linux-user: remove all traces of qemu from /proc/self/cmdline

Commit Message

Andreas Schwab Sept. 28, 2016, 2:36 p.m. UTC

Instead of post-processing the real contents use the remembered target
argv.  That removes all traces of qemu, including command line options,
and handles QEMU_ARGV0.

Signed-off-by: Andreas Schwab <[e-mail]>
---
 linux-user/syscall.c | 47 +++++++----------------------------------------
 1 file changed, 7 insertions(+), 40 deletions(-)

Comments

[e-mail] Sept. 28, 2016, 2:43 p.m. UTC | #1

Hi,

Your series seems to have some coding style problems. See output below for
more information:

Type: series
Message-id: [e-mail]
Subject: [Qemu-devel] [PATCH] linux-user: remove all traces of qemu from /proc/self/cmdline

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

# Useful git options
git config --local diff.renamelimit 0
git config --local diff.renames True

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git show --no-patch --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/[e-mail] -> patchew/[e-mail]
 * [new tag]         patchew/[e-mail] -> patchew/[e-mail]
Switched to a new branch 'test'
7506c8f linux-user: remove all traces of qemu from /proc/self/cmdline

=== OUTPUT BEGIN ===
Checking PATCH 1/1: linux-user: remove all traces of qemu from /proc/self/cmdline...
ERROR: space prohibited between function name and open parenthesis '('
#37: FILE: linux-user/syscall.c:7123:
+        size_t len = strlen (bprm->argv[i]) + 1;

total: 1 errors, 0 warnings, 59 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


---
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Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ca06943..e11eeab 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6988,52 +6988,19 @@  int host_to_target_waitstatus(int status)
 
 static int open_self_cmdline(void *cpu_env, int fd)
 {
-    int fd_orig = -1;
-    bool word_skipped = false;
-
-    fd_orig = open("/proc/self/cmdline", O_RDONLY);
-    if (fd_orig < 0) {
-        return fd_orig;
-    }
+    CPUState *cpu = ENV_GET_CPU((CPUArchState *)cpu_env);
+    struct linux_binprm *bprm = ((TaskState *)cpu->opaque)->bprm;
+    int i;
 
-    while (true) {
-        ssize_t nb_read;
-        char buf[128];
-        char *cp_buf = buf;
+    for (i = 0; i < bprm->argc; i++) {
+        size_t len = strlen (bprm->argv[i]) + 1;
 
-        nb_read = read(fd_orig, buf, sizeof(buf));
-        if (nb_read < 0) {
-            int e = errno;
-            fd_orig = close(fd_orig);
-            errno = e;
+        if (write(fd, bprm->argv[i], len) != len) {
             return -1;
-        } else if (nb_read == 0) {
-            break;
-        }
-
-        if (!word_skipped) {
-            /* Skip the first string, which is the path to qemu-*-static
-               instead of the actual command. */
-            cp_buf = memchr(buf, 0, nb_read);
-            if (cp_buf) {
-                /* Null byte found, skip one string */
-                cp_buf++;
-                nb_read -= cp_buf - buf;
-                word_skipped = true;
-            }
-        }
-
-        if (word_skipped) {
-            if (write(fd, cp_buf, nb_read) != nb_read) {
-                int e = errno;
-                close(fd_orig);
-                errno = e;
-                return -1;
-            }
         }
     }
 
-    return close(fd_orig);
+    return 0;
 }
 
 static int open_self_maps(void *cpu_env, int fd)