Commit 4fc3cdde authored by Filip Bozuta's avatar Filip Bozuta Committed by Laurent Vivier
Browse files

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: default avatarFilip Bozuta <Filip.Bozuta@syrmia.com>
Reviewed-by: default avatarLaurent Vivier <laurent@vivier.eu>
Message-Id: <20200619123331.17387-4-filip.bozuta@syrmia.com>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent c42569f6

linux-user/strace.c

+121 −0
Original line number Diff line number Diff line
@@ -826,6 +826,40 @@ print_syscall_ret_adjtimex(const struct syscallname *name, abi_long ret, 
}

#endif



#if defined(TARGET_NR_listxattr) || defined(TARGET_NR_llistxattr) \

 || defined(TARGGET_NR_flistxattr)

static void

print_syscall_ret_listxattr(const struct syscallname *name, abi_long ret,

                            abi_long arg0, abi_long arg1, abi_long arg2,

                            abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_err(ret);



    if (ret >= 0) {

        qemu_log(TARGET_ABI_FMT_ld, ret);

        qemu_log(" (list = ");

        if (arg1 != 0) {

            abi_long attr = arg1;

            while (ret) {

                if (attr != arg1) {

                    qemu_log(",");

                }

                print_string(attr, 1);

                ret -= target_strlen(attr) + 1;

                attr += target_strlen(attr) + 1;

            }

        } else {

            qemu_log("NULL");

        }

        qemu_log(")");

    }



    qemu_log("\n");

}

#define print_syscall_ret_llistxattr     print_syscall_ret_listxattr

#define print_syscall_ret_flistxattr     print_syscall_ret_listxattr

#endif



UNUSED static struct flags access_flags[] = {

    FLAG_GENERIC(F_OK),

    FLAG_GENERIC(R_OK),
@@ -1633,6 +1667,93 @@ print_fcntl(const struct syscallname *name, 
#define print_fcntl64   print_fcntl

#endif



#ifdef TARGET_NR_fgetxattr

static void

print_fgetxattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_raw_param("%d", arg0, 0);

    print_string(arg1, 0);

    print_pointer(arg2, 0);

    print_raw_param(TARGET_FMT_lu, arg3, 1);

    print_syscall_epilogue(name);

}

#endif



#ifdef TARGET_NR_flistxattr

static void

print_flistxattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_raw_param("%d", arg0, 0);

    print_pointer(arg1, 0);

    print_raw_param(TARGET_FMT_lu, arg2, 1);

    print_syscall_epilogue(name);

}

#endif



#if defined(TARGET_NR_getxattr) || defined(TARGET_NR_lgetxattr)

static void

print_getxattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_string(arg0, 0);

    print_string(arg1, 0);

    print_pointer(arg2, 0);

    print_raw_param(TARGET_FMT_lu, arg3, 1);

    print_syscall_epilogue(name);

}

#define print_lgetxattr     print_getxattr

#endif



#if defined(TARGET_NR_listxattr) || defined(TARGET_NR_llistxattr)

static void

print_listxattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_string(arg0, 0);

    print_pointer(arg1, 0);

    print_raw_param(TARGET_FMT_lu, arg2, 1);

    print_syscall_epilogue(name);

}

#define print_llistxattr     print_listxattr

#endif



#if defined(TARGET_NR_fremovexattr)

static void

print_fremovexattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_raw_param("%d", arg0, 0);

    print_string(arg1, 1);

    print_syscall_epilogue(name);

}

#endif



#if defined(TARGET_NR_removexattr) || defined(TARGET_NR_lremovexattr)

static void

print_removexattr(const struct syscallname *name,

    abi_long arg0, abi_long arg1, abi_long arg2,

    abi_long arg3, abi_long arg4, abi_long arg5)

{

    print_syscall_prologue(name);

    print_string(arg0, 0);

    print_string(arg1, 1);

    print_syscall_epilogue(name);

}

#define print_lremovexattr     print_removexattr

#endif



#ifdef TARGET_NR_futimesat

static void

print_futimesat(const struct syscallname *name,

linux-user/strace.list

+12 −9
Original line number Diff line number Diff line
@@ -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 },