1/*
2 smemcap - a tool for meaningful memory reporting
3
4 Copyright 2008-2009 Matt Mackall <mpm@selenic.com>
5
6 This software may be used and distributed according to the terms of
7 the GNU General Public License version 2 or later, incorporated
8 herein by reference.
9*/
10
11//applet:IF_SMEMCAP(APPLET(smemcap, _BB_DIR_USR_BIN, _BB_SUID_DROP))
12
13//kbuild:lib-$(CONFIG_SMEMCAP) += smemcap.o
14
15//config:config SMEMCAP
16//config:	bool "smemcap"
17//config:	default y
18//config:	help
19//config:	  smemcap is a tool for capturing process data for smem,
20//config:	  a memory usage statistic tool.
21
22#include "libbb.h"
23#include "unarchive.h"
24
25struct fileblock {
26	struct fileblock *next;
27	char data[TAR_BLOCK_SIZE];
28};
29
30static void writeheader(const char *path, struct stat *sb, int type)
31{
32	struct tar_header_t header;
33	int i, sum;
34
35	memset(&header, 0, TAR_BLOCK_SIZE);
36	strcpy(header.name, path);
37	sprintf(header.mode, "%o", sb->st_mode & 0777);
38	/* careful to not overflow fields! */
39	sprintf(header.uid, "%o", sb->st_uid & 07777777);
40	sprintf(header.gid, "%o", sb->st_gid & 07777777);
41	sprintf(header.size, "%o", (unsigned)sb->st_size);
42	sprintf(header.mtime, "%llo", sb->st_mtime & 077777777777LL);
43	header.typeflag = type;
44	//strcpy(header.magic, "ustar  "); - do we want to be standard-compliant?
45
46	/* Calculate and store the checksum (the sum of all of the bytes of
47	 * the header). The checksum field must be filled with blanks for the
48	 * calculation. The checksum field is formatted differently from the
49	 * other fields: it has 6 digits, a NUL, then a space -- rather than
50	 * digits, followed by a NUL like the other fields... */
51	header.chksum[7] = ' ';
52	sum = ' ' * 7;
53	for (i = 0; i < TAR_BLOCK_SIZE; i++)
54		sum += ((unsigned char*)&header)[i];
55	sprintf(header.chksum, "%06o", sum);
56
57	xwrite(STDOUT_FILENO, &header, TAR_BLOCK_SIZE);
58}
59
60static void archivefile(const char *path)
61{
62	struct fileblock *start, *cur;
63	struct fileblock **prev = &start;
64	int fd, r;
65	unsigned size = 0;
66	struct stat s;
67
68	/* buffer the file */
69	fd = xopen(path, O_RDONLY);
70	do {
71		cur = xzalloc(sizeof(*cur));
72		*prev = cur;
73		prev = &cur->next;
74		r = full_read(fd, cur->data, TAR_BLOCK_SIZE);
75		if (r > 0)
76			size += r;
77	} while (r == TAR_BLOCK_SIZE);
78
79	/* write archive header */
80	fstat(fd, &s);
81	close(fd);
82	s.st_size = size;
83	writeheader(path, &s, '0');
84
85	/* dump file contents */
86	for (cur = start; (int)size > 0; size -= TAR_BLOCK_SIZE) {
87		xwrite(STDOUT_FILENO, cur->data, TAR_BLOCK_SIZE);
88		start = cur;
89		cur = cur->next;
90		free(start);
91	}
92}
93
94static void archivejoin(const char *sub, const char *name)
95{
96	char path[sizeof(long long)*3 + sizeof("/cmdline")];
97	sprintf(path, "%s/%s", sub, name);
98	archivefile(path);
99}
100
101//usage:#define smemcap_trivial_usage ">SMEMDATA.TAR"
102//usage:#define smemcap_full_usage "\n\n"
103//usage:       "Collect memory usage data in /proc and write it to stdout"
104
105int smemcap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
106int smemcap_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
107{
108	DIR *d;
109	struct dirent *de;
110
111	xchdir("/proc");
112	d = xopendir(".");
113
114	archivefile("meminfo");
115	archivefile("version");
116	while ((de = readdir(d)) != NULL) {
117		if (isdigit(de->d_name[0])) {
118			struct stat s;
119			memset(&s, 0, sizeof(s));
120			s.st_mode = 0555;
121			writeheader(de->d_name, &s, '5');
122			archivejoin(de->d_name, "smaps");
123			archivejoin(de->d_name, "cmdline");
124			archivejoin(de->d_name, "stat");
125		}
126	}
127
128	return EXIT_SUCCESS;
129}
130