lxcfs/0011-lxcfs-add-proc-partitions.patch

From f4486dde281016cda897f1564dcb8ca0303f2fbf Mon Sep 17 00:00:00 2001
From: yangjiaqi <yangjiaqi16@huawei.com>
Date: Thu, 25 Nov 2021 16:01:12 +0800
Subject: [PATCH 11/17] lxcfs-add-proc-partitions

---
 src/bindings.h  |   3 ++
 src/proc_fuse.c | 131 +++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 126 insertions(+), 8 deletions(-)

diff --git a/src/bindings.h b/src/bindings.h
index cd7d466..91d44c7 100644
--- a/src/bindings.h
+++ b/src/bindings.h
@@ -55,6 +55,9 @@ enum lxcfs_virt_t {
 	LXC_TYPE_PROC_LOADAVG,
 #define LXC_TYPE_PROC_LOADAVG_PATH "/proc/loadavg"
 
+	LXC_TYPE_PROC_PARTITIONS,
+#define LXC_TYPE_PROC_PARTITIONS_PATH "/proc/partitions"
+
 	LXC_TYPE_SYS_DEVICES,
 	LXC_TYPE_SYS_DEVICES_SYSTEM,
 	LXC_TYPE_SYS_DEVICES_SYSTEM_CPU,
diff --git a/src/proc_fuse.c b/src/proc_fuse.c
index a613688..72f6de6 100644
--- a/src/proc_fuse.c
+++ b/src/proc_fuse.c
@@ -118,13 +118,14 @@ __lxcfs_fuse_ops int proc_getattr(const char *path, struct stat *sb)
 		return 0;
 	}
 
-	if (strcmp(path, "/proc/meminfo")	== 0 ||
-	    strcmp(path, "/proc/cpuinfo")	== 0 ||
-	    strcmp(path, "/proc/uptime")	== 0 ||
-	    strcmp(path, "/proc/stat")		== 0 ||
-	    strcmp(path, "/proc/diskstats")	== 0 ||
-	    strcmp(path, "/proc/swaps")		== 0 ||
-	    strcmp(path, "/proc/loadavg")	== 0) {
+	if (strcmp(path, "/proc/meminfo")	 == 0 ||
+	    strcmp(path, "/proc/cpuinfo")	 == 0 ||
+	    strcmp(path, "/proc/uptime")	 == 0 ||
+	    strcmp(path, "/proc/stat")		 == 0 ||
+	    strcmp(path, "/proc/diskstats")	 == 0 ||
+	    strcmp(path, "/proc/swaps")		 == 0 ||
+	    strcmp(path, "/proc/loadavg")	 == 0 ||
+		strcmp(path, "/proc/partitions") == 0) {
 		sb->st_size = get_procfile_size(path);
 		sb->st_mode = S_IFREG | 00444;
 		sb->st_nlink = 1;
@@ -146,7 +147,8 @@ __lxcfs_fuse_ops int proc_readdir(const char *path, void *buf,
 	    DIR_FILLER(filler, buf, "uptime",	NULL, 0) != 0 ||
 	    DIR_FILLER(filler, buf, "diskstats",	NULL, 0) != 0 ||
 	    DIR_FILLER(filler, buf, "swaps",	NULL, 0) != 0 ||
-	    DIR_FILLER(filler, buf, "loadavg",	NULL, 0) != 0)
+	    DIR_FILLER(filler, buf, "loadavg",	NULL, 0) != 0 ||
+		DIR_FILLER(filler, buf, "partitions",	NULL, 0) != 0)
 		return -EINVAL;
 
 	return 0;
@@ -171,6 +173,8 @@ __lxcfs_fuse_ops int proc_open(const char *path, struct fuse_file_info *fi)
 		type = LXC_TYPE_PROC_SWAPS;
 	else if (strcmp(path, "/proc/loadavg") == 0)
 		type = LXC_TYPE_PROC_LOADAVG;
+	else if (strcmp(path, "/proc/partitions") == 0)
+		type = LXC_TYPE_PROC_PARTITIONS;
 	if (type == -1)
 		return -ENOENT;
 
