[PATCH 3/6] libsepol/cil: constify some strings

[Nicolas Iooss <nicolas.iooss@m4x.org>]

Function cil_add_file() copies its input into a newly-allocated buffer,
and does not modify "name". State these properties in the types of
parameters by adding "const" qualifiers.

This enables using LibFuzzer directly on cil_add_file(), without a
warning about discarding "const" qualifier:

    fuzz-secilc.c: In function ‘LLVMFuzzerTestOneInput’:
    fuzz-secilc.c:57:31: warning: passing argument 3 of ‘cil_add_file’
    discards ‘const’ qualifier from pointer target type
    [-Wdiscarded-qualifiers]
       57 |  if (cil_add_file(db, "fuzz", data, size) != SEPOL_OK)
          |                               ^~~~
    In file included from fuzz-secilc.c:26:
    /usr/include/sepol/cil/cil.h:45:57: note: expected ‘char *’ but
    argument is of type ‘const uint8_t *’ {aka ‘const unsigned char *’}
       45 | extern int cil_add_file(cil_db_t *db, char *name, char *data, size_t size);
          |                                                   ~~~~~~^~~~

Signed-off-by: Nicolas Iooss <nicolas.iooss@m4x.org>
---
 libsepol/cil/include/cil/cil.h | 4 ++--
 libsepol/cil/src/cil.c         | 2 +-
 libsepol/cil/src/cil_log.c     | 6 +++---
 libsepol/cil/src/cil_parser.c  | 2 +-
 libsepol/cil/src/cil_parser.h  | 2 +-
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/libsepol/cil/include/cil/cil.h b/libsepol/cil/include/cil/cil.h
index f8cfc3be5015..e6f4503eb33a 100644
--- a/libsepol/cil/include/cil/cil.h
+++ b/libsepol/cil/include/cil/cil.h
@@ -42,7 +42,7 @@ typedef struct cil_db cil_db_t;
 extern void cil_db_init(cil_db_t **db);
 extern void cil_db_destroy(cil_db_t **db);
 
-extern int cil_add_file(cil_db_t *db, char *name, char *data, size_t size);
+extern int cil_add_file(cil_db_t *db, const char *name, const char *data, size_t size);
 
 extern int cil_compile(cil_db_t *db);
 extern int cil_build_policydb(cil_db_t *db, sepol_policydb_t **sepol_db);
@@ -67,7 +67,7 @@ enum cil_log_level {
 	CIL_INFO
 };
 extern void cil_set_log_level(enum cil_log_level lvl);
-extern void cil_set_log_handler(void (*handler)(int lvl, char *msg));
+extern void cil_set_log_handler(void (*handler)(int lvl, const char *msg));
 
 #ifdef __GNUC__
 __attribute__ ((format(printf, 2, 3)))
diff --git a/libsepol/cil/src/cil.c b/libsepol/cil/src/cil.c
index bb7f06d5c4b3..99c8e288912c 100644
--- a/libsepol/cil/src/cil.c
+++ b/libsepol/cil/src/cil.c
@@ -500,7 +500,7 @@ void cil_root_destroy(struct cil_root *root)
 	free(root);
 }
 
-int cil_add_file(cil_db_t *db, char *name, char *data, size_t size)
+int cil_add_file(cil_db_t *db, const char *name, const char *data, size_t size)
 {
 	char *buffer = NULL;
 	int rc;
diff --git a/libsepol/cil/src/cil_log.c b/libsepol/cil/src/cil_log.c
index b222b155120a..a8e4d2e94a78 100644
--- a/libsepol/cil/src/cil_log.c
+++ b/libsepol/cil/src/cil_log.c
@@ -37,14 +37,14 @@
 
 static enum cil_log_level cil_log_level = CIL_ERR;
 
-void cil_default_log_handler(__attribute__((unused)) int lvl, char *msg)
+void cil_default_log_handler(__attribute__((unused)) int lvl, const char *msg)
 {
 	fprintf(stderr, "%s", msg);
 }
 
-void (*cil_log_handler)(int lvl, char *msg) = &cil_default_log_handler;
+void (*cil_log_handler)(int lvl, const char *msg) = &cil_default_log_handler;
 
-void cil_set_log_handler(void (*handler)(int lvl, char *msg))
+void cil_set_log_handler(void (*handler)(int lvl, const char *msg))
 {
 	cil_log_handler = handler;
 }
diff --git a/libsepol/cil/src/cil_parser.c b/libsepol/cil/src/cil_parser.c
index a8af1dce2c4b..b62043b95806 100644
--- a/libsepol/cil/src/cil_parser.c
+++ b/libsepol/cil/src/cil_parser.c
@@ -196,7 +196,7 @@ static void add_cil_path(struct cil_tree_node **current, char *path)
 	insert_node(node, *current);
 }
 
-int cil_parser(char *_path, char *buffer, uint32_t size, struct cil_tree **parse_tree)
+int cil_parser(const char *_path, char *buffer, uint32_t size, struct cil_tree **parse_tree)
 {
 
 	int paren_count = 0;
diff --git a/libsepol/cil/src/cil_parser.h b/libsepol/cil/src/cil_parser.h
index 02ecb784e95c..1cec63944fdf 100644
--- a/libsepol/cil/src/cil_parser.h
+++ b/libsepol/cil/src/cil_parser.h
@@ -32,6 +32,6 @@
 
 #include "cil_tree.h"
 
-int cil_parser(char *path, char *buffer, uint32_t size, struct cil_tree **parse_tree);
+int cil_parser(const char *path, char *buffer, uint32_t size, struct cil_tree **parse_tree);
 
 #endif /* CIL_PARSER_H_ */
-- 
2.29.2