termux-elf-cleaner: Better error messages

diff --git a/packages/termux-tools/termux-elf-cleaner.cpp b/packages/termux-tools/termux-elf-cleaner.cpp
index aff3300..e0923c7 100644 (file)
--- a/packages/termux-tools/termux-elf-cleaner.cpp
+++ b/packages/termux-tools/termux-elf-cleaner.cpp
@@ -20,17 +20,17 @@
 template<typename ElfHeaderType /*Elf{32,64}_Ehdr*/,
         typename ElfSectionHeaderType /*Elf{32,64}_Shdr*/,
         typename ElfDynamicSectionEntryType /* Elf{32,64}_Dyn */>
-bool process_elf(uint8_t* bytes, size_t elf_file_size)
+bool process_elf(uint8_t* bytes, size_t elf_file_size, char const* file_name)
 {
        if (sizeof(ElfSectionHeaderType) > elf_file_size) {
-               fprintf(stderr, "ERROR: Elf header would end at %zu but file size only %zu\n", sizeof(ElfSectionHeaderType), elf_file_size);
+               fprintf(stderr, "termux-elf-cleaner: Elf header for '%s' would end at %zu but file size only %zu\n", file_name, sizeof(ElfSectionHeaderType), elf_file_size);
                return false;
        }
        ElfHeaderType* elf_hdr = reinterpret_cast<ElfHeaderType*>(bytes);
 
        size_t last_section_header_byte = elf_hdr->e_shoff + sizeof(ElfSectionHeaderType) * elf_hdr->e_shnum;
        if (last_section_header_byte > elf_file_size) {
-               fprintf(stderr, "ERROR: Section header would end at %zu but file size only %zu\n", last_section_header_byte, elf_file_size);
+               fprintf(stderr, "termux-elf-cleaner: Section header for '%s' would end at %zu but file size only %zu\n", file_name, last_section_header_byte, elf_file_size);
                return false;
        }
        ElfSectionHeaderType* section_header_table = reinterpret_cast<ElfSectionHeaderType*>(bytes + elf_hdr->e_shoff);
@@ -40,7 +40,7 @@ bool process_elf(uint8_t* bytes, size_t elf_file_size)
                if (section_header_entry->sh_type == SHT_DYNAMIC) {
                        size_t const last_dynamic_section_byte = section_header_entry->sh_offset + section_header_entry->sh_size;
                        if (last_dynamic_section_byte > elf_file_size) {
-                               fprintf(stderr, "ERROR: Dynamic section would end at %zu but file size only %zu\n", last_dynamic_section_byte, elf_file_size);
+                               fprintf(stderr, "termux-elf-cleaner: Dynamic section for '%s' would end at %zu but file size only %zu\n", file_name, last_dynamic_section_byte, elf_file_size);
                                return false;
                        }
 
@@ -67,7 +67,7 @@ bool process_elf(uint8_t* bytes, size_t elf_file_size)
                                        case DT_RUNPATH: removed_name = "DT_RUNPATH"; break;
                                }
                                if (removed_name != nullptr) {
-                                       printf("Removing the %s dynamic section entry\n", removed_name);
+                                       printf("termux-elf-cleaner: Removing the %s dynamic section entry from '%s'\n", removed_name, file_name);
                                        // Tag the entry with DT_NULL and put it last:
                                        dynamic_section_entry->d_tag = DT_NULL;
                                        // Decrease j to process new entry index:
@@ -80,7 +80,7 @@ bool process_elf(uint8_t* bytes, size_t elf_file_size)
 }
 
 
-int main(int argc, char **argv)
+int main(int argc, char const** argv)
 {
        if (argc < 2 || (argc == 2 && strcmp(argv[1], "-h")==0)) {
                fprintf(stderr, "usage: %s <filename>\n", argv[0]);
@@ -90,7 +90,8 @@ int main(int argc, char **argv)
        }
 
        for (int i = 1; i < argc; i++) {
-               int fd = open(argv[i], O_RDWR);
+               char const* file_name = argv[i];
+               int fd = open(file_name, O_RDWR);
                if (fd < 0) { perror("open()"); return 1; }
 
                struct stat st;
@@ -103,19 +104,25 @@ int main(int argc, char **argv)
 
                uint8_t* bytes = reinterpret_cast<uint8_t*>(mem);
                if (!(bytes[0] == 0x7F && bytes[1] == 'E' && bytes[2] == 'L' && bytes[3] == 'F')) {
+                       // Not the ELF magic number.
                        munmap(mem, st.st_size);
                        close(fd);
                        continue;
                }
 
-               uint8_t bit_value = bytes[4];
-               if (!(bit_value == 1 || bit_value == 2)) {
-                       printf("ERROR: Incorrect bit value: %d\n", bit_value);
-                       return 1;
-               } else if (bit_value == 1) {
-                       if (!process_elf<Elf32_Ehdr, Elf32_Shdr, Elf32_Dyn>(bytes, st.st_size)) return 1;
+               if (bytes[/*EI_DATA*/5] != 1) {
+                       fprintf(stderr, "termux-elf-cleaner: Not little endianness in '%s'\n", file_name);
+                       continue;
+               }
+
+               uint8_t const bit_value = bytes[/*EI_CLASS*/4];
+               if (bit_value == 1) {
+                       if (!process_elf<Elf32_Ehdr, Elf32_Shdr, Elf32_Dyn>(bytes, st.st_size, file_name)) return 1;
+               } else if (bit_value == 2) {
+                       if (!process_elf<Elf64_Ehdr, Elf64_Shdr, Elf64_Dyn>(bytes, st.st_size, file_name)) return 1;
                } else {
-                       if (!process_elf<Elf64_Ehdr, Elf64_Shdr, Elf64_Dyn>(bytes, st.st_size)) return 1;
+                       printf("termux-elf-cleaner: Incorrect bit value %d in '%s'\n", bit_value, file_name);
+                       return 1;
                }
 
                if (msync(mem, st.st_size, MS_SYNC) < 0) { perror("msync()"); return 1; }