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183 lines
3.3 KiB
183 lines
3.3 KiB
/*
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* fs.c filesystem APIs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Authors: David Ahern <dsa@cumulusnetworks.com>
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*
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*/
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/mount.h>
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#include <ctype.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <limits.h>
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#include "utils.h"
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#define CGROUP2_FS_NAME "cgroup2"
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/* if not already mounted cgroup2 is mounted here for iproute2's use */
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#define MNT_CGRP2_PATH "/var/run/cgroup2"
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/* return mount path of first occurrence of given fstype */
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static char *find_fs_mount(const char *fs_to_find)
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{
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char path[4096];
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char fstype[128]; /* max length of any filesystem name */
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char *mnt = NULL;
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FILE *fp;
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fp = fopen("/proc/mounts", "r");
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if (!fp) {
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fprintf(stderr,
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"Failed to open mounts file: %s\n", strerror(errno));
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return NULL;
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}
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while (fscanf(fp, "%*s %4095s %127s %*s %*d %*d\n",
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path, fstype) == 2) {
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if (strcmp(fstype, fs_to_find) == 0) {
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mnt = strdup(path);
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break;
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}
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}
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fclose(fp);
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return mnt;
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}
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/* caller needs to free string returned */
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char *find_cgroup2_mount(void)
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{
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char *mnt = find_fs_mount(CGROUP2_FS_NAME);
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if (mnt)
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return mnt;
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mnt = strdup(MNT_CGRP2_PATH);
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if (!mnt) {
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fprintf(stderr, "Failed to allocate memory for cgroup2 path\n");
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return NULL;
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}
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if (make_path(mnt, 0755)) {
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fprintf(stderr, "Failed to setup vrf cgroup2 directory\n");
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free(mnt);
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return NULL;
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}
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if (mount("none", mnt, CGROUP2_FS_NAME, 0, NULL)) {
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/* EBUSY means already mounted */
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if (errno == EBUSY)
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goto out;
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if (errno == ENODEV) {
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fprintf(stderr,
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"Failed to mount cgroup2. Are CGROUPS enabled in your kernel?\n");
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} else {
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fprintf(stderr,
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"Failed to mount cgroup2: %s\n",
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strerror(errno));
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}
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free(mnt);
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return NULL;
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}
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out:
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return mnt;
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}
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int make_path(const char *path, mode_t mode)
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{
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char *dir, *delim;
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int rc = -1;
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delim = dir = strdup(path);
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if (dir == NULL) {
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fprintf(stderr, "strdup failed copying path");
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return -1;
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}
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/* skip '/' -- it had better exist */
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if (*delim == '/')
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delim++;
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while (1) {
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delim = strchr(delim, '/');
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if (delim)
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*delim = '\0';
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rc = mkdir(dir, mode);
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if (mkdir(dir, mode) != 0 && errno != EEXIST) {
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fprintf(stderr, "mkdir failed for %s: %s\n",
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dir, strerror(errno));
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goto out;
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}
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if (delim == NULL)
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break;
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*delim = '/';
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delim++;
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if (*delim == '\0')
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break;
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}
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rc = 0;
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out:
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free(dir);
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return rc;
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}
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int get_command_name(const char *pid, char *comm, size_t len)
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{
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char path[PATH_MAX];
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char line[128];
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FILE *fp;
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if (snprintf(path, sizeof(path),
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"/proc/%s/status", pid) >= sizeof(path)) {
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return -1;
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}
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fp = fopen(path, "r");
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if (!fp)
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return -1;
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comm[0] = '\0';
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while (fgets(line, sizeof(line), fp)) {
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char *nl, *name;
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name = strstr(line, "Name:");
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if (!name)
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continue;
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name += 5;
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while (isspace(*name))
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name++;
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nl = strchr(name, '\n');
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if (nl)
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*nl = '\0';
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strlcpy(comm, name, len);
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break;
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}
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fclose(fp);
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return 0;
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}
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