Use new standard I/O for reading/writing sysctl values

thereby use one allocated buffer for I/O which now might
be increased by the stdio function getline(3) on the
file if required.

Signed-off-by: Werner Fink <werner@suse.de>

diff --git a/sysctl.c b/sysctl.c
index 42162f5b78afa74bd70bd91551e3acb9ee5eeaa7..7286b2e7766d807cbc3b0ad4d9e4e566e4dca3a6 100644 (file)
--- a/sysctl.c
+++ b/sysctl.c
@@ -45,6 +45,7 @@
 #include "fileutils.h"
 #include "nls.h"
 #include "xalloc.h"
+#include "proc/procio.h"
 #include "proc/procps.h"
 #include "proc/version.h"
 
@@ -66,6 +67,10 @@ static bool IgnoreError;
 static bool Quiet;
 static char *pattern;
 
+#define LINELEN 4096
+static char *iobuf;
+static size_t iolen = LINELEN;
+
 /* Function prototypes. */
 static int pattern_match(const char *string, const char *pat);
 static int DisplayAll(const char *restrict const path);
@@ -158,14 +163,12 @@ static char *StripLeadingAndTrailingSpaces(char *oneline)
 /*
  * Read a sysctl setting
  */
-#define IOBUFSIZ    (128<<10)
-static char *iobuf;
 static int ReadSetting(const char *restrict const name)
 {
        int rc = 0;
        char *restrict tmpname;
        char *restrict outname;
-       char inbuf[1025];
+       ssize_t rlen;
        FILE *restrict fp;
        struct stat ts;
 
@@ -220,7 +223,7 @@ static int ReadSetting(const char *restrict const name)
                goto out;
        }
 
-       fp = fopen(tmpname, "r");
+       fp = fprocopen(tmpname, "r");
 
        if (!fp) {
                switch (errno) {
@@ -243,11 +246,8 @@ static int ReadSetting(const char *restrict const name)
                        break;
                }
        } else {
-           if (iobuf)
-            setvbuf(fp, iobuf, _IOFBF, IOBUFSIZ);
-
                errno = 0;
-               if (fgets(inbuf, sizeof inbuf - 1, fp)) {
+               if ((rlen = getline(&iobuf, &iolen, fp)) > 0) {
                        /* this loop is required, see
                         * /sbin/sysctl -a | egrep -6 dev.cdrom.info
                         */
@@ -256,23 +256,23 @@ static int ReadSetting(const char *restrict const name)
                                if (PrintName) {
                                        fprintf(stdout, "%s = ", outname);
                                        do {
-                                               fprintf(stdout, "%s", inbuf);
-                                               nlptr = &inbuf[strlen(inbuf) - 1];
+                                               fprintf(stdout, "%s", iobuf);
+                                               nlptr = &iobuf[strlen(iobuf) - 1];
                                                /* already has the \n in it */
                                                if (*nlptr == '\n')
                                                        break;
-                                       } while (fgets(inbuf, sizeof inbuf - 1, fp));
+                                       } while ((rlen = getline(&iobuf, &iolen, fp)) > 0);
                                        if (*nlptr != '\n')
                                                putchar('\n');
                                } else {
                                        if (!PrintNewline) {
-                                               nlptr = strchr(inbuf, '\n');
+                                               nlptr = strchr(iobuf, '\n');
                                                if (nlptr)
                                                        *nlptr = '\0';
                                        }
-                                       fprintf(stdout, "%s", inbuf);
+                                       fprintf(stdout, "%s", iobuf);
                                }
-                       } while (fgets(inbuf, sizeof inbuf - 1, fp));
+                       } while ((rlen = getline(&iobuf, &iolen, fp)) > 0);
                } else {
                        switch (errno) {
                        case EACCES:
@@ -439,10 +439,7 @@ static int WriteSetting(const char *setting)
                goto out;
        }
 
-       fp = fopen(tmpname, "w");
-
-       if (iobuf)
-               setvbuf(fp, iobuf, _IOFBF, IOBUFSIZ);
+       fp = fprocopen(tmpname, "w");
 
        if (!fp) {
                switch (errno) {
@@ -503,20 +500,16 @@ static int pattern_match(const char *string, const char *pat)
        return (1);
 }
 
-#define LINELEN 4096
-
 /*
  * Preload the sysctl's from the conf file.  We parse the file and then
  * reform it (strip out whitespace).
  */
 static int Preload(const char *restrict const filename)
 {
-       char *oneline;
        FILE *fp;
        char *t;
        int n = 0;
        int rc = 0;
-       size_t blen = LINELEN;
        ssize_t rlen;
        char *name, *value;
        glob_t globbuf;
@@ -524,8 +517,6 @@ static int Preload(const char *restrict const filename)
        int globflg;
        int j;
 
-       oneline = xmalloc(blen);
-
        globflg = GLOB_NOCHECK;
 #ifdef GLOB_BRACE
        globflg |= GLOB_BRACE;
@@ -551,7 +542,7 @@ static int Preload(const char *restrict const filename)
                        goto out;
                }
 
-               while ((rlen =  getline(&oneline, &blen, fp)) != -1) {
+               while ((rlen =  getline(&iobuf, &iolen, fp)) > 0) {
                        size_t offset;
 
                        n++;
@@ -559,7 +550,7 @@ static int Preload(const char *restrict const filename)
                        if (rlen < 2)
                                continue;
 
-                       t = StripLeadingAndTrailingSpaces(oneline);
+                       t = StripLeadingAndTrailingSpaces(iobuf);
                        if (strlen(t) < 2)
                                continue;
 
@@ -579,8 +570,8 @@ static int Preload(const char *restrict const filename)
                                continue;
 
                        offset = strlen(name);
-                       memmove(&oneline[0], name, offset);
-                       oneline[offset++] = '=';
+                       memmove(&iobuf[0], name, offset);
+                       iobuf[offset++] = '=';
 
                        value = strtok(NULL, "\n\r");
                        if (!value || !*value) {
@@ -593,11 +584,11 @@ static int Preload(const char *restrict const filename)
                                value++;
 
                        /* should NameOnly affect this? */
-                       memmove(&oneline[offset], value, strlen(value));
+                       memmove(&iobuf[offset], value, strlen(value));
                        offset += strlen(value);
-                       oneline[offset] = '\0';
+                       iobuf[offset] = '\0';
 
-                       rc |= WriteSetting(oneline);
+                       rc |= WriteSetting(iobuf);
                }
 
                fclose(fp);
@@ -824,7 +815,7 @@ int main(int argc, char *argv[])
        argc -= optind;
        argv += optind;
 
-       iobuf = (char*)malloc(IOBUFSIZ);        /* Allow to fail */
+       iobuf = xmalloc(iolen);
 
        if (DisplayAllOpt)
                return DisplayAll(PROC_PATH);