On Tue, 2019-07-09 at 17:29 +0300, Tzvetomir Stoyanov (VMware) wrote:
> A new trace-cmd record option is added: "--user". If a comnmand is
> specified
> as trce-cmd argument, it is executed in the context of the given
> user.
>
> Suggested-by: Yordan Karadzhov (VMware) <y.karadz@xxxxxxxxx>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> [
> v3 changes:
> "--user" does not depend on option -F, it works with any
> command,
> specified as trace-cmd argument.
> v2 changes:
> - Check for errors in change_user(). If an error occurs while
> changing the user, the message is printed and the traced
> process is not executed.
> ]
>
>
> Documentation/trace-cmd-record.1.txt | 4 +++
> tracecmd/trace-record.c | 47
> ++++++++++++++++++++++++++--
> tracecmd/trace-usage.c | 1 +
> 3 files changed, 49 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/trace-cmd-record.1.txt
> b/Documentation/trace-cmd-record.1.txt
> index 4a59de9..6a0f975 100644
> --- a/Documentation/trace-cmd-record.1.txt
> +++ b/Documentation/trace-cmd-record.1.txt
> @@ -122,6 +122,10 @@ OPTIONS
> *--mmap*::
> Used with either *-F* or *-P*, save the traced process memory
> map into
> the trace.dat file.
> +
> +*--user*::
> + Execute the specified *command* as given user.
> +
> *-C* 'clock'::
> Set the trace clock to "clock".
>
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index 48081d4..acadd7a 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -33,6 +33,8 @@
> #include <errno.h>
> #include <limits.h>
> #include <libgen.h>
> +#include <pwd.h>
> +#include <grp.h>
>
> #include "version.h"
> #include "trace-local.h"
> @@ -208,6 +210,7 @@ struct common_record_context {
> struct buffer_instance *instance;
> const char *output;
> char *date2ts;
> + char *user;
> int data_flags;
>
> int record_all;
> @@ -1417,7 +1420,34 @@ static void trace_or_sleep(enum trace_type
> type)
> sleep(10);
> }
>
> -static void run_cmd(enum trace_type type, int argc, char **argv)
> +static int change_user(char *user)
Nit: `const char *user` would be more appropriate.
> +{
> + struct passwd *pwd;
> +
> + if (!user)
> + return 0;
> +
> + pwd = getpwnam(user);
> + if (!pwd)
> + return -1;
> + if (initgroups(user, pwd->pw_gid) < 0)
> + return -1;
> + if (setgid(pwd->pw_gid) < 0)
> + return -1;
> + if (setuid(pwd->pw_uid) < 0)
> + return -1;
> +
> + if (setenv("HOME", pwd->pw_dir, 1) < 0)
> + return -1;
> + if (setenv("USER", pwd->pw_name, 1) < 0)
> + return -1;
> + if (setenv("LOGNAME", pwd->pw_name, 1) < 0)
> + return -1;
> +
> + return 0;
> +}
> +
> +static void run_cmd(enum trace_type type, char *user, int argc, char
> **argv)
Nit: same as above.
> {
> int status;
> int pid;
> @@ -1438,6 +1468,10 @@ static void run_cmd(enum trace_type type, int
> argc, char **argv)
> dup2(save_stdout, 1);
> close(save_stdout);
> }
> +
> + if (change_user(user) < 0)
> + die("Failed to change user to %s", user);
> +
> if (execvp(argv[0], argv)) {
> fprintf(stderr, "\n********************\n");
> fprintf(stderr, " Unable to exec %s\n",
> argv[0]);
> @@ -4548,6 +4582,7 @@ void update_first_instance(struct
> buffer_instance *instance, int topt)
> }
>
> enum {
> + OPT_user = 243,
> OPT_mmap = 244,
> OPT_quiet = 245,
> OPT_debug = 246,
> @@ -4780,6 +4815,7 @@ static void parse_record_options(int argc,
> {"quiet", no_argument, NULL, OPT_quiet},
> {"help", no_argument, NULL, '?'},
> {"mmap", no_argument, NULL, OPT_mmap},
> + {"user", required_argument, NULL, OPT_user},
> {"module", required_argument, NULL,
> OPT_module},
> {NULL, 0, NULL, 0}
> };
> @@ -5011,6 +5047,9 @@ static void parse_record_options(int argc,
> case 'i':
> ignore_event_not_found = 1;
> break;
> + case OPT_user:
> + ctx->user = strdup(optarg);
This is missing a check for allocation failure.
Other than that, looks great.
Reviewed-by: Slavomir Kaslev <kaslevs@xxxxxxxxxx>
Cheers,
-- Slavi
|