emo/procps
1
0
Fork 0
Code Issues Pull Requests Packages Releases Activity

better -L support

Browse Source
This commit is contained in:
albert 2006-06-23 03:18:12 +00:00
parent 6baa2fd34e
commit 7e2f073fbd
1 changed files with 38 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
pgrep.c
View File

@ -148,6 +148,42 @@ static int strict_atol (const char *restrict str, long *restrict value)
#include <sys/file.h>
// Seen non-BSD code do this:
//
//if (fcntl_lock(pid_fd, F_SETLK, F_WRLCK, SEEK_SET, 0, 0) == -1)
// return -1;
int fcntl_lock(int fd, int cmd, int type, int whence, int start, int len)
{
struct flock lock[1];
lock->l_type = type;
lock->l_whence = whence;
lock->l_start = start;
lock->l_len = len;
return fcntl(fd, cmd, lock);
}
// We try a read lock. The daemon should have a write lock.
// Seen using flock: FreeBSD code
static int has_flock(int fd)
{
return flock(fd, LOCK_SH|LOCK_NB)==-1 && errno==EWOULDBLOCK;
}
// We try a read lock. The daemon should have a write lock.
// Seen using fcntl: libslack
static int has_fcntl(int fd)
{
struct flock f; // seriously, struct flock is for a fnctl lock!
f.l_type = F_RDLCK;
f.l_whence = SEEK_SET;
f.l_start = 0;
f.l_len = 0;
return fcntl(fd,F_SETLK,&f)==-1 && (errno==EACCES || errno==EAGAIN);
}
static union el *read_pidfile(void)
{
char buf[12];
@ -162,13 +198,9 @@ static union el *read_pidfile(void)
goto out;
if(fstat(fd,&sbuf) || !S_ISREG(sbuf.st_mode) || sbuf.st_size<1)
goto out;
if(opt_flock){ // Not that Linux uses this? Maybe fcntl is used?
// an errno==EWOULDBLOCK means we accept the PID
if(!flock(fd, LOCK_SH|LOCK_NB)) // success is bad
// type of lock, if any, is not standardized on Linux
if(opt_flock && !has_flock(fd) && !has_fcntl(fd))
goto out;
if(errno != EWOULDBLOCK)
goto out;
}
memset(buf,'\0',sizeof buf);
buf[read(fd,buf+1,sizeof buf-2)] = '\0';
pid = strtoul(buf+1,&endp,10);