From: Davin McCall <davmac@davmac.org>
Date: Sat, 18 Jun 2016 17:05:01 +0000 (+0100)
Subject: Fix calculation of buffer size for LISTEN_FDS environment variable.
X-Git-Tag: v0.03~10
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=3fe7413b4dc54fc4190e41b210823707d9f24414;p=oweals%2Fdinit.git

Fix calculation of buffer size for LISTEN_FDS environment variable.
(Fortunately, it still gave the correct result in all expected cases).
---

diff --git a/src/service.cc b/src/service.cc
index 770f875..b81c323 100644
--- a/src/service.cc
+++ b/src/service.cc
@@ -682,8 +682,10 @@ bool ServiceRecord::start_ps_process(const std::vector<const char *> &cmd, bool
         sigaddset(&sigwait_set, SIGTERM);
         sigprocmask(SIG_UNBLOCK, &sigwait_set, NULL);
 
-        constexpr int bufsz = ((CHAR_BIT * sizeof(pid_t) - 1) / 3 + 2) + 11;
-        // "LISTEN_PID=" - 11 characters
+        constexpr int bufsz = ((CHAR_BIT * sizeof(pid_t)) / 3 + 2) + 11;
+        // "LISTEN_PID=" - 11 characters; the expression above gives a conservative estimate
+        // on the maxiumum number of bytes required for LISTEN=xxx, including nul terminator,
+        // where xxx is a pid_t in decimal (i.e. one decimal digit is worth just over 3 bits).
         char nbuf[bufsz];
 
         if (socket_fd != -1) {