ps,top: add an option to show threads. +260 bytes of code

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

5 files changed, 74 insertions, 13 deletions

diff --git a/include/libbb.h b/include/libbb.h
index fd61517c2..1694d2c2d 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1275,6 +1275,7 @@ enum { COMM_LEN = 16 };
 #endif
 typedef struct procps_status_t {
         DIR *dir;
+        IF_FEATURE_SHOW_THREADS(DIR *task_dir;)
         uint8_t shift_pages_to_bytes;
         uint8_t shift_pages_to_kb;
 /* Fields are set to 0/NULL if failed to determine (or not requested) */
@@ -1348,6 +1349,7 @@ enum {
         PSSCAN_CPU      = (1 << 19) * ENABLE_FEATURE_TOP_SMP_PROCESS,
         PSSCAN_NICE     = (1 << 20) * ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS,
         PSSCAN_RUIDGID  = (1 << 21) * ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS,
+        PSSCAN_TASKS    = (1 << 22) * ENABLE_FEATURE_SHOW_THREADS,
         /* These are all retrieved from proc/NN/stat in one go: */
         PSSCAN_STAT     = PSSCAN_PPID | PSSCAN_PGID | PSSCAN_SID
         /**/            | PSSCAN_COMM | PSSCAN_STATE
diff --git a/libbb/procps.c b/libbb/procps.c
index 974661785..845a2141b 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -110,6 +110,10 @@ static procps_status_t* FAST_FUNC alloc_procps_scan(void)
 void FAST_FUNC free_procps_scan(procps_status_t* sp)
 {
         closedir(sp->dir);
+#if ENABLE_FEATURE_SHOW_THREADS
+        if (sp->task_dir)
+                closedir(sp->task_dir);
+#endif
         free(sp->argv0);
         free(sp->exe);
         IF_SELINUX(free(sp->context);)
@@ -189,14 +193,35 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                 sp = alloc_procps_scan();
 
         for (;;) {
+#if ENABLE_FEATURE_SHOW_THREADS
+                if ((flags & PSSCAN_TASKS) && sp->task_dir) {
+                        entry = readdir(sp->task_dir);
+                        if (entry)
+                                goto got_entry;
+                        closedir(sp->task_dir);
+                        sp->task_dir = NULL;
+                }
+#endif
                 entry = readdir(sp->dir);
                 if (entry == NULL) {
                         free_procps_scan(sp);
                         return NULL;
                 }
+ IF_FEATURE_SHOW_THREADS(got_entry:)
                 pid = bb_strtou(entry->d_name, NULL, 10);
                 if (errno)
                         continue;
+#if ENABLE_FEATURE_SHOW_THREADS
+                if ((flags & PSSCAN_TASKS) && !sp->task_dir) {
+                        /* We found another /proc/PID. Do not use it,
+                         * there will be /proc/PID/task/PID (same PID!),
+                         * so just go ahead and dive into /proc/PID/task. */
+                        char task_dir[sizeof("/proc/%u/task") + sizeof(int)*3];
+                        sprintf(task_dir, "/proc/%u/task", pid);
+                        sp->task_dir = xopendir(task_dir);
+                        continue;
+                }
+#endif
 
                 /* After this point we have to break, not continue
                  * ("continue" would mean that current /proc/NNN
diff --git a/procps/Config.in b/procps/Config.in
index 9146ff6bf..6a9a36638 100644
--- a/procps/Config.in
+++ b/procps/Config.in
@@ -188,6 +188,13 @@ config FEATURE_TOPMEM
         help
           Enable 's' in top (gives lots of memory info).
 
+config FEATURE_SHOW_THREADS
+        bool "Support for showing threads in ps/top"
+        default n
+        depends on PS || TOP
+        help
+          Enables ps -T option and 'h' command in top
+
 config UPTIME
         bool "uptime"
         default n
@@ -203,5 +210,4 @@ config WATCH
           watch is used to execute a program periodically, showing
           output to the screen.
 
-
 endmenu
diff --git a/procps/ps.c b/procps/ps.c
index 6523f0f38..b35b49c04 100644
--- a/procps/ps.c
+++ b/procps/ps.c
@@ -17,7 +17,6 @@ enum { MAX_WIDTH = 2*1024 };
 #if ENABLE_DESKTOP
 
 #include <sys/times.h> /* for times() */
-//#include <sys/sysinfo.h> /* for sysinfo() */
 #ifndef AT_CLKTCK
 #define AT_CLKTCK 17
 #endif
@@ -61,6 +60,7 @@ struct globals {
 #define kernel_HZ          (G.kernel_HZ         )
 #define seconds_since_boot (G.seconds_since_boot)
 #define default_o          (G.default_o         )
+#define INIT_G() do { } while (0)
 
 #if ENABLE_FEATURE_PS_TIME
 /* for ELF executables, notes are pushed before environment and args */
@@ -452,21 +452,34 @@ int ps_main(int argc UNUSED_PARAM, char **argv)
 {
         procps_status_t *p;
         llist_t* opt_o = NULL;
-        IF_SELINUX(int opt;)
+        int opt;
+        enum {
+                OPT_Z = (1 << 0),
+                OPT_o = (1 << 1),
+                OPT_a = (1 << 2),
+                OPT_A = (1 << 3),
+                OPT_d = (1 << 4),
+                OPT_e = (1 << 5),
+                OPT_f = (1 << 6),
+                OPT_l = (1 << 7),
+                OPT_T = (1 << 8) * ENABLE_FEATURE_SHOW_THREADS,
+        };
+
+        INIT_G();
 
