On Fri, 20 Oct 2023, RVP wrote:
/*
printf("%d %d %s ", uid, pid, execname);
system("pr_realpath -p %d %s", pid, copyinstr(arg0));
printf("\n");
*/
I forgot to provide you with pr_realpath (in case you wanted the full path):
```
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/* Functions */
static int do_opts(int argc, char* argv[]);
static void usage(FILE* fp);
static void error(char* fmt, ...);
/* Globals */
static struct options {
pid_t pid;
} opts;
static char* prog;
int
main(int argc, char* argv[])
{
char cwd[PATH_MAX];
char buf[PATH_MAX];
char* fname, *p;
int idx, len, rc;
prog = argv[0];
rc = EXIT_FAILURE;
idx = do_opts(argc, argv);
argc -= idx;
argv += idx;
if (argc != 1) {
usage(stderr);
exit(rc);
}
fname = argv[0];
if (opts.pid == 0)
opts.pid = getpid();
snprintf(buf, sizeof buf, "/proc/%d/cwd", opts.pid);
if ((len = readlink(buf, cwd, sizeof(cwd)-1)) == -1) {
error("%s: %s: readlink failed.", prog, buf);
exit(rc);
}
cwd[len] = '\0';
if (*fname != '/') /* relative path */
snprintf(buf, sizeof buf, "%s/%s", cwd, fname);
else
strcpy(buf, fname);
if ((p = realpath(buf, NULL)) == NULL) {
error("%s: %s: realpath failed.", prog, buf);
exit(rc);
}
printf("%s\n", p);
free(p);
rc = EXIT_SUCCESS;
exit(rc);
}
/**
* Process program options.
*/
static int
do_opts(int argc, char* argv[])
{
int opt;
/* defaults */
opts.pid = 0; /* use own PID */
while ((opt = getopt(argc, argv, "hp:")) != -1) {
switch (opt) {
case 'h':
usage(stdout);
exit(EXIT_SUCCESS);
break;
case 'p':
opts.pid = atoi(optarg);
if (opts.pid <= 0) {
error("%s: PID must be > 0", prog);
exit(EXIT_FAILURE);
}
break;
default:
usage(stderr);
exit(EXIT_FAILURE);
break;
}
}
return optind;
}
/**
* Print usage information.
*/
static void
usage(FILE* fp)
{
fprintf(fp, "Usage: %s [-h] [-p PID] FILENAME\n", prog);
fprintf(fp, "%s: Canonicalize FILENAME belonging to PID using
realpath(3)\n", prog);
fprintf(fp, "\n");
fprintf(fp, " -h This message.\n");
fprintf(fp, " -p PID Owner of FILENAME (default: self)\n");
}
/**
* Print an error message.
*/
static void
error(char* fmt, ...)
{
va_list ap;
int e = errno;
fflush(stdout);
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
if (e != 0) {
fprintf(stderr, " (%s)", strerror(e));
errno = 0;
}
fprintf(stderr, "\n");
fflush(stderr);
}
```
You must have /proc mounted for this to work. I should make it use kinfo, but
this too was written a couple of years ago--when I was a NetBSD newbie :)
-RVP
