meson: read more progs from PATH

Find more progs on PATH instead of hardcoding them.

(cherry picked from commit 5b193a8e23)
(cherry picked from commit 78371e5549)

meson.build

@@ -265,7 +265,6 @@ conf.set_quoted('KERNEL_INSTALL_DIR',                         kernelinstalldir)
 conf.set_quoted('MODPROBE_DIR',                               modprobedir)
 conf.set_quoted('MODULESLOAD_DIR',                            modulesloaddir)
 conf.set_quoted('PKGSYSCONFDIR',                              pkgsysconfdir)
-conf.set_quoted('POLKIT_AGENT_BINARY_PATH',                   bindir / 'pkttyagent')
 conf.set_quoted('POLKIT_RULES_DIR',                           polkitrulesdir)
 conf.set_quoted('PREFIX',                                     prefixdir)
 conf.set_quoted('PREFIX_NOSLASH',                             prefixdir_noslash)

src/journal/cat.c

@@ -158,7 +158,7 @@ static int run(int argc, char *argv[]) {
                 return log_error_errno(r, "Failed to rearrange stdout/stderr: %m");
 
         if (argc <= optind)
-                (void) execl("/bin/cat", "/bin/cat", NULL);
+                (void) execlp("cat", "cat", NULL);
         else {
                 struct stat st;
 

src/nspawn/nspawn-setuid.c

@@ -36,8 +36,7 @@ static int spawn_getent(const char *database, const char *key, pid_t *rpid) {
                 return r;
         }
         if (r == 0) {
-                execle("/usr/bin/getent", "getent", database, key, NULL, &(char*[1]){});
-                execle("/bin/getent", "getent", database, key, NULL, &(char*[1]){});
+                execlp("getent", "getent", database, key, NULL);
                 _exit(EXIT_FAILURE);
         }
 

src/shared/polkit-agent.c

@@ -4,11 +4,13 @@
 #include <signal.h>
 #include <unistd.h>
 
+#include "alloc-util.h"
 #include "bus-util.h"
 #include "exec-util.h"
 #include "fd-util.h"
 #include "io-util.h"
 #include "log.h"
+#include "path-util.h"
 #include "polkit-agent.h"
 #include "process-util.h"
 #include "stdio-util.h"
@@ -32,6 +34,15 @@ int polkit_agent_open(void) {
         if (r <= 0)
                 return r;
 
+        _cleanup_free_ char *pkttyagent = NULL;
+        r = find_executable("pkttyagent", &pkttyagent);
+        if (r == -ENOENT) {
+                log_debug("pkttyagent binary not available, ignoring.");
+                return 0;
+        }
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine whether pkttyagent binary exists: %m");
+
         if (pipe2(pipe_fd, 0) < 0)
                 return -errno;
 
@@ -41,7 +52,7 @@ int polkit_agent_open(void) {
                        &pipe_fd[1],
                        1,
                        &agent_pid,
-                       POLKIT_AGENT_BINARY_PATH,
+                       pkttyagent,
                        "--notify-fd", notify_fd,
                        "--fallback");
         if (r < 0)

units/ldconfig.service

@@ -25,4 +25,4 @@ Before=shutdown.target initrd-switch-root.target
 [Service]
 Type=oneshot
 RemainAfterExit=yes
-ExecStart=/sbin/ldconfig -X
+ExecStart=ldconfig -X

units/modprobe@.service

@@ -32,4 +32,4 @@ StartLimitIntervalSec=0
 
 [Service]
 Type=oneshot
-ExecStart=-/sbin/modprobe -abq %i
+ExecStart=-modprobe -abq %i