third_party/ulib/musl/src/process/execvp.c

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

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);