C++-ify procrank

Change-Id: I1b006d2af04f21c0c02ac2d7629340d91b876886

2 files changed, 73 insertions, 138 deletions

diff --git a/procrank/Android.mk b/procrank/Android.mk
index f1eb3b6c..8a235fda 100644
--- a/procrank/Android.mk
+++ b/procrank/Android.mk
@@ -15,9 +15,9 @@
 LOCAL_PATH:= $(call my-dir)
 
 include $(CLEAR_VARS)
-LOCAL_SRC_FILES := procrank.c
+LOCAL_SRC_FILES := procrank.cpp
 LOCAL_CFLAGS := -Wall -Wextra -Wformat=2 -Werror
-LOCAL_SHARED_LIBRARIES := libpagemap
+LOCAL_SHARED_LIBRARIES := libpagemap libbase
 LOCAL_MODULE := procrank
 LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
 LOCAL_MODULE_TAGS := debug
diff --git a/procrank/procrank.c b/procrank/procrank.cpp
index 881f1108..6f9803fd 100644
--- a/procrank/procrank.c
+++ b/procrank/procrank.cpp
@@ -1,18 +1,18 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+//
+// Copyright (C) 2008 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
 
 #include <dirent.h>
 #include <errno.h>
@@ -24,6 +24,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <vector>
+
+#include <android-base/file.h>
+#include <android-base/stringprintf.h>
 #include <pagemap/pagemap.h>
 
 struct proc_info {
@@ -33,7 +37,7 @@ struct proc_info {
 };
 
 static void usage(char *myname);
-static int getprocname(pid_t pid, char *buf, int len);
+static std::string getprocname(pid_t pid);
 static int numcmp(uint64_t a, uint64_t b);
 
 #define declare_sort(field) \
@@ -94,7 +98,7 @@ void get_mem_info(uint64_t mem[]) {
             "Slab:",
             "SwapTotal:",
             "SwapFree:",
-            "ZRam:",            /* not read from meminfo but from /sys/block/zram0 */
+            "ZRam:",            // not read from meminfo but from /sys/block/zram0
             "Mapped:",
             "VmallocUsed:",
             "PageTables:",
@@ -148,7 +152,6 @@ int main(int argc, char *argv[]) {
     pm_kernel_t *ker;
     pm_process_t *proc;
     pid_t *pids;
-    struct proc_info **procs;
     size_t num_procs;
     uint64_t total_pss;
     uint64_t total_uss;
@@ -156,19 +159,19 @@ int main(int argc, char *argv[]) {
     uint64_t total_pswap;
     uint64_t total_uswap;
     uint64_t total_zswap;
-    char cmdline[256]; // this must be within the range of int
     int error;
     bool has_swap = false, has_zram = false;
     uint64_t required_flags = 0;
     uint64_t flags_mask = 0;
 
-    #define WS_OFF   0
-    #define WS_ONLY  1
-    #define WS_RESET 2
-    int ws;
-
     int arg;
-    size_t i, j;
+    size_t i;
+
+    enum {
+        WS_OFF,
+        WS_ONLY,
+        WS_RESET,
+    } ws;
 
     uint64_t mem[MEMINFO_COUNT] = { };
     pm_proportional_swap_t *p_swap;
@@ -215,21 +218,11 @@ int main(int argc, char *argv[]) {
         exit(EXIT_FAILURE);
     }
 
-    procs = calloc(num_procs, sizeof(struct proc_info*));
-    if (procs == NULL) {
-        fprintf(stderr, "calloc: %s", strerror(errno));
-        exit(EXIT_FAILURE);
-    }
-
+    std::vector<proc_info> procs(num_procs);
     for (i = 0; i < num_procs; i++) {
-        procs[i] = malloc(sizeof(struct proc_info));
-        if (procs[i] == NULL) {
-            fprintf(stderr, "malloc: %s\n", strerror(errno));
-            exit(EXIT_FAILURE);
-        }
-        procs[i]->pid = pids[i];
-        pm_memusage_zero(&procs[i]->usage);
-        pm_memusage_pswap_init_handle(&procs[i]->usage, p_swap);
+        procs[i].pid = pids[i];
+        pm_memusage_zero(&procs[i].usage);
+        pm_memusage_pswap_init_handle(&procs[i].usage, p_swap);
         error = pm_process_create(ker, pids[i], &proc);
         if (error) {
             fprintf(stderr, "warning: could not create process interface for %d\n", pids[i]);
@@ -238,11 +231,11 @@ int main(int argc, char *argv[]) {
 
