readproc.c

Linux下进程监控相关源代码

/*
 * New Interface to Process Table -- PROCTAB Stream (a la Directory streams)
 * Copyright (C) 1996 Charles L. Blake.
 * Copyright (C) 1998 Michael K. Johnson
 * May be distributed under the conditions of the
 * GNU Library General Public License; a copy is in COPYING
 */
#include "proc/version.h"
#include "proc/readproc.h"
#include "proc/devname.h"
#include "proc/procps.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/dir.h>
#include <sys/types.h>
#include <sys/stat.h>

#define Do(x) (flags & PROC_ ## x)	/* convenient shorthand */

/* initiate a process table scan
 */
PROCTAB* openproc(int flags, ...) {
    va_list ap;
    PROCTAB* PT = xmalloc(sizeof(PROCTAB));
    
    if (Do(PID))
      PT->procfs = NULL;
    else if (!(PT->procfs = opendir("/proc")))
      return NULL;
    PT->flags = flags;
    va_start(ap, flags);		/*  Init args list */
    if (Do(PID))
    	PT->pids = va_arg(ap, pid_t*);
    else if (Do(TTY))
    	PT->ttys = va_arg(ap, dev_t*);
    else if (Do(UID)) {
    	PT->uids = va_arg(ap, uid_t*);
	PT->nuid = va_arg(ap, int);
    } else if (Do(STAT))
    	PT->stats = va_arg(ap, char*);
    va_end(ap);				/*  Clean up args list */
    if (Do(ANYTTY) && Do(TTY))
	PT->flags = PT->flags & ~PROC_TTY; /* turn off TTY flag */
    return PT;
}

/* terminate a process table scan
 */
void closeproc(PROCTAB* PT) {
    if (PT->procfs) closedir(PT->procfs);
    if (PT)         free(PT);
}

/* deallocate the space allocated by readproc if the passed rbuf was NULL
 */
void freeproc(proc_t* p) {
    if (!p)	/* in case p is NULL */
	return;
    /* ptrs are after strings to avoid copying memory when building them. */
    /* so free is called on the address of the address of strvec[0]. */
    if (p->cmdline)
	free((void*)*p->cmdline);
    if (p->environ)
	free((void*)*p->environ);
    free(p);
}



void status2proc (char* S, proc_t* P, int fill) {
    char* tmp;
    if (fill == 1) {
        memset(P->cmd, 0, sizeof P->cmd);
        sscanf (S, "Name:\t%15c", P->cmd);
        tmp = strchr(P->cmd,'\n');
        *tmp='\0';
        tmp = strstr (S,"State");
        sscanf (tmp, "State:\t%c", &P->state);
    }

    tmp = strstr (S,"Pid:");
    if(tmp) sscanf (tmp,
        "Pid:\t%d\n"
        "PPid:\t%d\n",
        &P->pid,
        &P->ppid
    );
    else fprintf(stderr, "Internal error!\n");

    tmp = strstr (S,"Uid:");
    if(tmp) sscanf (tmp,
        "Uid:\t%d\t%d\t%d\t%d",
        &P->ruid, &P->euid, &P->suid, &P->fuid
    );
    else fprintf(stderr, "Internal error!\n");

    tmp = strstr (S,"Gid:");
    if(tmp) sscanf (tmp,
        "Gid:\t%d\t%d\t%d\t%d",
        &P->rgid, &P->egid, &P->sgid, &P->fgid
    );
    else fprintf(stderr, "Internal error!\n");

    tmp = strstr (S,"VmSize:");
    if(tmp) sscanf (tmp,
        "VmSize: %lu kB\n"
        "VmLck: %lu kB\n"
        "VmRSS: %lu kB\n"
        "VmData: %lu kB\n"
        "VmStk: %lu kB\n"
        "VmExe: %lu kB\n"
        "VmLib: %lu kB\n",
        &P->vm_size, &P->vm_lock, &P->vm_rss, &P->vm_data,
        &P->vm_stack, &P->vm_exe, &P->vm_lib
    );
    else /* looks like an annoying kernel thread */
    {
        P->vm_size  = 0;
        P->vm_lock  = 0;
        P->vm_rss   = 0;
        P->vm_data  = 0;
        P->vm_stack = 0;
        P->vm_exe   = 0;
        P->vm_lib   = 0;
    }

