From a146bfc359a4d4d96c438f3a0fa988c6a171d40d Mon Sep 17 00:00:00 2001
From: Craig Small <csmall@dropbear.xyz>
Date: Wed, 13 Mar 2024 22:01:07 +1100
Subject: [PATCH] killall,pstree use clock_gettime not uptime

/proc/uptime can become a container uptime in LXC containers
but the process start time is still relative to the boot time.

This means things like "newer than" or "older than" will be incorrect
in some containers, using clock_gettime() fixes this as its always the
hosts boot time.

References:
 https://bugs.debian.org/1066090
 https://gitlab.com/procps-ng/procps/-/commit/b5e19c1730bcc68d553f44b5585704e3c92267bf#83c45d853acc8384452b404946e4a0c484b16a4e

Signed-off-by: Craig Small <csmall@dropbear.xyz>
---
 ChangeLog     |  4 ++++
 src/killall.c | 39 +++++++++++++++++++--------------------
 src/pstree.c  | 39 +++++++++++++++++++--------------------
 3 files changed, 42 insertions(+), 40 deletions(-)

diff --git ChangeLog ChangeLog
index 15c5725..f4dcfd2 100644
--- ChangeLog
+++ ChangeLog
@@ -1,3 +1,7 @@
+Changes in NEXT
+===============
+	* killall,pstree: Use gettime instead of uptime Debian 1066090
+
 Changes in 23.7
 ===============
 	* build-sys: Make disable-statx work
diff --git src/killall.c src/killall.c
index 81dcc4b..229e61c 100644
--- src/killall.c
+++ src/killall.c
@@ -45,6 +45,7 @@
 #include <regex.h>
 #include <ctype.h>
 #include <assert.h>
+#include <time.h>
 
 #ifdef WITH_SELINUX
 #include <dlfcn.h>
@@ -132,30 +133,28 @@ ask (char *name, pid_t pid, const int signal)
     /* Never should get here */
 }
 
-static double
-uptime()
-{
-    char * savelocale;
-    char buf[2048];
-    FILE* file;
-    if (!(file=fopen( PROC_BASE "/uptime", "r"))) {
-        fprintf(stderr, "killall: error opening uptime file\n");    
-        exit(1);
-    }
-    savelocale = setlocale(LC_NUMERIC,"C");
-    if (fscanf(file, "%2047s", buf) == EOF) perror("uptime");
-    fclose(file);
-    setlocale(LC_NUMERIC,savelocale);
-    return atof(buf);
-}
 
-/* process age from jiffies to seconds via uptime */
+/* process age from jiffies to seconds via uptime
+ * Cannot use /proc/uptime as this can change in containers
+ * but process start time does not
+ */
 static double process_age(const unsigned long long jf)
 {
+    struct timespec ts;
+    double sc_clk_tck;
     double age;
-    double sc_clk_tck = sysconf(_SC_CLK_TCK);
-    assert(sc_clk_tck > 0);
-    age = uptime() - jf / sc_clk_tck;
+
+    if (clock_gettime(CLOCK_BOOTTIME, &ts) != 0) {
+        perror("clock_gettime():");
+        exit(EXIT_FAILURE);
+    }
+
+    if ( (sc_clk_tck = sysconf(_SC_CLK_TCK)) < 0) {
+        perror("sysconf(CLK_TCK):");
+        exit(EXIT_FAILURE);
+    }
+
+    age = (ts.tv_sec + ts.tv_nsec * 1.0e-9)  - jf / sc_clk_tck;
     if (age < 0L)
         return 0L;
     return age;
diff --git src/pstree.c src/pstree.c
index 39265d1..2545e24 100644
--- src/pstree.c
+++ src/pstree.c
@@ -44,6 +44,7 @@
 #include <sys/ioctl.h>
 #include <limits.h>
 #include <locale.h>
+#include <time.h>
 
 #include "i18n.h"
 #include "comm.h"
@@ -1028,30 +1029,28 @@ static void trim_tree_by_parent(PROC * current)
   trim_tree_by_parent(parent);
 }
 
-static double
-uptime()
-{
-    char * savelocale;
-    char buf[2048];
-    FILE* file;
-    if (!(file=fopen( PROC_BASE "/uptime", "r"))) {
-        fprintf(stderr, "pstree: error opening uptime file\n");
-        exit(1);
-    }
-    savelocale = setlocale(LC_NUMERIC,"C");
-    if (fscanf(file, "%2047s", buf) == EOF) perror("uptime");
-    fclose(file);
-    setlocale(LC_NUMERIC,savelocale);
-    return atof(buf);
-}
 
-/* process age from jiffies to seconds via uptime */
+/* process age from jiffies to seconds via uptime
+ * Cannot use /proc/uptime as this can change in containers
+ * but process start time does not
+ */
 static double process_age(const unsigned long long jf)
 {
+    struct timespec ts;
+    double sc_clk_tck;
     double age;
-    double sc_clk_tck = sysconf(_SC_CLK_TCK);
-    assert(sc_clk_tck > 0);
-    age = uptime() - jf / sc_clk_tck;
+
+    if (clock_gettime(CLOCK_BOOTTIME, &ts) != 0) {
+        perror("clock_gettime():");
+        exit(EXIT_FAILURE);
+    }
+
+    if ( (sc_clk_tck = sysconf(_SC_CLK_TCK)) < 0) {
+        perror("sysconf(CLK_TCK):");
+        exit(EXIT_FAILURE);
+    }
+
+    age = (ts.tv_sec + ts.tv_nsec * 1.0e-9)  - jf / sc_clk_tck;
     if (age < 0L)
         return 0L;
     return age;
-- 
2.35.3