         switch (ws) {
         case WS_OFF:
-            error = pm_process_usage_flags(proc, &procs[i]->usage, flags_mask,
+            error = pm_process_usage_flags(proc, &procs[i].usage, flags_mask,
                                            required_flags);
             break;
         case WS_ONLY:
-            error = pm_process_workingset(proc, &procs[i]->usage, 0);
+            error = pm_process_workingset(proc, &procs[i].usage, 0);
             break;
         case WS_RESET:
             error = pm_process_workingset(proc, NULL, 1);
@@ -253,7 +246,7 @@ int main(int argc, char *argv[]) {
             fprintf(stderr, "warning: could not read usage for %d\n", pids[i]);
         }
 
-        if (ws != WS_RESET && procs[i]->usage.swap) {
+        if (ws != WS_RESET && procs[i].usage.swap) {
             has_swap = true;
         }
 
@@ -264,17 +257,14 @@ int main(int argc, char *argv[]) {
 
     if (ws == WS_RESET) exit(0);
 
-    j = 0;
-    for (i = 0; i < num_procs; i++) {
-        if (procs[i]->usage.vss) {
-            procs[j++] = procs[i];
-        } else {
-            free(procs[i]);
-        }
-    }
-    num_procs = j;
+    procs.erase(std::remove_if(procs.begin(),
+                               procs.end(),
+                               [](auto proc){
+                                   return proc.usage.vss == 0;
+                               }),
+                procs.end());
 
-    qsort(procs, num_procs, sizeof(procs[0]), compfn);
+    qsort(procs.data(), procs.size(), sizeof(procs[0]), compfn);
 
     if (has_swap) {
         fd = open("/sys/block/zram0/mem_used_total", O_RDONLY);
@@ -319,47 +309,40 @@ int main(int argc, char *argv[]) {
     total_uswap = 0;
     total_zswap = 0;
 
-    for (i = 0; i < num_procs; i++) {
-        if (getprocname(procs[i]->pid, cmdline, (int)sizeof(cmdline)) < 0) {
-            /*
-             * Something is probably seriously wrong if writing to the stack
-             * failed.
-             */
-            free(procs[i]);
-            continue;
-        }
+    for (auto& proc: procs) {
+        std::string cmdline = getprocname(proc.pid);
 
-        total_pss += procs[i]->usage.pss;
-        total_uss += procs[i]->usage.uss;
-        total_swap += procs[i]->usage.swap;
+        total_pss += proc.usage.pss;
+        total_uss += proc.usage.uss;
+        total_swap += proc.usage.swap;
 
-        printf("%5d  ", procs[i]->pid);
+        printf("%5d  ", proc.pid);
 
         if (ws) {
             printf("%6zuK  %6zuK  %6zuK  ",
-                procs[i]->usage.rss / 1024,
-                procs[i]->usage.pss / 1024,
-                procs[i]->usage.uss / 1024
+                proc.usage.rss / 1024,
+                proc.usage.pss / 1024,
+                proc.usage.uss / 1024
             );
         } else {
             printf("%7zuK  %6zuK  %6zuK  %6zuK  ",
-                procs[i]->usage.vss / 1024,
-                procs[i]->usage.rss / 1024,
-                procs[i]->usage.pss / 1024,
-                procs[i]->usage.uss / 1024
+                proc.usage.vss / 1024,
+                proc.usage.rss / 1024,
+                proc.usage.pss / 1024,
+                proc.usage.uss / 1024
             );
         }
 
         if (has_swap) {
             pm_swapusage_t su;
 
