proc.c

snmp的源代码,已经在我的ubuntu下编译通过

#include <unistd.h>

int
sh_count_procs(char *procname)
{
    DIR *dir;
    char cmdline[512], *tmpc;
    struct dirent *ent;
#ifdef USE_PROC_CMDLINE
    int fd;
#endif
    int len,plen=strlen(procname),total = 0;
    FILE *status;

    if ((dir = opendir("/proc")) == NULL) return -1;
    while (NULL != (ent = readdir(dir))) {
      if(!(ent->d_name[0] >= '0' && ent->d_name[0] <= '9')) continue;
#ifdef USE_PROC_CMDLINE  /* old method */
      /* read /proc/XX/cmdline */
      sprintf(cmdline,"/proc/%s/cmdline",ent->d_name);
      if((fd = open(cmdline, O_RDONLY)) < 0) break;
      len = read(fd,cmdline,sizeof(cmdline) - 1);
      close(fd);
      if(len <= 0) continue;
      cmdline[len] = 0;
      while(--len && !cmdline[len]);
      while(--len) if(!cmdline[len]) cmdline[len] = ' ';
      if(!strncmp(cmdline,procname,plen)) total++;
#else
      /* read /proc/XX/status */
      sprintf(cmdline,"/proc/%s/status",ent->d_name);
      if ((status = fopen(cmdline, "r")) == NULL)
          break;
      if (fgets(cmdline, sizeof(cmdline), status) == NULL) {
          fclose(status);
          break;
      }
      fclose(status);
      cmdline[sizeof(cmdline)-1] = '\0';
      /* XXX: assumes Name: is first */
      if (strncmp("Name:",cmdline, 5) != 0)
          break;
      tmpc = skip_token(cmdline);
      if (!tmpc)
          break;
      for (len=0;; len++) {
	if (tmpc[len] && isgraph(tmpc[len])) continue;
	tmpc[len]='\0';
	break;
      }
      DEBUGMSGTL(("proc","Comparing wanted %s against %s\n",
                  procname, tmpc));
      if(len==plen && !strncmp(tmpc,procname,plen)) {
          total++;
          DEBUGMSGTL(("proc", " Matched.  total count now=%d\n", total));
      }
#endif      
    }
    closedir(dir);
    return total;
}

#elif OSTYPE == ULTRIXID

#define	NPROCS		32      /* number of proces to read at once */

extern int      kmem, mem, swap;

#include <sys/user.h>
#include <sys/proc.h>
#include <sys/file.h>
#include <sys/vm.h>
#include <machine/pte.h>
#ifdef HAVE_NLIST_H
#include <nlist.h>
#endif

static struct user *getuser(struct proc *);
static int      getword(off_t);
static int      getstruct(off_t, char *, off_t, int);

static struct nlist proc_nl[] = {
    {"_nproc"},
#define X_NPROC		0
    {"_proc"},
#define X_PROC		1
    {"_proc_bitmap"},
#define X_PROC_BITMAP	2
    {NULL}
};

int
sh_count_procs(char *procname)
{
    int             total, proc_active, nproc;
    int             thisproc = 0;
    int             absolute_proc_number = -1;
    struct user    *auser;
    struct proc    *aproc, *procp;
    unsigned        bitmap;
    struct proc     procs[NPROCS], *procsp;
    static int      inited = 0;

    procp = (struct proc *) getword(proc_nl[X_PROC].n_value);
    nproc = getword(proc_nl[X_NPROC].n_value);

    total = 0;
    for (;;) {
        do {
            while (thisproc == 0) {
                int             nread;
                int             psize;

                if (nproc == 0)
                    return (total);

                thisproc = MIN(NPROCS, nproc);
                psize = thisproc * sizeof(struct proc);
                nproc -= thisproc;
                if (lseek(kmem, (off_t) procp, L_SET) == -1 ||
                    (nread = read(kmem, (char *) procs, psize)) < 0) {
                    /*
                     * warn("read proc"); 
                     */
                    return (total);
                } else if (nread != psize) {
                    thisproc = nread / sizeof(struct proc);
                    nproc = 0;
                    /*
                     * warn("read proc: short read"); 
                     */
                }
                procsp = procs;
                procp += thisproc;
            }

