[Qemu-devel] [PATCH v3 1/2] linux-user: improve fake /proc/self/stat making `ps` not segfault.

[Qemu-devel] [PATCH v3 1/2] linux-user: improve fake /proc/self/stat making `ps` not segfault.

[Fabio Erculiani]

With the current fake /proc/self/stat implementation `ps` is
segfaulting because it expects to read PID and argv[0] as first and
second field respectively, with the latter being enclosed between
backets.

Reproducing is as easy as running: `ps` inside qemu-user chroot
with /proc mounted.

Signed-off-by: Fabio Erculiani <lxnay@sabayon.org>
---
 linux-user/syscall.c |   19 +++++++++++++++----
 1 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 9ba51bf..3e8e3dd 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -4678,11 +4678,22 @@ static int open_self_stat(void *cpu_env, int fd)
       int len;
       uint64_t val = 0;
 
-      if (i == 27) {
-          /* stack bottom */
-          val = start_stack;
+      if (i == 0) {
+        /* pid */
+        val = getpid();
+        snprintf(buf, sizeof(buf), "%"PRId64 " ", val);
+      } else if (i == 1) {
+        /* app name */
+        snprintf(buf, sizeof(buf), "(%s) ", ts->bprm->argv[0]);
+      } else if (i == 27) {
+        /* stack bottom */
+        val = start_stack;
+        snprintf(buf, sizeof(buf), "%"PRId64 " ", val);
+      } else {
+        /* for the rest, there is MasterCard */
+        snprintf(buf, sizeof(buf), "0%c", i == 43 ? '\n' : ' ');
       }
-      snprintf(buf, sizeof(buf), "%"PRId64 "%c", val, i == 43 ? '\n' : ' ');
+
       len = strlen(buf);
       if (write(fd, buf, len) != len) {
           return -1;
-- 
1.7.7

[Qemu-devel] [PATCH v3 2/2] linux-user: target_argv is placed on ts->bprm->argv and can't be freed()

[Fabio Erculiani]

TaskState contains linux_bprm struct which encapsulates argv among
other things.
argv might be used around the code and is expected to contain valid
data. Before this patch, ts->bprm->argv was NULL due to it being
freed right after loader_exec().

Signed-off-by: Fabio Erculiani <lxnay@sabayon.org>
---
 linux-user/main.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index 788ff98..513d583 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3492,11 +3492,6 @@ int main(int argc, char **argv, char **envp)
         _exit(1);
     }
 
-    for (i = 0; i < target_argc; i++) {
-        free(target_argv[i]);
-    }
-    free(target_argv);
-
     for (wrk = target_environ; *wrk; wrk++) {
         free(*wrk);
     }
-- 
1.7.7

Re: [Qemu-devel] [PATCH v3 1/2] linux-user: improve fake /proc/self/stat making `ps` not segfault.

[Alexander Graf]

On 03.01.2012, at 20:38, Fabio Erculiani wrote:

> With the current fake /proc/self/stat implementation `ps` is
> segfaulting because it expects to read PID and argv[0] as first and
> second field respectively, with the latter being enclosed between
> backets.
> 
> Reproducing is as easy as running: `ps` inside qemu-user chroot
> with /proc mounted.
> 
> Signed-off-by: Fabio Erculiani <lxnay@sabayon.org>

Acked-by: Alexander Graf <agraf@suse.de>


Alex

Re: [Qemu-devel] [PATCH v3 2/2] linux-user: target_argv is placed on ts->bprm->argv and can't be freed()

[Alexander Graf]

On 03.01.2012, at 20:38, Fabio Erculiani wrote:

> TaskState contains linux_bprm struct which encapsulates argv among
> other things.
> argv might be used around the code and is expected to contain valid
> data. Before this patch, ts->bprm->argv was NULL due to it being
> freed right after loader_exec().
> 
> Signed-off-by: Fabio Erculiani <lxnay@sabayon.org>

Acked-by: Alexander Graf <agraf@suse.de>


Alex