因为存在多进程和线程，Linux下同一个进程名有可能有多个进程号。下面的程序可以一次获得同一进程名的所有进程号。

process.h

#ifndef __PROCESS_H__

#define __PROCESS_H__

char *basename(const char *path);

int get_pid_by_name(const char* process_name, pid_t pid_list[], int list_size);

int is_process_exist(const char* process_name);

#endif /* __PROCESS_H__ */

process.c (使用/proc/pid/exe 查找进程名有时候会有问题，比如busybox中的命令，查到的是busybox)

修改为使用/proc/pid/cmdline来查找。

#include

#include

#include

#include

#include

#include

#include

#include

char *basename(const char *path)

{

register const char *s;

register const char *p;

p = s = path;

while (*s) {

if (*s++ == '/') {

p = s;

}

}

return (char *) p;

}

/* find all pid of process by name, only compare base name of pid_name

* pid_list: caller malloc pid_t array

* list_size: the size of pid_list

* RETURN:

* < 0: error number

* >=0: how many pid found, pid_list will store the founded pid

*/

int get_pid_by_name(const char* process_name, pid_t pid_list[], int list_size)

{

#define MAX_BUF_SIZE 256

DIR *dir;

struct dirent *next;

int count=0;

pid_t pid;

FILE *fp;

char *base_pname = NULL;

char *base_fname = NULL;

char cmdline[MAX_BUF_SIZE];

char path[MAX_BUF_SIZE];

if(process_name == NULL || pid_list == NULL)

return -EINVAL;

base_pname = basename(process_name);

if(strlen(base_pname) <= 0)

return -EINVAL;

dir = opendir("/proc");

if (!dir)

{

return -EIO;

}

while ((next = readdir(dir)) != NULL) {

/* skip non-number */

if (!isdigit(*next->d_name))

continue;

pid = strtol(next->d_name, NULL, 0);

sprintf(path, "/proc/%u/cmdline", pid);

fp = fopen(path, "r");

if(fp == NULL)

continue;

memset(cmdline, 0, sizeof(cmdline));

if(fread(cmdline, MAX_BUF_SIZE - 1, 1, fp) < 0){

fclose(fp);

continue;

}

fclose(fp);

base_fname = basename(cmdline);

if (strcmp(base_fname, base_pname) == 0 )

{

if(count >= list_size){

break;

}else{

pid_list[count] = pid;

count++;

}

}

}

closedir(dir) ;

return count;

}

/* If process is existed, return true */

int is_process_exist(const char* process_name)

{

pid_t pid;

return (get_pid_by_name(process_name, &pid, 1) > 0);

}

main.c

#include

#include

#include "process.h"

#define MAX_PID_NUM     32

int main(int argc, char* argv[])

{

char* process;

int ret = 0;

int n;

pid_t pid[MAX_PID_NUM];

if(argc < 2)

process = argv[0];

else

process = argv[1];

ret = get_pid_by_name(process, pid, MAX_PID_NUM);

printf("process '%s' is existed? (%d): %c\n", process, ret, (ret > 0)?'y':'n');

for(n=0;n

printf("%u\n", pid[n]);

}

return ret;

}

Makefile:

PROG=check_process

OBJS=process.o main.o

#CFLAGS = -g -ggdb

all:$(PROG)

check_process:$(OBJS)

$(CC) -o $@ $^ $(LDFLAGS)

%.o:%.c

$(CC) -c -o $@ $(CFLAGS) $<

clean:

rm -rf $(PROG) *.o