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Rename to hibernation-setup-tool
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@lpereira
lpereira committed Jul 30, 2021
1 parent fe6b720 commit 94e3f30
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24 changes: 12 additions & 12 deletions Makefile
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Original file line number Diff line number Diff line change
@@ -1,35 +1,35 @@
OBJS=az-hibernate-agent.o
OBJS=hibernation-setup-tool.o
CFLAGS+=-Os -Wall -Wextra -std=gnu11 -fstack-protector-all -D_FORTIFY_SOURCE=1
LDFLAGS+=-Wl,-z,relro,-z,now

%.o: %.c
$(CC) -c $< $(CFLAGS) -o $@

az-hibernate-agent: $(OBJS)
hibernation-setup-tool: $(OBJS)
$(CC) $(LDFLAGS) -o $@ $^

all: az-hibernate-agent
all: hibernation-setup-tool

.PHONY: clean
clean:
rm -f $(OBJS)
rm -f az-hibernate-agent
rm -f hibernation-setup-tool

.PHONY: install
install: all
ifneq (,$(wildcard az-hibernate-agent.1))
ifneq (,$(wildcard hibernation-setup-tool.1))
install -m 0755 -d $(DESTDIR)/usr/share/man/man1/
install -m 0644 az-hibernate-agent.1 $(DESTDIR)/usr/share/man/man1/
install -m 0644 hibernation-setup-tool.1 $(DESTDIR)/usr/share/man/man1/
endif
install -m 0755 -d $(DESTDIR)/usr/sbin
install -m 0755 -d $(DESTDIR)/lib/systemd/system/
install -m 0755 az-hibernate-agent $(DESTDIR)/usr/sbin
install -m 0644 az-hibernate-agent.service $(DESTDIR)/lib/systemd/system
install -m 0755 hibernation-setup-tool $(DESTDIR)/usr/sbin
install -m 0644 hibernation-setup-tool.service $(DESTDIR)/lib/systemd/system

.PHONY: indent
indent:
clang-format az-hibernate-agent.c > indented.c
mv indented.c az-hibernate-agent.c
clang-format hibernation-setup-tool.c > indented.c
mv indented.c hibernation-setup-tool.c

az-hibernate-agent.1: README.md
pandoc -f markdown -s -t man README.md -o az-hibernate-agent.1
hibernation-setup-tool.1: README.md
pandoc -f markdown -s -t man README.md -o hibernation-setup-tool.1
16 changes: 8 additions & 8 deletions README.md
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Original file line number Diff line number Diff line change
@@ -1,20 +1,20 @@
---
title: az-hibernate-agent
title: hibernation-setup-tool
section: 1
header: Azure VM Agents
footer: az-hibernate-agent 1.0
header: System Utilities
footer: hibernation-setup-tool 1.0
date: June 29, 2021
---


# NAME
az-hibernate-agent - sets up a VM for hibernation
hibernation-setup-tool - sets up a VM for hibernation

# SYNOPSIS
**az-hibernate-agent**
**hibernation-setup-tool**

# DESCRIPTION
**az-hibernate-agent** is a tool that sets up a swap file suitable for
**hibernation-setup-tool** is a tool that sets up a swap file suitable for
hibernation, and sets up the system to enable proper resuming.

It accomplishes that by creating a swap file in the root directory that's slightly
Expand Down Expand Up @@ -55,10 +55,10 @@ The tool will return 0 on success, and 1 on failure.
Written by [Leandro Pereira](mailto:[email protected]).

# BUGS
[Submit bug reports online](https://github.com/microsoft/az-hibernate-agent/issues).
[Submit bug reports online](https://github.com/microsoft/hibernation-setup-tool/issues).

# SEE ALSO
[Full source code is available](https://github.com/microsoft/az-hibernate-agent/).
[Full source code is available](https://github.com/microsoft/hibernation-setup-tool/).

