1 files changed, 126 insertions, 0 deletions

diff --git a/libbb/capability.c b/libbb/capability.c
new file mode 100644
index 000000000..f60062bfc
--- /dev/null
+++ b/libbb/capability.c
@@ -0,0 +1,126 @@
+/*
+ * 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 <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[] = {
+        "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);
+}
+
+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");
+}