如何在osx中​​使用c ++从pid中获取uid？ [英] How to programatically get uid from pid in osx using c++?

问题描述

给定一个pid，我想找到进程的所有者（作为uid）。有没有办法在osx（或任何unix）使用C ++？

Given a pid, I want to find the owner of the process (as uid). Is there a way to get this in osx (or any unix) using C++?

Google没有帮助。 'ps'能够做到;所以我认为应该有一种方法来获得它的程序。

Google didn't help. 'ps' is able to do it; so I assume there should be a way to get it programatically.

推荐答案

最后找到一种方法来编程无需解析输出的'ps'

Finally found a way to programatically do this without parsing the output of 'ps'

uint getUidUsingSysctl(uint pid)
{
    struct kinfo_proc *sProcesses = NULL, *sNewProcesses;
    int    aiNames[4];
    size_t iNamesLength;
    int    i, iRetCode, iNumProcs;
    size_t iSize;

    iSize = 0;
    aiNames[0] = CTL_KERN;
    aiNames[1] = KERN_PROC;
    aiNames[2] = KERN_PROC_ALL;
    aiNames[3] = 0;
    iNamesLength = 3;

    iRetCode = sysctl(aiNames, iNamesLength, NULL, &iSize, NULL, 0);

    /* allocate memory and populate info in the  processes structure */
    do
    {
        iSize += iSize / 10;
        sNewProcesses = (kinfo_proc *)realloc(sProcesses, iSize);

        if (sNewProcesses == 0)
        {
            if (sProcesses)
                free(sProcesses);
            /* could not realloc memory, just return */
            return -1;
        }
        sProcesses = sNewProcesses;
        iRetCode = sysctl(aiNames, iNamesLength, sProcesses, &iSize, NULL, 0);
    } while (iRetCode == -1 && errno == ENOMEM);

    iNumProcs = iSize / sizeof(struct kinfo_proc);

    for (i = 0; i < iNumProcs; i++)
    {
        if (sProcesses[i].kp_proc.p_pid == pid) 
        {
            return sProcesses[i].kp_eproc.e_ucred.cr_uid;
        }

    }

    /* clean up and return to the caller */
    free(sProcesses);

    return -1;
}

注意：可能有一个更好的方法来获取'kinfo_proc'，而不是迭代通过所有过程。

Note: There might be a better way to get 'kinfo_proc' instead of iterating through all process.

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