            aproc = procsp++;
            thisproc--;

            absolute_proc_number++;
            if ((absolute_proc_number % 32) == 0)
                bitmap =
                    getword((unsigned int) proc_nl[X_PROC_BITMAP].n_value +
                            ((absolute_proc_number / 32) * 4));
            proc_active =
                (bitmap & (1 << (absolute_proc_number % 32))) != 0;
            if (proc_active && aproc->p_stat != SZOMB
                && !(aproc->p_type & SWEXIT))
                auser = getuser(aproc);
        } while (!proc_active || auser == NULL);

        if (strcmp(auser->u_comm, procname) == 0)
            total++;
    }
}

#define	SW_UADDR	dtob(getword((off_t)dmap.dm_ptdaddr))
#define	SW_UBYTES	sizeof(struct user)

#define	SKRD(file, src, dst, size)			\
	(lseek(file, (off_t)(src), L_SET) == -1) ||	\
	(read(file, (char *)(dst), (size)) != (size))

static struct user *
getuser(struct proc *aproc)
{
    static union {
        struct user     user;
        char            upgs[UPAGES][NBPG];
    } u;
    static struct pte uptes[UPAGES];
    static struct dmap dmap;
    int             i, nbytes;

    /*
     * If process is not in core, we simply snarf it's user struct
     * from the swap device.
     */
    if ((aproc->p_sched & SLOAD) == 0) {
        if (!getstruct
            ((off_t) aproc->p_smap, "aproc->p_smap", (off_t) & dmap,
             sizeof(dmap))) {
            /*
             * warnx("can't read dmap for pid %d from %s", aproc->p_pid,
             * _PATH_DRUM); 
             */
            return (NULL);
        }
        if (SKRD(swap, SW_UADDR, &u.user, SW_UBYTES)) {
            /*
             * warnx("can't read u for pid %d from %s", aproc->p_pid, _PATH_DRUM); 
             */
            return (NULL);
        }
        return (&u.user);
    }

    /*
     * Process is in core.  Follow p_addr to read in the page
     * table entries that map the u-area and then read in the
     * physical pages that comprise the u-area.
     *
     * If at any time, an lseek() or read() fails, print a warning
     * message and return NULL.
     */
    if (SKRD(kmem, aproc->p_addr, uptes, sizeof(uptes))) {
        /*
         * warnx("can't read user pt for pid %d from %s", aproc->p_pid, _PATH_DRUM); 
         */
        return (NULL);
    }

    nbytes = sizeof(struct user);
    for (i = 0; i < UPAGES && nbytes > 0; i++) {
        if (SKRD(mem, ptob(uptes[i].pg_pfnum), u.upgs[i], NBPG)) {
            /*
             * warnx("can't read user page %u for pid %d from %s",
             * uptes[i].pg_pfnum, aproc->p_pid, _PATH_MEM); 
             */
            return (NULL);
        }
        nbytes -= NBPG;
    }
    return (&u.user);
}

static int
getword(off_t loc)
{
    int             val;

    if (SKRD(kmem, loc, &val, sizeof(val)))
        exit(1);
    return (val);
}

static int
getstruct(off_t loc, char *name, off_t dest, int size)
{
    if (SKRD(kmem, loc, dest, size))
        return (0);
    return (1);
}
#elif OSTYPE == SOLARISID

