Fix history when running multiple sessions

diff --git a/src/history.c b/src/history.c
index 899eaf9a0959c01d04cf3dac9700750ea40bf495..2c50ba5b35ad1ec839c9da981c409494fd7bec07 100644 (file)
--- a/src/history.c
+++ b/src/history.c
@@ -16,9 +16,18 @@
 
 static struct {
    char path[PATH_MAX], entries[MAXHIST + 1][MAXCHARS + 1];
-   size_t b, c, t;
+   size_t b, s, c, t;
 } history;
 
+static void readhistory(FILE *file) {
+   history.b = history.t = 0;
+   while (fgets(history.entries[history.t], sizeof*history.entries, file)) {
+       history.entries[history.t][strlen(history.entries[history.t]) - 1] = '\0';
+       if (INC(t) == history.b) INC(b);
+   }
+   history.s = history.c = history.t;
+}
+
 void inithistory(void) {
    FILE *file;
 
@@ -29,12 +38,8 @@ void inithistory(void) {
        if (errno == ENOENT) return;
        fatal("Unable to open history file for reading");
    }
-   while (fgets(history.entries[history.t], sizeof*history.entries, file)) {
-       history.entries[history.t][strlen(history.entries[history.t]) - 1] = '\0';
-       if ((history.c = INC(t)) == history.b) INC(b);
-   }
-   if (ferror(file) || !feof(file))
-       fatal("Unable to read from history file");
+   readhistory(file);
+   if (ferror(file) || !feof(file)) fatal("Unable to read from history file");
    if (fclose(file) == EOF) fatal("Unable to close history file");
 }
 
@@ -52,33 +57,50 @@ int gethistory(int back, char *buffer) {
 
 void sethistory(char *buffer) {
    strcpy(history.entries[history.t], buffer);
-   if ((history.c = INC(t)) == history.b) INC(b);
+   history.c = INC(t);
+   if (history.t == history.b) INC(b);
+   if (history.t == history.s) INC(s);
    *history.entries[history.t] = '\0';
 }
 
+static void writehistory(FILE *file) {
+   for (history.c = history.b; history.c != history.t; INC(c)) {
+       if (fputs(history.entries[history.c], file) == EOF) {
+           note("Unable to write to history file");
+           break;
+       }
+       if (fputc('\n', file) == EOF) {
+           note("Unable to terminate line of history file");
+           break;
+       }
+   }
+}
+
 void deinithistory(void) {
    int fd;
    FILE *file;
 
    if (!interactive) return;
 
-   if ((fd = open(history.path, O_WRONLY | O_CREAT | O_TRUNC, 0600)) == -1) {
+   if ((fd = open(history.path, O_WRONLY | O_CREAT | O_APPEND, 0600)) == -1) {
        note("Unable to open history file for writing");
        return;
    }
-   if (!(file = fdopen(fd, "w"))) {
+   if (!(file = fdopen(fd, "a"))) {
        note("Unable to open history file descriptor as FILE pointer");
        return;
    }
-   for (history.c = history.b; history.c != history.t; INC(c)) {
-       if (fputs(history.entries[history.c], file) == EOF) {
-           note("Unable to write to history file");
-           break;
-       }
-       if (fputc('\n', file) == EOF) {
-           note("Unable to terminate line of history file");
-           break;
-       }
+   history.b = history.s;
+   writehistory(file);
+   if (!freopen(history.path, "r", file)) {
+       note("Unable to reopen history file for reading");
+       return;
+   }
+   readhistory(file);
+   if (!freopen(history.path, "w", file)) {
+       note("Unable to reopen history file for writing");
+       return;
    }
+   writehistory(file);
    if (fclose(file) == EOF) note("Unable to close history stream");
 }