https://bugs.kde.org/show_bug.cgi?id=422261
Bug ID: 422261
Summary: platform selection fails for unqualified pathname
Product: valgrind
Version: unspecified
Platform: Compiled Sources
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: general
Assignee: jsew...@acm.org
Reporter: michael.woj...@microfocus.com
Target Milestone: ---
SUMMARY
coregrind/launcher-linux.c calls select_platform() to determine the client
platform. select_platform uses the wrong variable in attempting to open the
client binary, resulting in no platform detection and fallback to the default
platform (e.g. x86-64) if the client is specified as an unqualified filename
(i.e. neither an absolute nor relative pathname).
The problem and fix are trivial:
if (strchr(clientname, '/') == NULL)
client = find_client(clientname);
else
client = strdup(clientname);
...
if ((fd = open(clientname, O_RDONLY)) < 0) {
return_null:
free (client);
return NULL;
}
The first if-statement determines whether the client (clientname) is a bare
filename, and if so it invokes find_client to resolve it using $PATH. After
this, "client" is either the original name ("clientname") or the resolved
pathname.
The second if-statement attempts to open the client file. It should use the
result of the first if-statement, but instead uses the original parameter to
the function. So if the parameter was a bare filename, it attempts to open it
from the current directory instead of using the resolved pathame.
The second if-statement should be:
if ((fd = open(client, O_RDONLY)) < 0) {
that is, using "client" rather than "clientname".
I've tested this fix in my build of 3.16.0, and confirmed that the bug still
exists in the current sources in git.
STEPS TO REPRODUCE
1. Use a stock valgrind build on 64-bit x86-64 Linux. This will support both
x86-64 and x86-32 platforms, defaulting to '64.
2. Build a trivial 32-bit C program in a subdirectory. For example:
mkdir tmp
echo 'int main(void) {return 0;}' > tmp/nop.c
cc -o tmp/nop -m32 tmp/nop.c
3. Attempt to memgrind it (this must NOT be done in the directory containing
the client, or you'll get a false negative):
PATH=$PWD/tmp:$PATH valgrind -d nop
You should get the wrong-platform message, and the debug output should
include "no platform detected, defaulting platform to 'amd64-linux'".
OBSERVED RESULT
Valgrind fails because it's failing to detect the client platform.
EXPECTED RESULT
Valgrind should correctly open the client and detect the platform. (Run with
higher debug levels, e.g. "-d -d", to see what select_platform is doing.)
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