[systemd-devel] [PATCH 1/4] util: add functions getting proc cwd and root

[Lennart Poettering]

On Wed, 19.11.14 11:01, Jakub Filak (jfilak at redhat.com) wrote:

> /proc/[pid]/cwd and /proc/[pid]/root are symliks to corresponding
> directories

Looks good! Applied this one already! Thanks!

> 
> The added functions returns values of that symlinks.
> ---
>  src/shared/util.c    | 39 +++++++++++++++++++++++++++++++++++----
>  src/shared/util.h    |  2 ++
>  src/test/test-util.c | 13 ++++++++++++-
>  3 files changed, 49 insertions(+), 5 deletions(-)
> 
> diff --git a/src/shared/util.c b/src/shared/util.c
> index eeced47..0166052 100644
> --- a/src/shared/util.c
> +++ b/src/shared/util.c
> @@ -797,19 +797,30 @@ int get_process_capeff(pid_t pid, char **capeff) {
>          return get_status_field(p, "\nCapEff:", capeff);
>  }
>  
> +static int get_process_link_contents(const char *proc_file, char **name) {
> +        int r;
> +
> +        assert(proc_file);
> +        assert(name);
> +
> +        r = readlink_malloc(proc_file, name);
> +        if (r < 0)
> +                return r == -ENOENT ? -ESRCH : r;
> +
> +        return 0;
> +}
> +
>  int get_process_exe(pid_t pid, char **name) {
>          const char *p;
>          char *d;
>          int r;
>  
>          assert(pid >= 0);
> -        assert(name);
>  
>          p = procfs_file_alloca(pid, "exe");
> -
> -        r = readlink_malloc(p, name);
> +        r = get_process_link_contents(p, name);
>          if (r < 0)
> -                return r == -ENOENT ? -ESRCH : r;
> +                return r;
>  
>          d = endswith(*name, " (deleted)");
>          if (d)
> @@ -861,6 +872,26 @@ int get_process_gid(pid_t pid, gid_t *gid) {
>          return get_process_id(pid, "Gid:", gid);
>  }
>  
> +int get_process_cwd(pid_t pid, char **cwd) {
> +        const char *p;
> +
> +        assert(pid >= 0);
> +
> +        p = procfs_file_alloca(pid, "cwd");
> +
> +        return get_process_link_contents(p, cwd);
> +}
> +
> +int get_process_root(pid_t pid, char **root) {
> +        const char *p;
> +
> +        assert(pid >= 0);
> +
> +        p = procfs_file_alloca(pid, "root");
> +
> +        return get_process_link_contents(p, root);
> +}
> +
>  char *strnappend(const char *s, const char *suffix, size_t b) {
>          size_t a;
>          char *r;
> diff --git a/src/shared/util.h b/src/shared/util.h
> index 835fee4..fc59481 100644
> --- a/src/shared/util.h
> +++ b/src/shared/util.h
> @@ -295,6 +295,8 @@ int get_process_exe(pid_t pid, char **name);
>  int get_process_uid(pid_t pid, uid_t *uid);
>  int get_process_gid(pid_t pid, gid_t *gid);
>  int get_process_capeff(pid_t pid, char **capeff);
> +int get_process_cwd(pid_t pid, char **cwd);
> +int get_process_root(pid_t pid, char **root);
>  
>  char hexchar(int x) _const_;
>  int unhexchar(char c) _const_;
> diff --git a/src/test/test-util.c b/src/test/test-util.c
> index 01b0192..7bf8ff6 100644
> --- a/src/test/test-util.c
> +++ b/src/test/test-util.c
> @@ -490,13 +490,14 @@ static void test_u64log2(void) {
>  
>  static void test_get_process_comm(void) {
>          struct stat st;
> -        _cleanup_free_ char *a = NULL, *c = NULL, *d = NULL, *f = NULL, *i = NULL;
> +        _cleanup_free_ char *a = NULL, *c = NULL, *d = NULL, *f = NULL, *i = NULL, *cwd = NULL, *root = NULL;
>          unsigned long long b;
>          pid_t e;
>          uid_t u;
>          gid_t g;
>          dev_t h;
>          int r;
> +        pid_t me;
>  
>          if (stat("/proc/1/comm", &st) == 0) {
>                  assert_se(get_process_comm(1, &a) >= 0);
> @@ -532,6 +533,16 @@ static void test_get_process_comm(void) {
>          log_info("pid1 gid: "GID_FMT, g);
>          assert_se(g == 0);
>  
> +        me = getpid();
> +
> +        r = get_process_cwd(me, &cwd);
> +        assert_se(r >= 0 || r == -EACCES);
> +        log_info("pid1 cwd: '%s'", cwd);
> +
> +        r = get_process_root(me, &root);
> +        assert_se(r >= 0 || r == -EACCES);
> +        log_info("pid1 root: '%s'", root);
> +
>          assert_se(get_ctty_devnr(1, &h) == -ENOENT);
>  
>          getenv_for_pid(1, "PATH", &i);
> -- 
> 1.8.3.1
> 
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Lennart

-- 
Lennart Poettering, Red Hat