linux-user: Add strace support for printing argument of syscalls used for extended attributes

This patch implements strace argument printing functionality for following syscalls:

    *getxattr, lgetxattr, fgetxattr - retrieve an extended attribute value

        ssize_t getxattr(const char *path, const char *name, void *value, size_t size)
        ssize_t lgetxattr(const char *path, const char *name, void *value, size_t size)
        ssize_t fgetxattr(int fd, const char *name, void *value, size_t size)
        man page: https://www.man7.org/linux/man-pages/man2/getxattr.2.html

    *listxattr, llistxattr, flistxattr - list extended attribute names

        ssize_t listxattr(const char *path, char *list, size_t size)
        ssize_t llistxattr(const char *path, char *list, size_t size)
        ssize_t flistxattr(int fd, char *list, size_t size)
        man page: https://www.man7.org/linux/man-pages/man2/listxattr.2.html

    *removexattr, lremovexattr, fremovexattr - remove an extended attribute

         int removexattr(const char *path, const char *name)
         int lremovexattr(const char *path, const char *name)
         int fremovexattr(int fd, const char *name)
         man page: https://www.man7.org/linux/man-pages/man2/removexattr.2.html

Implementation notes:

    All of the syscalls have strings as argument types and thus a separate
    printing function was stated in file "strace.list" for every one of them.
    All of these printing functions were defined in "strace.c" using existing
    printing functions for appropriate argument types:
       "print_string()" - for (const char*) type
       "print_pointer()" - for (char*) and (void *) type
       "print_raw_param()" for (int) and (size_t) type
    Syscalls "getxattr()" and "lgetxattr()" have the same number and type of
    arguments and thus their print functions ("print_getxattr", "print_lgetxattr")
    share a same definition. The same statement applies to syscalls "listxattr()"
    and "llistxattr()".
    Function "print_syscall_ret_listxattr()" was added to print the returned list
    of extended attributes for syscalls "print_listxattr(), print_llistxattr() and
    print_flistxattr()".

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200619123331.17387-4-filip.bozuta@syrmia.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 12 insertions, 9 deletions

diff --git a/linux-user/strace.list b/linux-user/strace.list
index 8a887fc16d..d04ad507b0 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -218,13 +218,14 @@
 { TARGET_NR_fdatasync, "fdatasync" , "%s(%d)", NULL, NULL },
 #endif
 #ifdef TARGET_NR_fgetxattr
-{ TARGET_NR_fgetxattr, "fgetxattr" , NULL, NULL, NULL },
+{ TARGET_NR_fgetxattr, "fgetxattr" , NULL, print_fgetxattr, NULL },
 #endif
 #ifdef TARGET_NR_finit_module
 { TARGET_NR_finit_module, "finit_module" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_flistxattr
-{ TARGET_NR_flistxattr, "flistxattr" , NULL, NULL, NULL },
+{ TARGET_NR_flistxattr, "flistxattr" , NULL, print_flistxattr,
+                        print_syscall_ret_flistxattr},
 #endif
 #ifdef TARGET_NR_flock
 { TARGET_NR_flock, "flock" , NULL, NULL, NULL },
@@ -233,7 +234,7 @@
 { TARGET_NR_fork, "fork" , "%s()", NULL, NULL },
 #endif
 #ifdef TARGET_NR_fremovexattr
-{ TARGET_NR_fremovexattr, "fremovexattr" , NULL, NULL, NULL },
+{ TARGET_NR_fremovexattr, "fremovexattr" , NULL, print_fremovexattr, NULL },
 #endif
 #ifdef TARGET_NR_fsetxattr
 { TARGET_NR_fsetxattr, "fsetxattr" , NULL, NULL, NULL },
@@ -396,7 +397,7 @@
 { TARGET_NR_getuid32, "getuid32" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_getxattr
-{ TARGET_NR_getxattr, "getxattr" , NULL, NULL, NULL },
+{ TARGET_NR_getxattr, "getxattr" , NULL, print_getxattr, NULL },
 #endif
 #ifdef TARGET_NR_getxgid
 { TARGET_NR_getxgid, "getxgid" , NULL, NULL, NULL },
@@ -480,7 +481,7 @@
 { TARGET_NR_lchown32, "lchown32" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_lgetxattr
-{ TARGET_NR_lgetxattr, "lgetxattr" , NULL, NULL, NULL },
+{ TARGET_NR_lgetxattr, "lgetxattr" , NULL, print_lgetxattr, NULL },
 #endif
 #ifdef TARGET_NR_link
 { TARGET_NR_link, "link" , NULL, print_link, NULL },
@@ -495,10 +496,12 @@
 { TARGET_NR_listen, "listen" , "%s(%d,%d)", NULL, NULL },
 #endif
 #ifdef TARGET_NR_listxattr
-{ TARGET_NR_listxattr, "listxattr" , NULL, NULL, NULL },
+{ TARGET_NR_listxattr, "listxattr" , NULL, print_listxattr,
+                       print_syscall_ret_listxattr},
 #endif
 #ifdef TARGET_NR_llistxattr
-{ TARGET_NR_llistxattr, "llistxattr" , NULL, NULL, NULL },
+{ TARGET_NR_llistxattr, "llistxattr" , NULL, print_llistxattr,
+                        print_syscall_ret_llistxattr},
 #endif
 #ifdef TARGET_NR__llseek
 { TARGET_NR__llseek, "_llseek" , NULL, print__llseek, NULL },
@@ -510,7 +513,7 @@
 { TARGET_NR_lookup_dcookie, "lookup_dcookie" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_lremovexattr
-{ TARGET_NR_lremovexattr, "lremovexattr" , NULL, NULL, NULL },
+{ TARGET_NR_lremovexattr, "lremovexattr" , NULL, print_lremovexattr, NULL },
 #endif
 #ifdef TARGET_NR_lseek
 { TARGET_NR_lseek, "lseek" , NULL, NULL, NULL },
@@ -1116,7 +1119,7 @@
 { TARGET_NR_remap_file_pages, "remap_file_pages" , NULL, NULL, NULL },
 #endif
 #ifdef TARGET_NR_removexattr
-{ TARGET_NR_removexattr, "removexattr" , NULL, NULL, NULL },
+{ TARGET_NR_removexattr, "removexattr" , NULL, print_removexattr, NULL },
 #endif
 #ifdef TARGET_NR_rename
 { TARGET_NR_rename, "rename" , NULL, print_rename, NULL },