@@ -872,6 +876,111 @@ static int proc_diskstats_read(char *buf, size_t size, off_t offset,
 	return total_len;
 }
 
+static int proc_partitions_read(char *buf, size_t size, off_t offset,
+		struct fuse_file_info *fi)
+{
+	char dev_name[72] = {0};
+	struct fuse_context *fc = fuse_get_context();
+	struct file_info *d = (struct file_info *)fi->fh;
+	struct devinfo *container_devinfo = NULL, *ptr = NULL;
+	char *cg = NULL;
+	char *cache = d->buf;
+	size_t cache_size = d->buflen;
+	char *line = NULL;
+	size_t linelen = 0, total_len = 0;
+	int rv = 0;
+	unsigned int major = 0, minor = 0;
+	unsigned long long blocks = 0;
+	int i = 0, lines = 0;
+	bool found = false;
+	FILE *f = NULL;
+
+	if (offset > 0){
+		if (offset > d->size)
+			return -EINVAL;
+		if (d->cached == 0)
+			return 0;
+		int left = d->size - offset;
+		total_len = left > size ? size: left;
+
+		memcpy(buf, cache + offset, total_len);
+		return total_len;
+	}
+
+	pid_t initpid = lookup_initpid_in_store(fc->pid);
+	if (initpid <= 0)
+		initpid = fc->pid;
+	cg = get_pid_cgroup(initpid, "blkio");
+	if (cg == NULL)
+		return read_file_fuse("/proc/partitions", buf, size, d);
+	prune_init_slice(cg);
+
+	f = fopen("/proc/partitions", "r");
+	if (f == NULL)
+		goto err;
+
+	lock_mutex(&container_dev_mutex);
+	container_devinfo = container_dev_read(initpid);
+	unlock_mutex(&container_dev_mutex);
+
+	while (getline(&line, &linelen, f) != -1) {
+		ssize_t l;
+		char lbuf[256];
+
+		if (lines < 2) {
+			strncpy(lbuf, line, sizeof(lbuf)-1);
+			lines++;
+		} else {
+			memset(dev_name, 0, sizeof(dev_name));
+
+			i = sscanf(line, "%u %u %llu %71s", &major, &minor, &blocks, dev_name);
+			if (i != 4)
+				continue;
+			found = false;
+			for (ptr = container_devinfo; ptr != NULL; ptr = ptr->next) {
+				if (major == ptr->major && minor == ptr->minor) {
+					snprintf(lbuf, 256, "%4u  %7u %10llu %s\n", major, minor, blocks, ptr->name);
+					found = true;
+				}
+			}
+			if (!found)
+				continue;
+		}
+
+		l = snprintf(cache, cache_size, "%s", lbuf);
+		if (l < 0) {
+			perror("Error writing to fuse buf");
+			rv = 0;
+			goto err;
+		}
+		if (l >= cache_size) {
+			lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+			rv = 0;
+			goto err;
+		}
+		cache += l;
+		cache_size -= l;
+		total_len += l;
+	}
+	d->cached = 1;
+	d->size = total_len;
+	if (total_len > size )
+		total_len = size;
+
+	memcpy(buf, d->buf, total_len);
+
+	rv = total_len;
+err:
+	free(cg);
+	cg = NULL;
+	if (f != NULL)
+		fclose(f);
+	free(line);
+	line = NULL;
+	free_devinfo_list(container_devinfo);
+	return rv;
+}
+
 #ifdef RELOADTEST
 static inline void iwashere(void)
 {
@@ -1676,6 +1785,12 @@ __lxcfs_fuse_ops int proc_read(const char *path, char *buf, size_t size,
 
 		return read_file_fuse_with_offset(LXC_TYPE_PROC_LOADAVG_PATH,
 						  buf, size, offset, f);
+	case LXC_TYPE_PROC_PARTITIONS:
+		if(liblxcfs_functional())
+			return proc_partitions_read(buf, size, offset, fi);
+
+		return read_file_fuse_with_offset(LXC_TYPE_PROC_PARTITIONS_PATH,
+						  buf, size, offset, f);
 	}
 
 	return -EINVAL;
-- 
2.27.0