killall, pidof: use argv0 for process matching too

top: show cmdline, not comm field
(fixes problems with re-execed applets showing as processes with name "exe",
and not being found by pidof/killall by applet name)

function                                             old     new   delta
find_pid_by_name                                      98     156     +58
procps_scan                                          692     732     +40
top_main                                            2724    2762     +38
find_pair                                            164     180     +16
collect_int                                          114     123      +9
cmp_main                                             547     555      +8
collect_fork                                         112     119      +7
collect_ctx                                          112     119      +7
read_package_field                                   253     257      +4
passwd_main                                         1983    1985      +2
process_stdin                                        435     433      -2
xstrtoul_range_sfx                                   229     226      -3
get_next_block                                      1852    1849      -3
arith                                               2042    2033      -9
sv_main                                             1236    1226     -10
singlemount                                         4690    4672     -18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 10/6 up/down: 189/-45)          Total: 144 bytes
   text    data     bss     dec     hex filename
 734789    3028   14400  752217   b7a59 busybox_old
 734933    3028   14400  752361   b7ae9 busybox_unstripped

4 files changed, 60 insertions, 27 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 124b11fa8..e80e76403 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -836,6 +836,8 @@ typedef struct {
         DIR *dir;
 /* Fields are set to 0/NULL if failed to determine (or not requested) */
         char *cmd;
+        char *argv0;
+        /*char *exe;*/
         USE_SELINUX(char *context;)
         /* Everything below must contain no ptrs to malloc'ed data:
          * it is memset(0) for each process in procps_scan() */
@@ -861,13 +863,15 @@ enum {
         PSSCAN_UIDGID   = 1 << 4,
         PSSCAN_COMM     = 1 << 5,
         PSSCAN_CMD      = 1 << 6,
-        PSSCAN_STATE    = 1 << 7,
-        PSSCAN_VSZ      = 1 << 8,
-        PSSCAN_RSS      = 1 << 9,
-        PSSCAN_STIME    = 1 << 10,
-        PSSCAN_UTIME    = 1 << 11,
-        PSSCAN_TTY      = 1 << 12,
-        USE_SELINUX(PSSCAN_CONTEXT  = 1 << 13,)
+        PSSCAN_ARGV0    = 1 << 7,
+        PSSCAN_EXE      = 1 << 8, /* not implemented yet */
+        PSSCAN_STATE    = 1 << 9,
+        PSSCAN_VSZ      = 1 << 10,
+        PSSCAN_RSS      = 1 << 11,
+        PSSCAN_STIME    = 1 << 12,
+        PSSCAN_UTIME    = 1 << 13,
+        PSSCAN_TTY      = 1 << 14,
+        USE_SELINUX(PSSCAN_CONTEXT  = 1 << 15,)
         /* 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/find_pid_by_name.c b/libbb/find_pid_by_name.c
index 13ccb545d..cfc5b3468 100644
--- a/libbb/find_pid_by_name.c
+++ b/libbb/find_pid_by_name.c
@@ -38,6 +38,14 @@ execXXX("/proc/self/exe", applet_name, params....)
 and therefore comm field contains "exe".
 */
 
+static const char *bb_basename(const char *name)
+{
+        const char *cp = strrchr(name, '/');
+        if (cp)
+                return cp + 1;
+        return name;
+}
+
 /* find_pid_by_name()
  *
  *  Modified by Vladimir Oleynik for use with libbb/procps.c
@@ -55,8 +63,16 @@ pid_t* find_pid_by_name(const char* procName)
         procps_status_t* p = NULL;
 
         pidList = xmalloc(sizeof(*pidList));
-        while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM))) {
-                if (strncmp(p->comm, procName, sizeof(p->comm)-1) == 0) {
+        while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGV0))) {
+                if (
+                /* we require comm to match and to not be truncated */
+                /* in Linux, if comm is 15 chars, it may be a truncated
+                 * name, so we don't allow that to match */
+                    (!p->comm[sizeof(p->comm)-2] && strcmp(p->comm, procName) == 0)
+                /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
+                 || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
+                /* TOOD: we can also try exe, do we want that? */
+                ) {
                         pidList = xrealloc(pidList, sizeof(*pidList) * (i+2));
                         pidList[i++] = p->pid;
                 }
diff --git a/libbb/procps.c b/libbb/procps.c
index 5924d60a8..8413ce8a1 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -92,7 +92,7 @@ static int read_to_buf(const char *filename, void *buf)
         return ret;
 }
 
