top: add -m ("memory") option

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

TODO

@@ -320,6 +320,29 @@ vdprintf() -> similar sized functionality
 
 Unicode work needed:
 
+Unicode support uses libc multibyte functions if LOCALE_SUPPORT is on
+(in this case, the code will also support many more encodings),
+or uses a limited subset of re-implemented multibyte functions
+which only understand "one byte == one char" and unicode.
+This is useful if you build against uclibc with locale support disabled.
+
+Unicode-dependent applets must call check_unicode_in_env() when they
+begin executing.
+
+Applet code may conditionalize on FEATURE_ASSUME_UNICODE
+in order to use more efficient code if unicode support is not requested.
+
+Available functions (if you need more, implement them in libbb/unicode.c
+so that they work without LOCALE_SUPPORT too):
+
+int bb_mbstrlen(str) - multibyte-aware strlen
+size_t mbstowcs(wdest, src, n)
+size_t wcstombs(dest, wsrc, n)
+size_t wcrtomb(str, wc, wstate)
+int iswspace(wc)
+int iswalnum(wc)
+int iswpunct(wc)
+
 Applets which only need to align columns on screen correctly:
 
 ls - already done, use source as an example

include/usage.h

@@ -4566,7 +4566,7 @@
        "Defaults: SECS: 10, SIG: TERM." \
 
 #define top_trivial_usage \
-       "[-b] [-nCOUNT] [-dSECONDS]"
+       "[-b] [-nCOUNT] [-dSECONDS]" IF_FEATURE_TOPMEM(" [-m]")
 #define top_full_usage "\n\n" \
        "Provide a view of process activity in real time.\n" \
        "Read the status of all processes from /proc each SECONDS\n" \

libbb/getopt32.c

@@ -147,15 +147,15 @@ const char *opt_complementary
 
 Special characters:
 
- "-"    A dash as the first char in a opt_complementary group forces
-        all arguments to be treated as options, even if they have
-        no leading dashes. Next char in this case can't be a digit (0-9),
-        use ':' or end of line. For example:
+ "-"    A group consisting of just a dash forces all arguments
+        to be treated as options, even if they have no leading dashes.
+        Next char in this case can't be a digit (0-9), use ':' or end of line.
+        Example:
 
-        opt_complementary = "-:w-x:x-w";
-        getopt32(argv, "wx");
+        opt_complementary = "-:w-x:x-w"; // "-w-x:x-w" would also work,
+        getopt32(argv, "wx");            // but is less readable
 
-        Allows any arguments to be given without a dash (./program w x)
+        This makes it possible to use options without a dash (./program w x)
         as well as with a dash (./program -x).
 
         NB: getopt32() will leak a small amount of memory if you use

procps/top.c

@@ -131,7 +131,8 @@ enum {
 	OPT_d = (1 << 0),
 	OPT_n = (1 << 1),
 	OPT_b = (1 << 2),
-	OPT_EOF = (1 << 3), /* pseudo: "we saw EOF in stdin" */
+	OPT_m = (1 << 3),
+	OPT_EOF = (1 << 4), /* pseudo: "we saw EOF in stdin" */
 };
 #define OPT_BATCH_MODE (option_mask32 & OPT_b)
 
@@ -895,7 +896,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 
 	pfd[0].fd = 0;
 	pfd[0].events = POLLIN;
-#endif /* FEATURE_USE_TERMIOS */
+#endif
 
 	INIT_G();
 
@@ -909,10 +910,15 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 #endif
 
 	/* all args are options; -n NUM */
-	opt_complementary = "-";
-	col = getopt32(argv, "d:n:b", &str_interval, &str_iterations);
+	opt_complementary = "-"; /* options can be specified w/o dash */
+	col = getopt32(argv, "d:n:b"IF_FEATURE_TOPMEM("m"), &str_interval, &str_iterations);
+#if ENABLE_FEATURE_TOPMEM
+	if (col & OPT_m) /* -m (busybox specific) */
+		scan_mask = TOPMEM_MASK;
+#endif
 	if (col & OPT_d) {
-		/* work around for "-d 1" -> "-d -1" done by getopt32 */
+		/* work around for "-d 1" -> "-d -1" done by getopt32
+		 * (opt_complementary == "-" does this) */
 		if (str_interval[0] == '-')
 			str_interval++;
 		/* Need to limit it to not overflow poll timeout */
@@ -934,7 +940,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 
 	bb_signals(BB_FATAL_SIGS, sig_catcher);
 	tcsetattr_stdin_TCSANOW(&new_settings);
-#endif /* FEATURE_USE_TERMIOS */
+#endif
 
 #if ENABLE_FEATURE_TOP_CPU_USAGE_PERCENTAGE
 	sort_function[0] = pcpu_sort;
@@ -942,7 +948,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 	sort_function[2] = time_sort;
 #else
 	sort_function[0] = mem_sort;
-#endif /* FEATURE_TOP_CPU_USAGE_PERCENTAGE */
+#endif
 
 	while (1) {
 		procps_status_t *p = NULL;
@@ -956,7 +962,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 			sleep(interval);
 			continue;
 		}
-#endif /* FEATURE_USE_TERMIOS */
+#endif
 		if (col > LINE_BUF_SIZE-2) /* +2 bytes for '\n', NUL, */
 			col = LINE_BUF_SIZE-2;
 
@@ -1015,7 +1021,7 @@ int top_main(int argc UNUSED_PARAM, char **argv)
 			qsort(top, ntop, sizeof(top_status_t), (void*)mult_lvl_cmp);
 #else
 			qsort(top, ntop, sizeof(top_status_t), (void*)(sort_function[0]));
-#endif /* FEATURE_TOP_CPU_USAGE_PERCENTAGE */
+#endif
 		}
 #if ENABLE_FEATURE_TOPMEM
 		else { /* TOPMEM */