    tmp = strstr (S,"SigPnd:");
    if(tmp) sscanf (tmp,
#ifdef SIGNAL_STRING
        "SigPnd: %s SigBlk: %s SigIgn: %s %*s %s",
        P->signal, P->blocked, P->sigignore, P->sigcatch
#else
        "SigPnd: %Lx SigBlk: %Lx SigIgn: %Lx %*s %Lx",
        &P->signal, &P->blocked, &P->sigignore, &P->sigcatch
#endif
    );
    else fprintf(stderr, "Internal error!\n");
}



/* stat2proc() makes sure it can handle arbitrary executable file basenames
   for `cmd', i.e. those with embedded whitespace or embedded ')'s.  Such names
   confuse %s (see scanf(3)), so the string is split and %39c is used instead.
   (except for embedded ')' "(%[^)]c)" would work.
*/
void stat2proc(char* S, proc_t* P) {
    int num;
    char* tmp = strrchr(S, ')');	/* split into "PID (cmd" and "<rest>" */
    *tmp = '\0';			/* replace trailing ')' with NUL */
    /* parse these two strings separately, skipping the leading "(". */
    memset(P->cmd, 0, sizeof P->cmd);	/* clear even though *P xcalloc'd ?! */
    sscanf(S, "%d (%15c", &P->pid, P->cmd);   /* comm[16] in kernel */
    num = sscanf(tmp + 2,			/* skip space after ')' too */
       "%c "
       "%d %d %d %d %d "
       "%lu %lu %lu %lu %lu %lu %lu "
       "%ld %ld %ld %ld %ld %ld "
       "%lu %lu "
       "%ld "
       "%lu %lu %lu %lu %lu %lu "
       "%*s %*s %*s %*s " /* discard, no RT signals & Linux 2.1 used hex */
       "%lu %lu %lu %*d %d",
       &P->state,
       &P->ppid, &P->pgrp, &P->session, &P->tty, &P->tpgid,
       &P->flags, &P->min_flt, &P->cmin_flt, &P->maj_flt, &P->cmaj_flt, &P->utime, &P->stime,
       &P->cutime, &P->cstime, &P->priority, &P->nice, &P->timeout, &P->it_real_value,
       &P->start_time, &P->vsize,
       &P->rss,
       &P->rss_rlim, &P->start_code, &P->end_code, &P->start_stack, &P->kstk_esp, &P->kstk_eip,
/*     P->signal, P->blocked, P->sigignore, P->sigcatch,   */ /* can't use */
       &P->wchan, &P->nswap, &P->cnswap /* , &P->exit_signal  */, &P->lproc);
/* TODO: add &P->exit_signal support here, perhaps to identify Linux threads */
    
/*    fprintf(stderr, "stat2proc converted %d fields.\n",num); */
    if (P->tty == 0)
	P->tty = -1;  /* the old notty val, update elsewhere bef. moving to 0 */
    if (linux_version_code < LINUX_VERSION(1,3,39)) {
	P->priority = 2*15 - P->priority;	/* map old meanings to new */
	P->nice = 15 - P->nice;
    }
    if (linux_version_code < LINUX_VERSION(1,1,30) && P->tty != -1)
	P->tty = 4*0x100 + P->tty;		/* when tty wasn't full devno */
}

void statm2proc(char* s, proc_t* P) {
    int num;
    num = sscanf(s, "%ld %ld %ld %ld %ld %ld %ld",
	   &P->size, &P->resident, &P->share,
	   &P->trs, &P->lrs, &P->drs, &P->dt);
/*    fprintf(stderr, "statm2proc converted %d fields.\n",num); */
}

void nulls2sep(char* str, int len, char sep) {
    int i;
    for (i = 0; i < len; i++)
    	if (str[i] == 0)
    	    str[i] = sep;
}

