smemcap: new applet

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/procps/smemcap.c b/procps/smemcap.c
new file mode 100644 (file)
index 0000000..cdcc891
--- /dev/null
+++ b/procps/smemcap.c
@@ -0,0 +1,152 @@
+/*
+ smemcap - a tool for meaningful memory reporting
+
+ Copyright 2008-2009 Matt Mackall <mpm@selenic.com>
+
+ This software may be used and distributed according to the terms of
+ the GNU General Public License version 2 or later, incorporated
+ herein by reference.
+*/
+
+//applet:IF_SMEMCAP(APPLET(smemcap, _BB_DIR_USR_BIN, _BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_SMEMCAP) += smemcap.o
+
+//config:config SMEMCAP
+//config:      bool "smemcap"
+//config:      default y
+//config:      help
+//config:        smemcap is a tool for capturing process data for smem,
+//config:        a memory usage statistic tool.
+
+#include "libbb.h"
+
+struct tar_header {
+       char name[100];           /*   0-99 */
+       char mode[8];             /* 100-107 */
+       char uid[8];              /* 108-115 */
+       char gid[8];              /* 116-123 */
+       char size[12];            /* 124-135 */
+       char mtime[12];           /* 136-147 */
+       char chksum[8];           /* 148-155 */
+       char typeflag;            /* 156-156 */
+       char linkname[100];       /* 157-256 */
+       /* POSIX:   "ustar" NUL "00" */
+       /* GNU tar: "ustar  " NUL */
+       /* Normally it's defined as magic[6] followed by
+        * version[2], but we put them together to save code.
+        */
+       char magic[8];            /* 257-264 */
+       char uname[32];           /* 265-296 */
+       char gname[32];           /* 297-328 */
+       char devmajor[8];         /* 329-336 */
+       char devminor[8];         /* 337-344 */
+       char prefix[155];         /* 345-499 */
+       char padding[12];         /* 500-512 (pad to exactly TAR_512) */
+};
+
+struct fileblock {
+       struct fileblock *next;
+       char data[512];
+};
+
+static void writeheader(const char *path, struct stat *sb, int type)
+{
+       struct tar_header header;
+       int i, sum;
+
+       memset(&header, 0, 512);
+       strcpy(header.name, path);
+       sprintf(header.mode, "%o", sb->st_mode & 0777);
+       /* careful to not overflow fields! */
+       sprintf(header.uid, "%o", sb->st_uid & 07777777);
+       sprintf(header.gid, "%o", sb->st_gid & 07777777);
+       sprintf(header.size, "%o", (unsigned)sb->st_size);
+       sprintf(header.mtime, "%llo", sb->st_mtime & 077777777777LL);
+       header.typeflag = type;
+       //strcpy(header.magic, "ustar  "); - do we want to be standard-compliant?
+
+       /* Calculate and store the checksum (the sum of all of the bytes of
+        * the header). The checksum field must be filled with blanks for the
+        * calculation. The checksum field is formatted differently from the
+        * other fields: it has 6 digits, a NUL, then a space -- rather than
+        * digits, followed by a NUL like the other fields... */
+       header.chksum[7] = ' ';
+       sum = ' ' * 7;
+       for (i = 0; i < 512; i++)
+               sum += ((unsigned char*)&header)[i];
+       sprintf(header.chksum, "%06o", sum);
+
+       xwrite(STDOUT_FILENO, &header, 512);
+}
+
+static void archivefile(const char *path)
+{
+       struct fileblock *start, *cur;
+       struct fileblock **prev = &start;
+       int fd, r;
+       unsigned size = 0;
+       struct stat s;
+
+       /* buffer the file */
+       fd = xopen(path, O_RDONLY);
+       do {
+               cur = xzalloc(sizeof(*cur));
+               *prev = cur;
+               prev = &cur->next;
+               r = full_read(fd, cur->data, 512);
+               if (r > 0)
+                       size += r;
+       } while (r == 512);
+
+       /* write archive header */
+       fstat(fd, &s);
+       close(fd);
+       s.st_size = size;
+       writeheader(path, &s, '0');
+
+       /* dump file contents */
+       for (cur = start; (int)size > 0; size -= 512) {
+               xwrite(STDOUT_FILENO, cur->data, 512);
+               start = cur;
+               cur = cur->next;
+               free(start);
+       }
+}
+
+static void archivejoin(const char *sub, const char *name)
+{
+       char path[sizeof(long long)*3 + sizeof("/cmdline")];
+       sprintf(path, "%s/%s", sub, name);
+       archivefile(path);
+}
+
+//usage:#define smemcap_trivial_usage ">SMEMDATA.TAR"
+//usage:#define smemcap_full_usage "\n\n"
+//usage:       "Collect memory usage data in /proc and write it to stdout"
+
+int smemcap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int smemcap_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
+{
+       DIR *d;
+       struct dirent *de;
+
+       xchdir("/proc");
+       d = xopendir(".");
+
+       archivefile("meminfo");
+       archivefile("version");
+       while ((de = readdir(d)) != NULL) {
+               if (isdigit(de->d_name[0])) {
+                       struct stat s;
+                       memset(&s, 0, sizeof(s));
+                       s.st_mode = 0555;
+                       writeheader(de->d_name, &s, '5');
+                       archivejoin(de->d_name, "smaps");
+                       archivejoin(de->d_name, "cmdline");
+                       archivejoin(de->d_name, "stat");
+               }
+       }
+
+       return EXIT_SUCCESS;
+}