[Buildroot] [PATCH] makedevs: add xattr support

[Philippe Reynes]

Add the support of capabilities to makedevs.
Now, it's possible to add "|xattr <capability>"
after a file description to also add a capability
to this file. It's possible to add severals
capabilities with severals lines.

Signed-off-by: Philippe Reynes <philippe.reynes at sagemcom.com>
---
 package/makedevs/makedevs.c  |   66 ++++++++++++++++++++++++++++++++++++++++--
 package/makedevs/makedevs.mk |    4 ++-
 2 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/package/makedevs/makedevs.c b/package/makedevs/makedevs.c
index e5ef164..225b441 100644
--- a/package/makedevs/makedevs.c
+++ b/package/makedevs/makedevs.c
@@ -35,6 +35,7 @@
 #include <sys/sysmacros.h>     /* major() and minor() */
 #endif
 #include <ftw.h>
+#include <sys/capability.h>
 
 const char *bb_applet_name;
 uid_t recursive_uid;
@@ -43,6 +44,8 @@ unsigned int recursive_mode;
 #define PASSWD_PATH "etc/passwd"  /* MUST be relative */
 #define GROUP_PATH "etc/group"  /* MUST be relative */
 
+void bb_xasprintf(char **string_ptr, const char *format, ...);
+
 void bb_verror_msg(const char *s, va_list p)
 {
 	fflush(stdout);
@@ -190,6 +193,55 @@ int bb_make_directory (char *path, long mode, int flags)
 	return -1;
 }
 
+int bb_set_xattr(const char *fpath, const char *xattr)
+{
+	cap_t cap, cap_file, cap_new;
+	char *cap_file_text, *cap_new_text;
+	ssize_t length;
+
+	cap = cap_from_text(xattr);
+	if (cap == NULL) {
+		bb_perror_msg("cap_from_text failed for %s", xattr);
+		return -1;
+	}
+
+	cap_file = cap_get_file(fpath);
+	if (cap_file == NULL) {
+		/* if no capability was set before, we initialize cap_file */
+		if (errno == ENODATA) {
+			cap_file = cap_init();
+		} else {
+			bb_perror_msg("cap_get_file failed on %s", fpath);
+			return -1;
+		}
+	}
+
+	if ((cap_file_text = cap_to_text(cap_file, &length)) == NULL) {
+		bb_perror_msg("cap_to_name failed on %s", fpath);
+		return -1;
+	}
+
+	bb_xasprintf(&cap_new_text, "%s %s", cap_file_text, xattr);
+
+	if ((cap_new = cap_from_text(cap_new_text)) == NULL) {
+		bb_perror_msg("cap_from_text failed on %s", cap_new_text);
+		return -1;
+	}
+
+	if (cap_set_file(fpath, cap_new) == -1) {
+		bb_perror_msg("cap_set_file failed for %s (xattr = %s)", fpath, xattr);
+		return -1;
+	}
+
+	cap_free(cap);
+	cap_free(cap_file);
+	cap_free(cap_file_text);
+	cap_free(cap_new);
+	cap_free(cap_new_text);
+
+	return 0;
+}
+
 const char * const bb_msg_memory_exhausted = "memory exhausted";
 
 void *xmalloc(size_t size)
@@ -413,6 +465,7 @@ int main(int argc, char **argv)
 	int opt;
 	FILE *table = stdin;
 	char *rootdir = NULL;
+	char *full_name = NULL;
 	char *line = NULL;
 	int linenum = 0;
 	int ret = EXIT_SUCCESS;
@@ -454,15 +507,22 @@ int main(int argc, char **argv)
 		unsigned int count = 0;
 		unsigned int increment = 0;
 		unsigned int start = 0;
+		char xattr[255];
 		char name[4096];
 		char user[41];
 		char group[41];
-		char *full_name;
 		uid_t uid;
 		gid_t gid;
 
 		linenum++;
 
+		if (1 == sscanf(line, "|xattr %254s", xattr))
+		{
+			if (bb_set_xattr(full_name, xattr) < 0)
+				ret = EXIT_FAILURE;
+			continue;
+		}
+
 		if ((2 > sscanf(line, "%4095s %c %o %40s %40s %u %u %u %u %u", name,
 						&type, &mode, user, group, &major,
 						&minor, &start, &increment, &count)) ||
@@ -487,6 +547,9 @@ int main(int argc, char **argv)
 		} else {
 			uid = getuid();
 		}
+
+		/* free previous full name */
+		free(full_name);
 		full_name = concat_path_file(rootdir, name);
 
 		if (type == 'd') {
@@ -585,7 +648,6 @@ int main(int argc, char **argv)
 		}
 loop:
 		free(line);
-		free(full_name);
 	}
 	fclose(table);
 
diff --git a/package/makedevs/makedevs.mk b/package/makedevs/makedevs.mk
index fa8e753..0a724ad 100644
--- a/package/makedevs/makedevs.mk
+++ b/package/makedevs/makedevs.mk
@@ -11,6 +11,8 @@ HOST_MAKEDEVS_SOURCE =
 MAKEDEVS_VERSION = buildroot-$(BR2_VERSION)
 MAKEDEVS_LICENSE = GPLv2
 
+HOST_MAKEDEVS_LDFLAGS = -lcap
+
 define MAKEDEVS_BUILD_CMDS
 	$(TARGET_CC) $(TARGET_CFLAGS) $(TARGET_LDFLAGS) \
 		package/makedevs/makedevs.c -o $(@D)/makedevs
@@ -22,7 +24,7 @@ endef
 
 define HOST_MAKEDEVS_BUILD_CMDS
 	$(HOSTCC) $(HOST_CFLAGS) $(HOST_LDFLAGS) \
-		package/makedevs/makedevs.c -o $(@D)/makedevs
+		package/makedevs/makedevs.c -o $(@D)/makedevs $(HOST_MAKEDEVS_LDFLAGS)
 endef
 
 define HOST_MAKEDEVS_INSTALL_CMDS
-- 
1.7.9.5


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