[PATCH for 6.2 20/49] bsd-user: save the path the qemu emulator

[Warner Losh <imp@bsdimp.com>]

Save the path to the qemu emulator. This will be used later when we have
a more complete implementation of exec.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/main.c | 21 +++++++++++++++++++++
 bsd-user/qemu.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/bsd-user/main.c b/bsd-user/main.c
index d9965e6611..c59edad155 100644
--- a/bsd-user/main.c
+++ b/bsd-user/main.c
@@ -43,6 +43,8 @@
 
 #include "host-os.h"
 
+#include <sys/sysctl.h>
+
 int singlestep;
 unsigned long mmap_min_addr;
 uintptr_t guest_base;
@@ -52,6 +54,7 @@ unsigned long reserved_va;
 static const char *interp_prefix = CONFIG_QEMU_INTERP_PREFIX;
 const char *qemu_uname_release;
 enum BSDType bsd_type;
+char qemu_proc_pathname[PATH_MAX];  /* full path to exeutable */
 
 /*
  * XXX: on x86 MAP_GROWSDOWN only works if ESP <= address + 32, so
@@ -336,6 +339,22 @@ void init_task_state(TaskState *ts)
     ts->sigqueue_table[i].next = NULL;
 }
 
+static void save_proc_pathname(char *argv0)
+{
+    int mib[4];
+    size_t len;
+
+    mib[0] = CTL_KERN;
+    mib[1] = KERN_PROC;
+    mib[2] = KERN_PROC_PATHNAME;
+    mib[3] = -1;
+
+    len = PATH_MAX;
+    if (sysctl(mib, 4, qemu_proc_pathname, &len, NULL, 0)) {
+        perror("sysctl");
+    }
+}
+
 int main(int argc, char **argv)
 {
     const char *filename;
@@ -360,6 +379,8 @@ int main(int argc, char **argv)
         usage();
     }
 
+    save_proc_pathname(argv[0]);
+
     error_init(argv[0]);
     module_call_init(MODULE_INIT_TRACE);
     qemu_init_cpu_list();
diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index cf248ad3df..6c4ec61d76 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -207,6 +207,7 @@ void mmap_fork_start(void);
 void mmap_fork_end(int child);
 
 /* main.c */
+extern char qemu_proc_pathname[];
 extern unsigned long x86_stack_size;
 
 /* user access */
-- 
2.32.0