current_exe

current_exe.c

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <stdlib.h>
#include <errno.h>

int main() {
    {
        char buf[1024];
        int sz = readlink("/proc/curproc/file", &buf, 1024);
        buf[sz] = 0;
        printf("procfs: %s\n", buf);
    }

    int mib[4];
    mib[0] = CTL_KERN;
    mib[1] = KERN_PROC;
    mib[2] = KERN_PROC_PATHNAME;
    mib[3] = -1;

    size_t sz = 0;
    int err = sysctl(mib, 4, NULL, &sz, NULL, 0);
    char *s = malloc(sz);
    err = sysctl(mib, 4, s, &sz, NULL, 0);
    s[sz-1] = 0;
    printf("sysctl: %s\n", s);

    return 0;
}

output

# uname -a
DragonFly babel.localnet 4.7-DEVELOPMENT DragonFly v4.7.0.94.g57eef-DEVELOPMENT #25: Wed Aug  3 20:20:48 CEST 2016     mneumann@babel.localnet:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64

# ./current_exe
procfs: /home/mneumann/current_exe
sysctl: /data2/pfs/@@-1:00001/mneumann/current_exe

## The problem is, that the path sysctl returns contains a ":", which is not allowed inside a regular path.

This commit fixes the issue. DragonFly >= 4.6.1 will not be affected:

# uname -a
DragonFly babel.localnet 4.7-DEVELOPMENT DragonFly v4.7.0.114.g726f7-DEVELOPMENT #27: Fri Aug  5 22:24:40 CEST 2016     mneumann@babel.localnet:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64

# ./current_exe
procfs: /home/mneumann/current_exe
sysctl: /home/mneumann/current_exe