diff mbox series

[v4,3/6] linux-user: Add strace support for printing argument of syscalls used for extended attributes

Message ID 20200616103927.20222-4-filip.bozuta@syrmia.com
State New
Headers show
Series Add strace support for printing arguments of selected syscalls | expand

Commit Message

Filip Bozuta June 16, 2020, 10:39 a.m. UTC 
From: Filip Bozuta <Filip.Bozuta@syrmia.com>

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>
---
 linux-user/strace.c    | 122 +++++++++++++++++++++++++++++++++++++++++
 linux-user/strace.list |  21 ++++---
 2 files changed, 134 insertions(+), 9 deletions(-)

Comments

Laurent Vivier June 18, 2020, 2:41 p.m. UTC | #1 
Le 16/06/2020 à 12:39, Filip Bozuta a écrit :
> From: Filip Bozuta <Filip.Bozuta@syrmia.com>
> 
> 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>
> ---
>  linux-user/strace.c    | 122 +++++++++++++++++++++++++++++++++++++++++
>  linux-user/strace.list |  21 ++++---
>  2 files changed, 134 insertions(+), 9 deletions(-)
> 
> diff --git a/linux-user/strace.c b/linux-user/strace.c
> index 6d7accaa4c..f76bbbc1ff 100644
> --- a/linux-user/strace.c
> +++ b/linux-user/strace.c
> @@ -833,6 +833,41 @@ 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 bts_printed = 0;
> +            abi_long attr = arg1;
> +            while (bts_printed < ret) {

I don't think you need a new variable, you can do

               while (ret) {

> +                if (attr != arg1) {
> +                    qemu_log(",");
> +                }
> +                print_string(attr, 1);
> +                bts_printed += target_strlen(attr) + 1;

and
                   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),

Thanks,
Laurent
diff mbox series

Patch

diff --git a/linux-user/strace.c b/linux-user/strace.c
index 6d7accaa4c..f76bbbc1ff 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -833,6 +833,41 @@  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 bts_printed = 0;
+            abi_long attr = arg1;
+            while (bts_printed < ret) {
+                if (attr != arg1) {
+                    qemu_log(",");
+                }
+                print_string(attr, 1);
+                bts_printed += 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),
@@ -1640,6 +1675,93 @@  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,
diff --git a/linux-user/strace.list b/linux-user/strace.list
index fb9799e7e6..af12b23276 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 },