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Diffstat (limited to 'user/tlecarrour/memstat.mdwn')
| -rw-r--r-- | user/tlecarrour/memstat.mdwn | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/user/tlecarrour/memstat.mdwn b/user/tlecarrour/memstat.mdwn new file mode 100644 index 00000000..d8c65884 --- /dev/null +++ b/user/tlecarrour/memstat.mdwn @@ -0,0 +1,162 @@ +[[!meta copyright="Copyright © 2010 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + + +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. + |