[Qemu-devel] [PATCH] Fix commandline handling for ARM semihosted executables, on Linux and BSD hosts

[Schildbach, Wolfgang]

This reuses the commandline copy setup in user space by
loader_build_argptr()
and fixes https://bugs.launchpad.net/qemu/+bug/673613 .

Signed-off-by: Wolfgang Schildbach <address@hidden>
---
 arm-semi.c             |   79
+++++++++++++++++++++++++++++------------------
 bsd-user/bsdload.c     |    2 -
 bsd-user/qemu.h        |    1 -
 linux-user/linuxload.c |    2 -
 linux-user/qemu.h      |    1 -
 5 files changed, 49 insertions(+), 36 deletions(-)

diff --git a/arm-semi.c b/arm-semi.c
index 0687b03..533bb34 100644
--- a/arm-semi.c
+++ b/arm-semi.c
@@ -373,45 +373,64 @@ uint32_t do_arm_semihosting(CPUState *env)
 #ifdef CONFIG_USER_ONLY
         /* Build a commandline from the original argv.  */
         {
-            char **arg = ts->info->host_argv;
-            int len = ARG(1);
-            /* lock the buffer on the ARM side */
-            char *cmdline_buffer = (char*)lock_user(VERIFY_WRITE,
ARG(0), len, 0);
+            char *arm_cmdline_buffer;
+            const char *host_cmdline_buffer;
 
-            if (!cmdline_buffer)
-                /* FIXME - should this error code be -TARGET_EFAULT ?
*/
-                return (uint32_t)-1;
+            unsigned int i;
+            unsigned int arm_cmdline_len = ARG(1);
+            unsigned int host_cmdline_len =
+                ts->info->arg_end-ts->info->arg_start;
+
+            if (!arm_cmdline_len || host_cmdline_len > arm_cmdline_len)
{
+                return -1; /* not enough space to store command line */
+            }
 
-            s = cmdline_buffer;
-            while (*arg && len > 2) {
-                int n = strlen(*arg);
+            if (!host_cmdline_len) {
+                /* We special-case the "empty command line" case
(arcg==0).
+                   Just provide the terminating 0. */
+                arm_cmdline_buffer = lock_user(VERIFY_WRITE, ARG(0), 1,
0);
+                arm_cmdline_buffer[0] = 0;
+                unlock_user(arm_cmdline_buffer, ARG(0), 1);
 
-                if (s != cmdline_buffer) {
-                    *(s++) = ' ';
-                    len--;
-                }
-                if (n >= len)
-                    n = len - 1;
-                memcpy(s, *arg, n);
-                s += n;
-                len -= n;
-                arg++;
+                /* Adjust the commandline length argument. */
+                SET_ARG(1, 0);
+                return 0;
             }
-            /* Null terminate the string.  */
-            *s = 0;
-            len = s - cmdline_buffer;
 
-            /* Unlock the buffer on the ARM side.  */
-            unlock_user(cmdline_buffer, ARG(0), len);
+            /* lock the buffers on the ARM side */
+            arm_cmdline_buffer =
+                lock_user(VERIFY_WRITE, ARG(0), host_cmdline_len, 0);
+            host_cmdline_buffer =
+                lock_user(VERIFY_READ, ts->info->arg_start,
+                                       host_cmdline_len, 1);
 
-            /* Adjust the commandline length argument.  */
-            SET_ARG(1, len);
+            if (arm_cmdline_buffer && host_cmdline_buffer)
+            {
+                /* the last argument is zero-terminated;
+                   no need for additional termination */
+                memcpy(arm_cmdline_buffer, host_cmdline_buffer,
+                       host_cmdline_len);
 
-            /* Return success if commandline fit into buffer.  */
-            return *arg ? -1 : 0;
+                /* separate arguments by white spaces */
+                for (i = 0; i < host_cmdline_len-1; i++) {
+                    if (arm_cmdline_buffer[i] == 0) {
+                        arm_cmdline_buffer[i] = ' ';
+                    }
+                }
+
+                /* Adjust the commandline length argument. */
+                SET_ARG(1, host_cmdline_len-1);
+            }
+
+            /* Unlock the buffers on the ARM side.  */
+            unlock_user(arm_cmdline_buffer, ARG(0), host_cmdline_len);
+            unlock_user((void*)host_cmdline_buffer,
ts->info->arg_start, 0);
+
+            /* Return success if we could return a commandline.  */
+            return (arm_cmdline_buffer && host_cmdline_buffer) ? 0 :
-1;
         }
 #else
-      return -1;
+        return -1;
 #endif
     case SYS_HEAPINFO:
         {
diff --git a/bsd-user/bsdload.c b/bsd-user/bsdload.c
index 14a93bf..6d9bb6f 100644
--- a/bsd-user/bsdload.c
+++ b/bsd-user/bsdload.c
@@ -176,8 +176,6 @@ int loader_exec(const char * filename, char ** argv,
char ** envp,
 
     retval = prepare_binprm(&bprm);
 
-    infop->host_argv = argv;
-
     if(retval>=0) {
         if (bprm.buf[0] == 0x7f
                 && bprm.buf[1] == 'E'
diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index 9763616..e343894 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -50,7 +50,6 @@ struct image_info {
     abi_ulong entry;
     abi_ulong code_offset;
     abi_ulong data_offset;
-    char      **host_argv;
     int       personality;
 };
 
diff --git a/linux-user/linuxload.c b/linux-user/linuxload.c
index 9ee27c3..ac8c486 100644
--- a/linux-user/linuxload.c
+++ b/linux-user/linuxload.c
@@ -174,8 +174,6 @@ int loader_exec(const char * filename, char ** argv,
char ** envp,
 
     retval = prepare_binprm(bprm);
 
-    infop->host_argv = argv;
-
     if(retval>=0) {
         if (bprm->buf[0] == 0x7f
                 && bprm->buf[1] == 'E'
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 708021e..8f0a81f 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -50,7 +50,6 @@ struct image_info {
         abi_ulong       saved_auxv;
         abi_ulong       arg_start;
         abi_ulong       arg_end;
-        char            **host_argv;
        int             personality;
 };
 
-- 
1.7.2.3