File 0032-library-skip-replacement-of-trailing-0-in-... of Package procps.12938

Overview Repositories Revisions Requests Users Attributes Meta

File 0032-library-skip-replacement-of-trailing-0-in-read_unvec.patch of Package procps.12938

From ae9676a337e38526b994d189444f3fd02ab800ad Mon Sep 17 00:00:00 2001
From: Jaromir Capik <jcapik@redhat.com>
Date: Fri, 24 Jan 2014 18:07:34 +0100
Subject: [PATCH] library: skip replacement of trailing '\0' in
 read_unvectored()

Under some circumstances the ksh shell doesn't fork new processes
when executing scripts and the script is interpreted by the
parent process. That makes the execution faster, but it means
ksh needs to reuse the /proc/PID/cmdline for the new script name
and arguments while the file length needs to stay untouched.
The fork is skipped only when the new cmdline is shorter than
the parent's cmdline and the rest of the file is filled
with '\0'. This is perfectly ok until we try to read the cmdline
of such process. As the read_unvectored() function replaces
all zeros with chosen separator, these trailing zeros are replaced
with spaces in case of the ps tool. Consequently it appends
multiple spaces at the end of the arguments string even when these
zeros do not represent any separators and therefore shouldn't
be replaced.
With this commit the read_unvectored() function skips the
replacement of trailing zeros and separates valid content only.

Reference: https://bugzilla.redhat.com/show_bug.cgi?id=1057600
---
 proc/readproc.c |    1 +
 1 file changed, 1 insertion(+)

diff --git proc/readproc.c proc/readproc.c
index 286e173..46dfa10 100644
--- proc/readproc.c
+++ proc/readproc.c
@@ -686,6 +686,7 @@ static int read_unvectored(char *restrict const dst, unsigned sz, const char* wh
     close(fd);
     if(n){
         int i=n;
+        while(i && dst[i-1]=='\0') --i; // skip trailing zeroes
         while(i--)
             if(dst[i]=='\n' || dst[i]=='\0') dst[i]=sep;
         if(dst[n-1]==' ') dst[n-1]='\0';
-- 
1.7.9.2

Places

File 0032-library-skip-replacement-of-trailing-0-in-read_unvec.patch of Package procps.12938

Places