-procps_status_t* alloc_procps_scan(int flags)
+procps_status_t *alloc_procps_scan(int flags)
 {
         procps_status_t* sp = xzalloc(sizeof(procps_status_t));
         sp->dir = xopendir("/proc");
@@ -133,7 +133,7 @@ static char *skip_fields(char *str, int count)
 #endif
 
 void BUG_comm_size(void);
-procps_status_t* procps_scan(procps_status_t* sp, int flags)
+procps_status_t *procps_scan(procps_status_t* sp, int flags)
 {
         struct dirent *entry;
         char buf[PROCPS_BUFSIZE];
@@ -266,24 +266,31 @@ procps_status_t* procps_scan(procps_status_t* sp, int flags)
 
                 }
 
-                if (flags & PSSCAN_CMD) {
-                        free(sp->cmd);
-                        sp->cmd = NULL;
+                if (flags & (PSSCAN_CMD|PSSCAN_ARGV0)) {
+                        if (sp->argv0) {
+                                free(sp->argv0);
+                                sp->argv0 = NULL;
+                        }
+                        if (sp->cmd) {
+                                free(sp->cmd);
+                                sp->cmd = NULL;
+                        }
                         strcpy(filename_tail, "/cmdline");
+                        /* TODO: to get rid of size limits, read into malloc buf,
+                         * then realloc it down to real size. */
                         n = read_to_buf(filename, buf);
                         if (n <= 0)
                                 break;
-                        if (buf[n-1] == '\n') {
-                                if (!--n)
-                                        break;
-                                buf[n] = '\0';
+                        if (flags & PSSCAN_ARGV0)
+                                sp->argv0 = xstrdup(buf);
+                        if (flags & PSSCAN_CMD) {
+                                do {
+                                        n--;
+                                        if ((unsigned char)(buf[n]) < ' ')
+                                                buf[n] = ' ';
+                                } while (n);
+                                sp->cmd = xstrdup(buf);
                         }
-                        do {
-                                n--;
-                                if ((unsigned char)(buf[n]) < ' ')
-                                        buf[n] = ' ';
-                        } while (n);
-                        sp->cmd = xstrdup(buf);
                 }
                 break;
         }
diff --git a/procps/top.c b/procps/top.c
index c6efe2d77..136f1404a 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -40,7 +40,8 @@ typedef struct top_status_t {
         unsigned pid, ppid;
         unsigned uid;
         char state[4];
-        char comm[COMM_LEN];
+/* TODO: read /proc/$PID/cmdline only for processes which are displayed */
+        char cmd[64];
 } top_status_t;
 
 typedef struct jiffy_counts_t{
@@ -444,7 +445,7 @@ static void display_status(int count, int scr_width)
 #endif
                 );
                 if (col > 0)
-                        printf("%.*s", col, s->comm);
+                        printf("%.*s", col, s->cmd);
                 /* printf(" %d/%d %lld/%lld", s->pcpu, total_pcpu,
                         jif.busy - prev_jif.busy, jif.total - prev_jif.total); */
                 s++;
@@ -559,6 +560,7 @@ int top_main(int argc, char **argv)
                                 | PSSCAN_UTIME
                                 | PSSCAN_STATE
                                 | PSSCAN_COMM
+                                | PSSCAN_CMD
                                 | PSSCAN_SID
                                 | PSSCAN_UIDGID
                 ))) {
@@ -572,7 +574,10 @@ int top_main(int argc, char **argv)
 #endif
                         top[n].uid = p->uid;
                         strcpy(top[n].state, p->state);
-                        strcpy(top[n].comm, p->comm);
+                        if (p->cmd)
+                                safe_strncpy(top[n].cmd, p->cmd, sizeof(top[n].cmd));
+                        else /* mimic ps */
+                                sprintf(top[n].cmd, "[%s]", p->comm);
                 }
                 if (ntop == 0) {
                         bb_error_msg_and_die("no process info in /proc");
@@ -585,6 +590,7 @@ int top_main(int argc, char **argv)
                         continue;
                 }
                 do_stats();
+/* TODO: we don't need to sort all 10000 processes, we need to find top 24! */
                 qsort(top, ntop, sizeof(top_status_t), (void*)mult_lvl_cmp);
 #else
                 qsort(top, ntop, sizeof(top_status_t), (void*)sort_function);