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[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]]
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id="license" text="Permission is granted to copy, distribute and/or modify this
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memstat
=======
Lists all the processes, executables, and shared libraries that are using up virtual memory. It's helpful to see how the shared memory is used and which 'old' libs are loaded.
**Home page**: [[http://sourceforge.net/projects/memstattool]]
[[!toc startlevel=2]]
* * *
Log
---
* **Started**: 2012-01-20
* **Discussed**: [2012-01-21](http://lists.debian.org/debian-hurd/2012/01/msg00081.html)
* **Draft Submitted**: [2012-01-25](http://lists.debian.org/debian-hurd/2012/01/msg00122.html)
* **Submitted**: -
* **Accepted**: -
* * *
ToDo
----
Here is the output of `grep -R PATH_MAX memstat-0.9/*`:
memstat.c: char *p, major[8], minor[8], buff[PATH_MAX + 300], *path, perm[4];
memstat.c: char linkname[PATH_MAX], filename[PATH_MAX];
memstat.c: if ((len = readlink(filename, linkname, PATH_MAX)) == -1) {
* * *
Comments
--------
Here are comments on the patch...
+#define FMT_PROC_MAPS "/proc/%d/maps"
+#define FMT_PROC_EXE "/proc/%d/exe"
Define string formats.
static void read_proc(void)
{
unsigned int nread, pid;
unsigned long inode, lo, hi, offs;
- char *p, major[8], minor[8], buff[PATH_MAX + 300], *path, perm[4];
+ char *p, major[8], minor[8], *path, perm[4];
+ char *buff = NULL;
+ size_t buff_size = 0;
In this function we turn `buff` into dynamically allocated string.
- sprintf(buff, "/proc/%d/maps", pid);
- f = fopen(buff, "r");
+ char filename[sizeof(FMT_PROC_MAPS) + (sizeof(int) * 3) + 1];
+ sprintf(filename, FMT_PROC_MAPS, pid);
+ f = fopen(filename, "r");
Compute the maximum size of `filename` using `sizeof(int) * 3` as explainend in the [[porting guide|porting_guide_for_dummies]].
- while (fgets(buff, sizeof(buff), f)) {
+ while (!feof(f)) {
+ buff = get_line(f);
+ if (buff == NULL)
+ break;
Read a line from the file using [[get_line()|porting_guide_for_dummies]].
- if ((strlen(buff) == 10) && (strcmp(buff, " (deleted)") == 0))
+ if ((strlen(buff) == 10) && (strcmp(buff, " (deleted)") == 0)) {
+ free(buff);
continue;
+ }
nread = sscanf(buff, "%lx %lx %4s %lx %s %s %lu %as", &lo, &hi, perm, &offs, major, minor, &inode, &path);
+ free(buff);
Free the `buff` when it's not used anymore.
+ buff_size = 4; /* size of the format string without "%x" expressions */
+ buff_size += strlen(major);
+ buff_size += strlen(minor);
+ buff_size += sizeof(int) * 3 + 1; /* inode */
+ buff_size += 1; /* '\0' */
+ buff = malloc(buff_size);
+ if (buff == NULL) {
+ perror("Cannot allocate memory!");
+ exit(1);
+ }
Compute the size that the `buff` must have.
- char linkname[PATH_MAX], filename[PATH_MAX];
- ssize_t len;
+ char *linkname = NULL;
+ struct stat sb;
+ ssize_t len = -1;
In this function we turn linkname into dynamically allocated string.
filename will be declared later.
- sprintf(filename, "/proc/%d/exe", pid);
- if ((len = readlink(filename, linkname, PATH_MAX)) == -1) {
+ char filename[sizeof(FMT_PROC_EXE) + (sizeof(int) * 3) + 1];
+ sprintf(filename, FMT_PROC_EXE, pid);
Same as above with `FMT_PROC_MAPS`.
+ if (lstat(filename, &sb) == -1) {
+ perror("lstat");
+ deleted = 1;
+ }
+ else {
+ linkname = malloc(sb.st_size + 1);
+ if (linkname == NULL) {
+ fprintf(stderr, "insufficient memory\n");
+ deleted = 1;
+ }
+ else {
+ len = readlink(filename, linkname, sb.st_size + 1);
+ }
+ }
+ if (len < 0 || len > sb.st_size) {
fprintf(stderr, "Cannot read link information for %s\n", filename);
deleted = 1;
}
- linkname[len] = '\0';
+ else {
+ linkname[sb.st_size] = '\0';
+ }
Use `readlink()` as explained in the porting guide.
Require lstat to get the link size.
+ free(linkname);
Free dynamically allocated variable that is not used anymore.
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