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/*
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* fs.c filesystem APIs
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*
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3880ab |
* This program is free software; you can redistribute it and/or
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3880ab |
* 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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3880ab |
#include <sys/stat.h>
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3880ab |
#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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|
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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(bool do_mount)
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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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if (!do_mount) {
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fprintf(stderr, "Failed to find cgroup2 mount\n");
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return NULL;
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}
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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 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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3880ab |
"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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3880ab |
"Failed to mount cgroup2: %s\n",
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3880ab |
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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__u64 get_cgroup2_id(const char *path)
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{
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char fh_buf[sizeof(struct file_handle) + sizeof(__u64)] = { 0 };
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struct file_handle *fhp = (struct file_handle *)fh_buf;
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union {
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__u64 id;
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unsigned char bytes[sizeof(__u64)];
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} cg_id = { .id = 0 };
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char *mnt = NULL;
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int mnt_fd = -1;
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int mnt_id;
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3880ab |
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if (!path) {
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fprintf(stderr, "Invalid cgroup2 path\n");
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return 0;
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}
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fhp->handle_bytes = sizeof(__u64);
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if (name_to_handle_at(AT_FDCWD, path, fhp, &mnt_id, 0) < 0) {
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/* try at cgroup2 mount */
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while (*path == '/')
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path++;
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if (*path == '\0') {
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fprintf(stderr, "Invalid cgroup2 path\n");
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goto out;
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}
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|
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mnt = find_cgroup2_mount(false);
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if (!mnt)
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goto out;
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3880ab |
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mnt_fd = open(mnt, O_RDONLY);
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if (mnt_fd < 0) {
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fprintf(stderr, "Failed to open cgroup2 mount\n");
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3880ab |
goto out;
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3880ab |
}
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3880ab |
|
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fhp->handle_bytes = sizeof(__u64);
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if (name_to_handle_at(mnt_fd, path, fhp, &mnt_id, 0) < 0) {
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fprintf(stderr, "Failed to get cgroup2 ID: %s\n",
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3880ab |
strerror(errno));
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|
Packit Service |
3880ab |
goto out;
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3880ab |
}
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}
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3880ab |
if (fhp->handle_bytes != sizeof(__u64)) {
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3880ab |
fprintf(stderr, "Invalid size of cgroup2 ID\n");
|
|
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3880ab |
goto out;
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|
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3880ab |
}
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3880ab |
|
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3880ab |
memcpy(cg_id.bytes, fhp->f_handle, sizeof(__u64));
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3880ab |
|
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out:
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3880ab |
close(mnt_fd);
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3880ab |
free(mnt);
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Packit Service |
3880ab |
|
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3880ab |
return cg_id.id;
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|
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3880ab |
}
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3880ab |
|
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3880ab |
#define FILEID_INO32_GEN 1
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|
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/* caller needs to free string returned */
|
|
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3880ab |
char *get_cgroup2_path(__u64 id, bool full)
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|
