source: azure_iot_hub/trunk/musl-1.1.18/src/process/execvp.c@ 388

#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>
#include "libc.h"

extern char **__environ;

int __execvpe(const char *file, char *const argv[], char *const envp[])
{
        const char *p, *z, *path = getenv("PATH");
        size_t l, k;
        int seen_eacces = 0;

        errno = ENOENT;
        if (!*file) return -1;

        if (strchr(file, '/'))
                return execve(file, argv, envp);

        if (!path) path = "/usr/local/bin:/bin:/usr/bin";
        k = strnlen(file, NAME_MAX+1);
        if (k > NAME_MAX) {
                errno = ENAMETOOLONG;
                return -1;
        }
        l = strnlen(path, PATH_MAX-1)+1;

        for(p=path; ; p=z) {
                char b[l+k+1];
                z = strchr(p, ':');
                if (!z) z = p+strlen(p);
                if (z-p >= l) {
                        if (!*z++) break;
                        continue;
                }
                memcpy(b, p, z-p);
                b[z-p] = '/';
                memcpy(b+(z-p)+(z>p), file, k+1);
                execve(b, argv, envp);
                if (errno == EACCES) seen_eacces = 1;
                else if (errno != ENOENT) return -1;
                if (!*z++) break;
        }
        if (seen_eacces) errno = EACCES;
        return -1;
}

int execvp(const char *file, char *const argv[])
{
        return __execvpe(file, argv, __environ);
}

weak_alias(__execvpe, execvpe);