ed4ff0e8c — BusyBox

Subject

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

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

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Commit Diff GitHub →

libbb/procps.c +71 -62

libbb/procps.c+71 -62

@@ -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;
	}