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3880ab |
{
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|
Packit Service |
3880ab |
char fh_buf[sizeof(struct file_handle) + sizeof(__u64)] = { 0 };
|
|
Packit Service |
3880ab |
struct file_handle *fhp = (struct file_handle *)fh_buf;
|
|
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3880ab |
union {
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|
Packit Service |
3880ab |
__u64 id;
|
|
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3880ab |
unsigned char bytes[sizeof(__u64)];
|
|
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3880ab |
} cg_id = { .id = id };
|
|
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3880ab |
int mnt_fd = -1, fd = -1;
|
|
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3880ab |
char link_buf[PATH_MAX];
|
|
Packit Service |
3880ab |
char *path = NULL;
|
|
Packit Service |
3880ab |
char fd_path[64];
|
|
Packit Service |
3880ab |
int link_len;
|
|
Packit Service |
3880ab |
char *mnt;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
if (!id) {
|
|
Packit Service |
3880ab |
fprintf(stderr, "Invalid cgroup2 ID\n");
|
|
Packit Service |
3880ab |
return NULL;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
mnt = find_cgroup2_mount(false);
|
|
Packit Service |
3880ab |
if (!mnt)
|
|
Packit Service |
3880ab |
return NULL;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
mnt_fd = open(mnt, O_RDONLY);
|
|
Packit Service |
3880ab |
if (mnt_fd < 0) {
|
|
Packit Service |
3880ab |
fprintf(stderr, "Failed to open cgroup2 mount\n");
|
|
Packit Service |
3880ab |
goto out;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
fhp->handle_bytes = sizeof(__u64);
|
|
Packit Service |
3880ab |
fhp->handle_type = FILEID_INO32_GEN;
|
|
Packit Service |
3880ab |
memcpy(fhp->f_handle, cg_id.bytes, sizeof(__u64));
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
fd = open_by_handle_at(mnt_fd, fhp, 0);
|
|
Packit Service |
3880ab |
if (fd < 0) {
|
|
Packit Service |
3880ab |
fprintf(stderr, "Failed to open cgroup2 by ID\n");
|
|
Packit Service |
3880ab |
goto out;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
snprintf(fd_path, sizeof(fd_path), "/proc/self/fd/%d", fd);
|
|
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3880ab |
link_len = readlink(fd_path, link_buf, sizeof(link_buf) - 1);
|
|
Packit Service |
3880ab |
if (link_len < 0) {
|
|
Packit Service |
3880ab |
fprintf(stderr,
|
|
Packit Service |
3880ab |
"Failed to read value of symbolic link %s\n",
|
|
Packit Service |
3880ab |
fd_path);
|
|
Packit Service |
3880ab |
goto out;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
link_buf[link_len] = '\0';
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
if (full)
|
|
Packit Service |
3880ab |
path = strdup(link_buf);
|
|
Packit Service |
3880ab |
else
|
|
Packit Service |
3880ab |
path = strdup(link_buf + strlen(mnt));
|
|
Packit Service |
3880ab |
if (!path)
|
|
Packit Service |
3880ab |
fprintf(stderr,
|
|
Packit Service |
3880ab |
"Failed to allocate memory for cgroup2 path\n");
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
out:
|
|
Packit Service |
3880ab |
close(fd);
|
|
Packit Service |
3880ab |
close(mnt_fd);
|
|
Packit Service |
3880ab |
free(mnt);
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
return path;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
int make_path(const char *path, mode_t mode)
|
|
Packit Service |
3880ab |
{
|
|
Packit Service |
3880ab |
char *dir, *delim;
|
|
Packit Service |
3880ab |
int rc = -1;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
delim = dir = strdup(path);
|
|
Packit Service |
3880ab |
if (dir == NULL) {
|
|
Packit Service |
3880ab |
fprintf(stderr, "strdup failed copying path");
|
|
Packit Service |
3880ab |
return -1;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
/* skip '/' -- it had better exist */
|
|
Packit Service |
3880ab |
if (*delim == '/')
|
|
Packit Service |
3880ab |
delim++;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
while (1) {
|
|
Packit Service |
3880ab |
delim = strchr(delim, '/');
|
|
Packit Service |
3880ab |
if (delim)
|
|
Packit Service |
3880ab |
*delim = '\0';
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
rc = mkdir(dir, mode);
|
|
Packit Service |
3880ab |
if (mkdir(dir, mode) != 0 && errno != EEXIST) {
|
|
Packit Service |
3880ab |
fprintf(stderr, "mkdir failed for %s: %s\n",
|
|
Packit Service |
3880ab |
dir, strerror(errno));
|
|
Packit Service |
3880ab |
goto out;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
if (delim == NULL)
|
|
Packit Service |
3880ab |
break;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
*delim = '/';
|
|
Packit Service |
3880ab |
delim++;
|
|
Packit Service |
3880ab |
if (*delim == '\0')
|
|
Packit Service |
3880ab |
break;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
rc = 0;
|
|
Packit Service |
3880ab |
out:
|
|
Packit Service |
3880ab |
free(dir);
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
return rc;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
int get_command_name(const char *pid, char *comm, size_t len)
|
|
Packit Service |
3880ab |
{
|
|
Packit Service |
3880ab |
char path[PATH_MAX];
|
|
Packit Service |
3880ab |
char line[128];
|
|
Packit Service |
3880ab |
FILE *fp;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
if (snprintf(path, sizeof(path),
|
|
Packit Service |
3880ab |
"/proc/%s/status", pid) >= sizeof(path)) {
|
|
Packit Service |
3880ab |
return -1;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
fp = fopen(path, "r");
|
|
Packit Service |
3880ab |
if (!fp)
|
|
Packit Service |
3880ab |
return -1;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
comm[0] = '\0';
|
|
Packit Service |
3880ab |
while (fgets(line, sizeof(line), fp)) {
|
|
Packit Service |
3880ab |
char *nl, *name;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
name = strstr(line, "Name:");
|
|
Packit Service |
3880ab |
if (!name)
|
|
Packit Service |
3880ab |
continue;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
name += 5;
|
|
Packit Service |
3880ab |
while (isspace(*name))
|
|
Packit Service |
3880ab |
name++;
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
nl = strchr(name, '\n');
|
|
Packit Service |
3880ab |
if (nl)
|
|
Packit Service |
3880ab |
*nl = '\0';
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
strlcpy(comm, name, len);
|
|
Packit Service |
3880ab |
break;
|
|
Packit Service |
3880ab |
}
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
fclose(fp);
|
|
Packit Service |
3880ab |
|
|
Packit Service |
3880ab |
return 0;
|
|
Packit Service |
3880ab |
}
|