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git.proxmox.com Git - mirror_lxc.git/blob - src/lxc/utils.h
1 /* SPDX-License-Identifier: LGPL-2.1+ */
6 /* Properly support loop devices on 32bit systems. */
7 #define _FILE_OFFSET_BITS 64
10 #define MAX_GRBUF_SIZE 65536
14 #include <linux/loop.h>
15 #include <linux/types.h>
19 #include <sys/syscall.h>
20 #include <sys/types.h>
24 #include "file_utils.h"
25 #include "initutils.h"
27 #include "raw_syscalls.h"
28 #include "string_utils.h"
30 /* returns 1 on success, 0 if there were any failures */
31 extern int lxc_rmdir_onedev(const char *path
, const char *exclude
);
32 extern int get_u16(unsigned short *val
, const char *arg
, int base
);
33 extern int mkdir_p(const char *dir
, mode_t mode
);
34 extern char *get_rundir(void);
36 /* Define getline() if missing from the C library */
39 #include <../include/getline.h>
43 static inline int lxc_set_cloexec(int fd
)
45 return fcntl(fd
, F_SETFD
, FD_CLOEXEC
);
49 * Struct to carry child pid from lxc_popen() to lxc_pclose(). Not an opaque
50 * struct to allow direct access to the underlying FILE without additional
53 struct lxc_popen_FILE
{
59 /* popen(command, "re") replacement that restores default signal mask
60 * via sigprocmask(2) (unblocks all signals) after fork(2) but prior to calling exec(3).
61 * In short, popen(command, "re") does pipe() + fork() + exec()
62 * while lxc_popen(command) does pipe() + fork() + sigprocmask() + exec().
63 * Returns pointer to struct lxc_popen_FILE, that should be freed with lxc_pclose().
64 * On error returns NULL.
66 extern struct lxc_popen_FILE
*lxc_popen(const char *command
);
68 /* pclose() replacement to be used on struct lxc_popen_FILE *,
69 * returned by lxc_popen().
70 * Waits for associated process to terminate, returns its exit status and
71 * frees resources, pointed to by struct lxc_popen_FILE *.
73 extern int lxc_pclose(struct lxc_popen_FILE
*fp
);
76 * wait on a child we forked
78 extern int wait_for_pid(pid_t pid
);
79 extern int lxc_wait_for_pid_status(pid_t pid
);
82 extern int sha1sum_file(char *fnam
, unsigned char *md_value
, unsigned int *md_len
);
85 /* initialize rand with urandom */
86 extern int randseed(bool);
88 /* are we unprivileged with respect to our namespaces */
89 inline static bool am_guest_unpriv(void) {
90 return geteuid() != 0;
93 /* are we unprivileged with respect to init_user_ns */
94 inline static bool am_host_unpriv(void)
97 uid_t user
, host
, count
;
103 /* Now: are we in a user namespace? Because then we're also
106 f
= fopen("/proc/self/uid_map", "r");
111 ret
= fscanf(f
, "%u %u %u", &user
, &host
, &count
);
117 if (user
!= 0 || host
!= 0 || count
!= UINT32_MAX
)
123 * parse /proc/self/uid_map to find what @orig maps to
125 extern uid_t
get_ns_uid(uid_t orig
);
127 * parse /proc/self/gid_map to find what @orig maps to
129 extern gid_t
get_ns_gid(gid_t orig
);
131 extern bool dir_exists(const char *path
);
133 #define FNV1A_64_INIT ((uint64_t)0xcbf29ce484222325ULL)
134 extern uint64_t fnv_64a_buf(void *buf
, size_t len
, uint64_t hval
);
136 extern bool is_shared_mountpoint(const char *path
);
137 extern int detect_shared_rootfs(void);
138 extern bool detect_ramfs_rootfs(void);
139 extern char *on_path(const char *cmd
, const char *rootfs
);
140 extern bool cgns_supported(void);
141 extern char *choose_init(const char *rootfs
);
142 extern bool switch_to_ns(pid_t pid
, const char *ns
);
143 extern char *get_template_path(const char *t
);
144 extern int safe_mount(const char *src
, const char *dest
, const char *fstype
,
145 unsigned long flags
, const void *data
,
147 extern int lxc_mount_proc_if_needed(const char *rootfs
);
148 extern int open_devnull(void);
149 extern int set_stdfds(int fd
);
150 extern int null_stdfds(void);
151 extern int lxc_preserve_ns(const int pid
, const char *ns
);
153 /* Check whether a signal is blocked by a process. */
154 extern bool task_blocks_signal(pid_t pid
, int signal
);
156 /* Switch to a new uid and gid.
157 * If LXC_INVALID_{G,U}ID is passed then the set{g,u}id() will not be called.
159 extern bool lxc_switch_uid_gid(uid_t uid
, gid_t gid
);
160 extern bool lxc_setgroups(int size
, gid_t list
[]);
162 /* Find an unused loop device and associate it with source. */
163 extern int lxc_prepare_loop_dev(const char *source
, char *loop_dev
, int flags
);
165 /* Clear all mounts on a given node.
166 * >= 0 successfully cleared. The number returned is the number of umounts
168 * < 0 error umounting. Return -errno.
170 extern int lxc_unstack_mountpoint(const char *path
, bool lazy
);
173 * run_command runs a command and collect it's std{err,out} output in buf.
175 * @param[out] buf The buffer where the commands std{err,out] output will be
176 * read into. If no output was produced, buf will be memset
178 * @param[in] buf_size The size of buf. This function will reserve one byte for
180 * @param[in] child_fn The function to be run in the child process. This
181 * function must exec.
182 * @param[in] args Arguments to be passed to child_fn.
184 extern int run_command(char *buf
, size_t buf_size
, int (*child_fn
)(void *),
188 * run_command runs a command and collect it's std{err,out} output in buf, returns exit status.
190 * @param[out] buf The buffer where the commands std{err,out] output will be
191 * read into. If no output was produced, buf will be memset
193 * @param[in] buf_size The size of buf. This function will reserve one byte for
195 * @param[in] child_fn The function to be run in the child process. This
196 * function must exec.
197 * @param[in] args Arguments to be passed to child_fn.
199 extern int run_command_status(char *buf
, size_t buf_size
, int (*child_fn
)(void *),
202 /* return copy of string @entry; do not fail. */
203 extern char *must_copy_string(const char *entry
);
205 /* Re-allocate a pointer, do not fail */
206 extern void *must_realloc(void *orig
, size_t sz
);
208 extern bool lxc_nic_exists(char *nic
);
210 static inline uint64_t lxc_getpagesize(void)
214 pgsz
= sysconf(_SC_PAGESIZE
);
221 /* If n is not a power of 2 this function will return the next power of 2
222 * greater than that number. Note that this function always returns the *next*
223 * power of 2 *greater* that number not the *nearest*. For example, passing 1025
224 * as argument this function will return 2048 although the closest power of 2
226 * If the caller passes in 0 they will receive 0 in return since this is invalid
227 * input and 0 is not a power of 2.
229 extern uint64_t lxc_find_next_power2(uint64_t n
);
231 /* Set a signal the child process will receive after the parent has died. */
232 extern int lxc_set_death_signal(int signal
, pid_t parent
, int parent_status_fd
);
233 extern int fd_cloexec(int fd
, bool cloexec
);
234 extern int recursive_destroy(const char *dirname
);
235 extern int lxc_setup_keyring(char *keyring_label
);
237 #endif /* __LXC_UTILS_H */