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 845a214..48e60a7 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;
 }