const char *name)
168	# endif	180	# endif
169	#endif	181	#endif
170		182
171	#if ENABLE_FEATURE_RTMINMAX	183	#if ENABLE_FEATURE_RTMINMAX && defined(SIGRTMIN) && defined(SIGRTMAX)
172	# if defined(SIGRTMIN) && defined(SIGRTMAX)	184	{
173	/* libc may use some rt sigs for pthreads and therefore "remap" SIGRTMIN/MAX,	185	# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
174	* but we want to use "raw" SIGRTMIN/MAX. Underscored names, if exist, provide	186	/* Use the libc provided values. */
175	* them. If they don't exist, fall back to non-underscored ones: */	187	unsigned sigrtmin = SIGRTMIN;
		188	unsigned sigrtmax = SIGRTMAX;
		189	# else
		190	/* Use the "raw" SIGRTMIN/MAX. Underscored names, if exist, provide
		191	* them. If they don't exist, fall back to non-underscored ones: */
176	# if !defined(__SIGRTMIN)	192	# if !defined(__SIGRTMIN)
177	# define __SIGRTMIN SIGRTMIN	193	# define __SIGRTMIN SIGRTMIN
178	# endif	194	# endif
179	# if !defined(__SIGRTMAX)	195	# if !defined(__SIGRTMAX)
180	# define __SIGRTMAX SIGRTMAX	196	# define __SIGRTMAX SIGRTMAX
181	# endif	197	# endif
182	if (strncasecmp(name, "RTMIN", 5) == 0) {	198
183	if (!name[5])	199	# define sigrtmin __SIGRTMIN
184	return __SIGRTMIN;	200	# define sigrtmax __SIGRTMAX
185	if (name[5] == '+') {	201	# endif
186	i = bb_strtou(name + 6, NULL, 10);	202	if (strncasecmp(name, "RTMIN", 5) == 0) {
187	if (!errno && i <= __SIGRTMAX - __SIGRTMIN)	203	if (!name[5])
188	return __SIGRTMIN + i;	204	return sigrtmin;
		205	if (name[5] == '+') {
		206	i = bb_strtou(name + 6, NULL, 10);
		207	if (!errno && i <= sigrtmax - sigrtmin)
		208	return sigrtmin + i;
		209	}
189	}	210	}
190	}	211	else if (strncasecmp(name, "RTMAX", 5) == 0) {
191	else if (strncasecmp(name, "RTMAX", 5) == 0) {	212	if (!name[5])
192	if (!name[5])	213	return sigrtmax;
193	return __SIGRTMAX;	214	if (name[5] == '-') {
194	if (name[5] == '-') {	215	i = bb_strtou(name + 6, NULL, 10);
195	i = bb_strtou(name + 6, NULL, 10);	216	if (!errno && i <= sigrtmax - sigrtmin)
196	if (!errno && i <= __SIGRTMAX - __SIGRTMIN)	217	return sigrtmax - i;
197	return __SIGRTMAX - i;	218	}
198	}	219	}
		220	# undef sigrtmin
		221	# undef sigrtmax
199	}	222	}
200	# endif
201	#endif	223	#endif
202		224
203	return -1;	225	return -1;
@@ -228,8 +250,16 @@ void FAST_FUNC print_signames(void)
228	printf("%2u) %s\n", signo, name);	250	printf("%2u) %s\n", signo, name);
229	}	251	}
230	#if ENABLE_FEATURE_RTMINMAX	252	#if ENABLE_FEATURE_RTMINMAX
231	# ifdef __SIGRTMAX	253	# if ENABLE_FEATURE_RTMINMAX_USE_LIBC_DEFINITIONS
		254	# if defined(SIGRTMIN) && defined(SIGRTMAX)
		255	printf("%2u) %s\n", SIGRTMIN, "RTMIN");
		256	printf("%2u) %s\n", SIGRTMAX, "RTMAX");
		257	# endif
		258	# else
		259	// __SIGRTMIN is included in signals[] array.
		260	# ifdef __SIGRTMAX
232	printf("%2u) %s\n", __SIGRTMAX, "RTMAX");	261	printf("%2u) %s\n", __SIGRTMAX, "RTMAX");
		262	# endif
233	# endif	263	# endif
234	#endif	264	#endif
235	}	265	}