git: d988621b0c25 - main - setusercontext(): Better error messages when priority is not set correctly

From: Olivier Certner <olce_at_FreeBSD.org>
Date: Mon, 29 Jan 2024 22:32:14 UTC
The branch main has been updated by olce:

URL: https://cgit.FreeBSD.org/src/commit/?id=d988621b0c25209866ed5a98b1a8b20269935761

commit d988621b0c25209866ed5a98b1a8b20269935761
Author:     Olivier Certner <olce@FreeBSD.org>
AuthorDate: 2023-05-29 16:39:04 +0000
Commit:     Olivier Certner <olce@FreeBSD.org>
CommitDate: 2024-01-29 21:58:07 +0000

    setusercontext(): Better error messages when priority is not set correctly
    
    Polish the syslog messages to contain readily useful information.
    
    Behavior of capability 'priority' is inconsistent with what is done for
    all other contexts: 'umask', 'cpumask', resource limits, etc., where an
    absence of capability means to inherit the value.  It is currently
    preserved for compatibility, but is subject to change on a future major
    release.
    
    Reviewed by:            emaste, kib (older version)
    Approved by:            emaste (mentor)
    MFC after:              3 days
    Sponsored by:           Kumacom SAS
    Differential Revision:  https://reviews.freebsd.org/D40349
---
 lib/libutil/login_class.c | 51 +++++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 17 deletions(-)

diff --git a/lib/libutil/login_class.c b/lib/libutil/login_class.c
index ee0cec3423f5..269349a49dad 100644
--- a/lib/libutil/login_class.c
+++ b/lib/libutil/login_class.c
@@ -473,9 +473,7 @@ setlogincontext(login_cap_t *lc, const struct passwd *pwd, unsigned long flags)
 int
 setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned int flags)
 {
-    rlim_t	p;
     login_cap_t *llc = NULL;
-    struct rtprio rtp;
     int error;
 
     if (lc == NULL) {
@@ -492,30 +490,49 @@ setusercontext(login_cap_t *lc, const struct passwd *pwd, uid_t uid, unsigned in
 
     /* Set the process priority */
     if (flags & LOGIN_SETPRIORITY) {
-	p = login_getcapnum(lc, "priority", LOGIN_DEFPRI, LOGIN_DEFPRI);
+	const rlim_t def_val = LOGIN_DEFPRI, err_val = INT64_MIN;
+	rlim_t p = login_getcapnum(lc, "priority", def_val, err_val);
+	int rc;
+
+	if (p == err_val) {
+	    /* Invariant: 'lc' != NULL. */
+	    syslog(LOG_WARNING,
+		"%s%s%sLogin class '%s': "
+		"Invalid priority specification: '%s'",
+		pwd ? "Login '" : "",
+		pwd ? pwd->pw_name : "",
+		pwd ? "': " : "",
+		lc->lc_class,
+		login_getcapstr(lc, "priority", "", ""));
+	    /* Reset the priority, as if the capability was not present. */
+	    p = def_val;
+	}
 
 	if (p > PRIO_MAX) {
+	    struct rtprio rtp;
+
 	    rtp.type = RTP_PRIO_IDLE;
 	    p += RTP_PRIO_MIN - (PRIO_MAX + 1);
 	    rtp.prio = p > RTP_PRIO_MAX ? RTP_PRIO_MAX : p;
-	    if (rtprio(RTP_SET, 0, &rtp))
-		syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
-		    pwd ? pwd->pw_name : "-",
-		    lc ? lc->lc_class : LOGIN_DEFCLASS);
+	    rc = rtprio(RTP_SET, 0, &rtp);
 	} else if (p < PRIO_MIN) {
+	    struct rtprio rtp;
+
 	    rtp.type = RTP_PRIO_REALTIME;
 	    p += RTP_PRIO_MAX - (PRIO_MIN - 1);
 	    rtp.prio = p < RTP_PRIO_MIN ? RTP_PRIO_MIN : p;
-	    if (rtprio(RTP_SET, 0, &rtp))
-		syslog(LOG_WARNING, "rtprio '%s' (%s): %m",
-		    pwd ? pwd->pw_name : "-",
-		    lc ? lc->lc_class : LOGIN_DEFCLASS);
-	} else {
-	    if (setpriority(PRIO_PROCESS, 0, (int)p) != 0)
-		syslog(LOG_WARNING, "setpriority '%s' (%s): %m",
-		    pwd ? pwd->pw_name : "-",
-		    lc ? lc->lc_class : LOGIN_DEFCLASS);
-	}
+	    rc = rtprio(RTP_SET, 0, &rtp);
+	} else
+	    rc = setpriority(PRIO_PROCESS, 0, (int)p);
+
+	if (rc != 0)
+	    syslog(LOG_WARNING,
+		"%s%s%sLogin class '%s': "
+		"Setting priority failed: %m",
+		pwd ? "Login '" : "",
+		pwd ? pwd->pw_name : "",
+		pwd ? "': " : "",
+		lc ? lc->lc_class : "<none>");
     }
 
     /* Setup the user's group permissions */