# NOTES
This program requires superuser privileges to execute.
Expand Down
59 changes: 29 additions & 30 deletions az-hibernate-agent.c → hibernation-setup-tool.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
// Azure Hibernation Agent
// Sets up a swap area suitable to hibernate a virtual machine in an Azure
// environment.
// Hibernation Setup Tool
// Sets up a swap area suitable to hibernate a Linux system.
//
// Copyright (c) 2021 Microsoft Corp.
// Licensed under the terms of the MIT license.
Expand Down Expand Up @@ -70,7 +69,7 @@ static const char swap_file_name[] = "/hibfile.sys";

/* Prefix is needed when not running as a service. Output from this the tool is fed to the
* system log while systemd is processing the request to hibernate. This makes it easier to
* grep for az-hibernate-agent there too in case of a failure. */
* grep for hibernation-setup-tool there too in case of a failure. */
static bool log_needs_prefix = false;

/* We don't always want to spam syslog: spamming stdout is fine as this is supposed to be
Expand All @@ -81,7 +80,7 @@ static bool log_needs_syslog = false;

/* This is a link pointing to a file in a tmpfs filesystem and is mostly used to detect
* if we got a cold boot or not. */
static const char hibernate_lock_file_name[] = "/etc/az-hibernate-agent.last_hibernation";
static const char hibernate_lock_file_name[] = "/etc/hibernation-setup-tool.last_hibernation";

enum host_vm_notification {
HOST_VM_NOTIFY_COLD_BOOT, /* Sent every time system cold boots */
Expand All @@ -105,7 +104,7 @@ static void log_impl(int log_level, const char *fmt, va_list ap)
flockfile(stdout);

if (log_needs_prefix)
printf("az-hibernate-agent: ");
printf("hibernation-setup-tool: ");

if (log_level & LOG_INFO)
printf("INFO: ");
Expand Down Expand Up @@ -994,7 +993,7 @@ static bool update_kernel_cmdline_params_for_grub(
if (!conf)
log_fatal("Could not open initramfs-tools configuration file: %s", strerror(errno));

fprintf(conf, "# Updated automatically by az-hibernate-agent. Do not modify.\n");
fprintf(conf, "# Updated automatically by hibernation-setup-tool. Do not modify.\n");
fprintf(conf, "RESUME=UUID=%s\n", dev_uuid);
fclose(conf);
spawn_and_wait("update-initramfs", 1, "-u");
Expand Down Expand Up @@ -1028,12 +1027,12 @@ static bool update_kernel_cmdline_params_for_grub(
bool in_az_hibernate_agent_block = false;
while (fgets(buffer, sizeof(buffer), resume_cfg)) {
if (in_az_hibernate_agent_block) {
if (strstr(buffer, "# az-hibernate-agent:end"))
if (strstr(buffer, "# hibernation-setup-tool:end"))
in_az_hibernate_agent_block = false;
continue;
}

if (strstr(buffer, "# az-hibernate-agent:start")) {
if (strstr(buffer, "# hibernation-setup-tool:start")) {
in_az_hibernate_agent_block = true;
continue;
}
Expand All @@ -1060,9 +1059,9 @@ static bool update_kernel_cmdline_params_for_grub(
free(old_contents);
}

fprintf(resume_cfg, "\n# az-hibernate-agent:start\n");
fprintf(resume_cfg, "\n# hibernation-setup-tool:start\n");
fprintf(resume_cfg, "GRUB_CMDLINE_LINUX_DEFAULT=\"$GRUB_CMDLINE_LINUX_DEFAULT %s\"\n", args);
fprintf(resume_cfg, "# az-hibernate-agent:end\n");
fprintf(resume_cfg, "# hibernation-setup-tool:end\n");

fclose(resume_cfg);

Expand Down Expand Up @@ -1330,57 +1329,57 @@ static int handle_pre_systemd_suspend_notification(const char *action)
for (int try = 0;; try++) {
if (try > 10) {
notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
log_fatal("Tried too many times to create /tmp/az-hibernate-agent and failed. Giving up");
log_fatal("Tried too many times to create /tmp/hibernation-setup-tool and failed. Giving up");
}

if (!mkdir("/tmp/az-hibernate-agent", 0700))
if (!mkdir("/tmp/hibernation-setup-tool", 0700))
break;
if (errno != EEXIST) {
notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
log_fatal("Couldn't create location to store hibernation agent state: %s", strerror(errno));
}

struct stat st;
if (!stat("/tmp/az-hibernate-agent", &st)) {
if (!stat("/tmp/hibernation-setup-tool", &st)) {
if (S_ISDIR(st.st_mode)) {
log_info("/tmp/az-hibernate-agent exists, removing it");
log_info("/tmp/hibernation-setup-tool exists, removing it");

if (umount2("/tmp/az-hibernate-agent", UMOUNT_NOFOLLOW | MNT_DETACH) < 0) {
if (umount2("/tmp/hibernation-setup-tool", UMOUNT_NOFOLLOW | MNT_DETACH) < 0) {
/* See comment related to the umount2() call in handle_post_systemd_suspend_notification(). */
if (errno != EINVAL)
log_fatal("Error while unmounting /tmp/az-hibernate-agent: %s", strerror(errno));
log_fatal("Error while unmounting /tmp/hibernation-setup-tool: %s", strerror(errno));
}