int file2str(char *directory, char *what, char *ret, int cap) {
    static char filename[80];
    int fd, num_read;

    sprintf(filename, "%s/%s", directory, what);
    if ( (fd       = open(filename, O_RDONLY, 0)) == -1 ) return -1;
    if ( (num_read = read(fd, ret, cap - 1))      <= 0 ) num_read = -1;
    else ret[num_read] = 0;
    close(fd);
    return num_read;
}

char** file2strvec(char* directory, char* what) {
    char buf[2048];	/* read buf bytes at a time */
    char *p, *rbuf = 0, *endbuf, **q, **ret;
    int fd, tot = 0, n, c, end_of_file = 0;
    int align;

    sprintf(buf, "%s/%s", directory, what);
    if ( (fd = open(buf, O_RDONLY, 0) ) == -1 ) return NULL;

    /* read whole file into a memory buffer, allocating as we go */
    while ((n = read(fd, buf, sizeof buf - 1)) > 0) {
	if (n < sizeof buf - 1)
	    end_of_file = 1;
	if (n == 0 && rbuf == 0)
	    return NULL;	/* process died between our open and read */
	if (n < 0) {
	    if (rbuf)
		free(rbuf);
	    return NULL;	/* read error */
	}
	if (end_of_file && buf[n-1])		/* last read char not null */
	    buf[n++] = '\0';			/* so append null-terminator */
	rbuf = xrealloc(rbuf, tot + n);		/* allocate more memory */
	memcpy(rbuf + tot, buf, n);		/* copy buffer into it */
	tot += n;				/* increment total byte ctr */
	if (end_of_file)
	    break;
    }
    close(fd);
    if (n <= 0 && !end_of_file) {
	if (rbuf) free(rbuf);
	return NULL;		/* read error */
    }
    endbuf = rbuf + tot;			/* count space for pointers */
    align = (sizeof(char*)-1) - ((tot + sizeof(char*)-1) & (sizeof(char*)-1));
    for (c = 0, p = rbuf; p < endbuf; p++)
    	if (!*p)
	    c += sizeof(char*);
    c += sizeof(char*);				/* one extra for NULL term */

    rbuf = xrealloc(rbuf, tot + c + align);	/* make room for ptrs AT END */
    endbuf = rbuf + tot;			/* addr just past data buf */
    q = ret = (char**) (endbuf+align);		/* ==> free(*ret) to dealloc */
    *q++ = p = rbuf;				/* point ptrs to the strings */
    endbuf--;					/* do not traverse final NUL */
    while (++p < endbuf) 
    	if (!*p)				/* NUL char implies that */
	    *q++ = p+1;				/* next string -> next char */

    *q = 0;					/* null ptr list terminator */
    return ret;
}


/* These are some nice GNU C expression subscope "inline" functions.
   The can be used with arbitrary types and evaluate their arguments
   exactly once.
*/

/* Test if item X of type T is present in the 0 terminated list L */
#   define XinL(T, X, L) ( {			\
	    T  x = (X), *l = (L);		\
	    while (*l && *l != x) l++;		\
	    *l == x;				\
	} )

/* Test if item X of type T is present in the list L of length N */
#   define XinLN(T, X, L, N) ( {		\
	    T x = (X), *l = (L);		\
	    int i = 0, n = (N);			\
	    while (i < n && l[i] != x) i++;	\
	    i < n && l[i] == x;			\
	} )

/* readproc: return a pointer to a proc_t filled with requested info about the
 * next process available matching the restriction set.  If no more such
 * processes are available, return a null pointer (boolean false).  Use the
 * passed buffer instead of allocating space if it is non-NULL.  */

/* This is optimized so that if a PID list is given, only those files are
 * searched for in /proc.  If other lists are given in addition to the PID list,
 * the same logic can follow through as for the no-PID list case.  This is
 * fairly complex, but it does try to not to do any unnecessary work.
 * Unfortunately, the reverse filtering option in which any PID *except* the
 * ones listed is pursued.
 */