nkiss

commit c37dcd6c0ddfee55ec676ddf644e863c28c1b453
parent 858326c0faa59d484157d59cf713b2c572e6bfa7
Author: Nihal Jere <nihal@nihaljere.xyz>
Date:   Tue,  9 Mar 2021 23:23:15 -0600

add manifest.* to contain manifest operations

Diffstat:
M
common.h
 | 
1
+
A
manifest.c
 | 
101
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
manifest.h
 | 
9
+++++++++

3 files changed, 111 insertions(+), 0 deletions(-)
diff --git a/common.h b/common.h
@@ -10,6 +10,7 @@
 #define PATH_LEN 512
 #define URL_LEN 2048
 #define ALT_MAX 256
+#define MANIFEST_LINES 100
 #define KISS_INSTALLED "/var/db/kiss/installed"
 #define KISS_CHOICES "/var/db/kiss/choices"
 
diff --git a/manifest.c b/manifest.c
@@ -0,0 +1,101 @@
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include "common.h"
+#include "manifest.h"
+
+int
+manifest_open(struct manifest_t *manifest, char path[PATH_LEN])
+{
+    int fd, linelimit;
+    struct stat s;
+    char *start = NULL, **lines = NULL, **temp;
+    size_t lc, cc;
+
+    linelimit = MANIFEST_LINES;
+    if ((lines = calloc(MANIFEST_LINES, sizeof(char *))) == NULL)
+        goto err;
+
+    if ((fd = open(path, O_RDONLY)) == -1)
+        goto err;
+
+    if (fstat(fd, &s) == -1)
+        goto err;
+
+    /* load the whole manifest into memory, with permissions that will allow us
+     * to write to the memory map without writing to the file */
+    start = mmap(NULL, s.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+    if (start == MAP_FAILED) {
+        start = 0;
+        goto err;
+    }
+    close(fd);
+    fd = 0;
+
+    cc = s.st_size;
+
+    /* create array of pointers to the each line, and replace \n with \0.
+     * since manifest is sorted, we can use this to search for file names when
+     * validating a tarball on install */
+    lines[0] = start;
+    lc = 1;
+    for (int i = 0; i < cc; i++) {
+        if (start[i] != '\n')
+            continue;
+
+        if (lc == linelimit) {
+            if ((temp = realloc(lines, linelimit*2*sizeof(char *))) == NULL)
+                goto err;
+            lines = temp;
+            linelimit *= 2;
+        }
+
+        start[i] = '\0';
+
+        if (++i == cc)
+            break;
+
+        lines[lc++] = start + i;
+    }
+
+    /* one we know how many lines there are, we can shrink to only as much as
+     * we need */
+    if ((temp = realloc(lines, (lc+1)*sizeof(char *))) == NULL)
+        goto err;
+
+    /* null terminate to more easily know when we're done */
+    temp[lc] = 0;
+
+    manifest->start = start;
+    manifest->lines = temp;
+    manifest->lc = lc;
+    manifest->cc = cc;
+
+    return 0;
+err:
+    if (lines) free(lines);
+    if (fd) close(fd);
+    if (start) munmap(start, cc);
+    return -1;
+}
+
+int
+manifest_close(struct manifest_t *manifest)
+{
+    if (munmap(manifest->start, manifest->cc) == -1)
+        return -1;
+    manifest->start = NULL;
+
+    free(manifest->lines);
+    manifest->lines = NULL;
+
+    manifest->lc = 0;
+    manifest->cc = 0;
+
+    return 0;
+}
diff --git a/manifest.h b/manifest.h
@@ -0,0 +1,9 @@
+struct manifest_t {
+    char *start;
+    char **lines;
+    size_t lc;
+    size_t cc;
+};
+
+int manifest_open(struct manifest_t *manifest, char path[PATH_LEN]);
+int manifest_close(struct manifest_t *manifest);