#ifdef _SLASH_PROC_METHOD_

#include <fcntl.h>
#include <dirent.h>

#include <procfs.h>

/*
 * Gets process information from /proc/.../psinfo
 */

int
sh_count_procs(char *procname)
{
    int             fd, total = 0;
    struct psinfo   info;
    char            fbuf[32];
    struct dirent  *ent;
    DIR            *dir;

    if (!(dir = opendir("/proc"))) {
        snmp_perror("/proc");
        return -1;
    }

    while ((ent = readdir(dir))) {
        if (!strcmp(ent->d_name, "..") || !strcmp(ent->d_name, "."))
            continue;

        snprintf(fbuf, sizeof fbuf, "/proc/%s/psinfo", ent->d_name);
        if ((fd = open(fbuf, O_RDONLY)) < 0) {  /* Continue or return error? */
            snmp_perror(fbuf);
	    continue;
        }

        if (read(fd, (char *) &info, sizeof(struct psinfo)) !=
            sizeof(struct psinfo)) {
            snmp_perror(fbuf);
            close(fd);
            closedir(dir);
            return -1;
        }

        if (!info.pr_nlwp && !info.pr_lwp.pr_lwpid) {
            /*
             * Zombie process 
             */
        } else {
            DEBUGMSGTL(("proc","Comparing wanted %s against %s\n",
                        procname, info.pr_fname));
            if (!strcmp(procname, info.pr_fname)) {
                total++;
                DEBUGMSGTL(("proc", " Matched.  total count now=%d\n", total));
            }
        }

        close(fd);
    }
    closedir(dir);
    return total;
}

#else                           /* _SLASH_PROC_METHOD_ */

#define _KMEMUSER               /* Needed by <sys/user.h> */

#include <kvm.h>
#include <fcntl.h>
#include <sys/user.h>
#include <sys/proc.h>

int
sh_count_procs(char *procname)
{
    struct proc    *p;
    struct user    *u;
    int             total;

    if (kd == NULL) {
        return -1;
    }
    if (kvm_setproc(kd) < 0) {
        return (-1);
    }
    kvm_setproc(kd);
    total = 0;
    while ((p = kvm_nextproc(kd)) != NULL) {
        if (!p) {
            return (-1);
        }
        u = kvm_getu(kd, p);
        /*
         * Skip this entry if u or u->u_comm is a NULL pointer 
         */
        if (!u) {
            continue;
        }
        if (strcmp(procname, u->u_comm) == 0)
            total++;
    }
    return (total);
}
#endif                          /* _SLASH_PROC_METHOD_ */
#else
int
sh_count_procs(char *procname)
{
    char            line[STRMAX], *cptr, *cp;
    int             ret = 0, fd;
    FILE           *file;
#ifndef EXCACHETIME
#endif
    struct extensible ex;
    int             slow = strstr(PSCMD, "ax") != NULL;

    strcpy(ex.command, PSCMD);
    if ((fd = get_exec_output(&ex)) >= 0) {
        if ((file = fdopen(fd, "r")) == NULL) {
            setPerrorstatus("fdopen");
            close(fd);
            return (-1);
        }
        while (fgets(line, sizeof(line), file) != NULL) {
            if (slow) {
                cptr = find_field(line, 5);
                cp = strrchr(cptr, '/');
                if (cp)
                    cptr = cp + 1;
                else if (*cptr == '-')
                    cptr++;
                else if (*cptr == '[') {
                    cptr++;
                    cp = strchr(cptr, ']');
                    if (cp)
                        *cp = 0;
                }
                copy_nword(cptr, line, sizeof(line));
                cp = line + strlen(line) - 1;
                if (*cp == ':')
                    *cp = 0;
            } else {
                if ((cptr = find_field(line, LASTFIELD)) == NULL)
                    continue;
                copy_nword(cptr, line, sizeof(line));
            }
            if (!strcmp(line, procname))
                ret++;
        }
        if (ftell(file) < 2) {
#ifdef USING_UCD_SNMP_ERRORMIB_MODULE
            seterrorstatus("process list unreasonable short (mem?)", 2);
#endif
            ret = -1;
        }
        fclose(file);
        wait_on_exec(&ex);
    } else {
        ret = -1;
    }
    return (ret);
}
#endif