get_pid_by_name_linux get pid by proc name-优快云博客

本文介绍了一种在Linux环境下通过进程名称获取其PID的方法。利用C语言编程，通过对/proc目录下各子目录的遍历及解析，能够有效地找到对应进程的PID。文章提供了具体的实现代码，并指出了关键步骤。

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Linux 通过名字获得一个thread 的Pid，/proc中保存的所有thread的信息，可以通过ls看到，各个进程的目录以PID命名，/proc/PID/stat 文件记录了thread的信息，通过遍历这个文件，就可以通过名字找到对应的PID。stat文件中的内容：

cat stat
1400 (rild) S 1 1400 0 0 -1 4194560 288 9108 3 2 10 15 10 194 20 0 3 0 785 4673536 167 4294967295 32768 37204 3198446656 3198445164 4294903072 0 0 0 3
8120 4294967295 0 0 17 0 0 0 0 0 0

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>

#include <string.h>

#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>

#include <pwd.h>

#include <cutils/sched_policy.h>
#define isdigit(a) ((unsigned)((a) - '0') <= 9)

static char *nexttoksep(char **strp, char *sep)
{
    char *p = strsep(strp,sep);
    return (p == 0) ? "" : p;
}
static char *nexttok(char **strp)
{
    return nexttoksep(strp, " ");
}


static int ps_line(int pidloop,char *namefilter)
{
    char statline[1024];
    int fd, r,pid;
    char *ptr, *name;

    sprintf(statline, "/proc/%d/stat", pidloop);
    fd = open(statline, O_RDONLY);
    if(fd == 0) return -1;
    r = read(fd, statline, 1023);
    close(fd);
    if(r < 0) return -1;
    statline[r] = 0;

    ptr = statline;
    nexttok(&ptr); // skip pid
    ptr++;          // skip "("

    name = ptr;
    ptr = strrchr(ptr, ')'); // Skip to *last* occurence of ')',
    *ptr++ = '\0';           // and null-terminate name.

    if(!namefilter || !strncmp(name, namefilter, strlen(namefilter))) 
	{	
		pid = pidloop;
		return pid;
    }
	else
    	return 0;
}
int get_pid_by_name(char *name)
{
    DIR *d;
    struct dirent *de;
    char *namefilter = 0;
	int pidloop = 0;
	int pid = 0;
    
    d = opendir("/proc");
    if(d == 0) return -1;
	namefilter = name;
    while(((de = readdir(d)) != 0)&&(pid == 0) ){
        if(isdigit(de->d_name[0])){
            pidloop = atoi(de->d_name);
            pid = ps_line(pidloop,namefilter);
        }
    }
    closedir(d);
    return pid;
}

参考代码：busybox:find_pid_by_name.c

Android:system\core\toolbox\ps.c