-            pm_memusage_pswap_get_usage(&procs[i]->usage, &su);
-            printf("%6zuK  ", procs[i]->usage.swap / 1024);
+            pm_memusage_pswap_get_usage(&proc.usage, &su);
+            printf("%6zuK  ", proc.usage.swap / 1024);
             printf("%6zuK  ", su.proportional / 1024);
             printf("%6zuK  ", su.unique / 1024);
             total_pswap += su.proportional;
             total_uswap += su.unique;
-            pm_memusage_pswap_free(&procs[i]->usage);
+            pm_memusage_pswap_free(&proc.usage);
             if (has_zram) {
                 size_t zpswap = su.proportional * zram_cr;
                 printf("%6zuK  ", zpswap / 1024);
@@ -367,15 +350,12 @@ int main(int argc, char *argv[]) {
             }
         }
 
-        printf("%s\n", cmdline);
-
-        free(procs[i]);
+        printf("%s\n", cmdline.c_str());
     }
 
-    free(procs);
     pm_memusage_pswap_destroy(p_swap);
 
-    /* Print the separator line */
+    // Print the separator line
     printf("%5s  ", "");
 
     if (ws) {
@@ -393,7 +373,7 @@ int main(int argc, char *argv[]) {
 
     printf("%s\n", "------");
 
-    /* Print the total line */
+    // Print the total line
     printf("%5s  ", "");
     if (ws) {
         printf("%7s  %6" PRIu64 "K  %6" PRIu64 "K  ",
@@ -448,63 +428,18 @@ static void usage(char *myname) {
     myname);
 }
 
-/*
- * Get the process name for a given PID. Inserts the process name into buffer
- * buf of length len. The size of the buffer must be greater than zero to get
- * any useful output.
- *
- * Note that fgets(3) only declares length as an int, so our buffer size is
- * also declared as an int.
- *
- * Returns 0 on success, a positive value on partial success, and -1 on
- * failure. Other interesting values:
- *   1 on failure to create string to examine proc cmdline entry
- *   2 on failure to open proc cmdline entry
- *   3 on failure to read proc cmdline entry
- */
-static int getprocname(pid_t pid, char *buf, int len) {
-    char *filename;
-    FILE *f;
-    int rc = 0;
-    static const char* unknown_cmdline = "<unknown>";
-
-    if (len <= 0) {
-        return -1;
-    }
+// Get the process name for a given PID.
+static std::string getprocname(pid_t pid) {
+    std::string filename = android::base::StringPrintf("/proc/%d/cmdline", pid);
 
-    if (asprintf(&filename, "/proc/%d/cmdline", pid) < 0) {
-        rc = 1;
-        goto exit;
-    }
+    std::string procname;
 
-    f = fopen(filename, "r");
-    if (f == NULL) {
-        rc = 2;
-        goto releasefilename;
-    }
-
-    if (fgets(buf, len, f) == NULL) {
-        rc = 3;
-        goto closefile;
-    }
-
-closefile:
-    (void) fclose(f);
-releasefilename:
-    free(filename);
-exit:
-    if (rc != 0) {
-        /*
-         * The process went away before we could read its process name. Try
-         * to give the user "<unknown>" here, but otherwise they get to look
-         * at a blank.
-         */
-        if (strlcpy(buf, unknown_cmdline, (size_t)len) >= (size_t)len) {
-            rc = 4;
-        }
+    if (!android::base::ReadFileToString(filename, &procname)) {
+        // The process went away before we could read its process name.
+        procname = "<unknown>";
     }
 
-    return rc;
+    return procname;
 }
 
 static int numcmp(uint64_t a, uint64_t b) {
@@ -516,8 +451,8 @@ static int numcmp(uint64_t a, uint64_t b) {
 #define create_sort(field, compfn) \
     static int sort_by_ ## field (const void *a, const void *b) { \
         return order * compfn( \
-            (*((struct proc_info**)a))->usage.field, \
-            (*((struct proc_info**)b))->usage.field \
+            ((struct proc_info*)(a))->usage.field, \
+            ((struct proc_info*)(b))->usage.field  \
         ); \
     }