Re: Patch to add -p (reading/parsing /etc/sysctl.conf) option to sysctl

[jhx]

Thanks to all the suggestions/hints from Crystal Kolipe and Janne 
Johansson I made a few changes to the patch.

This also fixes reading commented lines.
Thanks!

--- sysctl.c.dist       Tue Feb 21 12:17:57 2023
+++ sysctl.c    Tue Feb 21 13:41:13 2023
@@ -138,6 +138,9 @@
 /* Maximum size object to expect from sysctl(2) */
 #define SYSCTL_BUFSIZ  8192

+/* Default sysctl.conf location */
+#define SYSCTL_CONF "/etc/sysctl.conf"
+
 struct list {
        struct  ctlname *list;
        int     size;
@@ -161,7 +164,7 @@
        { 0, 0 },                       /* CTL_VFS */
 };

-int    Aflag, aflag, nflag, qflag;
+int    Aflag, aflag, nflag, pflag, qflag;

 time_t boottime;

@@ -192,6 +195,7 @@
 ssize_t parse_hex_string(unsigned char *, size_t, const char *);
 void parse(char *, int);
 void parse_baddynamic(int *, size_t, char *, void **, size_t *, int, int);
+void read_config(void);
 void usage(void);
 int findname(char *, char *, char **, struct list *);
 int sysctl_inet(char *, char **, int *, int, int *);
@@ -232,7 +236,7 @@
 {
        int ch, lvl1;

-       while ((ch = getopt(argc, argv, "Aanqw")) != -1) {
+       while ((ch = getopt(argc, argv, "Aanpqw")) != -1) {
                switch (ch) {

                case 'A':
@@ -247,6 +251,10 @@
                        nflag = 1;
                        break;

+               case 'p':
+                       pflag = 1;
+                       break;
+
                case 'q':
                        qflag = 1;
                        break;
@@ -268,9 +276,16 @@
                err(1,"unveil %s", _PATH_DEVDB);
        if (unveil("/dev", "r") == -1 && errno != ENOENT)
                err(1, "unveil /dev");
+       if(unveil(SYSCTL_CONF, "r") == -1 && errno != ENOENT)
+               err(1, "unveil /etc/sysctl.conf");
        if (unveil(NULL, NULL) == -1)
                err(1, "unveil");

+       if (pflag) {
+               read_config();
+               return (0);
+       }
+
        if (argc == 0 || (Aflag || aflag)) {
                debuginit();
                vfsinit();
@@ -278,9 +293,33 @@
                        listall(topname[lvl1].ctl_name, &secondlevel[lvl1]);
                return (0);
        }
+
        for (; *argv != NULL; ++argv)
                parse(*argv, 1);
        return (0);
+}
+
+/*
+ * Read sysctl.conf and parse every line
+ */
+void
+read_config(void)
+{
+       char line[SYSCTL_BUFSIZ];
+       FILE *file;
+
+       file = fopen(SYSCTL_CONF, "r");
+       if(!file)
+               errx(1, "Cannot open %s", SYSCTL_CONF);
+
+       while(fgets(line, SYSCTL_BUFSIZ, file) != NULL) {
+               /* Ignore comments */
+               if (strncmp(line, "#", 1) == 0)
+                       continue;
+               line[strlen(line)-1] = '\0';
+               parse(line, 1);
+               memset(line, '\0', SYSCTL_BUFSIZ);
+       }
 }

 /*


--- sysctl.8.dist       Tue Feb 21 12:18:21 2023
+++ sysctl.8    Tue Feb 21 12:09:59 2023
@@ -38,7 +38,7 @@
 .Nd get or set kernel state
 .Sh SYNOPSIS
 .Nm sysctl
-.Op Fl Aanq
+.Op Fl Aanpq
 .Op Ar name Ns Op = Ns Ar value
 .Sh DESCRIPTION
 The
@@ -74,6 +74,8 @@
 For example, to set the psize shell variable to the pagesize of the 
hardware:
 .Pp
 .Dl # set psize=`sysctl -n hw.pagesize`
+.It Fl p
+Read and apply all settings from /etc/sysctl.conf.
 .It Fl q
 Suppress all output when setting a variable.
 This option overrides the behaviour of
@@ -133,6 +135,10 @@
 To retrieve information about the load average history:
 .Pp
 .Dl $ sysctl vm.loadavg
+.Pp
+To apply all settings from /etc/sysctl.conf
+.Pp
+.Dl # sysctl -p
 .Pp
 To make the
 .Xr chown 2