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-rw-r--r--libblkid/procutils.c124
1 files changed, 124 insertions, 0 deletions
diff --git a/libblkid/procutils.c b/libblkid/procutils.c
new file mode 100644
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+++ b/libblkid/procutils.c
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+/*
+ * Copyright (C) 2011 Davidlohr Bueso <dave@gnu.org>
+ *
+ * procutils.c: General purpose procfs parsing utilities
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library Public License as published by
+ * the Free Software Foundation; either version 2, 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 Library Public License for more details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <ctype.h>
+
+#include "procutils.h"
+#include "c.h"
+
+/*
+ * @pid: process ID for which we want to obtain the threads group
+ *
+ * Returns: newly allocated tasks structure
+ */
+struct proc_tasks *proc_open_tasks(pid_t pid)
+{
+ struct proc_tasks *tasks;
+ char path[PATH_MAX];
+
+ sprintf(path, "/proc/%d/task/", pid);
+
+ tasks = malloc(sizeof(struct proc_tasks));
+ if (tasks) {
+ tasks->dir = opendir(path);
+ if (tasks->dir)
+ return tasks;
+ }
+
+ free(tasks);
+ return NULL;
+}
+
+/*
+ * @tasks: allocated tasks structure
+ *
+ * Returns: nothing
+ */
+void proc_close_tasks(struct proc_tasks *tasks)
+{
+ if (tasks && tasks->dir)
+ closedir(tasks->dir);
+ free(tasks);
+}
+
+/*
+ * @tasks: allocated task structure
+ * @tid: [output] one of the thread IDs belonging to the thread group
+ * If when an error occurs, it is set to 0.
+ *
+ * Returns: 0 on success, 1 on end, -1 on failure or no more threads
+ */
+int proc_next_tid(struct proc_tasks *tasks, pid_t *tid)
+{
+ struct dirent *d;
+ char *end;
+
+ if (!tasks || !tid)
+ return -1;
+
+ *tid = 0;
+ errno = 0;
+
+ do {
+ d = readdir(tasks->dir);
+ if (!d)
+ return errno ? -1 : 1; /* error or end-of-dir */
+
+ if (!isdigit((unsigned char) *d->d_name))
+ continue;
+
+ *tid = (pid_t) strtol(d->d_name, &end, 10);
+ if (errno || d->d_name == end || (end && *end))
+ return -1;
+
+ } while (!*tid);
+
+ return 0;
+}
+
+#ifdef TEST_PROGRAM
+
+int main(int argc, char *argv[])
+{
+ pid_t tid, pid;
+ struct proc_tasks *ts;
+
+ if (argc != 2) {
+ fprintf(stderr, "usage: %s <pid>\n", argv[0]);
+ return EXIT_FAILURE;
+ }
+
+ pid = strtol(argv[1], (char **) NULL, 10);
+ printf("PID=%d, TIDs:", pid);
+
+ ts = proc_open_tasks(pid);
+ if (!ts)
+ err(EXIT_FAILURE, "open list of tasks failed");
+
+ while (proc_next_tid(ts, &tid) == 0)
+ printf(" %d", tid);
+
+ printf("\n");
+ proc_close_tasks(ts);
+ return EXIT_SUCCESS;
+}
+#endif /* TEST_PROGRAM */