Description: ps displays cgroup 
Author: Swann Perarnau <swann.perarnau@imag.fr>
Bug-Debian: http://bugs.debian.org/469669
Reviewed-by: Craig Small <csmall@debian.org>
--- a/proc/readproc.c
+++ b/proc/readproc.c
@@ -598,6 +598,17 @@
 	p->environ = file2strvec(path, "environ");
     else
         p->environ = NULL;
+
+    if(linux_version_code>=LINUX_VERSION(2,6,24) && (flags & PROC_FILLCGROUP)) {
+	p->cgroup = file2strvec(path, "cgroup"); 	/* read /proc/#/cgroup */
+    	if(p->cgroup && *p->cgroup) {
+		int i = strlen(*p->cgroup);
+		if( (*p->cgroup)[i-1]=='\n' )
+			(*p->cgroup)[i-1] = ' '; //little hack to remove trailing \n
+	}
+    }
+    else
+	p->cgroup = NULL;
     
     return p;
 next_proc:
@@ -686,7 +697,7 @@
     t->cmdline = p->cmdline;  // better not free these until done with all threads!
     t->environ = p->environ;
 #endif
-
+    t->cgroup = p->cgroup;
     t->ppid = p->ppid;  // ought to put the per-task ppid somewhere
 
     return t;
@@ -896,6 +907,8 @@
 	free((void*)*p->cmdline);
     if (p->environ)
 	free((void*)*p->environ);
+    if (p->cgroup)
+	free((void*)*p->cgroup);
     free(p);
 }
 
--- a/proc/readproc.h
+++ b/proc/readproc.h
@@ -139,6 +139,7 @@
 	tpgid,		// stat            terminal process group id
 	exit_signal,	// stat            might not be SIGCHLD
 	processor;      // stat            current (or most recent?) CPU
+    	char **cgroup;  // cgroup	   current cgroup, looks like a classic filepath
 } proc_t;
 
 // PROCTAB: data structure holding the persistent information readproc needs
@@ -236,8 +237,9 @@
 #define PROC_FILLSTAT        0x0040 // read stat -- currently unconditional
 #define PROC_FILLWCHAN       0x0080 // look up WCHAN name
 #define PROC_FILLARG         0x0100 // alloc and fill in `cmdline'
+#define PROC_FILLCGROUP      0x0200 // alloc and fill in `cgroup`
 
-#define PROC_LOOSE_TASKS     0x0200 // threat threads as if they were processes
+#define PROC_LOOSE_TASKS     0x2000 // threat threads as if they were processes
 
 // Obsolete, consider only processes with one of the passed:
 #define PROC_PID             0x1000  // process id numbers ( 0   terminated)
--- a/ps/display.c
+++ b/ps/display.c
@@ -223,8 +223,7 @@
 
 #define needs_for_format (proc_format_needs|task_format_needs)
 
-#define PROC_ONLY_FLAGS (PROC_FILLENV|PROC_FILLARG|PROC_FILLCOM|PROC_FILLMEM)
-
+#define PROC_ONLY_FLAGS (PROC_FILLENV|PROC_FILLARG|PROC_FILLCOM|PROC_FILLMEM|PROC_FILLCGROUP)
 /***** munge lists and determine openproc() flags */
 static void lists_and_needs(void){
   check_headers();
@@ -342,6 +341,7 @@
       }
       if(buf.cmdline) free((void*)*buf.cmdline); // ought to reuse
       if(buf.environ) free((void*)*buf.environ); // ought to reuse
+      if(buf.cgroup)  free((void*)*buf.cgroup);
     }
     break;
   case TF_show_proc|TF_loose_tasks:    // H option
@@ -354,6 +354,7 @@
       }
       if(buf.cmdline) free((void*)*buf.cmdline); // ought to reuse
       if(buf.environ) free((void*)*buf.environ); // ought to reuse
+      if(buf.cgroup)  free((void*)*buf.cgroup);
     }
     break;
   case TF_show_proc|TF_show_task:      // m and -m options
@@ -366,7 +367,8 @@
       }
       if(buf.cmdline) free((void*)*buf.cmdline); // ought to reuse
       if(buf.environ) free((void*)*buf.environ); // ought to reuse
-    }
+      if(buf.cgroup)  free((void*)*buf.cgroup);
+     }
     break;
   case TF_show_task:                   // -L and -T options
     while(readproc(ptp,&buf)){
@@ -377,7 +379,8 @@
       }
       if(buf.cmdline) free((void*)*buf.cmdline); // ought to reuse
       if(buf.environ) free((void*)*buf.environ); // ought to reuse
-    }
+      if(buf.cgroup)  free((void*)*buf.cgroup);
+   }
     break;
   }
   closeproc(ptp);
--- a/ps/output.c
+++ b/ps/output.c
@@ -376,6 +376,26 @@
   return max_rightward-rightward;
 }
 
+static int pr_cgroup(char *restrict const outbuf,const proc_t *restrict const pp) {
+ if(pp->cgroup && *pp->cgroup) {
+   char *endp = outbuf;
+   int rightward=max_rightward;
+   if(forest_prefix){
+       int fh = forest_helper(outbuf);
+       endp += fh;
+       rightward -= fh;
+   }
+   if(rightward>1){
+     *endp++ = ' ';
+     rightward--;
+     endp += escape_str(endp, *pp->cgroup, OUTBUF_SIZE, &rightward);
+   }
+   return max_rightward-rightward;
+ }
+ else
+   return pr_nop(outbuf,pp);
+}
+
 /* "ucomm" is the same thing: short unless -f */
 static int pr_comm(char *restrict const outbuf, const proc_t *restrict const pp){
   char *endp = outbuf;
@@ -1274,7 +1294,7 @@
 #define GRP PROC_FILLGRP     /* gid_t -> group names */
 #define WCH PROC_FILLWCHAN   /* do WCHAN lookup */
 
-
+#define CGRP PROC_FILLCGROUP /* read cgroup */
 /* TODO
  *      pull out annoying BSD aliases into another table (to macro table?)
  *      add sorting functions here (to unify names)
@@ -1310,6 +1330,7 @@
 {"bsdtime",   "TIME",    pr_bsdtime,  sr_nop,     6,   0,    LNX, ET|RIGHT},
 {"c",         "C",       pr_c,        sr_pcpu,    2,   0,    SUN, ET|RIGHT},
 {"caught",    "CAUGHT",  pr_sigcatch, sr_nop,     9,   0,    BSD, TO|SIGNAL}, /*sigcatch*/
+{"cgroup",    "CGROUP",  pr_cgroup,     sr_nop,     27, CGRP,  LNX, PO|UNLIMITED},
 {"class",     "CLS",     pr_class,    sr_sched,   3,   0,    XXX, TO|LEFT},
 {"cls",       "CLS",     pr_class,    sr_sched,   3,   0,    HPU, TO|RIGHT}, /*says HPUX or RT*/
 {"cmaj_flt",  "-",       pr_nop,      sr_cmaj_flt, 1,  0,    LNX, AN|RIGHT},