Show which processes are using which tun/tap devices, e.g.: $ ip -d tuntap tun0: tun Attached to processes: vpnc(9531) vnet0: tap vnet_hdr Attached to processes: qemu-system-x86(10442) virbr0-nic: tap UNKNOWN_FLAGS:800 Attached to processes:
Signed-off-by: Hannes Frederic Sowa <han...@stressinduktion.org> --- ip/iptuntap.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 109 insertions(+) diff --git a/ip/iptuntap.c b/ip/iptuntap.c index 43774f96e335ef..b5aa0542c1f8f2 100644 --- a/ip/iptuntap.c +++ b/ip/iptuntap.c @@ -25,6 +25,7 @@ #include <fcntl.h> #include <dirent.h> #include <errno.h> +#include <glob.h> #include "rt_names.h" #include "utils.h" @@ -273,6 +274,109 @@ static void print_flags(long flags) printf(" UNKNOWN_FLAGS:%lx", flags); } +static char *pid_name(pid_t pid) +{ + char *comm; + FILE *f; + int err; + + err = asprintf(&comm, "/proc/%d/comm", pid); + if (err < 0) + return NULL; + + f = fopen(comm, "r"); + free(comm); + if (!f) { + perror("fopen"); + return NULL; + } + + if (fscanf(f, "%ms\n", &comm) != 1) { + perror("fscanf"); + comm = NULL; + } + + + if (fclose(f)) + perror("fclose"); + + return comm; +} + +static void show_processes(const char *name) +{ + glob_t globbuf = { }; + char **fd_path; + int err; + + err = glob("/proc/[0-9]*/fd/[0-9]*", GLOB_NOSORT, + NULL, &globbuf); + if (err) + return; + + fd_path = globbuf.gl_pathv; + while (*fd_path) { + const char *dev_net_tun = "/dev/net/tun"; + const size_t linkbuf_len = strlen(dev_net_tun) + 2; + char linkbuf[linkbuf_len], *fdinfo; + int pid, fd; + FILE *f; + + if (sscanf(*fd_path, "/proc/%d/fd/%d", &pid, &fd) != 2) + goto next; + + if (pid == getpid()) + goto next; + + err = readlink(*fd_path, linkbuf, linkbuf_len - 1); + if (err < 0) { + perror("readlink"); + goto next; + } + linkbuf[err] = '\0'; + if (strcmp(dev_net_tun, linkbuf)) + goto next; + + if (asprintf(&fdinfo, "/proc/%d/fdinfo/%d", pid, fd) < 0) + goto next; + + f = fopen(fdinfo, "r"); + free(fdinfo); + if (!f) { + perror("fopen"); + goto next; + } + + while (!feof(f)) { + char *key = NULL, *value = NULL; + + err = fscanf(f, "%m[^:]: %ms\n", &key, &value); + if (err == EOF) { + if (ferror(f)) + perror("fscanf"); + break; + } else if (err == 2 && + !strcmp("iff", key) && !strcmp(name, value)) { + char *pname = pid_name(pid); + printf(" %s(%d)", pname ? pname : "<NULL>", pid); + free(pname); + } + + free(key); + free(value); + } + if (fclose(f)) + perror("fclose"); + +next: + ++fd_path; + } + + globfree(&globbuf); + return; +} + + static int do_show(int argc, char **argv) { DIR *dir; @@ -302,6 +406,11 @@ static int do_show(int argc, char **argv) if (group != -1) printf(" group %ld", group); printf("\n"); + if (show_details) { + printf("\tAttached to processes:"); + show_processes(d->d_name); + printf("\n"); + } } closedir(dir); return 0; -- 2.7.4