hush/libbb/find_pid_by_name.c
Eric Andersen 8a6dbf6709 Patch from Pierre PEIFFER <pierre.peiffer@sxb.bsf.alcatel.fr>
that copes with the fact that processes may have been swapped
out.
2001-03-17 00:05:42 +00:00

176 lines
4.4 KiB
C

/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) tons of folks. Tracking down who wrote what
* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under the GPL.
*
*/
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <dirent.h>
#include <stdlib.h>
#include "libbb.h"
#define READ_BUF_SIZE 50
/* For Erik's nifty devps device driver */
#ifdef BB_FEATURE_USE_DEVPS_PATCH
#include <linux/devps.h>
/* find_pid_by_name()
*
* This finds the pid of the specified process,
* by using the /dev/ps device driver.
*
* Returns a list of all matching PIDs
*/
extern pid_t* find_pid_by_name( char* pidName)
{
int fd, i, j;
char device[] = "/dev/ps";
pid_t num_pids;
pid_t* pid_array = NULL;
pid_t* pidList=NULL;
/* open device */
fd = open(device, O_RDONLY);
if (fd < 0)
perror_msg_and_die("open failed for `%s'", device);
/* Find out how many processes there are */
if (ioctl (fd, DEVPS_GET_NUM_PIDS, &num_pids)<0)
perror_msg_and_die("\nDEVPS_GET_PID_LIST");
/* Allocate some memory -- grab a few extras just in case
* some new processes start up while we wait. The kernel will
* just ignore any extras if we give it too many, and will trunc.
* the list if we give it too few. */
pid_array = (pid_t*) xcalloc( num_pids+10, sizeof(pid_t));
pid_array[0] = num_pids+10;
/* Now grab the pid list */
if (ioctl (fd, DEVPS_GET_PID_LIST, pid_array)<0)
perror_msg_and_die("\nDEVPS_GET_PID_LIST");
/* Now search for a match */
for (i=1, j=0; i<pid_array[0] ; i++) {
char* p;
struct pid_info info;
info.pid = pid_array[i];
if (ioctl (fd, DEVPS_GET_PID_INFO, &info)<0)
perror_msg_and_die("\nDEVPS_GET_PID_INFO");
/* Make sure we only match on the process name */
p=info.command_line+1;
while ((*p != 0) && !isspace(*(p)) && (*(p-1) != '\\')) {
(p)++;
}
if (isspace(*(p)))
*p='\0';
if ((strstr(info.command_line, pidName) != NULL)
&& (strlen(pidName) == strlen(info.command_line))) {
pidList=xrealloc( pidList, sizeof(pid_t) * (j+2));
pidList[j++]=info.pid;
}
}
if (pidList)
pidList[j]=0;
/* Free memory */
free( pid_array);
/* close device */
if (close (fd) != 0)
perror_msg_and_die("close failed for `%s'", device);
return pidList;
}
#else /* BB_FEATURE_USE_DEVPS_PATCH */
/* find_pid_by_name()
*
* This finds the pid of the specified process.
* Currently, it's implemented by rummaging through
* the proc filesystem.
*
* Returns a list of all matching PIDs
*/
extern pid_t* find_pid_by_name( char* pidName)
{
DIR *dir;
struct dirent *next;
pid_t* pidList=NULL;
int i=0;
dir = opendir("/proc");
if (!dir)
perror_msg_and_die("Cannot open /proc");
while ((next = readdir(dir)) != NULL) {
FILE *status;
char filename[READ_BUF_SIZE];
char buffer[READ_BUF_SIZE];
char name[READ_BUF_SIZE];
/* If it isn't a number, we don't want it */
if (!isdigit(*next->d_name))
continue;
sprintf(filename, "/proc/%s/status", next->d_name);
if (! (status = fopen(filename, "r")) ) {
continue;
}
if (fgets(buffer, READ_BUF_SIZE-1, status) == NULL) {
fclose(status);
continue;
}
fclose(status);
/* Buffer should contain a string like "Name: binary_name" */
sscanf(buffer, "%*s %s", name);
if (strcmp(name, pidName) == 0) {
pidList=xrealloc( pidList, sizeof(pid_t) * (i+2));
pidList[i++]=strtol(next->d_name, NULL, 0);
}
}
if (pidList)
pidList[i]=0;
return pidList;
}
#endif /* BB_FEATURE_USE_DEVPS_PATCH */
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/