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Diffstat (limited to 'libbb')
-rw-r--r--libbb/capability.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/libbb/capability.c b/libbb/capability.c
index 692024f2f..f60062bfc 100644
--- a/libbb/capability.c
+++ b/libbb/capability.c
@@ -6,6 +6,14 @@
//kbuild:lib-$(CONFIG_PLATFORM_LINUX) += capability.o
#include <linux/capability.h>
+// #include <sys/capability.h>
+// This header is in libcap, but the functions are in libc.
+// Comment in the header says this above capset/capget:
+/* system calls - look to libc for function to system call mapping */
+extern int capset(cap_user_header_t header, cap_user_data_t data);
+extern int capget(cap_user_header_t header, const cap_user_data_t data);
+// so for bbox, let's just repeat the declarations.
+// This way, libcap needs not be installed in build environment.
#include "libbb.h"
static const char *const capabilities[] = {
@@ -77,3 +85,42 @@ void FAST_FUNC printf_cap(const char *pfx, unsigned cap_no)
}
printf("%scap_%u", pfx, cap_no);
}
+
+DEFINE_STRUCT_CAPS;
+
+void FAST_FUNC getcaps(void *arg)
+{
+ static const uint8_t versions[] = {
+ _LINUX_CAPABILITY_U32S_3, /* = 2 (fits into byte) */
+ _LINUX_CAPABILITY_U32S_2, /* = 2 */
+ _LINUX_CAPABILITY_U32S_1, /* = 1 */
+ };
+ int i;
+ struct caps *caps = arg;
+
+ caps->header.pid = 0;
+ for (i = 0; i < ARRAY_SIZE(versions); i++) {
+ caps->header.version = versions[i];
+ if (capget(&caps->header, NULL) == 0)
+ goto got_it;
+ }
+ bb_simple_perror_msg_and_die("capget");
+ got_it:
+
+ switch (caps->header.version) {
+ case _LINUX_CAPABILITY_VERSION_1:
+ caps->u32s = _LINUX_CAPABILITY_U32S_1;
+ break;
+ case _LINUX_CAPABILITY_VERSION_2:
+ caps->u32s = _LINUX_CAPABILITY_U32S_2;
+ break;
+ case _LINUX_CAPABILITY_VERSION_3:
+ caps->u32s = _LINUX_CAPABILITY_U32S_3;
+ break;
+ default:
+ bb_error_msg_and_die("unsupported capability version");
+ }
+
+ if (capget(&caps->header, caps->data) != 0)
+ bb_simple_perror_msg_and_die("capget");
+}