pidof/killall: fix bug 625 (kernel threads get stale "binary name")

function                                             old     new   delta
procps_scan                                         1622    1642     +20

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

1 files changed, 71 insertions, 62 deletions

diff --git a/libbb/procps.c b/libbb/procps.c
index 845a2141b..48e60a792 100644
--- a/libbb/procps.c
+++ b/libbb/procps.c
@@ -138,8 +138,8 @@ static unsigned long fast_strtoul_16(char **endptr)
         return n;
 }
 /* TOPMEM uses fast_strtoul_10, so... */
-#undef ENABLE_FEATURE_FAST_TOP
-#define ENABLE_FEATURE_FAST_TOP 1
+# undef ENABLE_FEATURE_FAST_TOP
+# define ENABLE_FEATURE_FAST_TOP 1
 #endif
 
 #if ENABLE_FEATURE_FAST_TOP
@@ -223,14 +223,16 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                 }
 #endif
 
-                /* After this point we have to break, not continue
-                 * ("continue" would mean that current /proc/NNN
-                 * is not a valid process info) */
+                /* After this point we can:
+                 * "break": stop parsing, return the data
+                 * "continue": try next /proc/XXX
+                 */
 
                 memset(&sp->vsz, 0, sizeof(*sp) - offsetof(procps_status_t, vsz));
 
                 sp->pid = pid;
-                if (!(flags & ~PSSCAN_PID)) break;
+                if (!(flags & ~PSSCAN_PID))
+                        break; /* we needed only pid, we got it */
 
 #if ENABLE_SELINUX
                 if (flags & PSSCAN_CONTEXT) {
@@ -243,7 +245,7 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
 
                 if (flags & PSSCAN_UIDGID) {
                         if (stat(filename, &sb))
-                                break;
+                                continue; /* process probably exited */
                         /* Effective UID/GID, not real */
                         sp->uid = sb.st_uid;
                         sp->gid = sb.st_gid;
@@ -259,10 +261,10 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                         strcpy(filename_tail, "stat");
                         n = read_to_buf(filename, buf);
                         if (n < 0)
-                                break;
+                                continue; /* process probably exited */
                         cp = strrchr(buf, ')'); /* split into "PID (cmd" and "<rest>" */
                         /*if (!cp || cp[1] != ' ')
-                                break;*/
+                                continue;*/
                         cp[0] = '\0';
                         if (sizeof(sp->comm) < 16)
                                 BUG_comm_size();
@@ -282,12 +284,12 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                                 "%lu "                 /* start_time */
                                 "%lu "                 /* vsize */
                                 "%lu "                 /* rss */
-#if ENABLE_FEATURE_TOP_SMP_PROCESS
+# if ENABLE_FEATURE_TOP_SMP_PROCESS
                                 "%*s %*s %*s %*s %*s %*s " /*rss_rlim, start_code, end_code, start_stack, kstk_esp, kstk_eip */
                                 "%*s %*s %*s %*s "         /*signal, blocked, sigignore, sigcatch */
                                 "%*s %*s %*s %*s "         /*wchan, nswap, cnswap, exit_signal */
                                 "%d"                       /*cpu last seen on*/
-#endif
+# endif
                                 ,
                                 sp->state, &sp->ppid,
                                 &sp->pgid, &sp->sid, &tty,
@@ -296,17 +298,17 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                                 &sp->start_time,
                                 &vsz,
                                 &rss
-#if ENABLE_FEATURE_TOP_SMP_PROCESS
+# if ENABLE_FEATURE_TOP_SMP_PROCESS
                                 , &sp->last_seen_on_cpu
-#endif
+# endif
                                 );
 
                         if (n < 11)
-                                break;
-#if ENABLE_FEATURE_TOP_SMP_PROCESS
+                                continue; /* bogus data, get next /proc/XXX */
+# if ENABLE_FEATURE_TOP_SMP_PROCESS
                         if (n < 11+15)
                                 sp->last_seen_on_cpu = 0;
-#endif
+# endif
 
                         /* vsz is in bytes and we want kb */
                         sp->vsz = vsz >> 10;
@@ -336,14 +338,14 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                         sp->vsz = fast_strtoul_10(&cp) >> 10;
                         /* vsz is in bytes but rss is in *PAGES*! Can you believe that? */
                         sp->rss = fast_strtoul_10(&cp) << sp->shift_pages_to_kb;
-#if ENABLE_FEATURE_TOP_SMP_PROCESS
+# if ENABLE_FEATURE_TOP_SMP_PROCESS
                         /* (6): rss_rlim, start_code, end_code, start_stack, kstk_esp, kstk_eip */
                         /* (4): signal, blocked, sigignore, sigcatch */
                         /* (4): wchan, nswap, cnswap, exit_signal */
                         cp = skip_fields(cp, 14);
 //FIXME: is it safe to assume this field exists?
                         sp->last_seen_on_cpu = fast_strtoul_10(&cp);
-#endif
+# endif
 #endif /* end of !ENABLE_FEATURE_TOP_SMP_PROCESS */
 
 #if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS
@@ -368,48 +370,48 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
 
