libbb: move capability names code to libbb

function                                             old     new   delta
cap_name_to_number                                     -      77     +77
parse_cap                                            117      29     -88
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 0/1 up/down: 77/-88)            Total: -11 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

include/libbb.h

@@ -1473,6 +1473,12 @@ extern void run_shell(const char *shell, int loginshell, const char **args) NORE
  */
 const char *get_shell_name(void) FAST_FUNC;
 
+unsigned cap_name_to_number(const char *cap) FAST_FUNC;
+void printf_cap(const char *pfx, unsigned cap_no) FAST_FUNC;
+
+unsigned cap_name_to_number(const char *name) FAST_FUNC;
+void printf_cap(const char *pfx, unsigned cap_no) FAST_FUNC;
+
 #if ENABLE_SELINUX
 extern void renew_current_security_context(void) FAST_FUNC;
 extern void set_current_security_context(security_context_t sid) FAST_FUNC;

libbb/capability.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2017 by  <assafgordon@gmail.com>
+ *
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
+ */
+//kbuild:lib-$(CONFIG_PLATFORM_LINUX) += capability.o
+
+#include <linux/capability.h>
+#include "libbb.h"
+
+static const char *const capabilities[] = {
+	"chown",
+	"dac_override",
+	"dac_read_search",
+	"fowner",
+	"fsetid",
+	"kill",
+	"setgid",
+	"setuid",
+	"setpcap",
+	"linux_immutable",
+	"net_bind_service",
+	"net_broadcast",
+	"net_admin",
+	"net_raw",
+	"ipc_lock",
+	"ipc_owner",
+	"sys_module",
+	"sys_rawio",
+	"sys_chroot",
+	"sys_ptrace",
+	"sys_pacct",
+	"sys_admin",
+	"sys_boot",
+	"sys_nice",
+	"sys_resource",
+	"sys_time",
+	"sys_tty_config",
+	"mknod",
+	"lease",
+	"audit_write",
+	"audit_control",
+	"setfcap",
+	"mac_override",
+	"mac_admin",
+	"syslog",
+	"wake_alarm",
+	"block_suspend",
+	"audit_read",
+};
+
+unsigned FAST_FUNC cap_name_to_number(const char *cap)
+{
+	unsigned i, n;
+
+	if ((sscanf(cap, "cap_%u", &n)) == 1) {
+		i = n;
+		goto found;
+	}
+	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
+		if (strcasecmp(capabilities[i], cap) != 0)
+			goto found;
+	}
+	bb_error_msg_and_die("unknown capability '%s'", cap);
+
+ found:
+	if (!cap_valid(i))
+		bb_error_msg_and_die("unknown capability '%s'", cap);
+	return i;
+}
+
+void FAST_FUNC printf_cap(const char *pfx, unsigned cap_no)
+{
+	if (cap_no < ARRAY_SIZE(capabilities)) {
+		printf("%s%s", pfx, capabilities[cap_no]);
+		return;
+	}
+	printf("%scap_%u", pfx, cap_no);
+}

util-linux/setpriv.c

@@ -5,7 +5,6 @@
  * Copyright (C) 2017 by  <assafgordon@gmail.com>
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
- *
  */
 //config:config SETPRIV
 //config:	bool "setpriv (3.4 kb)"
@@ -131,49 +130,6 @@ struct caps {
 	int u32s;
 };
 
-# if ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
-static const char *const capabilities[] = {
-	"chown",
-	"dac_override",
-	"dac_read_search",
-	"fowner",
-	"fsetid",
-	"kill",
-	"setgid",
-	"setuid",
-	"setpcap",
-	"linux_immutable",
-	"net_bind_service",
-	"net_broadcast",
-	"net_admin",
-	"net_raw",
-	"ipc_lock",
-	"ipc_owner",
-	"sys_module",
-	"sys_rawio",
-	"sys_chroot",
-	"sys_ptrace",
-	"sys_pacct",
-	"sys_admin",
-	"sys_boot",
-	"sys_nice",
-	"sys_resource",
-	"sys_time",
-	"sys_tty_config",
-	"mknod",
-	"lease",
-	"audit_write",
-	"audit_control",
-	"setfcap",
-	"mac_override",
-	"mac_admin",
-	"syslog",
-	"wake_alarm",
-	"block_suspend",
-	"audit_read",
-};
-# endif /* FEATURE_SETPRIV_CAPABILITY_NAMES */
-
 static void getcaps(struct caps *caps)
 {
 	static const uint8_t versions[] = {
@@ -211,10 +167,8 @@ static void getcaps(struct caps *caps)
 		bb_simple_perror_msg_and_die("capget");
 }
 
-static unsigned long parse_cap(const char *cap)
+static unsigned parse_cap(const char *cap)
 {
-	unsigned long i;
-
 	switch (cap[0]) {
 	case '-':
 		break;
@@ -226,24 +180,7 @@ static unsigned long parse_cap(const char *cap)
 	}
 
 	cap++;
-	if ((sscanf(cap, "cap_%lu", &i)) == 1) {
+	return cap_name_to_number(cap);
-		if (!cap_valid(i))
-			bb_error_msg_and_die("unsupported capability '%s'", cap);
-		return i;
-	}
-
-# if ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
-	for (i = 0; i < ARRAY_SIZE(capabilities); i++) {
-		if (strcasecmp(capabilities[i], cap) != 0)
-			continue;
-
-		if (!cap_valid(i))
-			bb_error_msg_and_die("unsupported capability '%s'", cap);
-		return i;
-	}
-# endif
-
-	bb_error_msg_and_die("unknown capability '%s'", cap);
 }
 
 static void set_inh_caps(char *capstring)
@@ -254,7 +191,7 @@ static void set_inh_caps(char *capstring)
 
 	capstring = strtok(capstring, ",");
 	while (capstring) {
-		unsigned long cap;
+		unsigned cap;
 
 		cap = parse_cap(capstring);
 		if (CAP_TO_INDEX(cap) >= caps.u32s)
@@ -280,7 +217,7 @@ static void set_ambient_caps(char *string)
 
 	cap = strtok(string, ",");
 	while (cap) {
-		unsigned long index;
+		unsigned index;
 
 		index = parse_cap(cap);
 		if (cap[0] == '+') {
@@ -296,16 +233,7 @@ static void set_ambient_caps(char *string)
 #endif /* FEATURE_SETPRIV_CAPABILITIES */
 
 #if ENABLE_FEATURE_SETPRIV_DUMP
-# if ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
+# if !ENABLE_FEATURE_SETPRIV_CAPABILITY_NAMES
-static void printf_cap(const char *pfx, unsigned cap_no)
-{
-	if (cap_no < ARRAY_SIZE(capabilities)) {
-		printf("%s%s", pfx, capabilities[cap_no]);
-		return;
-	}
-	printf("%scap_%u", pfx, cap_no);
-}
-# else
 #  define printf_cap(pfx, cap_no) printf("%scap_%u", (pfx), (cap_no))
 # endif