dt_subr_apple.c   [plain text]

#include <dt_impl.h>

#include <errno.h>
#include <sys/sysctl.h>
#include <stdlib.h>

static int
dt_pid_from_process_name(const char* name)
{
	/*
	 * Because of the statically cached array, this function is not thread safe.
	 * Most of this code is from [VMUProcInfo getProcessIds]
	 * The reason we don't call this code directly is because we only get the pids,
	 * and then we have to turn around and construct a VMUProcInfo for each pid to
	 * populate our proc table.
	 */

	static struct kinfo_proc *proc_buf = NULL;
	static int nprocs;

	if (proc_buf == NULL) {
		size_t buf_size;
		int mib[3] = { CTL_KERN, KERN_PROC, KERN_PROC_ALL};
		int err;

		/*
		 * Try to find out how many processes are around so we can
		 * size the buffer appropriately.  sysctl's man page specifically suggests
		 * this approach, and says it returns a bit larger size than needed to handle
		 * any new processes created between then and now.
		 */
		err = sysctl(mib, 4, NULL, &buf_size, NULL, 0);

		if( (err < 0) && (err != ENOMEM)) {
			/*
			 * ENOMEM says we didn't have enough room for the entire buffer.
			 * We don't care about that, we're trying to get the size of a buffer
			 * suitable for getting all the data.
			 */
			xyerror(D_UNKNOWN, "Failure calling sysctl to get process list buffer size");
			return -1;
		}

		/*
		 * Now for the real access.  Create the buffer, and grab the
		 * data.
		 */
		proc_buf = (struct kinfo_proc *)calloc(1, buf_size);

		if(sysctl(mib, 4, proc_buf, &buf_size, NULL, 0) < 0) {
			//perror("Failure calling sysctl to get proc buf");
			free(proc_buf);
			return -1;
		}
		nprocs = (int)(buf_size / (sizeof(struct kinfo_proc)));
	}

	int i;
	for (i = 0; i < nprocs; i++) {
		if (strncmp(name, proc_buf[i].kp_proc.p_comm, MAXCOMLEN) == 0)
			return proc_buf[i].kp_proc.p_pid;
	}

	return -1;
}


dt_ident_t*
dt_macro_lookup(dt_idhash_t *macros, const char *name)
{
	dt_ident_t *idp;
	idp = dt_idhash_lookup(macros, name);
	if (idp != NULL) {
		return idp;
	}
	/*
	 * If the macro was not found, check whether we are trying
	 * an expression that starts with pid_, look up the pid of a process
	 * with that name, and if found, add a macro with that name
	 */
	else if (strncmp(name, "pid_", strlen("pid_")) == 0) {
		int pid = dt_pid_from_process_name(name + strlen("pid_"));
		if (pid != -1) {
			idp = dt_idhash_insert(macros, name + strlen("pid_"), DT_IDENT_SCALAR, 0, pid, _dtrace_prvattr, 0, &dt_idops_thaw, NULL, 0);
			return idp;
		}
		else {
			xyerror(D_PROC_NOT_FOUND, "Could not find process with name %s\n", name + strlen("pid_"));
		}
	}
	return NULL;
}