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authorRob Landley <rob@landley.net>2019-01-21 12:36:31 -0600
committerRob Landley <rob@landley.net>2019-01-21 12:36:31 -0600
commitfacab519b3a3c2ddad43eeb42c0caad0f3c41d11 (patch)
treeb5e889498e4fc62d3630089bb695992182be6c06 /toys
parentb67a5a07b0c3173922b7f2305f90216375be0bd5 (diff)
downloadtoybox-facab519b3a3c2ddad43eeb42c0caad0f3c41d11.tar.gz
Add more comments to ps.c and replace hardcoded value with a macro.
If table grows >64 entries XX needs to change, but it can't be 128 yet because the slot value is a signed char. Currently 59 entries in table...
Diffstat (limited to 'toys')
-rw-r--r--toys/posix/ps.c62
1 files changed, 35 insertions, 27 deletions
diff --git a/toys/posix/ps.c b/toys/posix/ps.c
index f5e080c7..fef9c908 100644
--- a/toys/posix/ps.c
+++ b/toys/posix/ps.c
@@ -234,7 +234,7 @@ struct ofields {
* struct procpid contains a slot[] array of 64 bit values, with the following
* data at each position in the array. Most is read from /proc/$PID/stat (see
* https://kernel.org/doc/Documentation/filesystems/proc.txt table 1-4) but
- * we we replace several fields with don't use with other data. */
+ * we replace several fields with don't use with other data. */
enum {
SLOT_pid, /*process id*/ SLOT_ppid, // parent process id
@@ -297,7 +297,7 @@ struct procpid {
* get the overflow back).
*
* slot: which slot[] out of procpid. Negative means it's a string field.
- * Setting bit |64 requests extra display/sort processing.
+ * value|XX requests extra display/sort processing.
*
* The TAGGED_ARRAY plumbing produces an enum of indexes, the "tag" is the
* first string argument and the prefix is the first argument to TAGGED_ARRAY
@@ -308,8 +308,9 @@ struct procpid {
* if (TT.bits & _PS_NAME) printf("-o included PS_NAME");
*/
+#define XX 64 // force string representation for sorting, etc
+
// TODO: Android uses -30 for LABEL, but ideally it would auto-size.
-// 64|slot means compare as string when sorting
struct typography {
char *name, *help;
signed char width, slot;
@@ -349,13 +350,13 @@ struct typography {
// user/group (may call getpwuid() or similar)
{"UID", "User id", 5, SLOT_uid},
- {"USER", "User name", -12, 64|SLOT_uid},
+ {"USER", "User name", -12, XX|SLOT_uid},
{"RUID", "Real (before suid) user ID", 4, SLOT_ruid},
- {"RUSER", "Real (before suid) user name", -8, 64|SLOT_ruid},
+ {"RUSER", "Real (before suid) user name", -8, XX|SLOT_ruid},
{"GID", "Group ID", 8, SLOT_gid},
- {"GROUP", "Group name", -8, 64|SLOT_gid},
+ {"GROUP", "Group name", -8, XX|SLOT_gid},
{"RGID", "Real (before sgid) Group ID", 4, SLOT_rgid},
- {"RGROUP", "Real (before sgid) group name", -8, 64|SLOT_rgid},
+ {"RGROUP", "Real (before sgid) group name", -8, XX|SLOT_rgid},
// clock displays (00:00:00)
{"TIME", "CPU time consumed", 8, SLOT_utime},
@@ -382,20 +383,19 @@ struct typography {
// Misc (special cases)
{"STIME", "Start time (ISO 8601)", 5, SLOT_starttime},
- {"F", "Flags 1=FORKNOEXEC 4=SUPERPRIV", 1, 64|SLOT_flags},
+ {"F", "Flags 1=FORKNOEXEC 4=SUPERPRIV", 1, XX|SLOT_flags},
{"S", "Process state:\n"
"\t R (running) S (sleeping) D (device I/O) T (stopped) t (traced)\n"
"\t Z (zombie) X (deader) x (dead) K (wakekill) W (waking)",
- -1, 64},
+ -1, XX},
{"STAT", "Process state (S) plus:\n"
"\t < high priority N low priority L locked memory\n"
"\t s session leader + foreground l multithreaded",
- -5, 64},
- {"PCY", "Android scheduling policy", 3, 64|SLOT_pcy},
+ -5, XX},
+ {"PCY", "Android scheduling policy", 3, XX|SLOT_pcy},
);
// Show sorted "-o help" text for fields listed in toybuf[len]
-
static void help_fields(int len, int multi)
{
int i, j, k, left = 0;
@@ -429,7 +429,7 @@ static void help_fields(int len, int multi)
if (!multi && left) xputc('\n');
}
-// Print help text for all -o field, with categories.
+// Print help text for each -o field, with categories.
