Rename main.c

1 files changed, 184 insertions, 0 deletions

diff --git a/reloc.c b/reloc.c
new file mode 100644
index 0000000..ee3cc0b
--- /dev/null
+++ b/reloc.c
@@ -0,0 +1,184 @@
+#include "reloc.h"
+
+
+RelocMatch *reloc_match(char *haystack, const char *needle) {
+    char *data = haystack;
+    size_t needle_size = strlen(needle);
+    RelocMatch *match = NULL;
+
+    // Search the needle in the data
+    if (!(memcmp(data, needle, needle_size))) {
+        if (!(match = calloc(1, sizeof(RelocMatch)))) {
+            fprintf(stderr,"Failed to allocate RelocMatch structure: %s\n", strerror(errno));
+            exit(1);
+        }
+        size_t data_end = strlen(data);
+        match->begin = data;
+        match->end = match->begin + needle_size;
+        match->length = match->end - match->begin;
+        match->post = match->end;
+        match->post_length = strlen(match->post);
+        match->total_length = data_end;
+    }
+    return match;
+}
+
+
+RelocData *reloc_read(const char *filename) {
+    char *data = NULL;
+    FILE *fp = NULL;
+    size_t size = 0;
+    RelocData *result;
+
+    // Open file for reading in binary mode
+    if (!(fp = fopen(filename, "rb"))) {
+        fprintf(stderr, "Cannot open %s: %s\n", filename, strerror(errno));
+        exit(1);
+    }
+
+    // Determine file size
+    fseek(fp, 0, SEEK_END);
+    size = ftell(fp);
+    rewind(fp);
+
+    if (!(data = calloc(sizeof(char), size + 1))) {
+        fprintf(stderr, "Failed to allocate data array: %s\n", strerror(errno));
+        exit(1);
+    }
+
+    // Read data into array
+    fread(data, sizeof(char), size, fp);
+    if (!(result = (RelocData *)malloc(sizeof(RelocData)))) {
+        fprintf(stderr, "Failed to allocate RelocData structure: %s\n", strerror(errno));
+        exit(1);
+    }
+    result->size = size;
+    result->data = data;
+    result->path = strdup(filename);
+    return result;
+}
+
+
+size_t reloc_write(RelocData *finfo, const char *filename) {
+    FILE *fp;
+
+    // Open file for writing in binary mode
+    if (!(fp = fopen(filename, "w+b"))) {
+        fprintf(stderr,"Cannot open %s for writing: %s\n", filename, strerror(errno));
+        exit(1);
+    }
+
+    // Write data
+    return fwrite(finfo->data, sizeof(char), finfo->size, fp);
+}
+
+
+void reloc_deinit_data(RelocData *finfo) {
+    if (finfo) {
+        if (finfo->path) {
+            free(finfo->path);
+        }
+        free(finfo);
+    }
+}
+
+
+void reloc_replace(RelocMatch *match, const char *rstr) {
+    size_t rstr_length = strlen(rstr);
+    if (rstr_length > match->length) {
+        fprintf(stderr, "Replacement string is too long ("SIZE_T_FMT " > " SIZE_T_FMT ")\n", rstr_length, match->length);
+        return;
+    }
+    char *data = match->begin;
+    size_t i = 0;
+
+    // Overwrite data with replacement string
+    while (i < rstr_length) {
+        *data = *rstr;
+        data++;
+        rstr++;
+        i++;
+    }
+
+    i = 0;
+    // Append remaining bytes not part of the original match to the replaced string
+    char *post = match->post;
+    while (i < match->post_length) {
+        *data = *post;
+        data++;
+        post++;
+        i++;
+    }
+
+    // Destroy bytes between the end of the original data and the end of the replaced string
+    memset(data, '\0', post - data);
+}
+
+
+void show_version() {
+    printf("%s\n", VERSION);
+}
+
+
+int main(int argc, char *argv[]) {
+    char *program = argv[0];
+    char *program_relative = strrchr(program, DIRSEP);
+    if (program_relative) {
+        program = program_relative + 1;
+    }
+
+    for (int i = 0; i < argc; i++) {
+        if (!strcmp(argv[i], "--version") || !strcmp(argv[i], "-V")) {
+            show_version();
+            exit(0);
+        }
+    }
+
+    if (argc < 5) {
+        printf("%s [-V] <str1> <str2> <input_file> <output_file>\n"
+               "\n"
+               "Arguments:\n"
+               "--version (-V) - Display version and exit\n"
+               "str1           - Pattern to search for\n"
+               "str2           - Replace str1 with contents of str2\n"
+               "input_file     - Path to input file\n"
+               "output_file    - Path to output file\n"
+               "\n"
+               "Example:\n"
+               "%s /original/path /new/path input.bin output.bin\n"
+               "\n", program, program);
+        exit(1);
+    }
+
+    char *needle = strdup(argv[1]);
+    char *replacement = strdup(argv[2]);
+    char *input_file = strdup(argv[3]);
+    char *output_file = strdup(argv[4]);
+    RelocData *info = reloc_read(input_file);
+    size_t records = 0;
+
+    for (size_t i = 0; i < info->size; i++) {
+        RelocMatch *match = NULL;
+        if (!(match = reloc_match(&info->data[i], needle))) {
+            // No match found
+            continue;
+        }
+        // Replace string
+        reloc_replace(match, replacement);
+        free(match);
+        records++;
+    }
+
+    // Write output file to disk
+    reloc_write(info, output_file);
+
+    // Report number of strings processed
+    printf(SIZE_T_FMT"\n", records);
+
+    free(needle);
+    free(replacement);
+    free(input_file);
+    free(output_file);
+    reloc_deinit_data(info);
+    return 0;
+}