         // POSIX:
         // -a  Write information for all processes associated with terminals
         //     Implementations may omit session leaders from this list
         // -A  Write information for all processes
         // -d  Write information for all processes, except session leaders
-        // -e  Write information for all processes (equivalent to -A.)
+        // -e  Write information for all processes (equivalent to -A)
         // -f  Generate a full listing
         // -l  Generate a long listing
         // -o col1,col2,col3=header
         //     Select which columns to display
         /* We allow (and ignore) most of the above. FIXME */
         opt_complementary = "o::";
-        IF_SELINUX(opt =) getopt32(argv, "Zo:aAdefl", &opt_o);
+        opt = getopt32(argv, "Zo:aAdefl" IF_FEATURE_SHOW_THREADS("T"), &opt_o);
         if (opt_o) {
                 do {
                         parse_o(llist_pop(&opt_o));
@@ -474,7 +487,7 @@ int ps_main(int argc UNUSED_PARAM, char **argv)
         } else {
                 /* Below: parse_o() needs char*, NOT const char*... */
 #if ENABLE_SELINUX
-                if (!(opt & 1) || !is_selinux_enabled()) {
+                if (!(opt & OPT_Z) || !is_selinux_enabled()) {
                         /* no -Z or no SELinux: do not show LABEL */
                         strcpy(default_o, DEFAULT_O_STR + sizeof(SELINUX_O_PREFIX)-1);
                 } else
@@ -485,6 +498,10 @@ int ps_main(int argc UNUSED_PARAM, char **argv)
                 parse_o(default_o);
         }
         post_process();
+#if ENABLE_FEATURE_SHOW_THREADS
+        if (opt & OPT_T)
+                need_flags |= PSSCAN_TASKS;
+#endif
 
         /* Was INT_MAX, but some libc's go belly up with printf("%.*s")
          * and such large widths */
@@ -497,7 +514,7 @@ int ps_main(int argc UNUSED_PARAM, char **argv)
         format_header();
 
         p = NULL;
-        while ((p = procps_scan(p, need_flags))) {
+        while ((p = procps_scan(p, need_flags)) != NULL) {
                 format_process(p);
         }
 
@@ -558,7 +575,7 @@ int ps_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                         | PSSCAN_VSZ
                         | PSSCAN_COMM
                         | use_selinux
-        ))) {
+        )) != NULL) {
 #if ENABLE_SELINUX
                 if (use_selinux) {
                         len = printf("%5u %-32.32s %s  ",
diff --git a/procps/top.c b/procps/top.c
index a1ad7881e..dbaaca14f 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -976,7 +976,10 @@ int top_main(int argc UNUSED_PARAM, char **argv)
                 /* read process IDs & status for all the processes */
                 while ((p = procps_scan(p, scan_mask)) != NULL) {
                         int n;
-                        if (scan_mask == TOP_MASK) {
+#if ENABLE_FEATURE_TOPMEM
+                        if (scan_mask != TOPMEM_MASK)
+#endif
+                        {
                                 n = ntop;
                                 top = xrealloc_vector(top, 6, ntop++);
                                 top[n].pid = p->pid;
@@ -991,8 +994,9 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 #if ENABLE_FEATURE_TOP_SMP_PROCESS
                                 top[n].last_seen_on_cpu = p->last_seen_on_cpu;
 #endif
-                        } else { /* TOPMEM */
+                        }
 #if ENABLE_FEATURE_TOPMEM
+                        else { /* TOPMEM */
                                 if (!(p->mapped_ro | p->mapped_rw))
                                         continue; /* kernel threads are ignored */
                                 n = ntop;
@@ -1007,15 +1011,15 @@ int top_main(int argc UNUSED_PARAM, char **argv)
                                 topmem[n].dirty    = p->private_dirty + p->shared_dirty;
                                 topmem[n].dirty_sh = p->shared_dirty;
                                 topmem[n].stack    = p->stack;
-#endif
                         }
+#endif
                 } /* end of "while we read /proc" */
                 if (ntop == 0) {
                         bb_error_msg("no process info in /proc");
                         break;
                 }
 
-                if (scan_mask == TOP_MASK) {
+                if (scan_mask != TOPMEM_MASK) {
 #if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
                         if (!prev_hist_count) {
                                 do_stats();
@@ -1039,7 +1043,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
                 if (OPT_BATCH_MODE) {
                         lines_rem = INT_MAX;
                 }
-                if (scan_mask == TOP_MASK)
+                if (scan_mask != TOPMEM_MASK)
                         display_process_list(lines_rem, col);
 #if ENABLE_FEATURE_TOPMEM
                 else
@@ -1076,6 +1080,13 @@ int top_main(int argc UNUSED_PARAM, char **argv)
                                 sort_function[2] = time_sort;
 # endif
                         }
+#if ENABLE_FEATURE_SHOW_THREADS
+                        if (c == 'h'
+                         IF_FEATURE_TOPMEM(&& scan_mask != TOPMEM_MASK)
+                        ) {
+                                scan_mask ^= PSSCAN_TASKS;
+                        }
+#endif
 # if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
                         if (c == 'p') {
                                 IF_FEATURE_TOPMEM(scan_mask = TOP_MASK;)