sysctl: use - for stdin

3 files changed, 9 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 665e277..b3cd29a 100644
--- a/NEWS
+++ b/NEWS
@@ -11,7 +11,8 @@ pwdx: buffer overflow fixed -- thanks Ulf Harnhammar
 procps.spec needed a slash -- thanks Jesse Brandeburg
 w: stale utmp entries snuck in via uninitialized var -- thanks Robert A Basch
 pgrep/pkill: fix some realloc-related crashes       #353894
-pgrep/pkill: g is criteria (secret PLD Linux patch)
+pgrep/pkill: g is criteria (PLD Linux, patch found in locked filing cabinet)
+sysctl: use - for stdin (PLD Linux: beware of the leopard)
 
 procps-3.2.5 --> procps-3.2.6
 
diff --git a/sysctl.8 b/sysctl.8
index e8e44cf..e26c4fb 100644
--- a/sysctl.8
+++ b/sysctl.8
@@ -57,6 +57,7 @@ Use this option when you want to change a sysctl setting.
 .TP
 .B "-p"
 Load in sysctl settings from the file specified or /etc/sysctl.conf if none given.
+Specifying \- as filename means reading data from standard input.
 .TP
 .B "-a"
 Display all values currently available.
diff --git a/sysctl.c b/sysctl.c
index e25aeb9..0c0e73a 100644
--- a/sysctl.c
+++ b/sysctl.c
@@ -365,7 +365,12 @@ static int Preload(const char *restrict const filename) {
    int rc = 0;
    char *name, *value;
 
-   if (!filename || ((fp = fopen(filename, "r")) == NULL)) {
+   fp = (filename[0]=='-' && !filename[1])
+      ? stdin
+      : fopen(filename, "r")
+   ;
+
+   if (!fp) {
       fprintf(stderr, ERR_PRELOAD_FILE, filename);
       return -1;
    }