                         strcpy(filename_tail, "smaps");
                         file = fopen_for_read(filename);
-                        if (!file)
-                                break;
-                        while (fgets(buf, sizeof(buf), file)) {
-                                unsigned long sz;
-                                char *tp;
-                                char w;
+                        if (file) {
+                                while (fgets(buf, sizeof(buf), file)) {
+                                        unsigned long sz;
+                                        char *tp;
+                                        char w;
 #define SCAN(str, name) \
         if (strncmp(buf, str, sizeof(str)-1) == 0) { \
                 tp = skip_whitespace(buf + sizeof(str)-1); \
                 sp->name += fast_strtoul_10(&tp); \
                 continue; \
         }
-                                SCAN("Shared_Clean:" , shared_clean );
-                                SCAN("Shared_Dirty:" , shared_dirty );
-                                SCAN("Private_Clean:", private_clean);
-                                SCAN("Private_Dirty:", private_dirty);
+                                        SCAN("Shared_Clean:" , shared_clean );
+                                        SCAN("Shared_Dirty:" , shared_dirty );
+                                        SCAN("Private_Clean:", private_clean);
+                                        SCAN("Private_Dirty:", private_dirty);
 #undef SCAN
-                                // f7d29000-f7d39000 rw-s ADR M:m OFS FILE
-                                tp = strchr(buf, '-');
-                                if (tp) {
-                                        *tp = ' ';
-                                        tp = buf;
-                                        sz = fast_strtoul_16(&tp); /* start */
-                                        sz = (fast_strtoul_16(&tp) - sz) >> 10; /* end - start */
-                                        // tp -> "rw-s" string
-                                        w = tp[1];
-                                        // skipping "rw-s ADR M:m OFS "
-                                        tp = skip_whitespace(skip_fields(tp, 4));
-                                        // filter out /dev/something (something != zero)
-                                        if (strncmp(tp, "/dev/", 5) != 0 || strcmp(tp, "/dev/zero\n") == 0) {
-                                                if (w == 'w') {
-                                                        sp->mapped_rw += sz;
-                                                } else if (w == '-') {
-                                                        sp->mapped_ro += sz;
+                                        // f7d29000-f7d39000 rw-s ADR M:m OFS FILE
+                                        tp = strchr(buf, '-');
+                                        if (tp) {
+                                                *tp = ' ';
+                                                tp = buf;
+                                                sz = fast_strtoul_16(&tp); /* start */
+                                                sz = (fast_strtoul_16(&tp) - sz) >> 10; /* end - start */
+                                                // tp -> "rw-s" string
+                                                w = tp[1];
+                                                // skipping "rw-s ADR M:m OFS "
+                                                tp = skip_whitespace(skip_fields(tp, 4));
+                                                // filter out /dev/something (something != zero)
+                                                if (strncmp(tp, "/dev/", 5) != 0 || strcmp(tp, "/dev/zero\n") == 0) {
+                                                        if (w == 'w') {
+                                                                sp->mapped_rw += sz;
+                                                        } else if (w == '-') {
+                                                                sp->mapped_ro += sz;
+                                                        }
                                                 }
-                                        }
 //else printf("DROPPING %s (%s)\n", buf, tp);
-                                        if (strcmp(tp, "[stack]\n") == 0)
-                                                sp->stack += sz;
+                                                if (strcmp(tp, "[stack]\n") == 0)
+                                                        sp->stack += sz;
+                                        }
                                 }
+                                fclose(file);
                         }
-                        fclose(file);
                 }
 #endif /* TOPMEM */
 #if ENABLE_FEATURE_PS_ADDITIONAL_COLUMNS
@@ -418,23 +420,34 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
 
                         strcpy(filename_tail, "status");
                         file = fopen_for_read(filename);
-                        if (!file)
-                                break;
-                        while (fgets(buf, sizeof(buf), file)) {
-                                char *tp;
+                        if (file) {
+                                while (fgets(buf, sizeof(buf), file)) {
+                                        char *tp;
 #define SCAN_TWO(str, name, statement) \
         if (strncmp(buf, str, sizeof(str)-1) == 0) { \
                 tp = skip_whitespace(buf + sizeof(str)-1); \
                 sscanf(tp, "%u", &sp->name); \
                 statement; \
         }
-                                SCAN_TWO("Uid:", ruid, continue);
-                                SCAN_TWO("Gid:", rgid, break);
+                                        SCAN_TWO("Uid:", ruid, continue);
+                                        SCAN_TWO("Gid:", rgid, break);
 #undef SCAN_TWO
+                                }
+                                fclose(file);
                         }
-                        fclose(file);
                 }
 #endif /* PS_ADDITIONAL_COLUMNS */
+                if (flags & PSSCAN_EXE) {
+                        strcpy(filename_tail, "exe");
+                        free(sp->exe);
+                        sp->exe = xmalloc_readlink(filename);
+                }
+                /* Note: if /proc/PID/cmdline is empty,
+                 * code below "breaks". Therefore it must be
+                 * the last code to parse /proc/PID/xxx data
+                 * (we used to have /proc/PID/exe parsing after it
+                 * and were getting stale sp->exe).
+                 */
 #if 0 /* PSSCAN_CMD is not used */
                 if (flags & (PSSCAN_CMD|PSSCAN_ARGV0)) {
                         free(sp->argv0);
@@ -477,13 +490,9 @@ procps_status_t* FAST_FUNC procps_scan(procps_status_t* sp, int flags)
                         }
                 }
 #endif
-                if (flags & PSSCAN_EXE) {
-                        strcpy(filename_tail, "exe");
-                        free(sp->exe);
-                        sp->exe = xmalloc_readlink(filename);
-                }
                 break;
-        }
+        } /* for (;;) */
+
         return sp;
 }