if (recursive_rmdir("/tmp/az-hibernate-agent"))
if (recursive_rmdir("/tmp/hibernation-setup-tool"))
continue;

notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
log_fatal("Couldn't remove /tmp/az-hibernate-agent directory before proceeding");
log_fatal("Couldn't remove /tmp/hibernation-setup-tool directory before proceeding");
}

log_info("/tmp/az-hibernate-agent exists and isn't a directory! Removing it and trying again (try %d)", try);
log_info("/tmp/hibernation-setup-tool exists and isn't a directory! Removing it and trying again (try %d)", try);

if (!unlink("/tmp/az-hibernate-agent"))
if (!unlink("/tmp/hibernation-setup-tool"))
continue;

notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
log_fatal("Couldn't remove the file: %s, giving up", strerror(errno));
}

log_info("/tmp/az-hibernate-agent couldn't be found but mkdir() told us it exists, trying again (try %d)", try);
log_info("/tmp/hibernation-setup-tool couldn't be found but mkdir() told us it exists, trying again (try %d)", try);
continue;
}

if (!is_file_on_fs("/tmp/az-hibernate-agent", TMPFS_MAGIC)) {
log_info("/tmp isn't a tmpfs filesystem; trying to mount /tmp/az-hibernate-agent as such");
if (!is_file_on_fs("/tmp/hibernation-setup-tool", TMPFS_MAGIC)) {
log_info("/tmp isn't a tmpfs filesystem; trying to mount /tmp/hibernation-setup-tool as such");

if (mount("tmpfs", "/tmp/az-hibernate-agent", "tmpfs", 0, NULL) < 0) {
if (mount("tmpfs", "/tmp/hibernation-setup-tool", "tmpfs", 0, NULL) < 0) {
notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
log_fatal("Couldn't mount temporary filesystem: %s. We need this to detect cold boots!", strerror(errno));
}
}

char pattern[] = "/tmp/az-hibernate-agent/hibernatedXXXXXX";
char pattern[] = "/tmp/hibernation-setup-tool/hibernatedXXXXXX";
int fd = mkostemp(pattern, O_CLOEXEC);
if (fd < 0) {
notify_vm_host(HOST_VM_NOTIFY_PRE_HIBERNATION_FAILED);
Expand Down Expand Up @@ -1423,17 +1422,17 @@ static int handle_post_systemd_suspend_notification(const char *action)
if (unlink(hibernate_lock_file_name) < 0)
log_info("This is fine, but couldn't remove %s: %s", hibernate_lock_file_name, strerror(errno));

if (umount2("/tmp/az-hibernate-agent", UMOUNT_NOFOLLOW | MNT_DETACH) < 0) {
if (umount2("/tmp/hibernation-setup-tool", UMOUNT_NOFOLLOW | MNT_DETACH) < 0) {
/* EINVAL is returned if this isn't a mount point. This is normal if /tmp was already
* a tmpfs and we didn't create and mounted this directory in the pre-hibernate hook.
* Calling umount2() is cheaper than checking if this directory is indeed mounted as
* a tmpfs directory. */
if (errno != EINVAL)
log_info("While unmounting /tmp/az-hibernate-agent: %s", strerror(errno));
log_info("While unmounting /tmp/hibernation-setup-tool: %s", strerror(errno));
}

if (!recursive_rmdir("/tmp/az-hibernate-agent"))
log_info("While removing /tmp/az-hibernate-agent: %s", strerror(errno));
if (!recursive_rmdir("/tmp/hibernation-setup-tool"))
log_info("While removing /tmp/hibernation-setup-tool: %s", strerror(errno));

notify_vm_host(HOST_VM_NOTIFY_RESUMED_FROM_HIBERNATION);
log_info("Post-hibernation hooks executed successfully");
Expand Down
4 changes: 2 additions & 2 deletions az-hibernate-agent.service → hibernation-setup-tool.service
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Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
[Unit]
Description=Azure Hibernation Agent
Description=Hibernation Setup Tool

[Service]
Type=simple
ExecStart=/usr/sbin/az-hibernate-agent
ExecStart=/usr/sbin/hibernation-setup-tool
RemainAfterExit=false
StandardOutput=journal

Expand Down

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