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#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pwd.h>
#include <sys/stat.h>
#define BUF_MAX 1024
#define CMD_DISPLAY_MAX (9 + 1)
#define USER_DISPLAY_MAX (10 + 1)
struct pid_info_t {
pid_t pid;
char user[USER_DISPLAY_MAX];
char cmdline[CMD_DISPLAY_MAX];
char path[PATH_MAX];
ssize_t parent_length;
};
void print_header()
{
printf("%-9s %5s %10s %4s %9s %18s %9s %10s %s\n",
"COMMAND",
"PID",
"USER",
"FD",
"TYPE",
"DEVICE",
"SIZE/OFF",
"NODE",
"NAME");
}
void print_type(char *type, struct pid_info_t* info)
{
static ssize_t link_dest_size;
static char link_dest[PATH_MAX];
strncat(info->path, type, sizeof(info->path));
if ((link_dest_size = readlink(info->path, link_dest, sizeof(link_dest)-1)) < 0) {
if (errno == ENOENT)
goto out;
snprintf(link_dest, sizeof(link_dest), "%s (readlink: %s)", info->path, strerror(errno));
} else {
link_dest[link_dest_size] = '\0';
}
// Things that are just the root filesystem are uninteresting (we already know)
if (!strcmp(link_dest, "/"))
goto out;
printf("%-9s %5d %10s %4s %9s %18s %9s %10s %s\n",
info->cmdline, info->pid, info->user, type,
"???", "???", "???", "???", link_dest);
out:
info->path[info->parent_length] = '\0';
}
// Prints out all file that have been memory mapped
void print_maps(struct pid_info_t* info)
{
FILE *maps;
char buffer[PATH_MAX + 100];
size_t offset;
int major, minor;
char device[10];
long int inode;
char file[PATH_MAX];
strncat(info->path, "maps", sizeof(info->path));
maps = fopen(info->path, "r");
if (!maps)
goto out;
while (fscanf(maps, "%*x-%*x %*s %zx %5s %ld %s\n", &offset, device, &inode,
file) == 4) {
// We don't care about non-file maps
if (inode == 0 || !strcmp(device, "00:00"))
continue;
printf("%-9s %5d %10s %4s %9s %18s %9zd %10ld %s\n",
info->cmdline, info->pid, info->user, "mem",
"???", device, offset, inode, file);
}
fclose(maps);
out:
info->path[info->parent_length] = '\0';
}
// Prints out all open file descriptors
void print_fds(struct pid_info_t* info)
{
static char* fd_path = "fd/";
strncat(info->path, fd_path, sizeof(info->path));
int previous_length = info->parent_length;
info->parent_length += strlen(fd_path);
DIR *dir = opendir(info->path);
if (dir == NULL) {
char msg[BUF_MAX];
snprintf(msg, sizeof(msg), "%s (opendir: %s)", info->path, strerror(errno));
printf("%-9s %5d %10s %4s %9s %18s %9s %10s %s\n",
info->cmdline, info->pid, info->user, "FDS",
"", "", "", "", msg);
goto out;
}
struct dirent* de;
while ((de = readdir(dir))) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
continue;
print_type(de->d_name, info);
}
closedir(dir);
out:
info->parent_length = previous_length;
info->path[info->parent_length] = '\0';
}
void lsof_dumpinfo(pid_t pid)
{
int fd;
struct pid_info_t info;
struct stat pidstat;
struct passwd *pw;
info.pid = pid;
snprintf(info.path, sizeof(info.path), "/proc/%d/", pid);
info.parent_length = strlen(info.path);
// Get the UID by calling stat on the proc/pid directory.
if (!stat(info.path, &pidstat)) {
pw = getpwuid(pidstat.st_uid);
if (pw) {
strncpy(info.user, pw->pw_name, USER_DISPLAY_MAX - 1);
info.user[USER_DISPLAY_MAX - 1] = '\0';
} else {
snprintf(info.user, USER_DISPLAY_MAX, "%d", (int)pidstat.st_uid);
}
} else {
strcpy(info.user, "???");
}
// Read the command line information; each argument is terminated with NULL.
strncat(info.path, "cmdline", sizeof(info.path));
fd = open(info.path, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "Couldn't read %s\n", info.path);
return;
}
char cmdline[PATH_MAX];
if (read(fd, cmdline, sizeof(cmdline)) < 0) {
fprintf(stderr, "Error reading cmdline: %s: %s\n", info.path, strerror(errno));
close(fd);
return;
}
close(fd);
info.path[info.parent_length] = '\0';
// We only want the basename of the cmdline
strncpy(info.cmdline, basename(cmdline), sizeof(info.cmdline));
info.cmdline[sizeof(info.cmdline)-1] = '\0';
// Read each of these symlinks
print_type("cwd", &info);
print_type("exe", &info);
print_type("root", &info);
print_fds(&info);
print_maps(&info);
}
int lsof_main(int argc, char *argv[])
{
long int pid = 0;
char* endptr;
if (argc == 2) {
pid = strtol(argv[1], &endptr, 10);
}
print_header();
if (pid) {
lsof_dumpinfo(pid);
} else {
DIR *dir = opendir("/proc");
if (dir == NULL) {
fprintf(stderr, "Couldn't open /proc\n");
return -1;
}
struct dirent* de;
while ((de = readdir(dir))) {
if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, ".."))
continue;
// Only inspect directories that are PID numbers
pid = strtol(de->d_name, &endptr, 10);
if (*endptr != '\0')
continue;
lsof_dumpinfo(pid);
}
closedir(dir);
}
return 0;
}
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