Author: Jan Christoph Nordholz <hesso@pool.math.tu-berlin.de>
Description: Add lookup code for the creation time of each session.
 Requires digging in /proc/$pid and /proc/uptime, though, so it's
 definitely no candidate for the Beautiful C contest.
 .
 Affects screen's behaviour in the following situations:
 .
 * 'screen -ls' lists available sessions sorted chronologically
 * 'screen -RR' now picks the youngest session instead of an
   arbitrary one
 .
 Patch 2/3: new utility functions
Bug-Debian: https://bugs.debian.org/206572
Forwarded: not-yet

--- a/extern.h
+++ b/extern.h
@@ -395,6 +395,8 @@
 #else
 extern int   xsnprintf __P(());
 #endif
+extern time_t SessionCreationTime __P((const char *));
+extern time_t GetUptime __P((void));
 
 
 /* acl.c */
--- a/misc.c
+++ b/misc.c
@@ -30,6 +30,7 @@
 #include <sys/types.h>
 #include <sys/stat.h>	/* mkdir() declaration */
 #include <signal.h>
+#include <fcntl.h>
 
 #include "config.h"
 #include "screen.h"
@@ -796,3 +797,40 @@
 }
 
 #endif
+
+time_t SessionCreationTime(const char *fifo) {
+  char ppath[20];
+  int pfd;
+  char pdata[512];
+  char *jiffies;
+
+  int pid = atoi(fifo);
+  if (pid <= 0) return 0;
+  sprintf(ppath, "/proc/%u/stat", pid);
+  pfd = open(ppath, O_RDONLY);
+  if (pfd < 0) return 0;
+  while (1) {
+    int R=0, RR;
+    RR = read(pfd, pdata + R, 512-R);
+    if (RR < 0) {close(pfd); return 0;}
+    else if (RR == 0) break;
+  }
+  close(pfd);
+
+  for (pfd=21, jiffies=pdata; pfd; --pfd) {
+    jiffies = strchr(jiffies, ' ');
+    if (!jiffies) break; else ++jiffies;
+  }
+  if (!jiffies) return 0;
+
+  return atol(jiffies) / 100;
+}
+
+time_t GetUptime(void) {
+  char uptimestr[32];
+  int fd = open("/proc/uptime", O_RDONLY);
+  if (fd < 0) return 0;
+  (void)read(fd, uptimestr, 32);
+  close(fd);
+  return atol(uptimestr);
+}