static void help_help(void)
{
int i, jump = PS_CMD+1-PS_COMM;
@@ -454,7 +454,7 @@ static void help_help(void)
xexit();
}
-// Return 0 to discard, nonzero to keep
+// process match filter for top/ps/pgrep: Return 0 to discard, nonzero to keep
static int shared_match_process(long long *slot)
{
struct ptr_len match[] = {
@@ -478,8 +478,7 @@ static int shared_match_process(long long *slot)
return ll ? 0 : -1;
}
-
-// Return 0 to discard, nonzero to keep
+// process match filter for ps: Return 0 to discard, nonzero to keep
static int ps_match_process(long long *slot)
{
int i = shared_match_process(slot);
@@ -497,12 +496,12 @@ static int ps_match_process(long long *slot)
return 1;
}
-// Convert field to string representation
+// Generate display string (260 bytes at end of toybuf) from struct ofield
static char *string_field(struct procpid *tb, struct ofields *field)
{
char *buf = toybuf+sizeof(toybuf)-260, *out = buf, *s;
int which = field->which, sl = typos[which].slot;
- long long *slot = tb->slot, ll = (sl >= 0) ? slot[sl&63] : 0;
+ long long *slot = tb->slot, ll = (sl >= 0) ? slot[sl&(XX-1)] : 0;
// numbers, mostly from /proc/$PID/stat
if (which <= PS_BIT) {
@@ -536,7 +535,7 @@ static char *string_field(struct procpid *tb, struct ofields *field)
// user/group
} else if (which <= PS_RGROUP) {
sprintf(out, "%lld", ll);
- if (sl&64) {
+ if (sl&XX) {
if (which > PS_RUSER) {
struct group *gr = bufgetgrgid(ll);
@@ -576,7 +575,7 @@ static char *string_field(struct procpid *tb, struct ofields *field)
// Percentage displays
} else if (which <= PS__CPU) {
- ll = slot[sl&63]*1000;
+ ll = slot[sl&(XX-1)]*1000;
if (which==PS__VSZ || which==PS__MEM)
ll /= slot[SLOT_totalram]/((which==PS__VSZ) ? 1024 : 4096);
else if (slot[SLOT_upticks]) ll /= slot[SLOT_upticks];
@@ -624,7 +623,7 @@ static char *string_field(struct procpid *tb, struct ofields *field)
return out;
}
-// Display process data that get_ps() read from /proc, formatting with TT.fields
+// Display process data that get_ps() read from /proc, formatting via TT.fields
static void show_ps(void *p)
{
struct procpid *tb = p;
@@ -687,7 +686,7 @@ static void show_ps(void *p)
putchar(TT.time ? '\r' : '\n');
}
-// dirtree callback: read data about process, then display or store it.
+// dirtree callback: read data about a process, then display or store it.
// Fills toybuf with struct procpid and either DIRTREE_SAVEs a copy to ->extra
// (in -k mode) or calls show_ps directly on toybuf (for low memory systems).
static int get_ps(struct dirtree *new)
@@ -982,6 +981,7 @@ static int get_ps(struct dirtree *new)
return DIRTREE_SAVE;
}
+// wrapper for get_ps() that also collects threads under each processes
static int get_threads(struct dirtree *new)
{
struct dirtree *dt;
@@ -1033,6 +1033,7 @@ static int get_threads(struct dirtree *new)
return 0;
}
+// Parse one FIELD argument (with optional =name :width) into struct ofields
static char *parse_ko(void *data, char *type, int length)
{
struct ofields *field;
@@ -1100,6 +1101,8 @@ static char *parse_ko(void *data, char *type, int length)
return 0;
}
+// Write FIELD list into display header string (truncating at blen),
+// and return bitfield of which FIELDs are used.
static long long get_headers(struct ofields *field, char *buf, int blen)
{
long long bits = 0;
@@ -1114,7 +1117,7 @@ static long long get_headers(struct ofields *field, char *buf, int blen)
return bits;
}
-// Parse -p -s -t -u -U -g -G
+// Parse command line options -p -s -t -u -U -g -G
static char *parse_rest(void *data, char *str, int len)
{
struct ptr_len *pl = (struct ptr_len *)data;
@@ -1192,7 +1195,7 @@ static char *parse_rest(void *data, char *str, int len)
return str;
}
-// sort for -k
+// sort processes by FIELD(s) listed in option -k
static int ksort(void *aa, void *bb)
{
struct ofields *field;
@@ -1203,7 +1206,7 @@ static int ksort(void *aa, void *bb)
slot = typos[field->which].slot;
// Can we do numeric sort?
- if (!(slot&64)) {
+ if (!(slot&XX)) {
if (ta->slot[slot]<tb->slot[slot]) ret = -1;
if (ta->slot[slot]>tb->slot[slot]) ret = 1;
}
@@ -1220,6 +1223,8 @@ static int ksort(void *aa, void *bb)
return ret;
}
+// Collect ->extra field from leaf nodes DIRTREE_SAVEd by get_ps() into array
+// (recursion because tree from get_thread() isn't flat list of siblings)
static struct procpid **collate_leaves(struct procpid **tb, struct dirtree *dt)
{
while (dt) {
@@ -1234,6 +1239,8 @@ static struct procpid **collate_leaves(struct procpid **tb, struct dirtree *dt)
return tb;
}
+// Allocate struct procpid array of length count and populate it with ->extra
+// fields from dirtree leaf nodes. (top diffs old & new array to show changes)
static struct procpid **collate(int count, struct dirtree *dt)
{
struct procpid **tbsort = xmalloc(count*sizeof(struct procpid *));
@@ -1243,6 +1250,7 @@ static struct procpid **collate(int count, struct dirtree *dt)
return tbsort;
}
+// parse command line arguments (ala -k -o) with a comma separated FIELD list
static void default_ko(char *s, void *fields, char *err, struct arg_list *arg)
{
struct arg_list def;
@@ -1320,7 +1328,7 @@ void ps_main(void)
for (field = TT.fields; field; field = field->next) {
if (FLAG(n) && field->which>=PS_UID
- && field->which<=PS_RGROUP && (typos[field->which].slot&64))
+ && field->which<=PS_RGROUP && (typos[field->which].slot&XX))
field->which--;
}
}
@@ -1585,7 +1593,7 @@ static void top_common(
pos = stpcpy(toybuf, "Totals:");
for (field = TT.fields; field; field = field->next) {
long long ll, bits = 0;
- int slot = typos[field->which].slot&63;
+ int slot = typos[field->which].slot&(XX-1);
if (field->which<PS_C || field->which>PS_DIO) continue;
ll = 1LL<<field->which;